AIS Network Router AI2524 User Manual

TM  
AISwitch  
AI2524 Router  
User’s Manual  
August 1997  
Applied Innovation Inc.  
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AI2524 Router  
TM  
User’s Manual  
AISwitch  
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AI2524 Router User’s Manual  
Copyright Notice  
Copyright © 1983-1997 by Applied Innovation Incorporated (AII). The material discussed in  
this manual is the proprietary property of AII. AII retains all rights to reproduction and distribution  
of this document.  
AISwitch, AISwitch Series 180, and AISwitch Series 130 are registered trademarks of AII.  
UNIX is a registered trademark in the United States and other countries, licensed exclusively  
through X/Open Company Limited. Any other trademarks appearing in this manual are registered  
trademarks of their respective companies.  
FCC Warning  
The Federal Communications Commission has set limits for emitted radio interference. The  
AISwitch is constructed with this electromagnetic interference (EMI) limitation in mind. Th  
AISwitch is classified under FCC regulations as a Class A device, that is, a device for use in com-  
mercial environments and not in residential areas. This device has been tested and shown to comply  
with the following FCC rule: Part 15 Subpart J. Operation of this equipment in a residential are  
may cause interference to radio and TV reception, requiring the user to take whatever steps are nec-  
essary to correct the interference.  
Information is available from the FCC describing possible corrective actions. For lower EMI  
levels, we suggest using only metal connectors and shielded cables grounded to the frame.  
Electrostatic Discharge Warning  
Warning: The AISwitch and its peripherals contain electrostatic sensitive components. Proper  
handling, shipping, and storage precautions must be exercised:  
z
Removal and installation of circuit boards must be performed in a static-free en-  
vironment. Tthe technician should wear an anti-static wrist strap and stand on  
an anti-static mat. Both the wrist strap and mat must be grounded at the same  
point as the AISwitch enclosure.  
z
z
When not in use, circuit boards must be kept in their anti-static plastic bags.  
Circuit boards must only be removed from their anti-static plastic bags immedi-  
ately prior to installation into the AISwitch enclosure.  
z
z
Immediately upon removal from the enclosure, circuit boards must be inserted  
into their anti-static bags.  
Do not ship or store the electronic circuit boards near strong electrostatic, elec-  
tromagnetic, magnetic, or radioactive fields.  
Specifications are subject to change without notice.  
Applied Innovation Inc.  
5800 Innovation Driv  
Dublin, Ohio 43016-3271  
614-798-2000  
800-247-9482  
FAX: 614-798-1770  
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Contents  
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TOC-1  
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AI2524 Router Card User’s Manual  
TOC-2  
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TOC-3  
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TOC-4  
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Disable or  
Reenable Peer Neighbor Routes .................................................................................11-17  
TOC-6  
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TOC-8  
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Chapter 15: 56/64-kbps Switched and Digital Data Services (DDS) Interface Config-  
uration Steps...............................................................................................................15-1  
TOC-10  
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Chapter 1: Introduction  
Chapter 1: Introduction  
Documentation  
Overview  
This manual documents the use and operation of the AI2524 in an  
AISwitch system. These topics are covered:  
Chapter 1  
Chapter 2  
Chapter 3  
Chapter 4  
Introduction  
This chapter provides a documentation over-  
view, related documentation, contact infor  
mation, and text conventions.  
This chapter describes the Cisco IOS soft-  
ware features and AI2524 hardware specifi-  
cations.  
This chapter describes the process of booting  
the router for the first time and provides over-  
views of configuration methods.  
This chapter introduces Cisco IOS softwar  
interface, and includes instructions for ac-  
cessing command modes, context-sensitiv  
help, and command history and editing fea-  
tures.  
Chapter 5  
Chapter 6  
Chapter 7  
This chapter describes how use AutoInstall  
for automatic and dynamic configuration o  
the AI2524.  
This chapter describes how to use the System  
Configuration Dialog to manually configure  
the router.  
This chapter describes how to manually load  
system images in the event that typical start-  
up procedures malfunction.  
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Chapter 8  
This chapter describes how to configure th  
AI2524 for OSPF TCP/IP, IGRP TCP/IP, and  
RIP TCP/IP.  
Chapter 9  
This chapter describes how to configure th  
AI2524 for ISO IGRP dynamicrouting, IS-IS  
dynamic routing, and CLNS static routing.  
Chapter 10  
Chapter 11  
This chapter describes how to configure syn-  
chronous serial interfaces.  
This chapter describes how to enable PPP en-  
capsulation and perform a variety of PPP  
configuration tasks.  
Chapter 12  
Chapter 13  
This chapter describes how to configure th  
X.25 interface, and includes datagram trans-  
port, routing, and X.29 access lists and profile  
scripts.  
This chapter describes how to enable frame  
relay encapsulation and perform a variety of  
Frame Relay configuration tasks.  
Chapter 14  
Chapter 15  
This chapter describes how to configure th  
AI2524 for fractional T1.  
This chapter describes how to configure  
switched and DDS interfaces.  
Chapter 16  
Chapter 17  
This chapter describes the AI2524’s panel,  
cable connections, and firmware.  
This chapter contains a link to the AI2524/  
Cisco IOS v. 11.2 documentation CD.  
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Chapter 1: Introduction  
Chapter 18  
Chapter 19  
This chapter contains a link to the AI2524/  
Cisco IOS v. 11.2 documentation CD.  
This chapter contains a link to the AI2524/  
Cisco IOS v. 11.2 documentation CD.  
Appendix A  
Appendix B  
Includes the release notes for this version.  
This appendix defines acronyms used in this  
manual.  
Related  
Documentation for AISwitch products includes:  
Documentation  
AI120 Contact Alarm Monitor User’s  
Manual  
AI120UM  
AISwitch 130 Hardware Manual  
AI192-X User’s Manual  
AI193-ES User’s Manual  
AI193-TX User’s Manual  
AI194 User’s Manual  
HM130-0194  
192UM  
UM193ES  
193TXUM  
AI94U  
AI196-I User’s Manual  
AI196-IEGB User’s Manual  
AI196-X User’s Manual  
196IUM  
196TUM  
196XUM  
AI198 System Manager/User’s Manual 98UM  
Common Alarm Panel Manual  
RDC180HP Power Supply Manual  
AI325AC Power Supply Manual  
AI180FRF AICool Fan Manual  
AISwitch 180 Hardware Manual  
180CAPUM  
180PSUM  
AI325UM  
HMFRF-A  
HW0593  
AppliedView Network Management Sys- AV201UM  
tem User’s Manual  
To order these or any other AISwitch manuals, contact your sales rep-  
resentative at (800) 247-9482.  
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AI2524 Router Card User’s Manual  
Contact  
To register documentation, contact Applied Innovation Inc. at:  
Information  
Applied Innovation Inc.  
Publications Dept.  
5800 Innovation Dr.  
Dublin, OH 43216-3271  
Phone  
(614) 798-2000  
(800) 247-9482  
FAX  
(614) 798-1770  
Email  
Register your documentation by completing the registration form.  
The most current version of release notes and the AI198 CLC User’s  
Manual are available on the Applied Innovation web site at:  
http://www.aiinet.com  
Click on the Documentation option. These additional email contacts  
are also available:  
National Sales Department  
Customer Service Department  
Marketing Department  
Human Resources Department  
Technical Support Department  
Investment Relations  
Feedback for Engineering (R&D)  
About SNMP  
Webmaster  
Documentation Department  
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Chapter 1: Introduction  
Text Conventions  
Important concepts throughout this manual are emphasized with these  
special text styles:  
[Buttons]  
Function buttons that appear on a screen ar  
shown in regular body text and enclosed in  
square brackets. For example:  
[Close]  
[Send]  
Commands  
In command lines, type text that appears in  
this style exactly as shown:  
avdumpdb  
BNC OFF  
Press the <Return> or <Enter> key after all  
commands.  
Variable  
Arguments  
Variable arguments are text that you specify.  
They are shown in italics. For example:  
avaccess switch_name  
In this case, “switch_name” is variable text.  
To enter the command, type  
avaccess  
and then the actual name of the switch.  
...  
Ellipses (...) signify that the preceding argu-  
ment can be repeated a number of times. For  
example:  
c
at  
filename...  
means that you would typ cat followed  
by one or more filenames.  
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AI2524 Router Card User’s Manual  
[Optional  
Arguments]  
Some arguments are optional. This means  
that you have the choice of including them or  
not. Optional arguments are shown enclosed  
in square brackets, which are not entered.  
For example:  
avrestore [directory]  
means that you type  
avrestore  
and (if you need to include a directory) type  
the actual path name.  
CFGMSG n, [DEFAULT]  
means that you type CFGMSGfollowed by  
message number, a comma, and (optionally)  
the word DEFAULT without brackets.  
{argument|  
argument}  
Arguments between braces are grouped into  
one unit. The vertical bar signifies that either  
the first or second argument can be used. The  
braces and vertical bar are not entered. For  
example:  
ls {file | directory}  
means that you would type ls followed by  
either a file or a directory name.  
<Keys>  
Keyboard controls are shown in this style.  
Angle brackets depict keys that do not ap-  
pear on the screen when pressed, such as the  
<tab> or <return> keys. Keys used in combi-  
nation are connected with a dash. For exam-  
ple, to enter:  
<ALT-SysRq>  
hold down the Alt key while you press th  
SysRq key.  
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Chapter 1: Introduction  
Labels  
Labels are used in diagrams to designat  
physical components such as jumper straps,  
switches, and cable connectors. For exam-  
ple:  
COM1  
BOOT1  
If the physical component being described is  
part of the text, it appears as regular type:  
To reset the COM1 port connector, press th  
BOOT switch.  
Menu | Submenu  
Menu selections are shown in bold text. The  
bar separates the main menu from submenus.  
For example:  
File | Exit  
indicates that you should select the File  
menu, and then select the Exit menu item.  
Screen output  
Screen shots, system prompts, and error  
messages displayed on the screen are shown  
in this style:  
+CONFIG PORT,LPORT=40,HPORT=47,BITS=8  
+CONFIG PORT,LPORT=48,HPORT=49,BITS=7  
+CONFIG PORT,LPORT=50,BITS=8$0778  
Warning:  
Warning messages indicate critical informa-  
tion required for your safety or for correct  
system operation. For example:  
Warning: Failure to heed this important  
text could cause damage or unre-  
liable results.  
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Chapter 2: AI2524 Overview  
Chapter 2: AI2524 Overview  
Introduction  
This chapter describes the Cisco IOS software features and the AI2524  
hardware specifications. The AI2524 multi-protocol router adds the  
Cisco Internetworking Operating System (IOSTM) routing software to  
the NEBS compliant AISwitch 180 Series. The AI2524 adds leading  
edge routing capabilities through TCP/IP and OSI networks to the AI  
180 Switch protocol conversion and data port concentration capabili-  
ties.  
The AI2524 is designed for reliable connectivity to a Wide-Area Net-  
work (WAN). It can provide WAN/DCN connections to centralized  
operations support systems from central office based LAN/LCN or  
X.25 networks.  
The AI2524 has one Ethernet LAN interface with both a backplane  
(IRB) port and a 10BaseT port on the front panel. The backplane port  
provides connections to a large number of interfaces and protocols  
through a variety of AISwitch interface modules.  
The base module accepts two serial interface modules in any combi-  
nation. The three available modules are:  
T1 CSU/DSU  
The AI2524-T1 module is an integrated CSU/DSU that supports full  
or fractional T1 leased line services. It may be remotely managed  
using Simple Network Management Protocol (SNMP)  
Four Wires 56K CSU/DSU  
The AI2524-4W56 module is an integrated CSU/DSU that supports  
4-wire 56k leased line or switched services. It may be remotely man-  
aged using Simple Network Management Protocol (SNMP)  
5-IN-1 Serial Cable Interface  
The AI2524-5N1 module provides a cable interface to a synchronous  
serial line. It supports full and half duplex operations up to 2.048 MHz,  
full duplex. Dependent upon the interface, DTE/DCE and NRZ/NRZ1  
operations are available. Cables are available for the these interfaces:  
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RS-232 DTE or DCE, EIA-530 DTE, RS-449 DTE or DCE, OR V.35,  
DTE or DCE, up to E1 speeds.  
Software  
The AI 2524 incorporates Cisco IOS software. This software provides:  
Features and  
Functions  
z
z
z
z
Scalability  
Reliable, Adaptive Routing  
Remote Access and Protocol Translation  
Management and Security  
Scalability  
The Cisco IOS software uses scalable routing protocols to avoid need-  
less congestion, overcome inherent protocol limitations, and bypass  
many of the obstacles that result from the complex scope and geo-  
graphical dispersion of an internetwork.  
The Cisco IOS software eliminates the need for static routes and re-  
duces network costs by efficiently using network bandwidth and re-  
sources. Advanced features such as route filtering, protocol  
termination and translation, smart broadcasts, and helper address ser-  
vices combine to create a flexible, scalable infrastructure that can keep  
pace with evolving network requirements.  
Reliable, Adaptive Routing  
The AI2524 Cisco IOS software identifies the best network paths and  
routes traffic around network failures. Policy-based features such as  
route filtering and route redistribution save network resources by pre-  
venting data from being broadcast to nodes that do not need it. Priority  
output queuing and custom queuing grant priority to important ses-  
sions when network bandwidth is scarce. Load balancing uses every  
available path across the internetwork to preserve bandwidth and im-  
prove network performance. The Cisco IOS software also provides the  
most effective and efficient scaling available for network applications  
that require transparent or source-route bridging algorithms.  
Remote Access and Protocol Translation  
Your router connects terminals, modems, microcomputers, and net-  
works over serial lines to LANs or Wide-Area Networks (WANs). It  
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Chapter 2: AI2524 Overview  
also provides network access to terminals, printers, workstations, and  
other networks.  
On LANs, terminal services support Transmission Control Protocol/  
Internet Protocol (TCP/IP) on UNIX machines with Telnet and rlogin  
connections. You can use the router to make connections between  
hosts and resources running different protocols, including router and  
access server connections to X.25 machines using X.25 Packet Assem-  
bler/Disassembler (PAD).  
The Cisco IOS software supports three types of server operation:  
Remote Node Ser- Connect devices over a telephone network  
vices  
Serial Line Internet Protocol (SLIP), com-  
pressed SLIP (CSLIP), Point-to-Point Protocol  
(PPP), and X-Windows terminal protocol. See  
Terminal Service Connect asynchronous devices to a LAN or  
WAN through network and terminal-emulation  
software including Telnet and rlogin,.  
Protocol Transla- Convert one virtual terminal protocol into  
tion Services  
another protocol. See Figure 2-1.  
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Figure 2-1:Remote Access Functionality  
Figure 2-1 illustrates the functions available on access servers:  
z
z
z
z
Remote node service is demonstrated by the telecommuter’s (re-  
mote) PC connection running SLIP, PPP, CSLIP, or XRemote  
Terminal service is shown between the terminals and hosts run  
ning the same protocol (LAT-to-LAT or TCP-to-TCP)  
Protocol translation is shown between the terminals and hosts run-  
ning unlike protocols (LAT-to-TCP or TCP-to-LAT)  
Asynchronous IP routing is shown by the PC running SLIP or  
PPP, and between the two access servers.  
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Chapter 2: AI2524 Overview  
Management and Security  
The Cisco IOS software provides an array of network management  
and security capabilities. Integrated management simplifies adminis-  
trative procedures and shortens the time required to diagnose and fix  
problems. Automated operations reduce hands-on tasks and make it  
possible to manage large, geographically dispersed internetworks with  
a small staff of experts located at a central site.  
The Cisco IOS software provides several management features includ-  
ing configuration services, which lower the cost of installing, upgrad-  
ing, reconfiguring routers, and reconfiguring access servers, as well as  
comprehensive monitoring and diagnostic services. In addition, the  
Cisco IOS software provides information and services for router man-  
agement applications.  
Management services are matched by their security capabilities. Th  
Cisco IOS software includes a diverse tool kit for partitioning re-  
sources and prohibiting access to sensitive or confidential information  
and processes. Multidimensional filters prevent users from knowing  
that other users or resources are on the network. Encrypted passwords,  
dial-in authentication, multilevel configuration permissions, network  
data encryption, and accounting and logging features provide protec-  
tion from and information about unauthorized access attempts and data  
eavesdropping attempts.  
Software  
Supported Media  
Specifications  
The AI2524 supports these industry-standard networking media:  
z
z
z
z
z
Channelized T1  
Ethernet: IEEE 802.3 and Type I  
Fiber Distributed Data Interface (FDDI): single and dual mode  
High-Speed Serial Interface (HSSI): supports T1  
Synchronous serial: V.35, RS-232, RS-449, and RS-530  
Supported Network Protocols  
The Cisco IOS software supports many networking protocols, as well  
as their associated routing protocols. These protocols are based on  
both open standards and proprietary protocols from a variety of ven-  
dors.  
The Cisco IOS software can receive and forward packets concurrently  
from any of these combinations:  
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WAN protocols  
z
z
z
z
Frame Relay  
High-Level Data Link Control (HDLC)  
PPP  
X.25 a  
Network protocols  
z
z
IP  
OSI Connectionless Network Services (CLNS) and Connection  
Mode Network Services (CMNS)  
IP Routing Protocols  
The Cisco IOS software supports IP routing protocols, including inte-  
rior gateway protocols and exterior gateway protocols.  
Interior Gateway Protocols  
z
z
z
z
z
Internet Gateway Routing Protocol (IGRP)  
Enhanced IGRP  
Open Shortest Path First (OSPF)  
Routing Information Protocol (RIP) and RIP Version 2  
Intermediate System-to-Intermediate System (IS-IS  
Exterior Gateway Protocols  
z
z
z
z
Exterior Gateway Protocol (EGP)  
Router Discovery Protocols  
ICMP Router Discovery Protocol (IRDP)  
Hot Standby Router Protocol (HSRP)  
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Chapter 2: AI2524 Overview  
Connections  
External Connection Requirements  
The AI2524 provides LAN and WAN access in a modular router plat-  
form. The router includes an Ethernet (AUI or 10BaseT) LAN connec-  
tion, and accommodates two synchronous serial modules.  
The synchronous serial WAN modules include these external connec-  
tors:  
z
z
z
Four-wire 56/64-kbps DSU/CSU WAN module with an RJ-48S  
connector  
Fractional T1/T1 DSU/CSU WAN module with an RJ-48C con-  
nector  
Five-in-one synchronous serial WAN module with a DB-60 serial  
connector. The five-in-one synchronous serial interface supports  
the following signaling standards: EIA/TIA-232, EIA/TIA-449,  
V.35, X.21, and EIA-530  
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Chapter 3: Configuration Overview  
Chapter 3: Configuration Overview  
Introduction  
This chapter provides a brief overview of three ways that the AI2524  
can be configured including:  
z
z
z
Configuration Mode  
AutoInstall  
System Configuration Dialog  
These three and other procedures are described in detail in this manual.  
The first time the router is powered and booted, you must enter basic  
configuration information and save the configuration to a file in  
NVRAM.  
Boot Router for  
First Time  
Each time you power on the router, it goes through the boot sequence:  
1. The router goes through power-on self-test diagnostics to verify  
basic operation of the CPU, memory, and interfaces.  
2. The system bootstrap software (boot image) executes and searches  
for a valid Cisco IOS image (router operating system software).  
The source of the Cisco IOS image (Flash memory or a Trivial File  
Transfer Protocol [TFTP] server) is determined by the configura-  
tion register setting. The factory-default setting for the configura  
tion register is 0x2102, which indicates that the router should  
attempt to load a Cisco IOS image from Flash memory.  
3. If after five attempts a valid Cisco IOS image is not found in Flash  
memory, the router reverts to boot ROM mode (which is used to  
install or upgrade a Cisco IOS image).  
4. If a valid Cisco IOS image is found, then the router searches for a  
valid configuration file.  
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5. If a valid configuration file is not found in NVRAM, the router  
runs the System Configuration Dialog so you can configure it  
manually. For normal router operation, there must be a valid Cisco  
IOS image in Flash memory and a configuration file in NVRAM.  
The first time you boot your router, you will need to configure the  
router interfaces and then save the configuration to a file in  
NVRAM.  
Configure the  
Router  
You can configure the router using one of these procedures:  
z
Configuration mode: Recommended if you are familiarwith Cisco  
IOS software commands. Refer to the Understanding the User In-  
terface chapter.  
z
AutoInstall: Recommended for automatic installation if another  
router running Cisco IOS software is installed on the network.  
This configuration method must be set up by someone with expe-  
rience using Cisco IOS software. Refer to the Use AutoInstall  
chapter.  
z
System Configuration Dialog: Recommended if you are not famil-  
iar with Cisco IOS commands. Refer to th Using the System Con-  
figuration Dialog chapter.  
Use the procedure that best fits the needs of your network configura  
tion and level of Cisco IOS software experience.  
Using Configuration Mode  
You can configure the router manually if you prefer not to use Auto-  
Install or the System Configuration Dialog. Take these steps to config-  
ure the router manually:  
1. Connect a console terminal to the AI2524 and power ON th  
router.  
2. When you are prompted to enter the initial dialog, type noto go  
into the normal operating mode of the router:  
Would you like to enter the initial dialog? [yes]: no  
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Chapter 3: Configuration Overview  
3. After a few seconds you will see the user EXEC prompt  
(Router> . Enter the enable command to enter enable mode. You  
can only make configuration changes in enable mode.  
Router> enable  
The prompt changes to the privileged EXEC (enable) prompt:  
Router#  
4. Enter the configure terminal command at the enable  
prompt to enter configuration mode:  
Router# configure terminal  
You can now enter any changes you want to the configuration. Refer  
to the appropriate sections of this manual for help with specific con-  
figurations.  
5. Press <Ctrl-Z> to exit configuration mode.  
Show  
Configuration  
To see the current operating configuration, enter the show run-  
ning-config command at the enable prompt:  
Router# show running-config  
To see the configuration in NVRAM, enter th show startup-  
configcommand at the enable prompt:  
Router# show startup-config  
The results of the show running-configand show startup-  
configcommands will be different if you have made changes to the  
configuration but have not yet written them to NVRAM.  
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Save the  
Configuration  
To make your changes permanent, enter the copy running-con-  
fig startup-config command at the enable prompt:  
Router# copy running-config startup-config  
The router is now configured and will boot with the configuration you  
entered.  
Configuration  
Overviews  
This section describe the software tools you can use to configure your  
router via the Cisco IOS software:  
z
z
z
z
Configuration Builder  
Command Interpreter  
Web Browser Interface  
Use ClickStart  
Use Configuration Builder  
The Configuration Builder allows you to create configuration files for  
multiple routers or access servers without knowing the command-line  
language or syntax. It is a Microsoft Windows-based application that  
runs on an IBM PC or compatible computer.  
If you do not have the platform required to run Configuration Builder,  
configure your device using the command interpreter.  
Use the Command Interpreter  
You can build most straightforward configurations and create a con-  
figuration file using the setup command facility. Refer to the Using  
AutoInstall chapter for more information.  
Before configuring your router or access server, you must determine  
these items:  
z
Which network protocols you are supporting (for example, IP and  
Novell IPX)  
z
The addressing plan for each network protocol  
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Chapter 3: Configuration Overview  
z
z
Which WAN protocols you will run on each interface (for exam  
ple: Frame Relay, HDLC, SMDS, and X.25)  
Which routing protocol you will use for each network protocol  
The Cisco IOS software provides a user interface called a command  
interpreter, or EXEC, that allows you to configure and manage th  
router or access server. The user interface also provides context-sensi-  
tive help. The command interpreter has several command modes, each  
of which provides a group of related commands that you can use to  
configure the routing device and display its status. Some commands  
are available to all users, others can be executed only after the user en-  
ters an enabling password. Context-sensitive help gives information  
about command syntax. The command interpreter and its help feature  
are described in the Understanding the User Interface chapter.  
You use the command interpreter (also known as the command-line  
parser) to configure interfaces, terminal sessions, and asynchronous  
communications lines. Interfaces are connections to network media,  
such as Ethernet, Token Ring, and serial media. You configure them  
to run routing and networking protocols. You configure terminal ses-  
sions and modems connected to the router or access server so that  
other network users can log in to the network over asynchronous lines.  
You can configure and manage the router or access server, performing  
such tasks as naming the device, setting the time, configuring SNMP,  
and setting security.  
Follow this basic process to set up your access server or router:  
1. Attach an RS-232 ASCII terminal to the system console port lo  
cated at the rear of the router.  
2. Configure the terminal to operate at 9600 baud, 8 data bits, no par-  
ity, 2 stop bits.  
3. Power up the router. The setup command facility runs automati  
cally for initial startup.  
4. Perform general system configuration.  
5. Configure your system by referring to the appropriate part in th  
documentation.  
To enhance the configuration, perform the protocol-specific tasks de-  
scribed in the appropriate chapters of this guide.  
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Use the Web Browser Interface  
You can issue most of the AI2524 commands using a Web browser.  
You access the Web Browser interface through the router's home page.  
AI2524 routers loaded with the latest version of the Cisco IOS soft-  
ware have a home page, which is password protected.  
From the router's home page, click on the Monitor the Router hyper  
text link. This link takes you to a Web page that has a Command field.  
You can type commands in this field as if you were using the com  
mand interpreter on a terminal connected to the router. The page also  
displays a list of hypertext commands that can be executed with a  
mouse-click. This feature is documented in Web Browser Interface.  
Configuration  
Storage and Hot  
Swap  
The AI2524 card must have its configuration stored on the AI198 card  
to insure the ability to perform hot swap. The configuration is stored  
in Menu 4.18 for the port associated with the AI2524 card. When the  
AI2524 card boots, it uses the BOOTP protocol to obtain its IP ad-  
dress. The AI2524 card then uses TFTP to transfer its configuration in-  
formation from the AI198 card to the AI2524 card. Any changes made  
to the AI2524 card’s configuration must be stored back to the AI198  
card to maintain full hot swap capability. Here are two options for  
managing the AI2524 card configuration:  
Always Modify the Configuration Using Menu 4.18  
This option suggests that you use Menu 4.18 whenever you mak  
modifications to the AI2524 card configuration. After you complete  
the modifications, you can use the ENABLcommand to reset the  
AI2524 card. This allows the changes to take affect.  
Store the Configuration on the AI198 Card  
This option suggests that whenever you make modifications to the  
AI2524 card configuration using the AI2524 configuration mecha  
nism (telnet to the card and change the configuration, Quick Start, Cis-  
coWorks), you must store the modifications on the AI198 card. You  
can save the configuration to the AI198 card using TFTP on the  
AI2524 card.  
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Chapter 4: Understanding the User Interface  
Chapter 4: Understanding the User  
Interface  
Introduction  
This chapter describes the features of the user interface.The AI2524  
user interface provides access to several different command modes.  
Each command mode provides a group of related commands. This  
chapter describes how to access and list the commands available in  
each command mode and explains the primary uses for each command  
mode.  
Command Line  
Interface  
AI2524 commands can be entered at a terminal connected to the router  
using the command line interface (CLI). Commands may also be en-  
tered using the Web Browser interface. All routers using the Cisco IOS  
software have a home page. From this home page, you can access the  
Web Browser interface, which allows you to execute AI2524 com-  
mands. You can execute these commands by clicking on them or en-  
tering them in a command field. This feature is described in Web  
For security purposes, the Cisco IOS software provides two levels of  
access to commands: user and privileged. The unprivileged user mod  
is called user EXEC mode. The privileged mode is called privileged  
EXEC mode and requires a password. The commands available in user  
EXEC mode are a subset of the commands available in privileged  
EXEC mode.  
If your router or access server does not find a valid system image, or  
if its configuration file is corrupted at startup, the system might enter  
read-only-memory (ROM) monitor mode. ROM monitor mode can  
also be accessed through privileged EXEC mode.  
From privileged EXEC mode, you can access the global configuration  
mode and a number of specific configuration modes. These modes are  
listed in Command Modes.  
Entering a question mark (?) at the system prompt allows you to obtain  
a list of commands available for each command mode.  
Almost every configuration command also has anoform. In general,  
use the noform to disable a feature or function. Use the command  
without the keyword noto reenable a disabled feature or to enable a  
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AI2524 Router Card User’s Manual  
feature that is disabled by default. For example, IP routing is enabled  
by default. To disable IP routing, specify the no ip routingcom-  
mand and specify ip routing to reenable it.  
The user interface also provides context-sensitive help for command  
syntax. This chapter describes how to use the help system. It also de  
scribes the command editing and command history features that enable  
you to recall and easily edit command entries.  
End a Session  
After using the setupcommand or other configuration commands,  
exit the user interface and quit the session. To end a session, type:  
quit  
User Interface  
Task List  
You can perform these tasks to familiarize yourself with the AI2524  
user interface:  
z
z
z
z
z
z
z
Access Each Command Mode  
Get Context-Sensitive Help  
Check Command Syntax  
Use the Command History Features  
Use the Editing Features  
End a Session  
Use the Web Browser Interface to Issue Commands  
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Chapter 4: Understanding the User Interface  
Command Modes  
This section describes how to access each of the AI2524 command  
modes, including:  
z
z
z
z
These command modes are accessible from global configuration  
mode:  
z
z
z
z
z
z
z
z
z
The following table lists the command modes, how to access each  
mode, the prompt while in each mode, and how to exit each mode. The  
prompts listed assume that the default device name is Router unless it  
has been changed during initial configuration using the setupcom-  
mand. Refer to the product user guide for information on the setup fa-  
cility. You can also change the host name using thehostnameglobal  
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AI2524 Router Card User’s Manual  
configuration command. The following table does not include all o  
the possible ways to access or exit each command mode.  
For all command modes, typing a question mark (?) at the prompt will  
list the commands available. Refer to Context-Sensitive Help, for  
more information.  
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Chapter 4: Understanding the User Interface  
Command  
Mode  
Access Method  
Prompt  
Exit Method  
Router>  
Router#  
User EXEC  
Log in.  
Use the  
command.  
logout  
Privileged  
EXEC  
From user EXEC mode,  
type (requires a  
To exit back to user EXEC  
mode, type . To enter  
enable  
password).  
disable  
global configuration mode, use  
the privileged  
configure  
EXEC command.  
>
ROM monitor  
From privileged EXEC  
mode, type . Press  
To exit to user EXEC mode,  
type  
.
continue  
reload  
<Break> during the first 60  
seconds while the system is  
booting.  
Router(config)#  
Global configu-  
ration  
From privileged EXEC  
To exit to privileged EXEC  
mode, type or or  
mode, type  
.
configure  
exit end  
press <Ctrl-Z>.  
To enter interface configuration  
mode, enter an interface config-  
uration command.  
Router(config-if)#  
Interface config- From global configuration  
To exit to global configuration  
uration  
mode, type  
type numbe  
mode, type  
. To exit to  
interface  
exit  
privileged EXEC mode, type  
or press <Ctrl-Z>.To  
.
exit  
enter subinterface configuration  
mode, specify a subinterface  
with the  
mand.  
com-  
interface  
Router(config-subif)#  
Router(config-router)#  
Subinterface  
configuration  
From global configuration  
To exit to global configuration  
mode, type . To enter priv-  
mode, type  
interface  
exit  
;
ileged EXEC mode, type  
press <Ctrl-Z>.  
or  
end  
encap-  
type number  
sulation frame-  
;
relay interface  
type number.sub-  
.
interface-numbe  
Router configu-  
ration  
From global configuration  
To exit to global configuration  
mode, type . To exit to  
mode, type  
router  
exit  
privileged EXEC mode, type  
or press <Ctrl-Z>.  
key-  
.
word  
end  
Router(config-ipx-  
router)#  
IPX-router con-  
figuration  
From global configuration  
To exit to global configuration  
mode, type . To exit to  
mode, type  
ipx rout-  
exit  
privileged EXEC mode, type  
or press <Ctrl-Z>.  
.
ing  
keyword  
end  
Router(config-route-  
map)#  
Route-map con-  
figuration  
From global configuration  
mode, type  
To exit to global configuration  
mode, type . To exit to  
route-map  
exit  
privileged EXEC mode, type  
or press <Ctrl-Z>.  
.
tag  
end  
Router(config-keychain)#  
Key chain con-  
figuration  
From global configuration  
mode type  
To exit to global configuration  
mode, type command. To  
keychain  
exit  
exit to privileged EXEC mode,  
type or press <Ctrl-Z>.  
.
name  
end  
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Command  
Mode  
Access Method  
Prompt  
Exit Method  
(Contd.)  
Router(config-keychain-  
key)#  
Key chain key  
configuration  
From key chain configura-  
To exit to key chain configura-  
tion mode, type  
tion mode, type  
. To exit to  
key  
exit  
global configuration mode, type  
command. To exit to priv-  
num-  
.
ber  
exit  
ileged EXEC mode, type  
press <Ctrl-Z>.  
or  
end  
Router(config-rtr)#  
Response time  
reporter config-  
uration  
From global configuration  
mode, type  
To exit to global configuration  
mode, type . To exit to  
.
rtr probe  
exit  
privileged EXEC mode, type  
or press <Ctrl-Z>.  
end  
Router(config-std-nacl)#  
or  
Router(config-ext-nacl)#  
Access-list con-  
figuration  
From global configuration  
To exit to global configuration  
mode, type . To exit to  
mode, type  
ip access-  
exit  
privileged EXEC mode, type  
or press <Ctrl-Z>.  
.
list  
mode name  
end  
User EXEC Mode Commands  
After you log in to the router or access server, you are automatically in  
user EXEC command mode. The EXEC commands available at th  
user level are a subset of those available at the privileged level. In gen-  
eral, the user EXEC commands allow you to connect to remote de-  
vices, change terminal settings on a temporary basis, perform basic  
tests, and list system information.  
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Chapter 4: Understanding the User Interface  
?
Router>  
Exec commands:  
<1-99>  
connect  
disconnect  
enable  
exit  
Session number to resume  
Open a terminal connection  
Disconnect an existing telnet session  
Turn on privileged commands  
Exit from the EXEC  
help  
lat  
Description of the interactive help system  
Open a lat connection  
lock  
Lock the terminal  
login  
Log in as a particular use  
logout  
menu  
Exit from the EXEC  
Start a menu-based user interfac  
Trace multicast route for branch of tree  
Trace reverse multicast route to branch of tree  
Trace multicast route to group  
Name an existing telnet connection  
Open a X.29 PAD connection  
Send echo messages  
mbranch  
mrbranch  
mtrace  
name-connection  
pad  
ping  
resume  
show  
Resume an active telnet connection  
Show running system information  
Display information about terminal lines  
Open a telnet connection  
Set terminal line parameters  
Open a tn3270 connection  
Trace route to destination  
List active telnet connections  
Set X.3 parameters on PAD  
systat  
telnet  
terminal  
tn3270  
trace  
where  
x3  
xremote  
Enter XRemote mode  
Privileged EXEC Mode Commands  
Because many of the privileged commands set operating parameters,  
privileged access should be password protected to prevent unautho-  
rized use.  
If the system administrator has set a password, you are prompted to  
enter it before being allowed access to privileged EXEC mode. Th  
password is not displayed on the screen and is case sensitive. If a pass-  
word has not been set, privilege EXEC mode can be accessed only  
from the router console. The system administrator uses the enable  
password global configuration command to set the password that  
restricts access to privileged EXEC mode.  
The privileged command set includes those commands contained in  
user EXEC mode, as well as the configurecommand through  
which you can access the remaining command modes. Privileged  
EXEC mode also includes high-level testing commands, such as de-  
bug.  
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AI2524 Router Card User’s Manual  
Router> enable  
Password:  
?
Router#  
Exec commands:  
bfe  
clear  
For manual emergency modes setting  
Reset functions  
clock  
Manage the system clock  
configure  
connect  
copy  
Enter configuration mode  
Open a terminal connection  
Copy a config file to or from a tftp server  
Debugging functions  
debug  
disable  
disconnect  
enable  
exit  
Turn off privileged commands  
Disconnect an existing telnet session  
Turn on privileged commands  
Exit from the EXEC  
help  
lat  
Description of the interactive help system  
Open a lat connection  
llc2  
Execute llc2 tests  
lock  
Lock the terminal  
login  
Log in as a particular use  
logout  
menu  
name-connection  
ping  
Exit from the EXEC  
Start a menu-based user interf  
Name an existing telnet connection  
Send echo messages  
reload  
resume  
send  
setup  
show  
systat  
telnet  
terminal  
test  
tn3270  
trace  
where  
which-route  
write  
Halt and perform a cold restart  
Resume an active telnet connection  
Send a message to other tty lines  
Run the SETUP command facility  
Show running system information  
Display information about terminal lines  
Open a telnet connection  
Set terminal line parameters  
Test subsystems, memory, and interfaces  
Open a tn3270 connection  
Trace route to destination  
List active telnet connections  
Do route table lookup and display results  
Write running configuration to memory, network, or  
terminal  
x3  
Set X.3 parameters on PAD  
xremote  
Enter XRemote mode  
ROM Monitor Mode Commands  
If your router or access server does not find a valid system image, or  
if you interrupt the boot sequence, the system might enter ROM mon-  
itor mode. From ROM monitor mode, you can boot the device or per-  
form diagnostic tests.  
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Chapter 4: Understanding the User Interface  
You can also enter ROM monitor mode by entering the reload  
EXEC command and then pressing <Break> during the first 60 sec-  
onds of system startup. To save changes to the configuration file, us  
the copy running-config startup-config command be-  
fore issuing the reloadcommand.  
:
> ?  
$ state  
Toggle cache state (? for help)  
B [filename] [TFTP Server IP address | TFTP Server Name]  
Load and execute system image from ROM or from TFTP server  
C [address]  
D /S M L V  
E /S M L  
G [address]  
Continue execution [optional address]  
Deposit value V of size S into location L with modifier  
Examine location L with size S with modifier M  
Begin execution  
H
I
K
Help for commands  
Initialize  
Stack trace  
L [filename] [TFTP Server IP address | TFTP Server Name]  
Load system image from ROM or from TFTP server, but do not begin execution  
O
P
Show configuration register option settings  
Set the break point  
S
Single step next instruction  
Test device (? for help)  
T function  
Deposit and Examine sizes may be B (byte), L (long) or S (short).  
Modifiers may be R (register) or S (byte swap).  
Register names are: D0-D7, A0-A6, SS, US, SR, and PC  
To return to user EXEC mode, type continue. To initialize the  
router or access server, enter th icommand. Th icommand causes  
the bootstrap program to reinitialize the hardware, clear the contents  
of memory, and boot the system. (Use the icommand before you run  
any tests or boot the software.) To boot the system image file, use the  
bcommand.  
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Global Configuration Mode Commands  
Global configuration commands apply to features that affect the sys-  
tem as a whole. Use the configure privileged EXEC command to  
enter global configuration mode. When you enter this command, the  
system EXEC prompts you for the source of the configuration com-  
mands:  
Configuring from terminal, memory, or network [terminal]?  
You can specify either the terminal, nonvolatile random access mem-  
ory (NVRAM), or a file stored on a network server as the source of  
configuration commands. The default is to enter commands from th  
terminal console. Pressing <Enter> begins this configuration method.  
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Chapter 4: Understanding the User Interface  
Router# configure  
Configuring from terminal, memory, or network [terminal]? Enter configuration  
commands, one per line. End with CNTLZ  
?
Router(config)#  
Configure commands:  
access-list  
apollo  
appletalk  
arp  
Add an access list entry  
Apollo global configuration commands  
Appletalk global configuration commands  
Set a static ARP entry  
async-bootp  
autonomous-system  
banner  
Modify system bootp parameters  
Specify local AS number to which we belong  
Define a login banner  
boot  
bridge  
Modify system boot parameters  
Transparent bridging  
buffers  
Adjust system buffer pool parameters  
Display message when connection to host fails  
Define a modem chat script  
Global CLNS configuration subcommands  
Configure time-of-day clock  
busy-message  
chat-script  
clns  
clock  
decnet  
Global DECnet configuration subcommands  
Default character-bits values  
Create a dialer list entry  
Modify enable password parameters  
Exit from configure mode  
default-value  
dialer-list  
enable  
end  
exit  
Exit from configure mode  
frame-relay  
help  
hostname  
interface  
ip  
Global frame relay configuration commands  
Description of the interactive help system  
Set system's network name  
Select an interface to configure  
Global IP configuration subcommands  
Novell/IPX global configuration commands  
Configure a terminal lin  
ipx  
line  
lnm  
IBM Lan Manager  
locaddr-priority-list  
logging  
login-string  
mop  
Establish queueing priorities based on LU address  
Modify message logging facilities  
Define a host-specific login string  
The DEC MOP Server  
netbios  
no  
ntp  
NETBIOS access control filtering  
Negate a command or set its defaults  
Configure NTP  
priority-list  
queue-list  
rif  
Build a priority lis  
Build a custom queue lis  
Source-route RIF cache  
route-map  
router  
Create route-map or enter route-map command mode  
Enable a routing process  
scheduler-interval  
service  
smt-queue-threshold  
snmp-server  
source-bridge  
stun  
Maximum interval before running lowest priority process  
Modify use of network based services  
Set the max number of unprocessed SMT frames  
Modify SNMP parameters  
Source-route bridging ring groups  
STUN global configuration commands  
Modify TACACS query parameters  
Provide TFTP service for netload requests  
tacacs-server  
tftp-server  
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tn3270  
username  
vines  
X.25  
tn3270 configuration command  
Establish User Name Authentication  
Vines global configuration commands  
X.25 Level 3  
xns  
XNS global configuration commands  
Interface Configuration Mode Commands  
Many features are enabled on a per-interface basis. Interface configu-  
ration commands modify the operation of an interface such as an  
Ethernet, Fiber Distributed Data Interface (FDDI), or serial port. Inter-  
face configuration commands always follow an interfaceglobal  
configuration command, which defines the interface type.  
This example shows how to access interface configuration commands  
for serial interface 0 and how to list the available commands.  
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Chapter 4: Understanding the User Interface  
Router(config)# interface serial 0  
Router(config-if)# ?  
Interface configuration commands:  
access-expression  
apollo  
Build a bridge boolean access expression  
Apollo interface subcommands  
appletalk  
arp  
backup  
Appletalk interface subcommands  
Set arp type (arpa, probe, snap) or timeout  
Modify dial-backup parameters  
bandwidth  
bridge-group  
clns  
Set bandwidth informational parameter  
Transparent bridging interface parameters  
CLNS interface subcommands  
clockrate  
custom-queue-list  
decnet  
delay  
description  
dialer  
dialer-group  
down-when-looped  
encapsulation  
ethernet-transit-oui  
exit  
Configure serial interface clock speed  
Assign a custom queue list to an interface  
Interface DECnet config commands  
Specify interface throughput delay  
Interface specific description  
Dial-on-demand routing (DDR) commands  
Assign interface to dialer-list  
Force looped serial interface down  
Set encapsulation type for an interface  
Token-ring to Ethernet OUI handling  
Exit from interface configuration mode  
Set frame relay parameters  
frame-relay  
hdh  
Set HDH mode  
help  
hold-queue  
ip  
Description of the interactive help system  
Set hold queue depth  
Interface Internet Protocol config commands  
Novell interface subcommands  
ipx  
isis  
IS-IS commands  
iso-igrp  
keepalive  
lapb  
ISO-IGRP interface subcommands  
Enable keepalive  
X.25 Level 2 parameters (Link Access Procedure, Balanced)  
LLC2 Interface Subcommands  
llc2  
lnm  
IBM Lan Manager  
locaddr-priority  
loopback  
mac-address  
mop  
Assign a priority group  
Configure internal loopback on an interface  
Manually set interface MAC address  
DEC MOP server commands  
mtu  
netbios  
no  
ntp  
Set the interface Maximum Transmission Unit (MTU)  
Use a defined NETBIOS access list or enable name-caching  
Negate a command or set its defaults  
Configure NTP  
ppp  
Point-to-point protocol  
priority-group  
pulse-time  
pup  
Assign a priority group to an interface  
Enables pulsing of DTR during resets  
PUP interface subcommands  
sdlc  
SDLC commands  
sdllc  
shutdown  
smds  
Configure SDLC to LLC2 translation  
Shutdown the selected interface  
Modify SMDS parameters  
source-bridge  
stun  
Configure interface for source-route bridging  
STUN interface subcommands  
transmit-interface  
Assign a transmit interface to a receive-only interface  
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AI2524 Router Card User’s Manual  
transmitter-delay  
tunnel  
tx-queue-limit  
vines  
Set dead-time after transmitting a datagram  
protocol-over-protocol tunneling  
Configure card level transmit queue limit  
Vines interface subcommands  
xns  
XNS interface subcommands  
Subinterface Configuration Mode Commands  
You can configure multiple virtual interfaces (called subinterfaces) on  
a single physical interface. This feature is supported on serial inter  
faces with Frame Relay encapsulation.  
Subinterfaces appear to be distinct physical interfaces to the various  
protocols. For example, Frame Relay networks provide multiple point-  
to-point links called permanent virtual circuits (PVCs). PVCs can be  
grouped under separate subinterfaces that in turn are configured on a  
single physical interface. From a bridging spanning-tree viewpoint,  
each subinterface is a separate bridge port, and a frame arriving on one  
subinterface can be sent out on another subinterface.  
Subinterfaces also allow multiple encapsulations for a protocol on a  
single interface. For example, a router or access server can receive an  
ARPA-framed internet packet exchange (IPX) packet and forward the  
packet back out the same physical interface as a Subnetwork Access  
Protocol (SNAP)-framed IPX packet. The subinterfaces can be config-  
ured to support multiple Frame Relay PVCs.  
In this example, a subinterface is configured for serial line 2, which is  
configured for Frame Relay encapsulation. The subinterface is called  
2.1 to indicate that it is subinterface 1 of serial interface 2.  
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Chapter 4: Understanding the User Interface  
Router(config)# interface serial 2  
Router(config-if)# encapsulation frame-relay  
Router(config-if)# interface serial 2.1  
Router(config-subif)# ?  
Interface configuration commands:  
apollo  
appletalk  
bandwidth  
bridge-group  
clns  
Apollo interface subcommands  
Appletalk interface subcommands  
Set bandwidth informational parameter  
Transparent bridging interface parameters  
CLNS interface subcommands  
decnet  
delay  
description  
exit  
frame-relay  
ip  
ipx  
Interface DECnet config commands  
Specify interface throughput delay  
Interface specific description  
Exit from interface configuration mode  
Set frame relay parameters  
Interface Internet Protocol config commands  
Novell interface subcommands  
IS-IS commands  
isis  
iso-igrp  
no  
ntp  
ISO-IGRP interface subcommands  
Negate a command or set its defaults  
Configure NTP  
shutdown  
Shutdown the selected interface  
Router Configuration Mode  
Router configuration commands configure an IP routing protocol.  
router ?  
Router(config)#  
bgp  
Border Gateway Protocol (BGP)  
egp  
Exterior Gateway Protocol (EGP)  
Interior Gateway Routing Protocol (IGRP)  
ISO IS-IS iso-igrp IGRP for OSI networks  
Open Shortest Path First (OSPF)  
Routing Information Protocol (RIP)  
Static CLNS Routing  
igrp  
isis  
ospf  
rip  
static  
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AI2524 Router Card User’s Manual  
This example displays how a router is configured to support the Rout-  
ing Information Protocol (RIP).  
Router(config)# router rip  
Router(config-router)# ?  
router configuration commands:  
default-information  
default-metric  
distance  
Control distribution of default information  
Set metric of redistributed routes  
Define an administrative distance  
distribute-list  
exit  
help  
Filter networks in routing updates  
Exit from routing protocol configuration mode  
Description of the interactive help system  
Specify a neighbor router  
neighbor  
network  
Enable routing on an IP network  
no  
Negate or set default values of a command  
Add or subtract offset from IGRP, RIP, or HELLO metrics  
Suppress routing updates on an interface  
Redistribute information from another routing protocol  
Adjust routing timers  
offset-list  
passive-interface  
redistribute  
timers  
IPX-Router Configuration Mode  
Internet Packet Exchange (IPX) is a Novell network-layer protocol. In  
this example, IPX RIP routing is configured.  
Router(config)# ipx router rip  
Router(config-ipx-router)# ?  
Novell router configuration commands:  
distribute-list  
exit  
help  
network  
no  
redistribute  
Filter networks in routing updates  
Exit from IPX routing protocol configuration mode  
Description of the interactive help system  
Enable routing on an IPX network  
Negate or set default values of a command  
Enable routing protocol redistribution  
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Chapter 4: Understanding the User Interface  
Route-Map Configuration Mode  
Use the route-map configuration mode to configure routing table and  
source and destination information. In this example, a route map  
named arizona1 is configured.  
Router(config)# route-map arizona1  
Router(config-route-map)# ?  
Route Map configuration commands:  
exit  
help  
match  
no  
Exit from route-map configuration mode  
Description of the interactive help system  
Match values from routing table  
Negate or set default values of a command  
Set values in destination routing protocol  
set  
Key Chain Configuration Mode  
From key chain configuration mode, you can manage authentication  
keys that routing protocols use. To enter this configuration mode and  
use Key Chain configuration commands, you must first enable RIP au-  
thentication. For more information about enabling RIP, refer to Enable  
RIP.  
Key Chain Key Configuration Mode  
Once you define a key chain, use the key chain key configuration  
mode to configure the keys on the key chain.  
Response Time Reporter Configuration Mode  
Use the response time reporter feature to monitor network perfor-  
mance, network resources, and applications by measuring response  
times and availability. With this feature you can perform troubleshoot-  
ing, problem notifications, and pre-problem analysis based on re-  
sponse time reporter statistics.  
Access-List Configuration Mode  
All Internet Protocol (IP) access lists can be identified by a number;  
standard IP access lists are numbered 1 to 99 and extended IP access  
lists are numbered 100 to 199. Some IP access lists can also be identi-  
fied by a name. Use access-list configuration mode when you are cre-  
ating a named IP access list.  
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AI2524 Router Card User’s Manual  
In this example, an IP access list named flag is created and the com-  
mands available in access-list configuration mode are listed.  
Router(config)# ip access-list extended flag  
Router(config-ext-nacl)# ?  
Ext Access List configuration commands:  
deny  
Specify packets to reject  
dynamic  
exit  
no  
Specify a DYNAMIC list of PERMITs or DENYs  
Exit from access-list configuration mode  
Negate or set default values of a command  
Specify packets to forward  
permit  
Context-Sensitive  
Help  
The first level of help available with the user interface is context-sen-  
sitive help. Entering a question mark (?) at the system prompt displays  
a list of commands available for each command mode. You can also  
get a list of any command's associated keywords and arguments with  
the context-sensitive help feature.  
To get help specific to a command mode, a command, a keyword, or  
arguments, perform one of these tasks:  
Help Command  
Command Format  
Obtain a brief description of the help sys- help  
tem in any command mode.  
Receive help for the full set of user-level full-help  
commands when you type a question mark  
(?).  
Receive help for the full set of user-level terminal full-  
commands for this exec session.  
help  
Obtain a list of commands that begin with abbreviated-  
a particular character string.  
command-entry?  
Complete a partial command name.  
abbreviated-  
command-  
entry<Tab>  
List all commands available for a particu- ?  
lar command mode.  
List a command's associated keywords.  
List a keyword's associated arguments.  
command?  
command key-  
word?  
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Chapter 4: Understanding the User Interface  
Warning: When using context-sensitive help, the space (or lack of a  
space) before the question mark (?) is significant.  
Get Word Help  
To obtain a list of commands that begin with a particular character se-  
quence, type in those characters followed immediately by the question  
mark (?). Do not include a space. This is called word help because it  
completes a word for you.  
Get Command Syntax Help  
To list keywords or arguments, enter a question mark (?) in place of a  
keyword or argument. Include a space before the question mark (?).  
This form of help is called command syntax help, because it lists key-  
words or arguments that are applicable based on the command, key-  
words, and arguments you already have entered.  
Get Help for Abbreviated Commands  
You can abbreviate commands and keywords to the number of charac-  
ters that allow a unique abbreviation. For example, you can abbreviat  
the showcommand to sh.  
Examples  
Enter the helpcommand, which is available in any command mode,  
for a brief description of the help system:  
Router# help  
Help may be requested at any point in a command by entering a question mark '?'.  
If nothing matches, the help list will be empty and you must back up until  
entering a '?' shows the available options. Two styles of help are provided:  
1. Full help is available when you are ready to enter a command argument (e.g.  
'show ?') and describes each possible argument.  
2. Partial help is provided when an abbreviated argument is entered and you want  
to know what arguments match the input (e.g. 'show pr?'.)  
These examples illustrate how the context-sensitive help feature en-  
ables you to create an access list from configuration mode.  
z
Type the letters coat the system prompt, followed by a question  
mark (?). Do not leave a space between the last letter and the ques-  
tion mark (?). The system provides the commands that begin with  
co.  
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AI2524 Router Card User’s Manual  
Router# co?  
configure connect copy  
z
Enter the configurecommand followed by a space and a ques-  
tion mark (?) to list the command's keywords and a brief explana-  
tion:  
Router# configure ?  
memory  
Configure from NV memory  
network  
terminal  
Configure from a TFTP network host  
Configure from the terminal  
<cr>  
The <cr> symbol by itself indicates there are no more keywords or ar-  
guments. Press <Enter> to execute the command.  
z
Enter the terminalkeyword to enter configuration mode from  
the terminal:  
Router# configure terminal  
Enter configuration commands, one per line.End with CNTL/Z  
Router(config)#  
z
Enter the access-list command followed by a space and  
question mark (? ) to list the command's keywords:  
Router(config)# access-list ?  
<1-99>  
IP standard access list  
<100-199>  
<1000-1099>  
<1100-1199>  
<200-299>  
<300-399>  
<400-499>  
<500-599>  
<600-699>  
<700-799>  
<800-899>  
<900-999>  
IP extended access list  
IPX SAP access list  
Extended 48-bit MAC address access list  
Protocol type-code access list  
DECnet access list  
XNS standard access list  
XNS extended access list  
Appletalk access list  
48-bit MAC address access list  
IPX standard access list  
IPX extended access list  
z
Enter the access list number 99. Then, enter another question  
mark (?) to see the arguments and brief explanations for the key-  
word:  
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Chapter 4: Understanding the User Interface  
Router(config)# access-list 99 ?  
deny  
permit  
Specify packets to reject  
Specify packets to forward  
z
Enter the denykeyword followed by a question mark (?) to list  
additional options:  
Router(config)# access-list 99 deny ?  
A.B.C.D Address to match  
z
Enter the IP address followed by a question mark (?) to list addi-  
tional options:  
Router(config)# access-list 99 deny 131.108.134.0 ?  
A.B.C.D  
<cr>  
Mask of bits to ignore  
z
Enter the wildcard mask followed by a question mark (?) to list  
further options.  
Router(config)# access-list 99 deny 131.108.134.0 0.0.0.255 ?  
<cr>  
Router(config)# access-list 99 deny 131.108.134.0 0.0.0.255  
Check Command Syntax  
The user interface provides error isolation by using a caret symbol (^  
as an indicator. The ^ symbol appears at the point in the command  
string where you have entered an incorrect command, keyword, or ar-  
gument. The error location indicator and interactivehelp system allow  
you to find and correct syntax errors easily.  
In this example, context-sensitive help is used to check the syntax for  
setting the clock.  
Router# clock ?  
set  
Set the time and date  
Router# clock  
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AI2524 Router Card User’s Manual  
The help output shows that the set keyword is required. Check the syn-  
tax for entering the time:  
Router# clock set ?  
hh:mm:ss  
Current time  
Router# clock set  
Enter the current time:  
Router# clock set 13:32:00  
% Incomplete command.  
The system indicates that you need to provide additional arguments to  
complete the command. Press <Ctrl-P> (refer to Command History  
Features) to automatically repeat the previous command entry. Then  
add a space and question mark (?) to reveal the additional arguments:  
Router# clock set 13:32:00 ?  
<1-31>  
January  
February  
March  
Day of the month  
Month of the year  
April  
May  
June  
July  
August  
September  
October  
November  
December  
Now you can complete the command entry:  
Router# clock set 13:32:00 23 February 93  
% Invalid input detected at '^' marker.  
^
The caret symbol (^) and help response indicate an error at 93. To list  
the correct syntax, enter the command up to the point where the erro  
occurred and then enter a question mark (?):  
Router# clock set 13:32:00 23 February ?  
<1997-2035> Year  
Router# clock set 13:32:00 23 February  
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Chapter 4: Understanding the User Interface  
Enter the year using the correct syntax and press <Enter> to execut  
the command.  
Router# clock set 13:32:00 23 February 1997  
Command  
History Features  
The Cisco IOS software user interface provides a history, or record, o  
commands that you have entered. This feature is particularly useful fo  
recalling long or complex commands or entries, including access lists.  
By default, the system records 10 command lines in its history buffer.  
The following commands are entered from user EXEC mode.  
Warning: Many of the commands described in this section refer to  
arrow keys as well as alternate keystrokes. Please note  
that arrow keys function only on ANSI-compatible termi  
nals such as VT100s.  
History Commands  
Command Format  
Set the number of command lines the terminal history  
system will record during the current [size number-of-  
terminal session.  
lines]  
Reset the number of lines saved in th terminal no his-  
history buffer to the default of 10  
lines.  
tory size  
Recall commands in the history  
Press <Ctrl-P> or the up  
buffer, beginning with the most recent arrow key  
command. Repeat the key sequence to  
recall successively older commands.  
Return to more recent commands in  
Press <Ctrl-N> or the  
the history buffer after recalling com- down arrow key  
mands with <Ctrl-P> or the up arrow  
key. Repeat the key sequence to recall  
successively more recent commands.  
List the last several commands you  
entered while in EXEC mode.  
show history  
Disable command history during th terminal no his-  
current terminal session.  
tory  
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AI2524 Router Card User’s Manual  
Editing Features  
The current software release includes an enhanced editing mode that  
provides a set of editing key functions similar to those of the Emacs  
editor.  
Notes:  
z
z
Many of the commands described in this section refer to arrow  
keys as well as alternate keystrokes. Please note that arrow keys  
function only on ANSI-compatible terminals such as VT100s.  
The --More- prompt is used for any output that has more lines  
than can be displayed on the terminal screen, including show  
command output. You can use the keystrokes listed above when-  
ever you see th --More- prompt.  
z
You might want to disable enhanced editing if you have prebuilt  
scripts, such as scripts that do not interact well when enhanced  
editing is enabled. You can reenable enhanced editing mode  
with the terminal editing command  
.
Editing Commands  
Command Format  
In user EXEC mode, reenable the  
terminal editing  
enhanced editing mode for the current  
terminal session.  
Move the cursor back one character.  
Press <Ctrl-B> or press  
the left arrow key  
Move the cursor forward one charac- Press <Ctrl-F> or press the  
ter.  
right arrow key  
Move the cursor to the beginning of  
the command line.  
Press <Ctrl-A>  
Move the cursor to the end of th  
command line.  
Press <Ctrl-E>  
Move the cursor back one word.  
Press <Esc-B>  
Press <Esc-F>.  
Move the cursor forward one word.  
Prompt the system to complete a par- Press <Tab> or <Ctrl-I>  
tial entry.  
Obtain a list of commands that begin  
with that set of characters.  
?
Recall the most recent entry in the  
buffer.  
Press <Ctrl-Y>  
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Chapter 4: Understanding the User Interface  
Editing Commands  
Command Format  
(Contd.)  
Recall the next buffer entry. The  
buffer contains only the last 10 items  
you have deleted or cut. If you press  
<Esc-Y> more than 10 times, you will  
cycle back to the first buffer entry.  
Press <Esc-Y>  
Erase the character to the left of the  
cursor.  
Press <Delete> or <Back-  
space>  
Delete the character at the cursor.  
Press <Ctrl-D>  
Press <Ctrl-K>  
Delete all characters from the cursor  
to the end of the command line.  
Delete all characters from the cursor  
Press <Ctrl-U> or  
to the beginning of the command line. <Ctrl-X>  
Delete the word to the left of the cur- Press <Ctrl-W>  
sor.  
Scroll down one line.  
Press <Enter>  
Scroll down one screen.  
Press the <Space> bar  
Redisplay the current command line.  
Press <Ctrl-L> or  
<Ctrl-R>  
Transpose mistyped characters. The  
character to the left of the cursor will  
be transposed with the characte  
located at the cursor.  
Press <Ctrl-T>  
Capitalize at the cursor.  
Press <Esc>, then <C>  
Press <Esc>, then <L>  
Change the word at the cursor to low  
ercase.  
Capitalize letters from the cursor to  
the end of the word.  
Press <Esc>, then <U>  
Insert a system code for this purpose.  
Press <Ctrl-V> or  
<Esc-Q>  
Disable enhanced editing mode and terminal no edit-  
revert to the editing mode of previous ing  
releases.  
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Edit Command Lines that Wrap  
The Cisco IOS software assumes that you have a terminal screen that  
is 80 characters wide. If your terminal displays a different number of  
characters on each line, use the terminal width command.  
When the cursor reaches the right margin, the command line shifts 10  
spaces to the left. You cannot see the first ten characters of the line, but  
you can scroll back and check the syntax at the beginning of the com-  
mand. To scroll back, press <Ctrl-B> or the left arrow key repeatedly  
until you scroll back to the beginning of the command entry, or press  
<Ctrl-A> to return directly to the beginning of the line.  
In this example, the access-list command entry extends beyond  
one line. When the cursor first reaches the end of the line, the line is  
shifted 10 spaces to the left and is redisplayed. The dollar sign ($) in  
dicates that the line has been scrolled to the left. Each time the cursor  
reaches the end of the line, the line is again shifted 10 spaces to the left.  
Router(config)# access-list 101 permit tcp 131.108.2.5 255.255.255.0 131.108  
Router(config)# $ 101 permit tcp 131.108.2.5 255.255.255.0 131.108.1.20 255.2  
Router(config)# $t tcp 131.108.2.5 255.255.255.0 131.108.1.20 255.255.255.0  
Router(config)# $108.2.5 255.255.255.0 131.108.1.20 255.255.255.0 eq 45  
When you have completed the entry, press <Ctrl-A> to check the com-  
plete syntax before pressing <Enter> to execute the command. The  
dollar sign ($) appears at the end of the line to indicate that the line has  
been scrolled to the right:  
Router(config)# access-list 101 permit tcp 131.108.2.5 255.255.255.0 131.108$  
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Chapter 4: Understanding the User Interface  
Web Browser  
Interface  
You can issue most of the AI2524 commands using a Web browser.  
This AI2524 feature is accessed by using the Web Browser interface,  
which is accessed from the router's home page.  
From the router's home page, click on the Monitor the Router hyper  
text link to display a Web page with a Command field. You can typ  
commands in this field as if you were entering commands at a terminal  
connected to the router. The page also displays a list of commands (hy-  
pertext links) you can execute by clicking.  
Web Browser Interface Task List  
To use the Web Browser interface to issue commands, perform the  
tasks in the following list:  
z
z
z
z
z
z
z
Enable the Web Browser Interface  
Use the Correct Hardware and Software  
Access Your Router's Home Pag  
Issue Commands Using the Web Browser Interfac  
Enter Commands Using Hypertext Links  
Enter Commands Using the Command Field  
Enter Commands Using the URL Window  
Enable the Web Browser Interface  
To enable your router to be configured from a browser using the Web  
Browser interface, type this command in global configuration mode:  
ip http server  
Once the Web Browser interface is enabled, you can issue AI2524  
commands to your router using a Web browser.  
Use Compatible Hardware and Software  
To use the Web Browser interface, your computer must have a World  
Wide Web browser. The Web Browser interface works with most  
browsers, including Netscape Navigator. Your Web browser must be  
able to read and submit forms. The earliest versions of Mosaic might  
have problems using the Web Browser interface, because they either  
cannot submit forms or have difficulty doing so.  
The computer must be connected to the same network as the router or  
access server.  
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AI2524 Router Card User’s Manual  
Access Your Router's Home Page  
Perform these steps to access the home page for your router or access  
server:  
1. Enter the name of the router or access server in the URL field of  
your Web browser and press <Enter>. The browser prompts you  
for the password for the router or access server.  
2. Enter the password.  
Warning: The name and password for your router and access server  
are designated as part of the configuration process. Con-  
tact your network administrator if you do not have this in-  
formation.  
The browser should display the home page for your router or access  
server.The router's home page looks something like the home page  
shown in Figure 4-1.  
Figure 4-1:Example of a Home Page  
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Chapter 4: Understanding the User Interface  
Issue Commands Using the Web Browser Interface  
To issue commands using the Web Browser interface, click Monitor  
the router in the first list of hypertext links on the home page. This dis-  
plays the Web page shown in Figure 4-2.  
Figure 4-2:The Command Field Web Page for a Router  
Named example  
Enter Commands Using Hypertext Links  
To enter a command using hypertext links, scroll through the com-  
mands listed at the bottom of the screen and click the one you want to  
execute. If the link is a complete command, it is executed. If the com-  
mand has more parameters, another list of command hypertext links is  
displayed. Scroll through this second list and click the one you want to  
execute.  
If the command is a request for information, like showcommand,  
the information is displayed in the Web browser window.  
If the command requires a variable, a form in which you can enter the  
variable is displayed.  
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Enter Commands Using the Command Field  
Entering the command in the command field is just like entering it at  
a terminal console. If you are uncertain of the options available for  
particular command, type a question mark (?).  
For example, typing show ?in the command field displays the pa-  
rameters for the showcommand. The Web Browser interface displays  
the parameters as hypertext links. To select a parameter, click one of  
the links or enter the parameter in the command field.  
Enter Commands Using the URL Window  
You can issue a command using the Universal Resource Locator  
(URL) window for the Web browser.  
For example, to execute a show configuration command on a  
router named example, you would enter this in the URL window:  
http://example/exec/show/configuration  
The Web browser then displays the configuration for the exampl  
router. To save effort, modify the URL in the URL window in the  
browser control bar instead of retyping the entire URL.  
The difference between entering a command in the command field and  
entering a command in the URL window is that in the URL window,  
command modes and options should be separated by slashes, not  
spaces.  
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Chapter 5: Using AutoInstall  
Chapter 5: Using AutoInstall  
Introduction  
This chapter provides information about AutoInstall, a procedure that  
allows you to configure a new router automatically and dynamically.  
The AutoInstall procedure involves connecting a new router to a net-  
work where an existing router is preconfigured, turning on the new  
router, and enabling it with a configuration file that is automatically  
downloaded from a Trivial File Transfer Protocol (TFTP) server.  
Preparing for  
AutoInstall  
Take these steps to prepare your router for the AutoInstall process:  
1. Attach the WAN cable to the router.  
2. Turn ON power to the router.  
The router will load the operating system image from Flash mem-  
ory. If the remote end of the WAN connection is connected and  
properly configured, the AutoInstall process will begin.  
If AutoInstall successfully completes, you can write the configu-  
ration data to the router's NVRAM. Perform the following step to  
complete this task.  
3. Enter the copy running-config startup-config com-  
mand:  
Router# copy running-config startup-config  
Taking this step saves the configuration settings that the AutoIn  
stall process created in the router. If you do not do this, your con  
figuration will be lost the next time you reload the router.  
The next sections provide AutoInstall requirements and an overview  
of its procedure. For information about starting AutoInstall, refer to  
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AutoInstall  
Requirements  
The AutoInstall process is designed to configure the router automati-  
cally after connection to your WAN. In order for AutoInstall to work  
properly, a Transmission Control Protocol/Internet Protocol (TCP/IP)  
host on your network must be preconfigured to provide the required  
configuration files. The TCP/IP host may exist anywhere on the net-  
work as long as these two conditions are maintained:  
z
The host must be on the remote side of the router's synchronous  
serial connection to the WAN.  
z
User Datagram Protocol (UDP) broadcasts to and from the router  
and the TCP/IP host must be enabled.  
This functionality is coordinated by your system administrator at  
the site where the TCP/IP host is located. You should not attempt  
to use AutoInstall unless the required files have been provided on  
the TCP/IP host.  
Note:  
AutoInstall works on synchronous serial connections  
only. The 2-wire switched 56-kbps DSU/CSU module op  
erates on switched 56-kbps circuits only; therefore, you  
cannot use it for AutoInstall.  
In addition, your system must meet these requirements:  
z
Routers must be physically attached to the network using one o  
more of the following interface types: Ethernet, Token Ring, Fiber  
Distributed Data Interface (FDDI), serial with High-Level Dat  
Link Control (HDLC) encapsulation, or serial with Frame Relay  
encapsulation. HDLC is the default serial encapsulation. If the Au-  
toInstall process fails over HDLC, the Cisco IOS software auto-  
matically configures Frame Relay encapsulation.  
Note:  
For Token Ring interfaces, only those that set ring speed  
with physical jumpers support AutoInstall. AutoInstall  
does not work with Token Ring interfaces for which the  
ring speed must be set with software configuration  
commands. If the ring speed is not set, the interface is set  
to shutdown mode.  
z
You must complete Step 1 and either Step 2 or 3:  
1. A configuration file for the new router must reside on a TFTP  
server. This file can contain the minimum or full configuration  
needed for the administrator to Telnet into the new router for con-  
figuration. In addition, make sure to complete one of the next two  
procedures:  
2. A file named network-confg also must reside on the server. The  
file must have an Internet Protocol (IP) host name entry for the  
new router. The server must be reachable from the existing router.  
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Chapter 5: Using AutoInstall  
3. An IP address-to-host name mapping for the new router must be  
added to a Domain Naming System (DNS) database file.  
z
If the existing router is to help automatically install the new route  
via an HDLC-encapsulated serial interface using Serial Line Ad-  
dress Resolution Protocol (SLARP), that interface must be config-  
ured with an IP address whose host portion has the value 1 or 2.  
(AutoInstall over Frame Relay does not have this address con-  
straint.) Subnet masks of any size are supported.  
z
If the existing router is to help automatically install the new route  
using a Frame Relay-encapsulated serial interface, that interface  
must be configured with:  
An IP helper address pointing to the TFTP server. In this example,  
171.69.2.75 is the address of the TFTP server:  
ip helper 171.69.2.75  
A Frame Relay map pointing back to the new router. In this exam-  
ple, 172.21.177.100 is the IP address of the new router's serial in-  
terface, and 100 is the PVC identifier:  
frame-relay map ip 172.21.177.100 100 dlci  
z
If the existing router is to help automatically install the new route  
via an Ethernet, Token Ring, or FDDI interface using BOOTP o  
Reverse Address Resolution Protocol (RARP), a BOOTP or  
RARP server also must be set up to map the new router's Media  
Access Control (MAC) address to its IP address.  
z
IP helper addresses should be configured to forward the TFTP and  
DNS broadcast requests from the new router to the host providing  
those services.  
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Use a DOS-Based  
TFTP Server  
AutoInstall over Frame Relay and other WAN encapsulations support  
downloading configuration files from UNIX-based and DOS-based  
TFTP servers. Other booting mechanisms such as RARP and SLARP  
also support UNIX-based and DOS-based TFTP servers.  
The DOS format of the UNIX network-confg file that must reside on  
the server must be eight characters or fewer, with a three-letter exten  
sion. Therefore, when an attempt to load network-confg fails, AutoIn-  
stall automatically attempts to download the filecisconet.cfg from the  
TFTP server.  
If cisconet.cfg exists and is downloaded successfully, the server is as-  
sumed to be a DOS machine. The AutoInstall program then attempts  
to resolve the host name for the router through host commands in  
cisconet.cfg.  
If cisconet.cfg does not exist or cannot be downloaded, or if the pro-  
gram is unable to resolve a host name, DNS attempts to resolve the  
host name. If DNS cannot resolve the host name, the router attempts  
to download ciscortr.cfg. If the host name is longer than eight charac-  
ters, it is truncated to eight characters. For example, a router with a  
host name australia will be treated as australi and AutoInstall will at-  
tempt to download australi.cfg.  
The format of cisconet.cfg and ciscortr.cfg is the same as those de-  
scribed for network-confg and hostname-confg.  
If neither network-confg nor cisconet.cfg exists and DNS is unable to  
resolve the host name, AutoInstall attempts to load router-confg, and  
then ciscortr.cfg if router-confg does not exist or cannot be down-  
loaded. The cycle is repeated three times.  
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Chapter 5: Using AutoInstall  
How AutoInstall  
Works  
Once the requirements for using AutoInstall are met, the dynamic con-  
figuration of the new router occurs in this order:  
1. The new router acquires its IP address. Depending on the interface  
connection between the two routers and/or access servers, the new  
router's IP address is dynamically resolved by either SLARP re-  
quests or BOOTP or RARP requests.  
2. The new router resolves its name through network-confg, cisco-  
net.cfg, or DNS.  
3. The new router automatically requests and downloads its configu-  
ration file from a TFTP server.  
4. If a host name is not resolved, the new router attempts to load  
router-confg or ciscortr.cfg.  
Acquire the New Router's IP Address  
The new router (newrouter) resolves its interface's IP addresses as:  
z
If newrouter is connected by an HDLC-encapsulated serial line to  
the existing router (existing), newrouter sends a SLARP request to  
existing.  
z
z
If newrouter is connected by an Ethernet, Token Ring, or FDDI in-  
terface, it broadcasts BOOTP and RARP requests.  
If newrouter is connected by a Frame Relay-encapsulated serial  
interface, it first attempts the HDLC automatic installation process  
and then attempts the BOOTP or RARP process over Ethernet,  
Token Ring, or FDDI. If both attempts fail, the new router at-  
tempts to automatically install over Frame Relay. In this case, a  
BOOTP request is sent over the lowest numbered serial or HSSI  
interface.  
The existing router (existing) responds in oneof theseways depending  
on the request type:  
z
In response to a SLARP request, existing sends a SLARP reply  
packet to newrouter. The reply packet contains the IP address and  
netmask of existing. If the host portion of the IP address in the  
SLARP response is 1, newrouter configures its interface using the  
value 2 as the host portion of its IP address and vice versa. (See  
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Figure 5-1:Using SLARP to Acquire the New Router's IP  
Address  
z
In response to BOOTP or RARP requests, an IP address is sent  
from the BOOTP or RARP server to newrouter.  
A BOOTP or RARP server must have already been set up to map  
newrouter's MAC address to its IP address. If the BOOTP server  
does not reside on the directly attached network segment, routers  
between newrouter and the BOOTP server can be configured with  
the ip helper-address command to allow the request and  
response to be forwarded between segments, as shown in Figur  
5-2.  
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Chapter 5: Using AutoInstall  
Figure 5-2:Use BOOTP or RARP to Acquire the New  
Router's IP Address  
AutoInstall over Frame Relay is a special case in that the existing  
router acts as a BOOTP server and responds to the incoming BOOTP  
request. Only a helper address and a Frame Relay map need to be set  
up. No MAC-to-IP address map is needed on the existing router.  
The AI2524 routers can be configured to act as a RARP server.  
Because the router attempts to resolve its host name as soon as one in-  
terface resolves its IP address, only one IP address needs to be set up  
with SLARP, BOOTP, or RARP.  
Resolve the IP Address to the Host Name  
The new router resolves its IP address-to-host name mapping by send-  
ing a TFTP broadcast requesting the file network-confg, as shown in  
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Figure 5-3:Dynamically Resolve the New Router's IP Ad-  
dress-to-Host Name Mapping  
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Chapter 5: Using AutoInstall  
The network-confg file is a configuration file generally shared by sev-  
eral routers. In this case, it maps the IP address of the new router (just  
obtained dynamically) to the name of the newrouter. The file network-  
confg must reside on a reachable TFTP server and must be globally  
readable.  
This is an example of a minimal network-confg file that maps the IP  
address of the new router (131.108.10.2) to the name newrouter. The  
address of the new router was learned via SLARP and is based on ex-  
isting's IP address of 131.108.10.1.  
ip host newrouter 131.108.10.2  
If you are not using AutoInstall over Frame Relay, the host portion of  
the address must be 1 or 2. AutoInstall over Frame Relay does not hav  
this addressing constraint.  
If newrouter does not receive a network-confg or a cisconet.cfg file, or  
if the IP address-to-host-name mapping does not match the newly ac-  
quired IP address, newrouter sends a DNS broadcast. If DNS is con-  
figured and has an entry that maps newrouter's SLARP, BOOTP, or  
RARP-acquired IP address to its name, newrouter successfully re-  
solves its name.  
If DNS does not have an entry that maps the new router's SLARP,  
BOOTP, or RARP-acquired address to its name, the new router cannot  
resolve its host name. The new router attempts to download a default  
configuration file as described in the next section, and failing that, en-  
ters setup mode or enters user EXEC mode with AutoInstall over  
Frame Relay.  
Download the New Router's Host Configuration File  
After the router successfully resolves its host name, newrouter sends  
TFTP broadcast requesting the file newrouter-confg or newrouter.cfg.  
The name newrouter-confg must be in all lowercase letters, even if th  
true host name is not. If newrouter cannot resolve its host name, it  
sends a TFTP broadcast requesting the default host configuration fil  
router-confg. The file is downloaded to newrouter, where the configu-  
ration commands take effect immediately.  
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AI2524 Router Card User’s Manual  
When using AutoInstall over Frame Relay, you are put into setup  
mode while the AutoInstall process is running. If the configuration file  
is successfully installed, the setup process is terminated. If you expect  
the AutoInstall process to be successful, either do not respond to the  
setup prompts or respond to the prompts as:  
Would you like to enter the initial configuration dialog? [yes]: no  
Would you like to terminate autoinstall? [yes]: no  
If you do not expect the AutoInstall process to be successful, create  
configuration file by responding to the setup prompts. The AutoInstall  
process is terminated transparently.  
You will see this display as the AutoInstall operation is in progress:  
Please Wait. AutoInstall being attempted!!!!!!!!!!!!!  
If the host configuration file contains only the minimal information,  
you must connect to existing using Telnet. From there, connect via  
Telnet to newrouter. Then, run the setupcommand to configure ne  
wrouter. Refer to Use Setup for Configuration Changes, for specific  
information about the setupcommand.  
If the host configuration file is complete, newrouter should be fully op-  
erational. You can enter the enablecommand (with the system ad-  
ministrator password) at the system prompt on newrouter. Then, enter  
the copy running-config startup-config command to  
save the information in the recently obtained configuration file into  
nonvolatile random-access memory (NVRAM) or to the location spec-  
ified by the CONFIG_FILE environment variable. If it must reload,  
newrouter simply loads its configuration file from NVRAM.  
If the TFTP request fails, or if newrouter still has not obtained the IP  
addresses of all its interfaces, and if those addresses are not contained  
in the host configuration file, then newrouter enters setup mode auto-  
matically. Setup mode prompts you for manual configuration of the  
Cisco IOS software at the console. The new router continues to issue  
broadcasts to attempt to learn its host name and obtain any unresolved  
interface addresses. The broadcast frequency will dwindle to every 10  
minutes after several attempts. Refer to Use Setup for Configuration  
Change , for specific information about th setupcommand.  
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Chapter 5: Using AutoInstall  
Perform the  
AutoInstall  
Procedure  
To dynamically configure a new router using AutoInstall, complete  
these tasks. Steps 1, 2, and 3 are completed by the central administra-  
tor. Step 4 is completed by the person at the remote site.  
1. Modify the existing router's configuration to support AutoInstall.  
2. Set up the TFTP server to support AutoInstall.  
3. Set up the BOOTP or RARP server if needed. A BOOTP or RARP  
server is required for AutoInstall using an Ethernet, Token Ring,  
FDDI, or Frame Relay-encapsulated serial interface. With a  
Frame Relay-encapsulated serial interface, the existing router acts  
as the BOOTP server. A BOOTP or RARP server is not required  
for AutoInstall using an HDLC-encapsulated serial interface.  
4. Connect the new router to the network.  
Modify the Existing Router's Configuration  
You can use any of these interfaces:  
z
An HDLC-encapsulated serial line (the default configuration for  
serial line)  
z
z
An Ethernet, Token Ring, FDDI interface  
A Frame Relay-encapsulated serial line  
Use an HDLC-Encapsulated Serial Interface Connection  
To set up AutoInstall via a serial line with HDLC encapsulation (the  
default), you must configure the existing router. Perform these steps,  
beginning in global configuration mode:  
1. Configure the serial interface that connects to the new router with  
HDLC encapsulation (the default), and enter interface configura  
tion mode.  
interface serial interface-number  
2. Enter an IP address for the interface. The host portion of the ad  
dress must have a value of 1 or 2. (AutoInstall over Frame Relay  
does not have this address constraint.  
ip address address mask  
3. Configure a helper address for the serial interface to forward  
broadcasts associated with the TFTP, BOOTP, and DNS requests.  
ip helper-address address  
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4. Optionally, configure a DCE clock rate for the serial line, unless  
an external clock is being used. This step is needed only for DCE  
appliques.  
clock rate bps  
5. To exit configuration mode, press <Ctrl-Z>.  
6. Save the configuration file to your startup configuration.  
copy running-config startup-config  
In this example, the existing router's configuration file contains the  
commands needed to configure the router for AutoInstall on a serial  
line using HDLC encapsulation:  
Router# configure terminal  
interface serial 0  
ip address 172.31.10.1 255.255.255.0  
ip helper-address 172.31.20.5  
Ctrl-Z  
Router(config)# copy running-config startup-config  
Use an Ethernet, Token Ring, or FDDI Interface Connection  
To set up AutoInstall using an Ethernet, Token Ring, or FDDI inter  
face, you must modify the configuration of the existing router. Per  
form these steps, beginning in global configuration mode:  
1. Configure a LAN interface, and enter interface configuration  
mode.  
interface {ethernet |tokenring | fddi}  
interface-number  
2. Enter an IP address for the interface.  
ip address address mask  
3. Optionally, configure a helper address to forward broadcasts asso-  
ciated with the TFTP, BOOTP, and DNS requests.  
ip helper-address address2  
4. To exit configuration mode, press <Ctrl-Z>.  
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Chapter 5: Using AutoInstall  
5. Save the configuration file to your startup configuration. This step  
saves the configuration to NVRAM.  
copy running-config startup-config  
Typically, the local-area network (LAN) interface and IP address ar  
already configured on the existing router. You might need to configur  
an IP helper address if the TFTP server is not on the same network as  
the new router.  
In this example, the existing router's configuration file contains the  
commands needed to configure the router for AutoInstall on an Ether-  
net interface:  
Router# configure terminal  
interface Ethernet 0  
ip address 172.31.10.1 255.255.255.0  
ip helper-address 172.31.20.5  
Ctrl-Z  
Router(config)# copy running-config startup-config  
Use a Frame Relay-Encapsulated Serial Interface Connection  
To set up AutoInstall via a serial line with Frame Relay encapsulation,  
you must configure the existing router. Perform these tasks, beginning  
in global configuration mode:  
1. Configure the serial interface that connects to the new router, and  
enter interface configuration mode.  
interface serial 0  
2. Configure Frame Relay encapsulation on the interface that con-  
nects to the new router.  
encapsulation frame-relay  
3. Create a Frame Relay map pointing back to the new router, or  
point-to-point subinterfaces, assign a data link connection identi-  
fier (DLCI) to the interface that connects to the new router, and  
provide the IP address of the serial port on the new router.  
frame-relay map ip ip-address dlci  
or  
frame-relay interface-dlci dlci option  
[protocol ip ip-address]  
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4. Enter an IP address for the interface. This step sets the IP address  
of the existing router.  
ip address address mask  
5. Configure a helper address for the TFTP server.  
ip helper-address address3  
6. Optionally, configure a DCE clock rate for the serial line, unless  
an external clock is being used. This step is needed only for DCE  
applications.  
clock rate bps1  
7. To exit configuration mode, press <Ctrl-Z>.  
8. Save the configuration file to your startup configuration. This step  
saves the configuration to NVRAM.  
copy running-config startup-config  
You must use a DTE interface on the new router because the network  
always provides the clock signal.  
In this example, the existing router's configuration file contains the  
commands needed to configure the router for Frame Relay AutoInstall  
on a serial line:  
Router# configure terminal  
interface serial 0  
ip address 172.31.20.20 255.255.255.0  
encapsulation frame-relay  
frame-relay map ip 172.31.10.1 255.255.255.0 48  
ip helper-address 172.31.20.5  
Set Up the TFTP Server  
For AutoInstall to work correctly, the new router must resolve its host  
name and then download a name-confg or a name.cfg file from a TFTP  
server. The new router can resolve its host name by using a network-  
confg or a cisconet.cfg file downloaded from a TFTP server or by  
using the DNS.  
To set up a TFTP server to support AutoInstall, complete these tasks.  
Step 2 includes two ways to resolve the new router's host name. Use  
the first method if you want to us network-confg file to resolve the  
new router's host name. Use the second method if you want to us  
DNS to resolve the new router's host name.  
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Chapter 5: Using AutoInstall  
1. Enable TFTP on a server. Consult your host vendor's TFTP serve  
documentation and RFCs 906 and 783.  
2. If you want to use a network-confg or cisconet.cfg file to resolve  
the new router's name, create the network-confg or cisconet.cfg  
file containing an IP address-to-host name mapping for the new  
router.  
Enter the ip hostcommand into the TFTP config file, not into  
the router. The IP address must match the IP address that is to be  
dynamically obtained by the new router, or if you want to use DNS  
to resolve the new router's name, create an address-to-name map-  
ping entry for the new router in the DNS database. The IP address  
must match the IP address that is to be dynamically obtained by  
the new router.  
ip host hostname address  
Contact the DNS administrator or refer to RFCs 1101 and 1183.  
3. Create th name-confg or name.cfg file, which should reside in th  
tftpboot directory on the TFTP server. The name part of name-  
confg or name.cfg filename must match the host name you as-  
signed for the new router in the previous step. Enter configuration  
commands for the new router into this file.  
The name-confg or the name.cfg file can contain either the new  
router's full configuration or a minimal configuration.  
The minimal configuration file is a virtual terminal password and an  
enable password. It allows an administrator to gain access (via Telnet  
into the new router to configure it. If you are using BOOTP or RARP  
to resolve the address of the new router, the minimal configuration file  
must also include the IP address to be obtained dynamically using  
BOOTP or RARP.  
You can use the copy running-config tftp command to help you gen-  
erate the configuration file that you will download during the AutoIn-  
stall process.  
Note:  
The existing router might need to forward TFTP requests  
and response packets if the TFTP server is not on the  
same network segment as the new router. When you  
modified the existing router's configuration, you specified  
an IP helper address for this purpose.  
You can save a minimal configuration under a generic newrouter-  
confg file. Use the ip hostcommand in the network-confg or cisco-  
net.cfg file to specify newrouter as the host name with the address you  
dynamically resolve. The new router should then resolve its IP ad  
dress, host name, and minimal configuration automatically. Use Tel-  
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net to connect to the new router from the existing router and use the  
setup facility to configure the rest of the interfaces. For example, th  
line in the network-confg or cisconet.cfg file could be similar to:  
ip host newrouter 131.108.170.1  
This host configuration file contains the minimal set of commands  
needed for AutoInstall using SLARP or BOOTP:  
enable-password letmein  
!
line vty 0  
password letmein  
!
end  
The preceding example shows a minimal configuration for connecting  
from a router one hop away. From this configuration, use the setup fa-  
cility to configure the rest of the interfaces. If the router is more than  
one hop away, you also must include routing information in the mini-  
mal configuration.  
This example minimal network configuration file maps the new  
router's IP address, 131.108.10.2, to the host name newrouter. The  
new router's address was learned via SLARP and is based on the exist-  
ing router's IP address of 131.108.10.1.  
ip host newrouter 131.108.10.2  
Set Up the BOOTP or RARP Server  
If the new router is connected to the existing router using an Ethernet,  
Token Ring, or FDDI interface, you must configure a BOOTP or  
RARP server to map the new router's MAC address to its IP address.  
If the new router is connected to the existing router using a serial line  
with HDLC encapsulation or if you are configuring AutoInstall over  
Frame Relay, these tasks are not required.  
To configure a BOOTP or RARP server, complete one of these tasks:  
1. If BOOTP is to be used to resolve the new router's IP address, con-  
figure your BOOTP server. Refer to your host vendor's manual  
pages and to RFCs 951 and 1395.  
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Chapter 5: Using AutoInstall  
2. If RARP is to be used to resolve the new router's IP address, con-  
figure your RARP server. Refer to your host vendor's manual  
pages and to RFC 903.  
This example host configuration file contains the minimum set of  
commands needed for AutoInstall using RARP. It includes the IP ad-  
dress that will be obtained dynamically via BOOTP or RARP during  
the AutoInstall process. When RARP is used, this extra information is  
needed to specify the proper netmask for the interface.  
interface ethernet 0  
ip address 131.108.10.2 255.255.255.0  
enable-password letmein  
!
line vty 0  
password letmein  
!
end  
Connect the New Router to the Network  
Connect the new router to the network using either an HDLC-encap-  
sulated or Frame Relay-encapsulated serial interface or an Ethernet,  
Token Ring, or FDDI interface. After the router successfully resolves  
its host name, newrouter sends a TFTP broadcast requesting the file  
name-confg or name.cfg. The router name must be in all lowercase,  
even if the true host name is not. The file is downloaded to the new  
router, where the configuration commands take effect immediately. If  
the configuration file is complete, the new router should be fully oper-  
ational. To save the complete configuration to NVRAM, complete  
these tasks in privileged EXEC mode:  
1. Enter privileged mode at the system prompt on the new router.  
enable password  
2. Save the information from the name-config file into your startup  
configuration. This step saves the configuration to NVRAM.  
copy running-config startup-config  
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AI2524 Router Card User’s Manual  
Note:  
Verify that the existing and new routers and/or access  
servers are connected before entering th copy  
running-config startup-config EXEC  
command to save configuration changes. Use the ping  
EXEC command to verify connectivity. If an incorrect  
configuration file is downloaded, the new router will load  
NVRAM configuration information before it can enter  
AutoInstall mode.  
If the configuration file is a minimal configuration file, the new router  
comes up, but with only one interface operational. Complete the fol-  
lowing steps to connect to the new router and configure it:  
1. Establish a Telnet connection to the existing router.  
telnet existing  
2. From the existing router, establish a Telnet connection to the new  
router.  
telnet newrouter  
3. Enter privileged EXEC mode.  
enable password  
4. Enter setup mode to configure the new router.  
setup  
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Chapter 5: Using AutoInstall  
Use Setup for  
Configuration  
Changes  
The setup command facility is an interactive facility that allows you to  
perform first-time configuration and other basic configuration proce-  
dures on all routers. The facility prompts you to enter basic informa-  
tion needed to start a router quickly and uneventfully.  
Although the setup command facility is a quick way to set up a router,  
you can also use it after first-time startup to perform basic configura-  
tion changes. This section focuses on:  
z
z
Using the setup command facility after first-time startup  
Using the streamlined setup facility  
Refer to your hardware platform's user guide for more information on  
using setup for first-time startup.  
Whenever you use the setup command facility, be sure that you know:  
z
z
z
z
z
Router interfaces  
Router protocols  
Bridging setting  
Network addresses for the protocols being configured  
Password strategy for your environment  
Setup Command Facility Task List  
You can perform these tasks to make configuration changes using the  
setup command facility. Both tasks are optional.  
z
z
Use Setup after First-Time Startup  
Use the Streamlined Setup Facility  
Use Setup after First-Time Startup  
The command parser allows you to make very detailed changes to your  
configurations; however, some major configuration changes do not re-  
quire the granularity provided by the command parser. In these cases,  
you can use the setup command facility to make major enhancements  
to your configurations. For example, you might want to use setup to  
add a protocol suite, to make major addressing scheme changes, or to  
configure a newly installed interface. Although you can use the com-  
mand parser to make these major changes, the setup command facility  
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AI2524 Router Card User’s Manual  
provides you with a high-level view of the configuration and guides  
you through the configuration change process.  
Additionally, if you are not familiar with the command parser, the  
setup command facility is a particularly valuable tool because it asks  
you the questions required to make configuration changes.  
Note:  
If you use setup to modify a configuration because you  
have added or modified the hardware, be sure to verify the  
physical connections using the show version  
command. Also, verify the logical port assignments using  
the show running-config command to ensure that  
you configure the proper port. Refer to your platform's  
hardware publications for details on physical and logical  
port assignments.  
To enter the setup command facility, type this command in privileged  
EXEC mode:  
setup  
When you enter the setup command facility after first-time startup, an  
interactive dialog called the System Configuration Dialog appears on  
the system console screen. The System Configuration Dialog guides  
you through the configuration process. It prompts you first for global  
parameters and then for interface parameters. The values shown in  
brackets next to each prompt are the default values last set using either  
the setup command facility or the configurecommand.  
Note:  
The prompts and the order in which they appear on the  
screen vary depending on the platform and the interfaces  
installed in the device.  
You must run through the entire System Configuration Dialog until  
you find the item you intend to change. To accept default settings fo  
items you do not want to change, press <Enter>.  
To return to the privileged EXEC prompt without making changes and  
without running through the entire System Configuration Dialog,  
press <Ctrl-C>.  
The facility also provides help text for each prompt. To access help  
text, press the question mark (?) key at a prompt.  
When you complete your changes, the setup command facility shows  
you the configuration command script created during the setup ses-  
sion. It also asks you if you want to use this configuration. If you an-  
swer Yes, the configuration is saved to NVRAM. If you answer No,  
the configuration is not saved and the process begins again. There is  
no default for this prompt; you must answer either Yes or No.  
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Chapter 5: Using AutoInstall  
Note:  
If any problems exist with the configuration file pointed to  
in NVRAM, or if the ignore NVRAM bit is set in th  
configuration register, the router enters the streamlined  
setup command facility. Refer to Use the Streamlined  
Setup Facility, for more information.  
This example shows how to use the setup command facility to config-  
ure interface serial 0 and to add ARAP and IP/IPX PPP support on the  
asynchronous interfaces:  
Router# setup  
---System Configuration Dialog---  
At any point you may enter a question mark '?' for help.  
Use ctrl-c to abort configuration dialog at any prompt.  
Default settings are in square brackets '[]'.  
Continue with configuration dialog? [yes]:  
First, would you like to see the current interface summary? [yes]:  
Interface  
Ethernet0  
Serial0  
IP-Address  
172.16.72.2 YES  
unassigned YES  
172.16.72.2 YES  
OK?  
Method  
manual  
not set  
not set  
Status  
up  
down  
up  
Protocol  
up  
down  
up  
Serial1  
Configuring global parameters:  
Enter host name [Router]:  
The enable secret is a one-way cryptographic secret used instead of the enable  
password when it exists.  
Enter enable secret [<Use current secret>]:  
The enable password is used when there is no enable secret and when using older  
software and some boot images.  
Enter enable password [ww]:  
Enter virtual terminal password [ww]:  
Configure SNMP Network Management? [yes]:  
Community string [public]:  
Configure DECnet? [no]:  
Configure AppleTalk? [yes]:  
Multizone networks? [no]: yes  
Configure IPX? [yes]:  
Configure IP? [yes]:  
Configure IGRP routing? [yes]:  
Your IGRP autonomous system number [15]:  
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AI2524 Router Card User’s Manual  
Configure Async lines? [yes]:  
Async line speed [9600]: 57600  
Configure for HW flow control? [yes]:  
Configure for modems? [yes/no]: yes  
Configure for default chat script? [yes]: no  
Configure for Dial-in IP SLIP/PPP access? [no]: yes  
Configure for Dynamic IP addresses? [yes]: no  
Configure Default IP addresses? [no]: yes  
Configure for TCP Header Compression? [yes]: no  
Configure for routing updates on async links? [no]:  
Configure for Async IPX? [yes]:  
Configure for Appletalk Remote Access? [yes]:  
AppleTalk Network for ARAP clients [1]: 20  
Zone name for ARAP clients [ARA Dialins]:  
Configuring interface parameters:  
Configuring interface Ethernet0:  
Is this interface in use? [yes]:  
Configure IP on this interface? [yes]:  
IP address for this interface [172.16.72.2]:  
Number of bits in subnet field [8]:  
Class B network is 172.16.0.0, 8 subnet bits; mask is /24  
Configure AppleTalk on this interface? [yes]:  
Extended AppleTalk network? [yes]:  
AppleTalk starting cable range [1]:  
AppleTalk ending cable range [1]:  
AppleTalk zone name [Sales]:  
AppleTalk additional zone name:  
Configure IPX on this interface? [yes]:  
IPX network number [1]:  
Configuring interface Serial0:  
Is this interface in use? [no]: yes  
Configure IP on this interface? [no]: yes  
Configure IP unnumbered on this interface? [no]: yes  
Assign to which interface [Ethernet0]:  
Configure AppleTalk on this interface? [no]: yes  
Extended AppleTalk network? [yes]:  
AppleTalk starting cable range [2]: 3  
AppleTalk ending cable range [3]: 3  
AppleTalk zone name [myzone]: ZZ Serial  
AppleTalk additional zone name:  
Configure IPX on this interface? [no]: yes  
IPX network number [2]: 3  
Configuring interface Serial1:  
Is this interface in use? [yes]:  
Configure IP on this interface? [yes]:  
Configure IP unnumbered on this interface? [yes]:  
Assign to which interface [Ethernet0]:  
Configure AppleTalk on this interface? [yes]:  
Extended AppleTalk network? [yes]:  
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Chapter 5: Using AutoInstall  
AppleTalk starting cable range [2]:  
AppleTalk ending cable range [2]:  
AppleTalk zone name [ZZ Serial]:  
AppleTalk additional zone name:  
Configure IPX on this interface? [yes]:  
IPX network number [2]:  
Configuring interface Async1:  
IPX network number [4]:  
Default client IP address for this interface [none]: 172.16.72.4  
Configuring interface Async2:  
IPX network number [5]:  
]:  
Default client IP address for this interface [172.16.72.5  
Configuring interface Async3:  
IPX network number [6]:  
Default client IP address for this interface [172.16.72.6]:  
Configuring interface Async4:  
IPX network number [7]:  
Default client IP address for this interface [172.16.72.7]:  
Configuring interface Async5:  
IPX network number [8]:  
Default client IP address for this interface [172.16.72.8]:  
Configuring interface Async6:  
IPX network number [9]:  
Default client IP address for this interface [172.16.72.9]:  
Configuring interface Async7:  
IPX network number [A]:  
Default client IP address for this interface [172.16.72.10]:  
Configuring interface Async8:  
IPX network number [B]:  
Default client IP address for this interface [172.16.72.11]:  
Configuring interface Async9:  
IPX network number [C]:  
Default client IP address for this interface [172.16.72.12]:  
Configuring interface Async10:  
IPX network number [D]:  
Default client IP address for this interface [172.16.72.13]:  
Configuring interface Async11:  
IPX network number [E]:  
Default client IP address for this interface [172.16.72.14]:  
Configuring interface Async12:  
IPX network number [F]:  
Default client IP address for this interface [172.16.72.15]:  
Configuring interface Async13:  
IPX network number [10]:  
Default client IP address for this interface [172.16.72.16]:  
Configuring interface Async14:  
IPX network number [11]:  
Default client IP address for this interface [172.16.72.17]:  
Configuring interface Async15:  
IPX network number [12]:  
Default client IP address for this interface [172.16.72.18]:  
Configuring interface Async16:  
IPX network number [13]:  
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AI2524 Router Card User’s Manual  
Default client IP address for this interface [172.16.72.19]:  
The following configuration command script was created:  
hostname Router  
enable secret 5 $1$krIg$emfYm/1OwHVspDuS8Gy0K  
enable password ww  
line vty 0 4  
password ww  
snmp-server community public  
!
no decnet routing  
appletalk routing  
ipx routing  
ip routing  
!
line 1 16  
speed 57600  
flowcontrol hardware  
modem inout  
!
arap network 20 ARA Dialins  
line 1 16  
arap enable  
autoselect  
!
! Turn off IPX to prevent network conflicts.  
interface Ethernet0  
no ipx network  
interface Serial0  
no ipx network  
interface Serial1  
no ipx network  
!
interface Ethernet0  
ip address 172.16.72.2 255.255.255.0  
appletalk cable-range 1-1 1.204  
appletalk zone Sales  
ipx network 1  
no mop enabled  
!
interface Serial0  
no shutdown  
no ip address  
ip unnumbered Ethernet0  
appletalk cable-range 3-3  
appletalk zone ZZ Serial  
ipx network 3  
no mop enabled  
!
interface Serial1  
no ip address  
ip unnumbered Ethernet0  
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Chapter 5: Using AutoInstall  
appletalk cable-range 2-2 2.2  
appletalk zone ZZ Serial  
ipx network 2  
no mop enabled  
!
Interface Async1  
ipx network 4  
ip unnumbered Ethernet0  
async default ip address 172.16.72.4  
async mode interactive  
!
Interface Async2  
ipx network 5  
ip unnumbered Ethernet0  
async default ip address 172.16.72.5  
async mode interactive  
!
Interface Async3  
ipx network 6  
ip unnumbered Ethernet0  
asyncdefault ip address 172.16.72.6  
async mode interactive  
!
Interface Async4  
ipx network 7  
ip unnumbered Ethernet0  
async default ip address 172.16.72.7  
async mode interactive  
async dynamic address  
!
Interface Async5  
ipx network 8  
ip unnumbered Ethernet0  
async default ip address 172.16.72.8  
async mode interactive  
!
Interface Async6  
ipx network 9  
ip unnumbered Ethernet0  
async default ip address 172.16.72.9  
async mode interactive  
!
Interface Async7  
ipx network A  
ip unnumbered Ethernet0  
async default ip address 172.16.72.10  
asyncmode interactive  
!
Interface Async8  
ipx network B  
ip unnumbered Ethernet0  
async default ip address 172.16.72.11  
async mode interactive  
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AI2524 Router Card User’s Manual  
!
Interface Async9  
ipx network C  
ip unnumbered Ethernet0  
async default ip address 172.16.72.12  
async mode interactive  
!
Interface Async10  
ipx network D  
ip unnumbered Ethernet0  
async default ip address 172.16.72.13  
async mode interactive  
!
Interface Async11  
ipx network E  
ip unnumbered Ethernet0  
async default ip address 172.16.72.14  
async mode interactive  
!
Interface Async12  
ipx network F  
ip unnumbered Ethernet0  
async default ip address 172.16.72.15  
async mode interactive  
!
Interface Async13  
ipx network 10  
ip unnumbered Ethernet0  
async default ip address 172.16.72.16  
async mode interactive  
!
Interface Async14  
ipx network 11  
ip unnumbered Ethernet0  
async default ip address 172.16.72.17  
async mode interactive  
!
Interface Async15  
ipx network 12  
ip unnumbered Ethernet0  
async default ip address 172.16.72.18  
async mode interactive  
!
Interface Async16  
ipx network 13  
ip unnumbered Ethernet0  
async default ip address 172.16.72.19  
async mode interactive  
!
router igrp 15  
network 172.16.0.0  
!
end  
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Chapter 5: Using AutoInstall  
Use this configuration? [yes/no]: yes  
Building configuration...  
Use the enabled mode 'configure' command to modify this configuration.  
Router#  
Use the Streamlined Setup Facility  
The streamlined setup command facility is available only if you  
router is running from ROM monitor and has RXBOOT ROMs in-  
stalled. The streamlined setup command facility permits your router to  
load a system image from a network server when there are problems  
with the startup configuration. The Cisco IOS software automatically  
puts you in the streamlined setup command facility when your router  
is accidentally or intentionally rebooted (or you are attempting to load  
a system image from a network server) after:  
z
You issued an erase startup-config command, thereby  
deleting the startup configuration file.  
z
You have bit 6 (ignore NVRAM configuration) set in the config-  
uration register.  
z
z
Your startup configuration has been corrupted.  
You configured the router to boot from a network server (the last  
four bits of the configuration register are not equal to 0 or 1) and  
there is no Flash or no valid image in Flash.  
z
You configured the router to boot the RXBOOT image.  
The streamlined setup command facility differs from the standard  
setup command facility because the streamlined facility does not ask  
you to configure global router parameters. You are prompted only to  
configure interface parameters, which permit your router to boot.  
This example shows a router entering the streamlined setup command  
facility:  
— System Configuration Dialog —  
Default settings are in square brackets '[]'.  
Configuring interface IP parameters for netbooting:  
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AI2524 Router Card User’s Manual  
Note:  
The message Configuring interface IP parameters for  
netbooting only appears if you are booting over a network  
server and your configuration has insufficient IP  
information.  
The streamlined setup command facility continues, prompting you fo  
interface parameters for each installed interface. The facility asks if an  
interface is in use. If so, the facility prompts you to provide an IP ad  
dress and subnet mask bits for the interface. Enter the subnet mask bits  
as a decimal value, such as 5.  
This example shows the portion of the streamlined setup command fa-  
cility that prompts for interface parameters. In the example, the facility  
is prompting for Ethernet0 interface parameters and Serial0 interface  
parameters:  
Configuring interface Ethernet0:  
Is this interface in use? [yes]:  
Configure IP on this interface? [yes]:  
IP address for this interface: 192.195.78.50  
Number of bits in subnet field [0]: 5  
Class C network is 192.195.78.0, 5 subnet bits; mask is 255.255.255.248  
Configuring interface Serial0: Is this interface in use? [yes]:  
Configure IP on this interface? [yes]:  
IP address for this interface: 192.195.78.34  
Number of bits in subnet field [5]:  
Class C network is 192.195.78.0, 5 subnet bits; mask is 255.255.255.248  
The configuration information you provide on this screen is temporary  
and exists only so you can boot your system. When you reload the sys-  
tem, your original configuration remains intact. If your startup config-  
uration is corrupted, enter the setup command facility and configur  
the basic parameters. Then issue the copy running-config  
startup-config command to write this configuration to  
NVRAM.  
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Chapter 6: Using the System Configuration Dialog  
Chapter 6: Using the System  
Configuration Dialog  
Introduction  
This chapter describes the System Configuration Dialog process using  
a sample configuration. The System Configuration Dialog can be  
manually used to configure the router instead of using AutoInstall.  
System  
Configuration  
Dialog  
If you do not plan to use AutoInstall (refer to the Using AutoInstall  
chapter), make sure all the WAN cables are disconnected from the  
router. This will prevent the router from attempting to the run the Au-  
toInstall process. The router will attempt to run AutoInstall whenever  
you power it on if there is a WAN connection on both ends and the  
router does not haveaconfiguration file stored in NVRAM. It can take  
several minutes for the router to determine that AutoInstall is not set  
up to a remote TCP/IP host.  
If your router does not have a configuration (setup) file and you are not  
using AutoInstall, the router will automatically start the setup com  
mand facility. An interactive dialog called the System Configuration  
Dialog appears on the console screen. This dialog helps you navigat  
through the configuration process by prompting you for the configura-  
tion information necessary for the router to operate.  
Many prompts in the System Configuration Dialog include default re-  
sponses, which are included in square brackets following the question.  
To accept a default answer, press <Enter>. Otherwise, type your re-  
sponse.  
This section gives an example configuration using the System Config-  
uration Dialog. When you are configuring your router, respond as ap  
propriate for your network.  
At any time during the System Configuration Dialog, you can request  
help by typing a question mark (?) at a prompt.  
Before proceeding with the System Configuration Dialog, obtain from  
your system administrator the node addresses and the number of bits  
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AI2524 Router Card User’s Manual  
in the subnet field (if applicable) of the Ethernet and synchronous se-  
rial ports.  
Take these steps to configure the router using the System Configura  
tion Dialog:  
1. Connect a console terminal to the console connector on  
theAI2524.  
Note:  
The default parameters for the console port are 9600  
baud, 8 data bits, no parity, and 2 stop bits.  
2. After about 30 seconds, information similar to the following is dis-  
played on the console screen.  
Note:  
The messages displayed vary, depending on the Cisco IOS  
feature set you selected. The screen displays in this section  
are for reference only and may not exactly reflect the  
screen displays on your console.  
When you see this information, you have successfully booted your  
router:  
System Bootstrap, Version X.X(XXXX) [XXXXX XX], RELEASE SOFTWARE  
Copyright (c) 1986-1992 by Cisco Systems 2500 processor with 4096 Kbytes of main  
memory  
Notice: NVRAM invalid, possibly due to write erase.  
F3: 5797928+162396+258800 at 0x3000060  
Restricted Rights Legend  
Use, duplication, or disclosure by the Government is subject to restrictions as  
set forth in subparagraph (c) of the Commercial Computer Software - Restricted  
Rights clause at FAR sec. 52.227-19 and subparagraph (c) (1) (ii) of the Right in  
Technical Data and Computer Software clause at DFARS sec. 252.227-7013.  
Cisco Systems, Inc.  
170 West Tasman Drive  
San Jose, California 95134-1706  
Cisco Internetwork Operating System Software  
IOS (tm) X000 Software (IGS-J-L), Version XX.X(XXXX) [XXXXX XXX]  
Copyright (c) 1986-1996 by Cisco Systems, Inc.  
Compiled Fri 20-Oct-95 16:02 by XXXXX  
Image text-base: 0x03030FC0, data-base: 0x00001000  
Cisco 252X (68030) processor (revision A) with 4092K/2048K bytes of memory.  
Processor board ID 00000000  
Bridging software.  
SuperLAT software copyright 1990 by Meridian Technology Corp).  
X.25 software, Version X.X, NET2, BFE and GOSIP compliant.  
TN3270 Emulation software (copyright 1994 by TGV Inc).  
Basic Rate ISDN software, Version X.X.  
1 Ethernet/IEEE 802.3 interface.  
2 Serial network interfaces.  
1 ISDN Basic Rate interface.  
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Chapter 6: Using the System Configuration Dialog  
32K bytes of non-volatile configuration memory.  
8192K bytes of processor board System flash (Read ONLY)  
Notice: NVRAM invalid, possibly due to write erase.  
--- System Configuration Dialog ---  
At any point you may enter a question mark '?' for help. Refer to the 'Getting  
Started' Guide for additional help. Use ctrl-c to abort configuration dialog at  
any prompt. Default settings are in square brackets '[]'.  
Would you like to enter the initial configuration dialog? [yes]:  
3. Press <Enter> or type yes to begin the configuration process.  
4. When the System Configuration Dialog asks whether you want to  
view the current interface summary, press <Enter> or type yes.  
:
First, would you like to see the current interface summary? [yes]:  
Any interface listed with OK? value "NO" does not have a valid configuration  
Interface  
Ethernet0  
BRI0  
Serial0  
Serial1  
IP-Address OK?  
unassigned NO  
unassigned NO  
unassigned NO  
unassigned NO  
Method  
Status  
Protocol  
down  
up  
down  
down  
not set up  
not set up  
not set down  
not set down  
5. Configure the global parameters. Choose which protocols to sup  
port on the Ethernet interface. For IP installations, you can press  
<Enter> to accept the default values (in brackets) for most of the  
questions. A typical configuration is:  
:
Configuring global parameters:  
Enter host name [Router]:  
Next, you are prompted to enter an enable secret password. There are  
two types of privileged-level passwords:  
z
z
Enable secret password (a very secure, encrypted password  
Enable password (a less secure, nonencrypted password)  
The enable password is used when the enable secret password does not  
exist.  
For maximum security, be sure the passwords are different. If you  
enter the same password for both, the router will accept yourentry, but  
will display a warning message indicating that you should enter a dif-  
ferent password.  
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AI2524 Router Card User’s Manual  
6. Enter an enable secret password:  
The enable secret is a one-way cryptographic secret used instead of the enable  
password when it exists.  
Enter enable secret: pail  
The enable password is used when there is no enable secret and when using older  
software and some boot images.  
7. Enter the enable and virtual terminal passwords:  
Enter enable password: shovel  
Enter virtual terminal password: vterm1  
8. Press <Enter> to accept Simple Network Management Protocol  
(SNMP) management, or type no to refuse it:  
Configure SNMP Network Management? [yes]: no  
9.9.  
9. Configure the appropriate protocols for your router:  
Configure Vines? [no]:  
Configure LAT? [no]:  
Configure AppleTalk? [no]: yes  
Multizone networks? [no]: yes  
Configure DECnet? [no]:  
Configure IP? [yes]:  
Configure IGRP routing? [yes]:  
Your IGRP autonomous system number [1]: 15  
Configure CLNS? [no]:  
Configure bridging? [no]:  
Configure IPX? [no]: yes  
Configure XNS? [no]:  
Configure Apollo? [no]:  
10. Enter the ISDN BRI switch type for the router. The ISDN switch  
type appropriate for the router depends on the ISDN provider's  
equipment.  
Enter ISDN BRI Switch Type [none]: basic-5ess  
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Chapter 6: Using the System Configuration Dialog  
Refer to this table for ISDN switch types:  
Country  
ISDN SwitchType  
Description  
Australia  
Europe  
basic-ts013  
basic-1tr6  
basic-nwnet3  
basic-net3  
vn2  
Australian TS013 switches  
German 1TR6 ISDN switches  
Norwegian NET3 ISDN switches (phase 1)  
NET3 ISDN switches (UK and others)  
French VN2 ISDN switches  
French VN3 ISDN switches  
Japanese NTT ISDN switches  
AT&T basic rate switches  
vn3  
Japan  
ntt  
North  
America  
basic-5ess  
basic-dms100  
basic-ni1  
basic-nznet3  
NT DMS-100 basic rate switches  
National ISDN-1 switches  
New  
New Zealand NET3 switches  
Zealand  
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AI2524 Router Card User’s Manual  
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Chapter 7: Manually Loading System Images  
Chapter 7: Manually Loading System  
Images  
Introduction  
This chapter outlines the steps to load and maintain system images,  
microcode images, and configuration files. These instructions describe  
copying system images from routers to network servers (and vice  
versa), displaying and comparing different configuration files, and  
listing the Cisco IOS software version running on the router.  
This chapter also explains how to manually load system images from  
ROM monitor so you can successfully boot the router when typical  
startup processes malfunction.  
z
z
System images contain the system software.  
Microcode images contain microcode to be downloaded to various  
hardware devices.  
z
Configuration files contain commands entered to customize th  
function of the Cisco IOS software.  
To benefit most from these instructions, your router must contain  
minimal configuration that allows you to interact with the system soft-  
ware. You can create a basic configuration file using the setup com  
mand facility. See the user guide for your hardware platform for more  
information on using setup at first-time startup. Refer to Use Setup  
after First-Time Startup, for more information.  
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Image and  
Configuration  
File Load Task  
List  
To load and maintain system images, microcode images, and configu-  
ration files needed for startup, complete the tasks outlined in the next  
section.  
Note:  
The organization of tasks assumes you have a minimal  
configuration that you want to modify.  
The tasks in the first three sections are typical for all routers. Perform  
the remaining tasks as needed for your routing environment.  
z
z
z
z
z
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Chapter 7: Manually Loading System Images  
Retrieve System  
Images and  
Configuration  
Files  
If you have a minimal configuration that allows you to interact with  
the system software, you can retrieve other system images and config-  
uration files from a network server and modify them for use in you  
routing environment. This section describes tasks related to retrieving  
system images and configuration files for modification.  
Retrieve System Images and Configuration File Task List  
When retrieving system images and configuration files, perform these  
tasks. The first two are required; the rest are optional.  
z
z
z
z
z
z
z
Copy System Images from a Network Server to Flash Memory  
Copy System Images from a Network Server to Flash  
Memory  
You can copy system images from a Trivial File Transfer Protocol  
(TFTP) server to Flash memory:  
1. Make a backup copy of the current system software image. Refer  
for more information.  
2. Copy a system image to Flash memory.  
copy tftp flash  
3. When prompted, enter the server IP address or domain name.  
ip-address or name  
4. If prompted, enter the server system filename.  
filename  
5. If prompted, enter the Flash memory device that is to receive th  
copy of the system image.  
device  
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Note:  
Be sure there is enough available space before copying a  
file to Flash memory. Use the show flash command  
and compare the size of the file you want to copy to the  
amount of available Flash memory shown. If the space  
available is less than the space required by the file you  
want to copy, the copy process will continue, but the entire  
file will not be copied into Flash memory. The failure  
message  
will  
buffer overflow - xxxx/ xxxx  
appear, where xxxx/xxxxis the number of bytes read in  
relation to the number of bytes available.  
When you enter the copy tftp flash command, the system  
prompts you for the IP address or domain name of the TFTP server.  
This server can be another router serving ROM or Flash system soft  
ware images. The system then prompts you for the filename of the  
software image to copy.  
For the copy tftp flash and copy tftp file-idcom-  
mands, the router gives you the option of erasing the existing Flash  
memory before writing to it when there is space available to do so. If  
there is no free Flash memory available, or if the Flash memory has  
never been written to, you must run the erase routine before copying  
new files. The system will inform you of these conditions and prompt  
you for a response.  
The file-id argument of the copy tftp file-idcommand  
specifies a device and filename as the destination of the copy opera-  
tion. You can omit the device, entering only copy tftpfile-  
name. When you omit the device, the system uses the default device  
specified by th cdcommand.  
If you try to copy a file into Flash memory and that file is already in  
Flash memory, a prompt informs you that a file with the same nam  
already exists. The new file replaces the existing file. The first copy o  
the file still resides within Flash memory, but it is rendered unusable  
in favor of the newer version, and is listed with the deleted tag when  
you use the show flash command. If you terminate the copy pro-  
cess, the newer file is marked deleted because the entire file was not  
copied and is invalid. In this case, the original file in Flash memory is  
still available to the system.  
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Chapter 7: Manually Loading System Images  
This example demonstrates the use of thecopy tftp flashcom-  
mand to copy a system image named gs7-k when Flash memory is too  
full to copy the file. The filename gs7-k can be in lowercase or upper-  
case; the system sees GS7-K as gs7-k. If more than one file of the sam  
name is copied to Flash, regardless of case, the last file copied is th  
valid file.  
env-chassis# copy tftp flash  
IP address or name of remote host [255.255.255.255]? dirt  
Translating "DIRT"...domain server (255.255.255.255) [OK]  
Name of file to copy? gs7-k  
Copy gs7-k from 131.108.13.111 into flash memory? [confirm]  
Flash is filled to capacity.  
Erasure is needed before flash may be written.  
Erase flash before writing? [confirm]  
Erasing flash EPROMs bank 0  
Zeroing bank...zzzzzzzzzzzzzzzz  
Verify zeroed...vvvvvvvvvvvvvvvv  
Erasing bank...eeeeeeeeeeeeeeee  
Erasing flash EPROMs bank 1  
Zeroing bank...zzzzzzzzzzzzzzzz  
Verify zeroed...vvvvvvvvvvvvvvvv  
Erasing bank...eeeeeeeeeeeeeeee  
Erasing flash EPROMs bank 2  
Zeroing bank...zzzzzzzzzzzzzzzz  
Verify zeroed...vvvvvvvvvvvvvvvv  
Erasing bank...eeeeeeeeeeeeeeee  
Erasing flash EPROMs bank 3  
Zeroing bank...zzzzzzzzzzzzzzzz  
Verify zeroed...vvvvvvvvvvvvvvvv  
Erasing bank...eeeeeeeeeeeeeeee  
Loading from 131.108.1.111:!!!!...  
[OK - 1906676/4194240 bytes  
Verifying via checksum...  
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv  
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv  
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvv  
Flash verification successful. Length = 1906676, checksum = 0x12AD  
The exclamation point ( ) indicates that the copy process is taking  
!
place. Each exclamation point ( ) indicates that 10packets have been  
!
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AI2524 Router Card User’s Manual  
transferred successfully. A series of characters indicates that a  
V
checksum verification of the image is occurring after the image is writ-  
ten to Flash memory.  
Note:  
If you enter nafter the  
Erase flash before  
prompt, the copy process continues. If you  
writing?  
enter yand confirm the erasure, the erase routine begins.  
Be sure you have enough Flash memory space before  
entering nat the erasure prompt.  
This example demonstrates the process of copying a system image  
named gs7-k into the current Flash configuration when a file named  
gs7-k already exists:  
env-chassis# copy tftp flash  
IP address or name of remote host [131.108.13.111]?  
Name of file to copy? gs7-k  
File gs7-k already exists; it will be invalidated!  
Copy gs7-k from 131.108.13.111 into flash memory? [confirm]  
2287500 bytes available for writing without erasure.  
Erase flash before writing? [confirm]n  
Loading from 131.108.1.111:!!!!...  
[OK - 1906676/2287500 bytes]  
Verifying via checksum...  
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv  
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv  
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvv  
Flash verification successful. Length = 1902192, checksum = 0x12AD  
The exclamation point ( ) indicates that the copy process is taking  
!
place. Each exclamation point ( ) indicates that 10packets have been  
!
transferred successfully. A series of characters indicates that a  
V
checksum verification of the image is occurring after the image is writ-  
ten to Flash memory.  
In this example, the Flash security jumper is not installed, so you can-  
not write files to Flash memory. Also, be sure to set the write-protect  
switch on the Flash memory card to unprotected.  
Router# copy tftp flash  
Flash: embedded flash security jumper(12V) must be strapped to modify flash memory  
Note:  
To terminate this copy process, press <Ctrl-^> (th  
<Ctrl>, <Shift>, and <6> keys on a standard keyboard)  
simultaneously. Although the process terminates, the  
partial file copied before the termination remains until th  
entire Flash memory is erased.  
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Chapter 7: Manually Loading System Images  
You can copy normal or compressed images to Flash memory. You  
can produce a compressed system image on any UNIX platform using  
the compresscommand. Refer to your UNIX platform's documen-  
tation for the exact usage of the compresscommand.  
This example shows how to copy a system image named IJ09140Z  
into the current Flash configuration:  
Router# copy tftp flash  
IP address or name of remote host [255.255.255.255]? server1  
Name of tftp filename to copy into flash []? IJ09140Z  
copy IJ09140Z from 131.131.101.101 into flash memory? [confirm]  
xxxxxxxx bytes available for writing without erasure.  
erase flash before writing? [confirm]  
Clearing and initializing flash memory (please wait)####...  
Loading from 101.2.13.110:!!!!...  
[OK - 324572/524212 bytes]  
Verifying checksum...  
VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV... Flash verification successful. Length =  
1204637, checksum = 0x95D  
The series of pound signs ) indicates that each Flash device is being  
#
cleared and initialized—one per device. Different platforms use differ-  
ent methods to indicate that Flash is clearing.  
The exclamation point ( ) indicates that the copy process is taking  
!
place. Each exclamation point ) indicates that ten packets have been  
!
transferred successfully.  
The series of characters indicates that a checksum is being calcu-  
V
lated.  
An indicates an out-of-order packet.  
O
A period ( ) indicates a timeout. The last line in the sample configu-  
.
ration indicates that the copy is successful.  
Copy Configuration Files from a Network Server to the  
Router  
You can copy configuration files from a TFTP server to the router.  
You might use this process to restore a configuration file to the router  
if you have backed up the file to a server. If you replace a router and  
want to use the configuration file that you created for the original, you  
can restore that file instead of recreating it. You can also use this pro  
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AI2524 Router Card User’s Manual  
cess to copy a different configuration to the router that is stored on a  
network server.  
You can copy a configuration file from a TFTP server to the running  
configuration or to the startup configuration. When you copy a config-  
uration file to the running configuration, you copy to and run the file  
from RAM.  
When you copy a configuration file to the startup configuration, you  
copy it to the nonvolatile random-access memory (NVRAM).  
To copy a configuration file from a TFTP server to the router, com-  
plete these tasks from EXEC mode:  
1. Copy a file from a TFTP server to the router.  
copy tftp {running-config | startup-config}  
2. When prompted, enter the server IP address or domain name.  
{ip-address | name}  
3. If prompted, enter the filename of the server system image.  
filename  
Change the Buffer Size for Loading Configuration Files  
The buffer that holds the configuration commands is generally the size  
of NVRAM. Complex configurations might need a larger configura  
tion file buffer size. To change the buffer size:  
1. Enter configuration mode from the terminal.  
configure terminal  
2. Change the buffer size to use for booting a host or network config-  
uration file from a network server.  
boot buffersize bytes  
3. To exit configuration mode, press <Ctrl-Z>.  
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Chapter 7: Manually Loading System Images  
4. Save the configuration file to your startup configuration. This step  
saves the configuration to NVRAM.  
copy running-config startup-config  
In this example, the buffer size is set to 50000 bytes:  
Router1# configure terminal  
Router1(config)# boot buffersize 50000  
^Z  
Router1# copy running-config startup-config  
Verify the Image in Flash Memory  
Before booting from Flash memory, verify that the checksum of the  
image in Flash memory matches the checksum listed in the README  
file that was distributed with the system software image. The check  
sum of the image in Flash memory is displayed at the bottom of the  
screen when you issue th copy tftp flash command. The RE  
ADME file is copied to the network server automatically when you in-  
stall the system software image on the server.  
Note:  
If the checksum value does not match the value in the  
README  
file, do not reboot the router. Instead, issue the  
copycommand and compare the checksums again. If the  
checksum is repeatedly wrong, copy the original system  
software image back into Flash memory before you reboot  
the router from Flash memory. If you have a corrupted  
image in Flash memory and try to boot from Flash, the  
router will start the system image contained in ROM  
(assuming that booting from a network server is not  
configured). If ROM does not contain a fully functional  
system image, the router will not function and must be  
reconfigured through a direct console port connection.  
Display System Image and Configuration Information  
Perform these tasks in EXEC mode to display information about sys-  
tem software, system image files, and configuration files:  
1. List information about Flash memory, including system image  
filenames and amounts of used and remaining memory.  
show flash  
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AI2524 Router Card User’s Manual  
2. List information about Flash memory, including system image  
filenames, amounts of memory used and remaining, and Flash par-  
titions.  
show flash [all | chips | detailed | err |  
partition number [all | chips | detailed |  
err] | summary]  
3. View the console output generated during the Flash load helpe  
operation.  
show flh-log  
4. List the configuration information in running memory.  
show running-config  
5. List the startup configuration information. The startup configura-  
tion is usually NVRAM.  
show startup-config  
6. List the system software release version, configuration register  
setting, and so on.  
show version  
You can also use th ocommand in ROM monitor mode to list th  
configuration register settings on some models.  
The Flash memory content listing does not include the checksum of in-  
dividual files. To recompute and verify the image checksum after th  
image is copied into Flash memory, type the following in EXEC  
mode:  
verify flash  
When you enter this command, the screen prompts you for the file-  
name to verify. By default, it prompts for the last (most recent) file in  
Flash. Press <Enter> to recompute the default file checksum, or enter  
the filename of a different file at the prompt. Note that the checksum  
for microcode images is always 0x0000.  
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Chapter 7: Manually Loading System Images  
This example illustrates how to use this command:  
Router# verify flash  
Name of file to verify [gsxx]?  
Verifying via checksum...  
vvvvvvvvvvvvvvvvvvvvvvvvvvvvv  
Flash verification successful. Length = 1923712, checksum = 0xA0C1  
Router#  
Reexecute the Configuration Commands in Startup  
Configuration  
You can reexecute the configuration commands stored in NVRAM.  
To reexecute the commands located in the startup configuration, type  
this command in privileged EXEC mode:  
configure memory  
Clear the Configuration Information  
To clear the contents of your startup configuration, type this command  
in EXEC mode:  
erase startup-config  
If you try to erase or delete the configuration file specified by the  
CONFIG_FILE or BOOTLDR environment variable, the system  
prompts you to confirm the deletion. Also, if you try to erase or delete  
the last valid system image specified in the BOOT environment vari  
able, the system prompts you to confirm this deletion.  
This example erases the myconfig file from a Flash memory card in-  
serted in slot 0:  
Router# erase slot0:myconfig  
This example deletes the myconfig file from a Flash memory card in-  
serted in slot 0:  
Router# delete slot0:myconfig  
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Perform General  
Startup Tasks  
When modifying your routing environment, you perform general star-  
tup tasks. For example, to modify a configuration file, you enter con-  
figuration mode. You also modify the configuration register boot field  
to tell the router if and how to load a system image upon startup. Also,  
instead of using the default system image and configuration file to start  
up, you can specify a particular system image and configuration file  
that the router uses to start up.  
General Startup Task List  
General startup tasks include:  
z
z
z
Enter Configuration Mode and Select a Configuration Source  
Enter Configuration Mode and Select a Configuration  
Source  
To enter configuration mode, enter th configurecommand at the  
privileged EXEC prompt. The Cisco IOS software responds with this  
prompt by asking you to specify the terminal or memory or a file  
stored on a network server (network) as the source of configuration  
commands:  
Configuring from terminal, memory, or network [terminal]?  
These methods are described in these sections:  
z
z
z
The Cisco IOS software accepts one configuration command per line.  
You can enter as many configuration commands as you want.  
You can add comments to a configuration file describing the com-  
mands you have entered. Precede a comment with an exclamation  
point (!). Because comments are not stored in NVRAM or in the active  
copy of the configuration file, comments do not appear when you list  
the active configuration with th show running-config EXEC  
command. Also, when the startup configuration is NVRAM, com-  
ments do not show up when you list the startup configuration with th  
show startup-configEXEC command. Comments are stripped  
out of the configuration file when it is loaded onto the router. How-  
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Chapter 7: Manually Loading System Images  
ever, you can list the comments in configuration files stored on a TFTP  
server.  
Configure the Cisco IOS software from the Terminal  
When you configure the software from the terminal, it executes the  
commands you enter at the system prompts. To configure the software  
from the terminal:  
1. Enter configuration mode and select the terminal option.  
configure terminal  
2. Enter the necessary configuration commands.  
3. To exit configuration mode, press <Ctrl-Z>.  
4. Save the configuration file to your startup configuration. This step  
saves the configuration to NVRAM.  
copy running-config startup-config  
In this example, the software is configured from the terminal. The  
comment  
The following command provides the router  
identifies the purpose of the next command line. The  
host name  
hostnamecommand changes the router name from router1 to  
router2. By pressing <Ctrl-Z>, the user quits configuration mode. Fi-  
nally, the copy running-config startup-config com-  
mand saves the current configuration to the startup configuration.  
Router1# configure terminal  
Router1(config)#  
! The following command provides the router host name.  
Router1(config)# hostname router2  
^Z  
Router2# copy running-config startup-config  
When the startup configuration is NVRAM, it stores the current con-  
figuration information in text format as configuration commands, re-  
cording only nondefault settings. The memory is checksummed to  
guard against corrupted data.  
The startup software always checks for configuration information in  
NVRAM. If NVRAM holds valid configuration commands, the Cisco  
IOS software executes the commands automatically at startup. If th  
software detects a problem with NVRAM or the configuration it con-  
tains, it enters setup mode and prompts for configuration. Problems  
can include a bad checksum for the information in NVRAM or the ab-  
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AI2524 Router Card User’s Manual  
sence of critical configuration information. Refer to Use Setup for  
Configuration Changes, for details on the setup command facility.  
Configure the Cisco IOS software from Memory  
To configure the software to execute the commands located in  
NVRAM or to execute the configuration specified by the  
CONFIG_FILE environment variable, type this command in privi-  
leged EXEC mode:  
configure memory  
Configure the Cisco IOS software from the Network  
You can configure the software by retrieving and modifying a config-  
uration file stored on one of your network servers:  
1. Enter configuration mode with the network option.  
copy tftp running-config  
2. At the system prompt, select a network or host configuration file.  
The network configuration file contains commands that apply to  
all network servers and terminal servers on the network. The host  
configuration file contains commands that apply to one network  
server in particular.  
{host | network}  
3. At the system prompt, enter the optional IP address of the remote  
host from which you are retrieving the configuration file.  
ip-address  
4. At the system prompt, enter the name of the configuration file or  
accept the default name.  
filename  
5. Confirm the configuration filename that the system supplies.  
y
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Chapter 7: Manually Loading System Images  
In this example, the software is configured from the file tokyo-config  
at IP address 131.108.2.155:  
Router1# copy tftp running-config  
Host or network configuration file [host]?  
IP address of remote host [255.255.255.255]? 131.108.2.155  
Name of configuration file [tokyo-confg]?  
Configure using tokyo-confg from 131.108.2.155? [confirm] y  
Booting tokyo-confg from 131.108.2.155:!!!  
[OK - 874/16000 bytes]  
Copy a Configuration File Directly to the Startup  
Configuration  
You can copy a configuration file directly to your startup configura-  
tion without affecting the running configuration. This task loads a con-  
figuration file directly into NVRAM in a location specified by th  
CONFIG_FILE environment variable.  
To copy a configuration file directly to the startup configuration, type  
this command in EXEC mode:  
copy tftp startup-config  
Modify the Configuration Register Boot Field  
The configuration register boot field determines whether the router  
loads an operating system image and, if so, where it obtains this sys-  
tem image. The next sections describe the process for using the con-  
figuration register boot field, your process for setting this field, and the  
tasks you must perform to modify the configuration register boot field.  
How the Router Uses the Boot Field  
The lowest four bits of the 16-bit configuration register (bits 3, 2, 1,  
and 0) form the boot field. These boot field values determine whether  
the router loads an operating system and where it obtains the system  
image:  
z
When the entire boot field equals 0-0-0-0, the router does not load  
a system image. Instead, it enters ROM monitor or "maintenance"  
mode from which you can enter ROM monitor commands to man-  
ually load a system image.  
z
When the entire boot field equals 0-0-0-1, the router loads the sys-  
tem image found in boot ROMs.  
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z
When the entire boot field equals a value between 0-0-1-0 and  
1-1-1-1, the router loads the system image specified by boot sys-  
tem commands in the startup configuration file. When the startup  
configuration file does not contain boot system commands, th  
router loads a default system image stored on a network server.  
When loading a default system image from a network server, the  
router uses the configuration register settings to determine the default  
system image filename for booting from a network server. The router  
forms the default boot filename by starting with the word cisco and  
then appending the octal equivalent of the boot field number in th  
configuration register, followed by a hyphen (-) and the processor type  
name (cisconn-cpu). See the appropriate hardware installation guide  
for details on the configuration register and default filename.  
Setting the Boot Field  
You must correctly set the configuration register boot field to ensure  
that your router loads the operating system image as you intend. To set  
the boot field:  
1. Obtain the current configuration register setting. This setting is  
hexadecimal value.  
2. Modify the current configuration register setting to reflect the way  
you want to load a system image. To do so, change the least sig-  
nificant hexadecimal digit to:  
0 to load the system image manually using thebootcommand in  
ROM monitor mode.  
1 to load the system image from boot ROMs.  
2 through F to load the system image from bootsystem com-  
mands in the startup configuration file or from a default system  
image stored on a network server.  
For example, if the current configuration register setting is 0x101 and  
you want to load a system image from boot system commands in the  
startup configuration file, you would change the configuration register  
setting to 0x102.  
1. Reboot the router to make your changes to the configuration reg-  
ister take effect.  
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Chapter 7: Manually Loading System Images  
Perform the Boot Field Modification Tasks  
You modify the boot field from the hardware configuration register or  
the software configuration register, depending on the platform.  
The hardware configuration register can be changed only on the pro-  
cessor card or with dual in-line package (DIP) switches located at the  
back of the router. For information on modifying the hardware config-  
uration register, refer to the appropriate hardware installation guide.  
To modify the software configuration register boot field, complet  
these tasks:  
1. Obtain the current configuration register setting.  
show version  
2. Enter configuration mode, selecting the terminal option.  
configure terminal  
3. Modify the existing configuration register setting to reflect the  
way in which you want to load a system image.  
config-register value  
4. To exit configuration mode, press <Ctrl-Z>.  
5. Reboot the router to make your changes take effect.  
reload  
Use the show versionEXEC command to display the current con-  
figuration register setting. In ROM monitor mode, use the o command  
to list the value of the configuration register boot field.  
In this example, the show versioncommand indicates the current  
configuration register is set so the router does not automatically load  
an operating system image. Instead, it enters ROM monitor mode and  
waits for user-entered ROM monitor commands. The new setting in  
structs the router to a load a system image from commands in the star-  
tup configuration file or from a default system image stored on a  
network server.  
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Router1# show version  
GS Software, Version 9.0(1)  
Copyright (c) 1986-1992 by Cisco Systems, Inc.  
Compiled Fri 14-Feb-92 12:37  
System Bootstrap, Version 4.3  
Router1 uptime is 2 days, 10 hours, 0 minute  
System restarted by reload  
System image file is unknown, booted via tftp from 131.108.13.111  
Host configuration file is "thor-boots", booted via tftp from 131.108.13.111  
Network configuration file is "network-confg", booted via tftp from 131.108.13.111  
CSC3 (68020) processor with 4096K bytes of memory.  
X.25 software.  
Bridging software.  
1 MCI controller (2 Ethernet, 2 Serial).  
2 Ethernet/IEEE 802.3 interface.  
2 Serial network interface.  
32K bytes of non-volatile configuration memory.  
Configuration register is 0x0  
Router1# configure terminal  
Router1(config)# config-register 0xF  
^Z  
Router1# reload  
Specify the Startup Configuration File  
Configuration files can be stored on network servers. You can config-  
ure the router to automatically request and receive two configuration  
files from the network server at startup:  
z
z
Network configuration fil  
Host configuration file  
The server first attempts to load the network configuration file. This  
file contains information shared among several routers. For example,  
you can use it to provide mapping between IP addresses and host  
names.  
The second file the server attempts to load is the host configuration  
file, containing commands applicable to one router in particular. Both  
the network and host configuration files must reside on a network  
server reachable via TFTP and must be readable.  
You can specify an ordered list of network configuration and host con-  
figuration filenames. The Cisco IOS software scans this list until it  
successfully loads the appropriate network or host configuration file.  
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Chapter 7: Manually Loading System Images  
Specify the Startup Configuration File Task List  
To specify a startup configuration file, perform either the first two  
tasks or the third task:  
z
z
Download the Network Configuration File  
Download the Network Configuration File  
To configure the Cisco IOS software to download a network configu  
ration file from a server at startup:  
1. Enter configuration mode from the terminal.  
configure terminal  
2. Enter the network configuration filename to download a file using  
TFTP.  
boot network tftp filename [ip-address]}  
3. Enable the router to automatically load the network file upon re  
start.  
service config  
4. To exit configuration mode, press <Ctrl-Z>.  
1. Save the configuration file to your startup configuration. On most  
platforms, this step saves the configuration to NVRAM.  
copy running-config startup-config  
For Step 2, if you do not specify a network configuration filename, th  
Cisco IOS software uses the default filename network-confg. If you  
omit the tftp keyword, the software assumes that you are using TFTP  
to transfer the file and that the server whose IP address you specify  
supports TFTP.  
You can specify more than one network configuration file. The soft-  
ware tries them in order until it loads one successfully. This procedur  
can be useful for keeping files with different configuration information  
loaded on a network server.  
Download the Host Configuration File  
To configure the Cisco IOS software to download a host configuration  
file from a server at startup, complete the following tasks. Step 2 is op-  
tional. If you do not specify a host configuration filename, the router  
uses its own name to form a host configuration filename by converting  
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AI2524 Router Card User’s Manual  
the name to all lowercase letters, removing all domain information,  
and appending -confg. If no host name information is available, the  
software uses the default host configuration filename router-confg.  
1. Enter configuration mode from the terminal.  
configure terminal  
2. Optionally, enter the host configuration filename to be down-  
loaded.  
boot host {tftp filename [ip-address]}  
3. Enable the device to automatically load the host file upon restart.  
service config  
4. To exit configuration mode, press <Ctrl-Z>.  
5. Save the configuration file to your startup configuration. This step  
saves the configuration to NVRAM.  
copy running-config startup-config  
6. Reset the router with the new configuration information.  
reload  
You can specify more than one host configuration file. The Cisco IOS  
software tries them in order until it loads one successfully. This proce-  
dure can be useful for keeping files with different configuration infor-  
mation loaded on a network server.  
In this example, a router is configured to boot from the host configu-  
ration file hostfile1 and from the network configuration file  
networkfile1:  
Router1# configure terminal  
Router1(config)# boot host hostfile1  
Router1(config)# boot network networkfile1  
Router1(config)# service config  
^Z  
Router1# copy running-config startup-config  
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If the network server fails to load a configuration file during startup, it  
tries again every 1 0minutes (the default setting) until a host provides  
the requested files. With each failed attempt, the network server dis-  
plays a message on the console terminal. If the network server is un  
able to load the specified file, it displays this message:  
Booting host-confg... [timed out]  
If there are any problems with the startup configuration file, or if th  
configuration register is set to ignore NVRAM, the router enters the  
setup command facility. Refer to Use Setup for Configuration  
Change , for details on the setup command.  
Store System  
Images and  
Configuration  
Files  
After modifying and saving your routing environment's unique config-  
urations, you might want to store them on a network server. You can  
use these network server copies of system images and configuration  
files as backup copies.  
Store System Images and Configuration Files Task List  
To store system images and configuration files:  
z
z
Copy System Images from Flash Memory to a Network Server  
Copy System Images from Flash Memory to a Network  
Server  
You can copy system images from Flash memory to a TFTP server.  
You can use this server copy of the system image as a backup copy, or  
you can use it to verify that the copy in Flash is the same as the original  
file on disk.  
In some implementations of TFTP, you must first create a "dummy"  
file on the TFTP server and give it read, write, and execute permis-  
sions before copying a file over it. Refer to your TFTP documentation  
for more information.  
To copy a system image to a TFTP network server, perform these tasks  
in EXEC mode:  
1. (Optional) If you do not already know it, learn the exact spelling  
of the system image filename in Flash memory.  
show flash all  
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2. Copy the system image from Flash memory to a TFTP server.  
copy flash tftp  
3. When prompted, enter the IP address or domain name of the TFTP  
server.  
{ip-address | name}  
4. When prompted, enter the filename of the system image in Flash  
memory.  
filename  
This example uses the show flash all command to learn the  
name of the system image file and thecopy flash tftpcommand  
to copy the system image to a TFTP server. The name of the system  
image file (xk09140z) is listed near the end of the show flash all  
output.  
Router# show flash all  
2048K bytes of flash memory on embedded flash (in XX).  
ROM  
0
1
2
3
4
5
6
7
socket  
U42  
U44  
U46  
U48  
U41  
U43  
U45  
U47  
code  
89BD  
89BD  
89BD  
89BD  
89BD  
89BD  
89BD  
89BD  
bytes  
name  
0x40000  
0x40000  
0x40000  
0x40000  
0x40000  
0x40000  
0x40000  
0x40000  
INTEL 28F020  
INTEL 28F020  
INTEL 28F020  
INTEL 28F020  
INTEL 28F020  
INTEL 28F020  
INTEL 28F020  
INTEL 28F020  
security jumper(12V) is installed,  
flash memory is programmable.  
file  
0
offset  
0x40  
length  
1204637  
name  
xk09140z  
[903848/2097152 bytes free]  
Router# copy flash tftp  
IP address of remote host [255.255.255.255]? 101.2.13.110  
filename to write on tftp host? xk09140z  
writing xk09140z !!!!...  
successful tftp write.  
Router#  
The exclamation point ( ) indicates that the copy process is taking  
!
place. Each exclamation point ) indicates that ten packets have been  
!
transferred successfully. To stop the copy process, press <Ctrl-^>.  
Once you have configured Flash memory, you might want to configure  
the system (using th configure terminal command) with the  
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no boot system flash configuration command to revert to  
booting from ROM. For example, you might want to revert to booting  
from ROM if you do not yet need this functionality, if you choose to  
boot from a network server, or if you do not have the proper image in  
Flash memory. After you enter the no boot system flash com-  
mand, use the copy running-config startup-config  
command to save the new configuration command to the startup con-  
figuration.  
Copy Configuration Files from the Router to a Network  
Server  
You can copy configuration files from the router to a TFTP server.  
You might do this to back up a current configuration file to a server  
before changing its contents, allowing you to later restore the original.  
Usually, the configuration file that you copy to must already exist on  
the TFTP server and be globally writable before the TFTP server al  
lows you to write to it.  
To store configuration information on a TFTP network server, com-  
plete these tasks in the EXEC mode:  
1. Specify that the running or startup configuration file be stored on  
a network server.  
copy {running-config | startup-config} tftp  
2. Enter the IP address of the network server.  
ip-address  
3. Enter the name of the configuration file to store on the server.  
filename  
4. Confirm the entry.  
y
The command prompts you for the destination host's address and a  
filename, as the following example illustrates. This example copies  
configuration file from a router to a TFTP server:  
Tokyo# copy running-config tftp  
Remote host [131.108.2.155]?  
Name of configuration file to write [tokyo-confg]?  
Write file tokyo-confg on host 131.108.2.155?[confirm] y  
#
Writing tokyo-confg!!! [OK]  
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Perform Startup  
Tasks  
The startup tasks in this section are optional.  
Startup Task List  
You can perform these optional startup tasks:  
z
z
Partition Flash Memory Using Dual Flash Bank  
Partition Flash Memory Using Dual Flash Bank  
Dual Flash bank allows you to partition banks of Flash memory into  
separate, logical devices so that the router can hold and maintain two  
different software images. (A bank is a set of four chips.) No down-  
time is required: you can write software into Flash memory while run-  
ning software in another bank of Flash memory.  
Systems that Support Dual Flash Bank  
To use dual Flash bank, you must have at least two banks of Flash  
memory. The minimum partition size is the size of a bank.  
Dual Flash bank is supported on low-end systems that have at least two  
banks of Flash memory, including systems that support a single SIMM  
that has two banks of Flash memory.  
Benefits  
Partitioning Flash memory provides these benefits:  
z
For any system, partitioning—rather than having one logical Flash  
memory device—provides a cleaner way of managing different  
files in Flash memory, especially if the Flash memory size is large.  
z
For systems that execute code out of Flash memory, partitioning  
allows you to download a new image into the file system in one  
Flash memory bank while an image is being executed from the file  
system in the other bank. The download is simple and causes no  
network disruption or downtime. After the download is complete,  
you can switch over to the new image at a convenient time.  
z
One system can hold two different images, one image acting as  
backup for the other. Therefore, if a downloaded image fails to  
boot for some reason, the earlier running, good image is still avail-  
able. Each bank is treated as a separate device.  
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Chapter 7: Manually Loading System Images  
Flash Load Helper versus Dual Flash Bank  
You might use Flash load helper rather than dual Flash bank for one of  
these reasons:  
z
z
z
You want to download a new file into the same bank from which  
the current system image is executing.  
You want to download a file that is larger than the size of a bank,  
and hence want to switch to a single-bank mode.  
You have only one single-bank Flash SIMM installed. In this case,  
Flash load helper is the best option for upgrading your software.  
Flash Systems, for more information about working with Flash load  
helper.  
Understanding Relocatable Images  
Because partitioning requires that run-from-Flash images be loaded  
into different Flash memory banks at different physical addresses, im-  
ages must be relocatable. A relocatable imageis an image that contains  
special relocation information that allows:  
z
The image to relocate itself whenever it is loaded into RAM fo  
execution  
z
A download program with appropriate support to relocate the im  
age before it is stored in Flash memory so the image can run in  
place in Flash memory, regardless of where in Flash memory it is  
stored  
Run-from-Flash systems formerly ran nonrelocatable images that  
needed to be stored in Flash memory at a specific address. As a result,  
the image had to be stored as the first file in Flash memory. If th  
image was stored at any other location in Flash memory, it could not  
be executed in Flash memory, nor could the image be executed from  
RAM. The relocatable image overcomes this limitation.  
With Flash partitioning, the run-from-Flash images will not work un-  
less they are loaded into the first device as the first file. This require  
ment defeats the purpose of partitioning. However, relocatable images  
can be loaded into any Flash partition (and not necessarily as the first  
file within the partition) and executed in place.  
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Unless the image is downloaded as the first file in the first partition,  
this download must be performed by an image that recognizes relocat-  
able images.  
In contrast, a nonrelocatable image is an image that does not recognize  
relocatable images.  
You can identify a relocatable image by its name. The naming conven-  
tion for images that are stored on a UNIX system is:  
platform-capabilities-type  
The letter l in the type field indicates a relocatable image. Examples of  
some relocatable image names include  
igs-i-l—IP-only imag  
z
z
z
igs-d-l—Desktop feature image  
igs-bpx-l—Enterprise image  
Only images with the igs prefix used by the AI2524 are available as  
relocatable images. Images distributed on floppy diskettes might have  
different naming conventions.  
For backward compatibility, the relocatable images are linked to exe-  
cute as the first file in the first Flash memory bank. This makes the im-  
ages similar to previous Flash memory images. Thus, if you download  
a relocatable image into a nonrelocatable image system, the image  
runs correctly from Flash memory.  
Dual Flash Bank Configuration Task List  
To use dual Flash memory bank, perform these tasks:  
z
z
z
z
z
Partition Flash Memory  
Copy a File into a Flash Partition  
Manually Boot from Flash Memory  
Configure the Router to Automatically Boot from Flash Memory  
Configure a Flash Partition as a TFTP Serve  
formation about monitoring dual Flash bank.  
To upgrade your software, you must erase Flash memory when  
prompted during the download. This ensures that the image is down-  
loaded as the first file in Flash memory.  
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Chapter 7: Manually Loading System Images  
Partition Flash Memory  
To partition Flash memory, type the following in global configuration  
mode:  
partition flash partitions [size1 size2]  
This task succeeds only if the system has at least two banks of Flash  
and if the partitioning does not cause an existing file in Flash memory  
to be split across the two partitions.  
Copy a File into a Flash Partition  
In EXEC mode, download a file into a Flash partition:  
copy tftp flash  
The prompts displayed after you execute these tasks indicate the  
method by which the file can be downloaded into each partition. The  
possible methods are:  
None  
No known way to copy into the parti  
tion.  
RXBOOT-Manual  
RXBOOT-FLH  
Direct  
You must manually reload to the rxboot  
image in ROM to copy the image.  
The copy is automatic via the Flash load  
helper software in boot ROMs.  
The copy is created directly.  
If the image can be downloaded into more than one partition, you ar  
prompted for the partition number. Enter any of these commands at th  
partition number prompt to obtain help:  
?
Display the directory listings of all par-  
titions.  
?1  
?2  
q
Display the directory of the first parti-  
tion.  
Display the directory of the second par-  
tition.  
Quit the copy command.  
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Manually Boot from Flash Memory  
To manually boot the router from Flash memory, perform one of thes  
tasks in ROM monitor mode:  
z
Boot the first bootable file found in any partition.  
boot {flash | flash flash:}  
z
Boot the first bootable file from the specified partition.  
boot {flash | flash flash:} partition-  
number:  
z
z
Boot the specified file from the first partition.  
boot {flash | flash flash:} filename  
Boot the specified file from the specified partition.  
boot {flash | flash flash:} partition-  
number:filename  
The result of booting a relocatable image from Flash memory depends  
on where and how the image was downloaded into Flash memory.  
This table describes the various ways an image might be downloaded  
and the corresponding results of booting from Flash memory.  
Result of Booting from  
Method of Downloading  
Flash  
The image was downloaded as The image will execute in place  
the first file by a nonrelocat-  
able image.  
from Flash memory, like a run-  
from-Flash image.  
The image was downloaded  
not as the first file by a nonre-  
locatable image.  
The nonrelocatable image will  
not relocate the image before  
storage in Flash memory. This  
image will not be booted.  
The image was downloaded as The image will execute in place  
the first file by a relocatabl  
image.  
from Flash memory, like a run-  
from-Flash image.  
The image was downloaded  
The relocatable image relocates  
not as the first file by a relocat the image before storage in Flash  
able image (including down- memory. Hence, the image will  
load into the second partition). execute in place from Flash  
memory, like any other run  
from-Flash image.  
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Configure the Router to Automatically Boot from Flash Memory  
To configure the router to boot automatically from Flash memory, per-  
form one of these tasks in global configuration mode:  
z
Boot the first bootable file found in any partition.  
boot system {flash | flash flash:}  
z
Boot the first bootable file from the specified partition.  
boot system {flash | flash flash:}  
partition-number:  
z
z
Boot the specified file from the first partition.  
boot system {flash | flash flash:} filename  
Boot the specified file from the specified partition.  
boot system {flash | flash flash:}  
partition-number:filename  
The result of booting a relocatable image from Flash memory depends  
on where and how the image was downloaded into Flash memory.  
Configure a Flash Partition as a TFTP Serve  
To configure a Flash partition as a TFTP server, perform one of these  
tasks in global configuration mode:  
z
z
z
Specify a file.  
tftp-server flash filename  
Specify a file in the first partition of Flash.  
tftp-server flash filename  
Specify a file in the specified partition of Flash.  
tftp-server flash partition-number:  
filename  
Once you have specified TFTP server operation, exit configuration  
mode and save the configuration information to your startup configu-  
ration.  
Use Flash Load Helper to Upgrade Software on Run-from-  
Flash Systems  
Flash load helper is a software option that enables you to upgrade sys-  
tem software on run-from-Flash systems that have a single bank of  
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Flash memory. It is a lower-cost software upgrade solution than dual-  
bank Flash, which requires two banks of Flash memory on one SIMM.  
The Flash load helper software upgrade process is simple and does not  
require additional hardware; however, it does require some brief net-  
work downtime. A system image running from Flash can use Flash  
load helper only if the boot ROMs support Flash load helper. Other-  
wise, you must perform the Flash upgrade manually. Refer to Manu  
ally Boot from Flash, for more information.  
Flash load helper is an automated procedure that reloads the ROM-  
based image, downloads the software to Flash memory, and reboots to  
the system image in Flash memory. Flash load helper performs checks  
and validations to maximize the success of a Flash upgrade and mini  
mize the chance of leaving Flash memory either in an erased state or  
with a file that cannot boot.  
In run-from-Flash systems, the software image is stored in and exe-  
cuted from the Flash EPROM rather than from RAM. This method re-  
duces memory cost. A run-from-Flash system requires enough Flash  
EPROM to hold the image and enough main system RAM to hold the  
routing tables and data structures. The system does not need the same  
amount of main system RAM as a run-from-RAM system because the  
full image does not reside in RAM. The AI2524 is a Run-from-Flash  
system.  
Flash load helper:  
z
Confirms access to the specified source file on the specified server  
before erasing Flash memory and reloading to the ROM image for  
the actual upgrade.  
z
z
Warns you if the image being downloaded is not appropriate fo  
the system.  
Prevents reloads to the ROM image for a Flash upgrade if the sys-  
tem is not set up for automatic booting and if the user is not on the  
console terminal. In the event of a catastrophic failure during the  
upgrade, Flash load helper can bring up the boot ROM image as  
last resort rather than forcing the system to wait at the ROM mon-  
itor prompt for input from the console terminal.  
z
Retries Flash downloads automatically up to six times. The retry  
sequence is:  
First try  
Immediate retry  
Retry after 30 seconds  
Reload ROM image and retry  
Immediate retry  
Retry after 30 seconds  
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z
z
Allows you to save any configuration changes made before you  
exit out of the system image.  
Notifies users logged in to the system of the impending switch to  
the boot ROM image so that they do not lose their connections un-  
expectedly.  
z
Logs console output during the Flash load helper operation into a  
buffer that is preserved through system reloads. You can retrieve  
the buffer contents from a running image. The output is useful  
when console access is unavailable or when a failure occurs in the  
download operation.  
Flash load helper can also be used on systems with multiple banks of  
Flash memory that support Flash memory partitioning. Flash load  
helper enables you to download a new file into the same partition from  
which the system is executing an image.  
For information about how to partition multiple banks of Flash mem-  
ory so your system can hold two different images, refer to Partition  
Flash Load Helper Configuration Task List  
Perform these tasks to use and monitor Flash load helper:  
z
z
Download a File Using Flash Load Helper  
Download a File Using Flash Load Helper  
To download a new file to Flash memory using Flash load helper,  
check to make sure that your boot ROMssupport Flash load helper and  
then type the following in privileged EXEC mode:  
copy tftp flash  
This error message appears if you are in a Telnet session and the sys-  
tem is set for manual booting (the boot bits in the configuration regis-  
ter are zero):  
ERR: Config register boot bits set for manual booting  
In case of catastrophic failure in the Flash memory upgrade, this erro  
message helps to minimize the chance of the system going down to  
ROM monitor mode and being taken out of the remote Telnet user's  
control.  
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The system tries to bring up at least the boot ROM image if it cannot  
boot an image from Flash memory. Before reinitiating the copy  
tftp flashcommand, you must set the configuration register boot  
field to a nonzero value, using th config-register global con-  
figuration command.  
The copy tftp flash command initiates a series of prompts to  
which you must provide responses. This example illustrates this dia  
log:  
Router# copy tftp flash  
*********************** NOTICE **************************  
Flash load helper v1.0  
This process will accept the TFTP copy options and then terminate the current  
system image to use the ROM based image for the copy. Router functionality will  
not be available during that time. If you are logged in via telnet, this  
connection will terminate. Users with console access can see the results of the  
copy operation. **********************************************************  
If terminals other than the one on which this command is executed are  
active, this message appears:  
There are active users logged into the system.  
Proceed? [confirm] y  
System flash directory:  
File  
1
Length  
2251320  
Name/status  
abc/igs-kf.914  
[2251384 bytes used, 1942920 available, 4194304 total]  
Enter the IP address or the name of the remote host you are copying  
from:  
Address or name of remote host [255.255.255.255]? 131.108.1.111  
Enter the name of the file you want to copy:  
Source file name? abc/igs-kf.914  
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Chapter 7: Manually Loading System Images  
Enter the name of the destination file:  
Destination file name [default = source name]?  
Accessing file `abc/igs-kf.914' on 131.108.1.111....  
Loading from 131.108.13.111:  
Erase flash device before writing? [confirm]  
If you choose to erase Flash memory, the dialog continues. The copy  
tftp flash operation verifies the request from the running image  
by trying to copy a single block from the remote TFTP server. Then  
the Flash load helper is executed, causing the system to reload to th  
ROM-based system image.  
Erase flash device before writing? [confirm] y  
Flash contains files. Are you sure? [confirm] y  
If the file is not a valid image for the system, a warning appears and  
the system requests a separate confirmation:  
Copy `abc/igs-kf.914' from TFTP server  
as `abc/igs-kf.914' into Flash WITH erase? y  
%SYS-5-RELOAD: Reload requested  
%FLH: rxboot/igs-kf.914r from 131.108.1.111 to flash...  
If you do not erase Flash memory and there is no file duplication, th  
dialog continues:  
Erase flash device before writing? [confirm] n  
Copy `abc/igs-kf.914' from TFTP server  
as `abc/igs-kf.914' into Flash WITHOUT erase? y  
If you do not erase Flash memory and if there was file duplication, the  
dialog continues:  
Erase flash device before writing? [confirm] n  
File `abc/igs-kf.914' already exists; it will be invalidated!  
Invalidate existing copy of `abc/igs-kf' in flash memory? [confirm] y  
Copy `abc/igs-kf.914' from TFTP server  
as `abc/igs-kf.914' into Flash WITHOUT erase? y  
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AI2524 Router Card User’s Manual  
If the configuration was modified but not saved, you are asked to save  
the configuration:  
System configuration has been modified. Save? [confirm]  
If you confirm to save the configuration, you might also receive this  
message:  
Warning: Attempting to overwrite an NVRAM configuration previously written by a  
different version of the system image. Overwrite the previous NVRAM configuration?  
[confirm]  
Users with open Telnet connections are notified of the system reload,  
as:  
**System going down for Flash upgrade**  
If the TFTP process fails, the copy operation is retried up to thre  
times. If the failure happens in the middle of a copy operation so only  
part of the file has been written to Flash memory, the retry does not  
erase Flash memory unless you specified an erase operation. Th  
partly written file is marked as deleted, and a new file is opened with  
the same name. If Flash memory runs out of free space in this process,  
the copy operation terminates.  
After Flash load helper finishes copying (whether or not the copy op-  
eration is successful), it automatically attempts an automatic or a man-  
ual boot, depending on the value o f bit0 of the configuration registe  
boot field:  
z
Bit 0 = 0  
The system attempts a default boot from Flash  
memory to load the first bootable file in Flash  
memory. This default boot is equivalent to a  
manual b flashcommand at the ROM  
monitor prompt.  
z
Bit 0 = 1  
The system attempts to boot based on the boot  
configuration commands. If no boot  
configuration commands exist, the system  
attempts a default boot from Flash memory; that  
is, it attempts to load the first bootable file in  
Flash memory.  
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Chapter 7: Manually Loading System Images  
Monitor Flash Load Helper  
To view the system console output generated during the Flash load  
helper operation, use the image booted up after the Flash memory up-  
grade. Type this command in privileged EXEC mode:  
show flh-log  
If you are a remote Telnet user performing the Flash upgrade without  
a console connection, this task allows you to retrieve console output  
when your Telnet connection terminates due to the switch to the ROM  
image. The output indicates events occurring during the download and  
is particularly useful if the download fails.  
Manually Load a  
System Image  
from ROM  
If your router does not find a valid system image, or if its configuration  
file is corrupted at startup, and if the configuration register is set to  
enter ROM monitor mode, the system enters ROM monitor mode.  
From this mode, you can manually load a system image from Flash  
memory, from a network server file, or from ROM.  
Monitor  
You can also enter ROM monitor mode by restarting the router and  
then pressing <Break> during the first 60 seconds of startup.  
Manually Boot from Flash  
To manually boot from Flash memory:  
1. Restart the router  
reload  
2. Press <Break> during the first 60 seconds of system startup.  
3. Manually boot the router from Flash.  
boot flash [filename]  
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AI2524 Router Card User’s Manual  
In this example, a router is manually booted from Flash memory. Be-  
cause the optional filename argument is absent, the first file in Flash  
memory is loaded.  
> boot flash  
F3: 1858656+45204+166896 at 0x1000  
Booting gs7-k from flash memory RRRRRRRRRRRRRRRRRR  
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR  
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR  
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR [OK - 1903912/13765276 bytes]  
F3: 1858676+45204+166896 at 0x1000  
Restricted Rights Legend  
Use, duplication, or disclosure by the Government is subject to restrictions as  
set forth in subparagraph (c) of the Commercial Computer Software - Restricted  
In this example, the boot flash command is used with the filename gs7-  
k; the name of the file that is loaded:  
> boot flash gs7-k  
F3: 1858656+45204+166896 at 0x1000  
Booting gs7-k from flash memory  
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR  
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR  
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR [OK - 1903912/13765276 bytes]  
F3: 1858676+45204+166896 at 0x1000  
Restricted Rights Legend  
Use, duplication, or disclosure by the Government is subject to restrictions as  
set forth in subparagraph (c) of the Commercial Computer Software - Restricted  
System Bootstrap, Version 4.6(1012) [mlw 99], INTERIM SOFTWARE Copyright (c) 1986-  
1992 by cisco Systems RP1 processor with 16384 Kbytes of memory  
Manually Boot from a Network File  
To manually boot from a network file, complete these tasks in EXEC  
mode:  
1. Restart the router  
reload  
2. Press <Break> during the first 60 seconds of system startup.  
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Chapter 7: Manually Loading System Images  
3. Manually boot the router from a network file.  
boot filename [ip-address]  
In this example, a router is manually booted from the network fil  
network1:  
>boot network1  
Manually Boot from ROM  
To manually boot the router from ROM, complete these steps in  
EXEC mode:  
1. Restart the router  
reload  
2. Press <Break> during the first 60 seconds of system startup.  
3. Manually boot the router from ROM.  
boot  
In this example, a router is manually booted from ROM:  
>boot  
Use the System Image Instead of Reloading  
To return to EXEC mode from the ROM monitor to use the system  
image instead of reloading, type the following in ROM monitor mode:  
continue  
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AI2524 Router Card User’s Manual  
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Chapter 8: AI2524 Protocol Configuration Steps  
Chapter 8: AI2524 Protocol Configuration  
Steps  
Introduction  
This chapter describes the AI2524 protocol configuration steps for th  
OSPF TCP/IP, IGRP TCP/IP and RIP TCP/IP.  
AI2524 OSPF  
TCP/IP  
Configuration  
Steps  
Open Shortest Path First (OSPF) is an IGP designed expressly for IP  
networks. OSPF supports IP subnetting and tagging of externally de-  
rived routing information. OSPF also allows packet authentication and  
uses IP multicast when sending/receiving packets.  
OSPF typically requires coordination among many internal routers,  
area border routers (routers connected to multiple areas), and autono-  
mous system boundary routers. At a minimum, OSPF-based routers or  
access servers can be configured with all default parameter values, no  
authentication, and interfaces assigned to areas. If you plan to custom-  
ize your environment, ensure coordinated configurations of all routers.  
To configure OSPF, complete these tasks. You must enable OSPF; the  
other tasks are optional, but might be required for your application.  
z
z
z
z
z
z
z
z
z
z
z
z
z
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AI2524 Router Card User’s Manual  
z
z
Enable OSPF  
To enable OSPF, you mustcreate an OSPF routing process, specify the  
range of IP addresses to be associated with the routing process, and as-  
sign area IDs to be associated with that range of IP addresses.  
1. Enable OSPF routing. This places you in the router configuration  
mode.  
router ospf process-id  
2. Define an interface on which OSPF runs and define the area ID for  
that interface.  
network address wildcard-mask area area-id  
Configure OSPF Interface Parameters  
OSPF implementation allows you to alter certain interface-specific  
OSPF parameters. You may need to change these parameters for con-  
sistency. If you do configure any of these parameters, be sure the con-  
figurations for all routers on your network have compatible values.  
In interface configuration mode, specify any of these interface param-  
eters as needed for your network:  
1. Explicitly specify the cost of sending a packet on an OSPF inter-  
face.  
ip ospf cost cost  
2. Specify the number of seconds between link state advertisement  
retransmissions for adjacencies belonging to an OSPF interface.  
ip ospf retransmit-interval seconds  
3. Setthe estimated number of seconds it takes to transmit a link stat  
update packet on an OSPF interface.  
ip ospf transmit-delay seconds  
4. Set priority to help determine the OSPF designated router for  
network.  
ip ospf priority number  
5. Specify the length of time, in seconds, between the hello packets  
that the Cisco IOS software sends on an OSPF interface.  
ip ospf hello-interval seconds  
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Chapter 8: AI2524 Protocol Configuration Steps  
6. Set the number of seconds that a device's hello packets must not  
have been seen before its neighbors declare the OSPF route  
down.  
ip ospf dead-interval seconds  
7. Assign a specific password to be used by neighboring OSPF rout-  
ers on a network segment that is using OSPF's simple password  
authentication.  
ip ospf authentication-key key  
8. Enable OSPF MD5 authentication.  
ip ospf message-digest-key key id md5 key  
Configure OSPF over Different Physical Networks  
OSPF classifies different media into three types of networks by de  
fault:  
z
z
z
Broadcast networks (Ethernet, Token Ring, FDDI)  
Nonbroadcast multi-access networks (SMDS, Frame Relay, X.25  
Point-to-point networks (HDLC, PPP)  
Configure your network as either a broadcast or a nonbroadcast multi-  
access network.  
X.25 and Frame Relay provide an optional broadcast capability that  
can be configured in the map to allow OSPF to run as a broadcast net-  
work.  
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AI2524 Router Card User’s Manual  
Configure OSPF for Nonbroadcast Networks  
Because there might be many routers attached to an OSPF network, a  
designated router is selected for the network. It is necessary to use spe-  
cial configuration parameters in the designated router selection if  
broadcast capability is not configured.  
These parameters need only be configured in those devices that are  
themselves eligible to become the designated router or backup desig-  
nated router  
To configure routers that interconnect to nonbroadcast networks, type  
this command in router configuration mode:  
neighbor ip-address [priority number]  
[poll-interval seconds]  
You can specify the following neighbor parameters, as required:  
z
z
z
Priority for a neighboring route  
Nonbroadcast poll interval  
Interface through which the neighbor is reachable  
Configure OSPF Area Parameters  
OSPF software allows you to configure several area parameters. Thes  
area parameters, shown in the following list, include enabling authen-  
tication, defining stub areas, and assigning specific costs to the default  
summary route. Authentication allows password-based protection  
against unauthorized access to an area.  
Stub areas are areas into which information on external routes is not  
sent. Instead, there is a default external route generated by the area bor-  
der router, into the stub area for destinations outside the autonomous  
system. To further reduce the number of link state advertisements sent  
into a stub area, you can configur no-summaryon the Area Border  
Router (ABR) to prevent it from sending summary link advertisement  
(link state advertisements Type 3) into the stub area.  
In router configuration mode, specify any of these area parameters as  
needed for your network:  
z
Enable authentication for an OSPF area.  
area area-id authentication  
z
Enable MD5 authentication for an OSPF area.  
area area-id authentication message-digest  
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Chapter 8: AI2524 Protocol Configuration Steps  
z
z
Define an area to be a stub area.  
area area-id stub [no-summary]  
Assign a specific cost to the default summary route used for th  
stub area.  
area area-id default-cost cost  
Configure OSPF Not So Stubby Area (NSSA)  
NSSA area is similar to OSPF stub area. NSSA does not flood Type 5  
external link state advertisements (LSAs) from the core into the area,  
but it can import AS external routes in a limited fashion within the  
area.  
NSSA allows importing of Type 7 AS external routes within NSSA  
area by redistribution. These Type 7 LSAs are translated into Type 5  
LSAs by NSSA Area Border Router (ABR), which are flooded  
throughout the whole routing domain. Summarization and filtering are  
supported during the translation.  
Use NSSA to simplify administration if you are an Internet service  
provider (ISP) or a network administrator that must connect a central  
site using OSPF to a remote site that is using a different routing proto-  
col.  
Prior to NSSA, the connection between the corporate siteborder router  
and the remote router could not be run as OSPF stub area because  
routes for the remote site could not be redistributed into stub area. A  
simple protocol like RIP was usually run to handle the redistribution.  
This meant maintaining two routing protocols. With NSSA, you can  
extend OSPF to cover the remote connection by defining the area be-  
tween the corporate router and the remote router as an NSSA.  
In router configuration mode, specify these area parameters as needed  
to configure OSPF NSSA:  
area area-id nssa [no-redistribution]  
[default-information-originate]  
In router configuration mode on the ABR, specify this command to  
control summarization and filtering of Type 7 LSA into Type 5 LSA  
(optional):  
summary address prefix mask [not advertise]  
[tag tag]  
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Implementation Considerations  
Before implementing this feature, consider these items:  
z
You can set a Type 7 default route that can be used to reach exter-  
nal destinations. When configured, the router generates a Type 7  
default into the NSSA by the NSSA ABR.  
z
z
Every router within the same area must agree that the area is NS-  
SA; otherwise, the routers will not be able to communicate with  
each other.  
If possible, avoid using explicit redistribution on NSSA ABR be-  
cause confusion may result over which packets are being translat-  
ed by which router.  
Configure Route Summarization between OSPF Areas  
Route summarization is the consolidation of advertised addresses.  
This feature causes a single summary route to be advertised to other  
areas by an ABR. In OSPF, an ABR will advertise networks in one  
area into another area. If the network numbers in an area are assigned  
sequentially, you can configure the ABR to advertise a summary route  
that covers all the individual networks within the area that fall into the  
specified range.  
To specify an address range, type this command in router configura-  
tion mode:  
area area-id range address mask  
Configure Route Summarization When Redistributing  
Routes into OSPF  
When redistributing routes from other protocols into OSPF, each route  
is advertised individually in an external link state advertisement  
(LSA). However, you can configure the Cisco IOS software to adver  
tise a single route for all the redistributed routes covered by a specified  
network address and mask. Doing so helps decrease the size of th  
OSPF link state database.  
To have the software advertise one summary route for all redistributed  
routes covered by a network address and mask, type this command in  
router configuration mode:  
summary-address address mask  
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Chapter 8: AI2524 Protocol Configuration Steps  
Create Virtual Links  
In OSPF, all areas must be connected to a backbone area. If there is  
break in backbone continuity, or if the backbone is purposefully parti-  
tioned, you can establish a virtual link.  
To establish a virtual link, type this command in router configuration  
mode:  
area area-id virtual-link router-id [hello-  
interval seconds] [retransmit-interval  
seconds] [transmit-delay seconds]  
[deadinterval seconds] [[authentication-key  
key] | [message-digest-key keyid md5 key]]  
To display information about virtual links, use th show ip ospf  
virtual-links EXEC command. To display the router ID of an  
OSPF router, use the show ip ospf EXEC command.  
Generate a Default Route  
You can force an autonomous system boundary router to generate a  
default route into an OSPF routing domain. Whenever you specifically  
configure redistribution of routes into an OSPF routing domain, th  
router automatically becomes an autonomous system boundary router.  
However, an autonomous system boundary router does not, by default,  
generate a default route into the OSPF routing domain.  
To force the autonomous system boundary router to generate a default  
route, type this command in router configuration mode:  
default-information originate [always]  
[metric metricvalue] [metric-type type-  
value] [route-map map-name]  
Configure Lookup of DNS Names  
You can configure OSPF to look up Domain Naming System (DNS)  
names for use in all OSPF show command displays. This featur  
makes it easier to identify a router, because it is displayed by nam  
rather than by its router ID or neighbor ID.  
To configure DNS name lookup, type this command in global config-  
uration mode  
ip ospf name-lookup  
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Force the Router ID Choice with a Loopback Interface  
OSPF uses the largest IP address configured on the interfaces as its  
router ID. If the interface associated with this IP address is ever  
brought down, or if the address is removed, the OSPF process must re-  
calculate a new router ID and resend all its routing information over its  
interfaces.  
If a loopback interface is configured with an IP address, the Cisco IOS  
software will use this IP address as its router ID, even if other inter  
faces have larger IP addresses. Since loopback interfaces never go  
down, greater stability in the routing table is achieved.  
To configure an IP address on a loopback interface, perform thes  
tasks, starting in global configuration mode:  
1. Create a loopback interface, which places you in interface config-  
uration mode  
interface loopback 0  
2. Assign an IP address to this interface.  
ip address address mask  
Disable Default OSPF Metric Calculation Based on  
Bandwidth  
OSPF calculates the OSPF metric for an interface according to the  
bandwidth of the interface. To disable this feature, type this command  
in router configuration mode:  
no ospf auto-cost-determination  
Configure OSPF on Simplex Ethernet Interfaces  
Because simplex interfaces between two devices on an Ethernet repre-  
sent only one network segment, for OSPF you must configure the  
transmitting interface to be a passive interface. This prevents OSPF  
from sending hello packets for the transmitting interface. Both devices  
are able to see each other via the hello packet generated for the receiv-  
ing interface.  
To configure OSPF on simplex Ethernet interfaces, type this command  
in router configuration mode:  
passive-interface type number  
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Chapter 8: AI2524 Protocol Configuration Steps  
Configure Route Calculation Timers  
You can configure the delay time between when OSPF receives a to-  
pology change and when it starts a Shortest Path First (SPF) calcula-  
tion. You can also configure the hold time between two consecutive  
SPF calculations. Type this command in router configuration mode:  
timers spf spf-delay spf-holdtime  
Configure OSPF over On-Demand Circuits  
The OSPF on-demand circuit is an enhancement to the OSPF protocol  
that allows efficient operation over on-demand circuits like ISDN,  
X.25 SVCs, and dial-up lines. This feature supports RFC 1793, ex-  
tending OSPF to Support Demand Circuits.  
With this feature, periodic hellos are suppressed and the periodic re-  
freshes of LSAs are not flooded over the demand circuit.  
To configure OSPF for on-demand circuits, perform these tasks:  
1. Enable OSPF operation.  
router ospf process-id  
2. Configure OSPF on an on-demand circuit.  
ip ospf demand-circuit  
If the router is part of a point-to-point topology, then only one end of  
the demand circuit must be configured with this command. However,  
all routers must have this feature loaded.  
If the router is part of a point-to-multipoint topology, only the multi-  
point end must be configured with this command.  
Implementation Considerations  
Because LSAs that include topology changes are flooded over an on-  
demand circuit, it is advised to put demand circuits within OSPF.  
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Network Illustration  
This list outlines key features supported in OSPF implementation:  
Stub areas  
Definition of stub areas is supported.  
Route  
redistribution  
Routes learned via any IP routing protocol  
can be redistributed into any other IP routing  
protocol. At the intradomain level, this  
means that OSPF can import routes learned  
via IGRP, RIP, and IS-IS. OSPF routes can  
also be exported into IGRP, RIP,and IS-IS.  
At the interdomain level, OSPF can import  
routes learned via EGP and BGP. OSPF  
routes can be exported into EGP and BGP.  
Authentication  
Simple and MD5 authentication among  
neighboring routers within an area is sup-  
ported.  
Routing/Interface  
parameters  
Configurable parameters supported includ  
interface output cost, retransmission inter-  
val, interface transmit delay, router priority,  
router "dead" and hello intervals, and  
authentication key.  
Virtual links  
NSSA areas  
Virtual links are supported.  
RFC 1567  
OSPF over demand RFC 1793  
circuit  
Note:  
To take advantage of the OSPF stub area support, default  
routing must be used in the stub area.  
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Chapter 8: AI2524 Protocol Configuration Steps  
AI2524 IGRP  
TCP/IP  
Configuration  
Steps  
The Interior Gateway Routing Protocol (IGRP) is a dynamic distance-  
vector routing protocol for an autonomous system that contains large,  
arbitrarily complex networks with diverse bandwidth and delay char-  
acteristics.  
IGRP uses a combination of user-configurable metrics, including in  
ternetwork delay, bandwidth, reliability, and load.  
IGRP Updates  
By default, a router running IGRP sends an update broadcast every 90  
seconds. It declares a route inaccessible if it does not receive an update  
from the first router in the route within 3 update periods (270 seconds).  
After 7 update periods (630 seconds), the Cisco IOS software removes  
the route from the routing table.  
IGRP uses flash update and poison reverse updates to speed up th  
convergence of the routing algorithm. Flash updates are sent soone  
than the standard periodic update for notifying other routers of a metric  
change. Poison reverse updates are intended to defeat larger routing  
loops caused by increases in routing metrics. The poison reverse up-  
dates are sent to remove a route and place it in holddown, which keeps  
new routing information from being used for a certain period of time.  
IGRP Configuration Task List  
To configure IGRP, perform the tasks outlined in the next section. Cre-  
ating the IGRP routing process is mandatory; the other tasks are op  
tional.  
z
z
z
z
z
z
z
z
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AI2524 Router Card User’s Manual  
Create the IGRP Routing Process  
To create the IGRP routing process, perform these required tasks start-  
ing in global configuration mode:  
1. Enable an IGRP routing process, which places you in router con-  
figuration mode.  
router igrp process number  
2. Associate networks with an IGRP routing process.  
network network-number  
IGRP sends updates to the interfaces in the specified networks. If an  
interface's network is not specified, it will not be advertised in any  
IGRP update.  
It is not necessary to have a registered autonomous system number to  
use IGRP. If you do not have a registered number, you can create your  
own. We recommend that if you do have a registered number, you use  
it to identify the IGRP process.  
Allow Point-to-Point Updates for IGRP  
Because IGRP is normally a broadcast protocol, in order for IGRP  
routing updates to reach point-to-point or nonbroadcast networks, you  
must configure the Cisco IOS software to permit this exchange of rout-  
ing information.  
To permit information exchange, define a neighboring router by typ-  
ing this command in router configuration mode:  
neighbor ip-address  
To control the set of interfaces with which to exchange routing up-  
dates, you can disable the sending of routing updates on specified in  
terfaces by configuring th passive-interface command.  
Define Unequal-Cost Load Balancing  
IGRP can simultaneously use an asymmetric set of paths for a given  
destination. This feature is known as unequal-cost load balancing. Un-  
equal-cost load balancing allows traffic to be distributed among up to  
four unequal-cost paths to provide greater overall output and reliabil-  
ity. Alternate path variance (that is, the difference in desirability be  
tween the primary and alternate paths) is used to determine the  
feasibility of a potential route. Only paths that are feasible can be used  
for load balancing and are included in the routing table. These condi-  
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Chapter 8: AI2524 Protocol Configuration Steps  
tions limit the number of cases in which load balancing can occur, but  
ensure that the dynamics of the network will remain stable.  
These general rules apply to IGRP unequal-cost load balancing:  
z
z
IGRP will accept up to four paths for a given destination network.  
The local best metric must be greater than the metric learned from  
the next router; that is, the next-hop router must be closer (have a  
smaller metric value) to the destination than the local best metric.  
z
The alternative path metric must be within the specified variance  
of the local best metric. The multiplier times the local best metric  
for the destination must be greater than or equal to the metric  
through the next router  
If these conditions are met, the route is deemed feasible and can b  
added to the routing table.  
By default, the amount of variance is set to one (equal-cost load bal-  
ancing). You can define how much worse an alternate path can be be-  
fore that path is disallowed by defining the variance associated with a  
particular path variance multiplier.  
Note:  
By using the variance feature, the Cisco IOS software can  
balance traffic across all feasible paths and can  
immediately converge to a new path if one of the paths  
fails.  
Control Traffic Distribution  
By default, if IGRP or Enhanced IGRP have multiple routes of un-  
equal cost to the same destination, the Cisco IOS software will distrib-  
ute traffic among the different routes by giving each route a share o  
the traffic in inverse proportion to its metric. If you want to have faster  
convergence to alternate routes, but you do not want to send traffic  
across inferior routes in the normal case, you might prefer to have no  
traffic flow along routes with higher metrics.  
To control how traffic is distributed among multiple routes of unequal  
cost, type this command in router configuration mode:  
traffic-share {balanced | min}  
Adjust the IGRP Metric Weights  
You can alter the default behavior of IGRP routing and metric compu-  
tations. Although IGRP metric defaults were carefully selected to pro-  
vide excellent operation in most networks, you can adjust the IGRP  
metric. Adjusting IGRP metric weights can dramatically affect net-  
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AI2524 Router Card User’s Manual  
work performance, however, so ensure that you make all metric ad-  
justments carefully.  
Note:  
Because of the complexity of this task, we recommend that  
you only perform it with guidance from an experienced  
system designer.  
To adjust the IGRP metric weights, type this command in router con-  
figuration mode:  
metric weights tos k1 k2 k3 k4 k5  
By default, the IGRP composite metric is a 24-bit quantity that is a  
sum of the segment delays and the lowest segment bandwidth (scaled  
and inverted) for a given route. For a network of homogeneous media,  
this metric reduces to a hop count. For a network of mixed media  
(FDDI, Ethernet, and serial lines running from 9600 bps to T1 rates),  
the route with the lowest metric reflects the most desirable path to  
destination.  
Disable Holddown  
When the Cisco IOS software learns that a network is at a greater dis-  
tance than was previously known, or it learns the network is down, th  
route to that network is placed in holddown. During the holddown pe-  
riod, the route is advertised, but incoming advertisements about that  
network from any router other than the one that originally advertised  
the network's new metric will be ignored. All devices in an IGRP au-  
tonomous system must be consistent in their use of holddowns. To dis-  
able holddowns with IGRP, type this command in router configuration  
mode:  
no metric holddown  
Enforce a Maximum Network Diameter  
The Cisco IOS software enforces a maximum diameter to the IGRP  
network. Routes whose hop counts exceed this diameter are not adver-  
tised. The default maximum diameter is 100 hops. The maximum di-  
ameter is 255 hops.  
To configure the maximum diameter, type this command in router  
configuration mode:  
metric maximum-hops hops  
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Chapter 8: AI2524 Protocol Configuration Steps  
Validate Source IP Addresses  
To disable the default function that validates the source IP addresses  
of incoming routing updates, type this command in router configura  
tion mode:  
no validate-update-source  
Network Illustration  
IGRP advertises three types of routes: interior, system, and exterior, as  
shown in Figure 8-1. Interior routes are routes between subnets in the  
network attached to a router interface. If the network attached to a  
router is not subnetted, IGRP does not advertise interior routes.  
Figure 8-1:Interior, System, and Exterior Routes  
System routes are routes to networks within an autonomous system.  
The Cisco IOS software derives system routes from directly connected  
network interfaces and system route information provided by other  
IGRP-speaking routers or access servers. System routes do not include  
subnet information.  
Exterior routes are routes to networks outside the autonomous system  
that are considered when identifying a gateway of last resort. Th  
Cisco IOS software chooses a gateway of last resort from the list of ex-  
terior routes that IGRP provides. The software uses the gateway  
(router) of last resort if it does not have a better route for a packet and  
the destination is not a connected network. If the autonomous system  
has more than one connection to an external network, different routers  
can choose different exterior routers as the gateway of last resort.  
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AI2524 Router Card User’s Manual  
AI2524 RIP TCP/  
IP Configuration  
Routing Information Protocol (RIP) uses broadcast User Datagram  
Protocol (UDP) data packets to exchange routing information.  
The Cisco IOS software sends routing information updates (advertise-  
ments) every 30 seconds. If a router does not receive an update from  
another router for 180 seconds or more, it marks the routes served by  
the nonupdating router as being unusable. If there is still no update  
after 240 seconds, the router removes all routing table entries for the  
nonupdating router.  
RIP sends updates to the interfaces in the specified networks. If an in-  
terface's network is not specified, it will not be advertised in any RIP  
update.  
RIP Configuration Task List  
To configure RIP, complete the tasks outlined in the nest sections. You  
must enable RIP. The remaining tasks are optional.  
z
z
z
z
z
z
z
Enable RIP  
Allow Point-to-Point Updates for RI  
Enable RIP  
To enable RIP, perform these tasks, starting in global configuration  
mode:  
1. Enable a RIP routing process, which places you in router configu-  
ration mode.  
router rip  
2. Associate a network with a RIP routing process.  
network network-number  
Allow Point-to-Point Updates for RIP  
RIP is normally a broadcast protocol. Therefore, for RIP routing up-  
dates to reach point-to-point or nonbroadcast networks, you must con-  
figure the Cisco IOS software to permit this exchange of routing  
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Chapter 8: AI2524 Protocol Configuration Steps  
information. To define a neighboring router with which to exchange  
point-to-point routing information, type this command in router con-  
figuration mode:  
neighbor ip-address  
To control the set of interfaces with which to exchange routing up-  
dates, you can disable the sending of routing updates on specified in  
terfaces by configuring the passive interface command.  
Specify a RIP Version  
By default, the software receives RIP Versi on1 and Vers ion2 pack-  
ets, but sends only Vers ion1 packets. You can configure the softwar  
to receive and send only Ver sion1 packets. Alternatively, you can  
configure the software to receive and send only Vers ion2 packets. To  
configure the software to receive and send only RIP Ver sion1 or only  
RIP Version 2 packets, type this command in router configuration  
mode:  
version {1 | 2}  
The preceding task controls the default behavior of RIP. You can over-  
ride that behavior by configuring a particular interface to behave dif-  
ferently. To control which RIP version an interface sends, perform one  
of these tasks in interface configuration mode:  
z
z
z
Configure an interface to send only RIP Ver sion1 packets.  
ip rip send version 1  
Configure an interface to send only RIP Ver sion2 packets.  
ip rip send version 2  
Configure an interface to send RIP Ver sion1 and Ve rsion2 pack-  
ets.  
ip rip send version 1 2  
Similarly, to control how packets received from an interface are pro-  
cessed, perform one of these tasks in interface configuration mode:  
z
z
z
Configure an interface to accept only RIP Ver sion1 packets.  
ip rip receive version 1  
Configure an interface to accept only RIP Ver sion2 packets.  
ip rip receive version 2  
Configure an interface to accept either RIP Ve rsion1 or 2 packets.  
ip rip receive version 1 2  
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AI2524 Router Card User’s Manual  
Enable RIP Authentication  
RIP Version 1 does not support authentication. If you are sending and  
receiving RIP Versio n2 packets, you can enable RIP authentication on  
an interface.  
The key chain determines the set of keys that can be used on the inter-  
face. If a key chain is not configured, no authentication is performed  
on that interface, not even the default authentication. Therefore, you  
must also perform the tasks in the section Manage Authentication  
Keys later in this chapter.  
The software supports two modes of authentication on an interface for  
which RIP authentication is enabled: plain text authentication and  
MD5 authentication. The default authentication in every RIP  
Version 2 packet is plain text authentication.  
Note:  
For security purposes, do notuse plain text authentication  
in RIP packets, because the unencrypted authentication  
key is sent in every RIP Versio n2 packet. Use plain text  
authentication when security is not an issue, for example,  
to ensure that misconfigured hosts do not participate in  
routing.  
To configure RIP authentication, perform these tasks in interface con-  
figuration mode:  
1. Enable RIP authentication.  
ip rip authentication key-chain name-of-  
chain  
2. Configure the interface to use MD5 digest authentication (or let it  
default to plain text authentication).  
ip rip authentication mode {text | md5}  
Disable Route Summarization  
RIP Version 2 supports automatic route summarization by default.  
The software summarizes subprefixes to the classful network bound-  
ary when crossing classful network boundaries.  
If you have disconnected subnets, disable automatic route summariza-  
tion to advertise the subnets. When route summarization is disabled,  
the software transmits subnet and host routing information across  
classful network boundaries. To disable automatic summarization,  
type this command in router configuration mode:  
no auto-summary  
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Chapter 8: AI2524 Protocol Configuration Steps  
Run IGRP and RIP Concurrently  
It is possible to run IGRP and RIP concurrently. The IGRP informa-  
tion will override the RIP information by default because of IGRP's  
administrative distance.  
Running IGRP and RIP concurrently does not work well when the net-  
work topology changes. Because IGRP and RIP have different update  
timers, and because they require different amounts of time to propa-  
gate routing updates, one part of the network will follow IGRP routes  
and another part will follow RIP routes. This results in routing loops.  
Although these loops do not exist for long, the Time To Live (TTL)  
will quickly reach zero, and ICMP will send a TTL exceeded message.  
This message will cause most applications to stop attempting network  
connections.  
Disable the Validation of Source IP Addresses  
By default, the software validates the source IP address of incoming  
RIP routing updates. If that source address is not valid, the software  
discards the routing update.  
Consider disabling this feature if you have a router that is off network  
and you want to receive its updates. Disabling this feature is not rec  
ommended under normal circumstances. To disable the default func  
tion that validates the source IP addresses of incoming routing updates,  
perform this task in router configuration mode:  
z
Disable the validation of the source IP address of incoming RIP  
routing updates.  
no validate-update-source ion  
In addition to running multiple routing protocols simultaneously, the  
Cisco IOS software can redistribute information from one routing pro-  
tocol to another. For example, you can instruct the software to readver-  
tise IP Enhanced IGRP-derived routes using the RIP protocol or to  
readvertise static routes using the IP Enhanced IGRP protocol. This  
capability applies to all the IP-based routing protocols.  
You may also conditionally control the redistribution of routes be  
tween routing domains by defining a method known as route maps be-  
tween the two domains.  
z
To redistribute routes from one protocol into another, type this  
command in router configuration mode:  
redistribute protocol autonomous-system-  
number [route-map map-tag]  
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AI2524 Router Card User’s Manual  
z
z
To define route maps, type this command in global configuration  
mode:  
route-map map-tag [permit | deny]  
[sequence-number]  
By default, the redistribution of default information between IP  
Enhanced IGRP processes is enabled. To disable the redistribu-  
tion, type this command in router configuration mode:  
no default-information {in | out}  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
Chapter 9: AI2524 OSI/CLNP  
Configuration Steps  
Introduction  
This chapter describes how to configure ISO CLNS. The ISO CLNS  
protocol is a standard for the network layer of the OSI model.  
ISO CLNS  
Configuration  
Task List  
To configure ISO CLNS, you must configure the routing processes,  
associate addresses with the routing processes, and customize the rout-  
ing processes for your particular network.  
You must perform some combination of the tasks listed here to config-  
ure the ISO CLNS protocol:  
z
z
z
z
z
z
z
z
z
z
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AI2524 Router Card User’s Manual  
Understand  
Addresses  
Addresses in the ISO network architecture are referred to as NSAP ad-  
dresses and network entity titles (NETs). Each node in an OSI network  
has one or more NETs. In addition, each node has many NSAP ad-  
dresses. Each NSAP address differs from one of the NETs for that  
node in only the last byte. This byte is called the N-selector. Its func-  
tion is similar to the port number in other protocol suites.  
The AI2524 router supports all NSAP address formats that are defined  
by ISO 8348/Ad2; however, the AI2524 router provides ISO IGRP o  
IS-IS dynamic routing only for NSAP addresses that conform to the  
address constraints defined in the ISO standard for IS-IS (ISO 10589).  
An NSAP address consists of these two major fields, as shown inFig-  
z
The initial domain p art (IDP) is made up of 1-byte authority and  
format identifier (AFI) and a variable-length initial  
domai nidentifier (IDI). The length of the IDI and the encoding  
format for the domai nspecific part (DSP) are based on the value  
of the AFI.  
z
The DSP is made up of a high-order DSP, an area identifier, a sys-  
tem identifier, and a 1-byte N-selector (labeled S).  
Figure 9-1:NSAP Address Fields  
Assign addresses or NETs for your domains and areas. Th  
domai naddress uniquely identifies the routing domain. All routers  
within a given doma inare given the same dom ainaddress. Within  
each routing domain, you can set up one or more areas, as shown in  
Figure 9-2. Determine which routers are to be assigned to which areas.  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
The area address uniquely identifies the routing area and the system ID  
identifies each node.  
Figure 9-2:Sample Domain and Area Addresses  
The key difference between the ISO IGRP and IS-IS NSAP addressing  
schemes is in the definition of area addresses. Both use the system ID  
for Level 1 routing (routing within an area). However, they differ in  
the way addresses are specified for area routing. An ISO IGRP NSAP  
address includes three separate fields for routing: the domain, area,  
and system ID. An IS-IS address includes two fields: a single contin  
uous area field (comprising the doma inand area fields) and the system  
ID.  
ISO IGRP NSAP Address  
The ISO IGRP NSAP address is divided into three parts: a  
domai npart, an area address, and a system ID. D omainrouting is per-  
formed on the doma inpart of the address. Area routing for a given  
domai nuses the area address. System routing for a given area uses the  
system ID part. The NSAP address is laid out as:  
z
The domai npart is of variable length and comes before the area  
address.  
z
The area address is the 2 bytes before the system ID.  
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AI2524 Router Card User’s Manual  
z
z
The system ID is the 6 bytes before the N-selector.  
The N-selector (S) is the last byte of the NSAP address.  
Cisco's ISO IGRP routing implementation interprets the bytes from  
the AFI up to (but not including) the area field in the DSP as  
domai nidentifier. The area field specifies the area, and the system ID  
specifies the system.  
Figure 9-3 illustrates the ISO IGRP NSAP addressing structure. The  
maximum address size is 20 bytes.  
Figure 9-3:ISO IGRP NSAP Addressing Structure  
IS-IS NSAP Address  
An IS-IS NSAP address is divided into two parts: an area address and  
a system ID. Level 2 routing (routing between areas) uses the area ad-  
dress. Leve l1 routing (routing within an area) uses the system ID ad-  
dress. The NSAP address is laid out as:  
z
z
z
The area address is the NSAP address, not including the system ID  
and N-selector.  
The system ID is found between the area address and the N-selec-  
tor byte.  
The N-selector (S) is the last byte of the NSAP address.  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
The IS-IS routing protocol interprets the bytes from the AFI up to(but  
not including) the system ID field in the DSP as an area identifier. Th  
system ID specifies the system.  
Figure 9-4 illustrates the IS-IS NSAP addressing structure. The maxi-  
mum address size is 20 bytes.  
Figure 9-4:IS-IS NSAP Addressing Structure  
Addressing Rules  
All NSAP addresses must obey these constraints:  
z
z
z
z
No two nodes can have addresses with the same NET; that is, ad-  
dresses that match all but the N-selector (S) field in the DSP.  
No two nodes residing within the same area can have addresses in  
which the system ID fields are the same.  
ISO IGRP requires at least 10 bytes of length: 1 byte for domain,  
2 bytes for area, 6 bytes for system ID, and 1 byte for N-selector.  
ISO IGRP and IS-IS should not be configured for the same area.  
Do not specify an NSAP address where all bytes up to (but not in-  
cluding) the system ID are the same when enabling both ISO  
IGRP and IS-IS routing.  
z
z
A router can have one or more area addresses. The concept of mul-  
tiple area addresses is described in Assign Multiple Area Address-  
IS-IS requires at least 8 bytes: one byte for area, 6 bytes for system  
ID, and 1 byte for N-selector.  
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AI2524 Router Card User’s Manual  
Addressing Examples  
Examples of OSI network and GOSIP NSAP addresses using the ISO  
IGRP implementation are described in the next sections.  
The OSI network NSAP address format is illustrated as:  
|
Domain|Area|  
System ID| S| 47.0004.004D.0003.0000.0C00.62E6.00  
This is an example of the GOSIP NSAP address structure. This struc-  
ture is mandatory for addresses allocated from the International Code  
Designator (ICD) 0005 addressing domain. Refer to the GOSIP docu-  
ment, U.S. Government Open Systems Interconnection Profile (GO-  
SIP), Draft Version 2.0, April 1989, for more information.  
|
47.0005.80.ffff00.0000.ffff.0004.0000.0c00.62e6.00  
| |  
AFI IDI DFI AAI Resv RD  
Domain|  
Area|System ID| S|  
|
|
|
Routing Table Example  
You enter static routes by specifying NSAP prefix and next-hop NET  
pairs (by using the clns route command). The NSAP prefix can  
be any portion of the NSAP address. NETs are similar in function to  
NSAP addresses.  
If an incoming packet has a destination NSAP address that does not  
match any existing NSAP addresses in the routing table, the Cisco IOS  
software will try to match the NSAP address with an NSAP prefix to  
route the packet. In the routing table, the best match means the longest  
NSAP prefix entry that matches the beginning of the destination  
NSAP address.  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
This table shows a sample static routing table in which the nexthop  
NETs are listed for completeness, but are not necessary to understand  
the routing algorithm.  
NSAP Address  
Entry  
Next-Hop NET  
Prefix  
1
2
3
4
5
47.0005.000c.0001 47.0005.000c.0001.0000.1234.00  
47.0004  
47.0005.000c.0002.0000.0231.00  
47.0005.000c.0001.0000.1234.00  
47.0005.000c.0004.0000.0011.00  
47.0005.000c.0002.0000.0231.00  
47.0005.0003  
47.0005.000c  
47.0005  
This table offers examples of how the longest matching NSAP prefix  
can be matched with routing table entries in the table above.  
Datagram Destination NSAP  
Address  
Table Entry  
Number Used  
47.0005.000c.0001.0000.3456.01  
47.0005.000c.0001.6789.2345.01  
47.0004.1234.1234.1234.1234.01  
47.0005.0003.4321.4321.4321.01  
47.0005.000c.0004.5678.5678.01  
47.0005.0001.0005.3456.3456.01  
1
1
2
3
4
5
Octet boundaries must be used for the internal boundaries of NSAP ad-  
dresses and NETs.  
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Understand  
Routing Processes  
The basic function of a router is to forward packets: receive a packet  
in one interface and send it out another (or the same) interface to the  
proper destination. All routers do this by looking up the destination ad-  
dress in a table. The tables can be built eitherdynamically or statically.  
If you are configuring all the entries in the table yourself, you are using  
static routing. If you use a routing process to build the tables, you ar  
using dynamic routing. It is possible, and sometimes necessary, to use  
both static and dynamic routing simultaneously.  
When you configure only ISO CLNS and not routing protocols, the  
Cisco IOS software only makes forwarding decisions. It does not per-  
form other routing-related functions. In such a configuration, the soft-  
ware compiles a table of adjacency data, but does not advertise this  
information. The only information that is inserted into the routing table  
is the NSAP and NET addresses of this router, static routes, and adja-  
cency information.  
You can route ISO CLNS on some interfaces and transparently bridge  
it on other interfaces simultaneously. To do this, you must enable con-  
current routing and bridging by using th bridge crb command.  
Dynamic Routing  
Cisco supports these two dynamic routing protocols for ISO CLNP  
networks:  
z
z
ISO IGRP  
IS-IS  
When dynamically routing, you can choose either ISO IGRP or IS-IS,  
or you can enable both routing protocols at thesame time. Both routing  
protocols support the concept of areas. Within an area, all routers  
know how to reach all the system IDs. Between areas, routers know  
how to reach the proper area.  
ISO IGRP supports three levels of routing: system routing, area rout-  
ing, and interdomainrout ing. Routing across domains  
(interdomai nrouting) can be static or dynamic with ISO IGRP. IS-IS  
supports two levels of routing: station routing (within an area) and are  
routing (between areas).  
Intermediate Systems (IS) and End Systems (ES)  
Some ISs keep track of how to communicate with all the ESs in their  
areas and thereby function as Level 1 routers (also referred to as local  
routers). Other ISs keep track of how to communicate with other areas  
in the domain, functioning as Le vel2 routers (sometimes referred to as  
area routers). The AI2524 router is always Le vel1 and L evel2 when  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
routing ISO IGRP; it can be configured to be Level 1 only, Level2  
only, or both Level 1 and Leve l2 when routing IS-IS.  
ESs communicate with ISs using the ES-IS protocol. Lev el1 and  
Level 2 ISs communicate with each other using either ISO IS-IS or  
Cisco's ISO IGRP protocol.  
Static Routing  
Static routing is used when it is not possible or desirable to use dy-  
namic routing. Here are some instances of when you would use static  
routing:  
z
If your network includes WAN links that involve paying for con-  
nect time or for per-packet charges, use static routing, rather than  
paying to run a routing protocol and all its routing update packets  
over that link.  
z
z
z
If you want routers to advertise connectivity to external networks,  
but you are not running an interd o mainrouting protocol, you must  
use static routes.  
If you must interoperate with another vendor's equipment that  
does not support any of the dynamic routing protocols that Cisco  
supports, you must use static routing.  
For operation over X.25, Frame Relay, or SMDS networks, static  
routing is generally preferable.  
Warning: An interface that is configured for static routing cannot  
reroute around failed links.  
Routing Decisions  
A CLNP packet sent to any of the defined NSAP addresses or NETs  
will be received by the router. The Cisco IOS software uses this algo-  
rithm to select which NET to use when it sends a packet:  
z
If no dynamic routing protocol is running, use the NET defined for  
the outgoing interface, if it exists; otherwise, use the NET defined  
for the router.  
z
z
If ISO IGRP is running, use the NET of the ISO IGRP routing pro-  
cess that is running on the interface.  
If IS-IS is running, use the NET of the IS-IS routing process that  
is running on the interface.  
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Configure ISO  
IGRP Dynamic  
Routing  
The ISO IGRP is a dynamic distance-vector routing protocol designed  
by Cisco for routing an autonomous system that contains large, arbi-  
trarily complex networks with diverse bandwidth and delay character-  
istics.  
To configure ISO IGRP, complete the tasks outlined in these sections.  
Only enabling ISO IGRP is required; the remaining task is optional, al-  
though you might be required to perform it, depending upon your spe-  
cific application:  
z
z
Enable ISO IGRP  
In addition, you can also configure these miscellaneous features:  
z
z
z
Filter routing information (refer to Create Packet-Forwarding Fil-  
Redistribute routing information from one routing process to an-  
Configure administrative distances (refer to Specify Preferred  
Routes)  
Enable ISO IGRP  
To configure ISO IGRP dynamic routing, you must enable the ISO  
IGRP routing process, identify the address for the router, and specify  
the interfaces that are to route ISO IGRP. Optionally, you can set a  
level for your routing updates when you configure the interfaces.  
CLNS routing is enabled by default on routers when you configure  
ISO IGRP. You can specify up to ten ISO IGRP routing processes.  
In global configuration mode, configure ISO IGRP dynamic routing  
on the router:  
1. Enable the ISO IGRP routing process and enter router configura-  
tion mode.  
router iso-igrp [tag]  
2. Configure the NET or address for the routing process.  
net network-entity-title  
Although IS-IS allows you to configure multiple NETs, ISO IGRP al-  
lows only one NET per routing process.  
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You can assign a meaningful name for the routing process by using the  
tag option. You can also specify a name for a NET in addition to an  
address. For information on how to assign a name, see Specify Short-  
You can configure an interface to advertise L evel2 information only.  
This option reduces the amount of router-to-router traffic by telling th  
Cisco IOS software to send out only L evel2 routing updates on certain  
interfaces. Level 1 information is not passed on the interfaces for  
which the Level 2 option is set.  
In interface configuration mode, enable ISO IGRP on specified inter  
faces and set the level type for routing updates:  
clns router iso-igrp tag [level 2]  
Example: Dynamic Routing within the Same Area  
Figure 9-5, and the example configuration illustrate how to configure  
dynamic routing within a routing domain. The router can exist in on  
or more areas within the domain. The router named Router A exists in  
a single area:  
Figure 9-5:CLNS Dynamic Routing within a Single Area  
1. Define a tag castor for the routing process:  
router iso-igrp castor  
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2. Configure the net for the process in area 2, doma in47.0004.004d:  
net 47.0004.004d.0002.0000.0C00.0506.00  
3. Specify iso-igrp routing using the previously specified tag castor :  
interface ethernet 0  
clns router iso-igrp castor  
4. Specify iso-igrp routing using the previously specified tag castor :  
interface ethernet 1  
clns router iso-igrp castor  
5. Specify iso-igrp routing using the previously specified tag castor:  
interface serial 0  
clns router iso-igrp castor  
Example: Dynamic Routing in More Than One Area  
Figure 9-6 and the example configuration illustrate how to configure  
router named Router A that exists in two areas:  
Figure 9-6:CLNS Dynamic Routing within Two Areas  
.
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
1. Define a tag orion for the routing process:  
router iso-igrp orion  
2. Configure the net for the process in area 1, doma in47.0004.004d:  
net 47.0004.004d.0001.212223242526.00  
3. Specify iso-igrp routing using the previously specified tag orion:  
interface ethernet 0  
clns router iso-igrp orion  
4. Specify iso-igrp routing using the previously specified tag orion:  
interface ethernet 1  
clns router iso-igrp orion  
Example: Dynamic Routing in Overlapping Areas  
This example illustrates how to configure a router with overlapping ar-  
eas:  
1. Define a tag capricorn for the routing process:  
router iso-igrp capricorn  
2. Configure the NET for the process in area 3,  
domai n47.0004.004d:  
net 47.0004.004d.0003.0000.0C00.0508.00  
3. Define a tag cancer for the routing process:  
router iso-igrp cancer  
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4. Configure the NET for the process in area 4,  
domai n47.0004.004d:  
net 47.0004.004d.0004.0000.0C00.0506.00  
5. Specify iso-igrp routing on interface ethernet 0 using the tag cap-  
ricorn:  
interface ethernet 0  
clns router iso-igrp capricorn  
6. Specify iso-igrp routing on interface ethernet 1 using the tags cap-  
ricorn and cancer:  
interface ethernet 1  
clns router iso-igrp capricorn  
clns router iso-igrp cancer  
7. Specify iso-igrp routing on interface ethernet 2 using the tag can-  
cer:  
interface ethernet 2  
clns router iso-igrp cancer  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
Example: Dynamic Interdomain R outing  
Figure 9-7 and the example configurations illustrate how to configur  
three domains that are to be transparently connected.  
Figure 9-7:CLNS Dynamic Interdomain R outing  
Router Chicago  
This configuration shows how to configure Router Chicago for dy-  
namic interdomai nrouting:  
1. Define a tag A for the routing process:  
router iso-igrp A  
2. Configure the NET for the process in area 2,  
domai n47.0007.0200:  
net 47.0007.0200.0002.0102.0104.0506.00  
3. Redistribute iso-igrp routing information througho u t domainA:  
redistribute iso-igrp B  
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4. Define a tag B for the routing process:  
router iso-igrp B  
5. Configure the NET for the process in area 3,  
domai n47.0006.0200:  
net 47.0006.0200.0003.0102.0104.0506.00  
6. Redistribute iso-igrp routing information througho u t domainB:  
redistribute iso-igrp A  
7. Specify iso-igrp routing with the tag A:  
8. Specify iso-igrp routing with the tag B:  
interface ethernet 0  
clns router iso-igrp A  
interface serial 0  
clns router iso-igrp B  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
Router Detroit  
This configuration shows how to configure Router Detroit fordynamic  
interdomainrouting. Comment lines have been eliminated from this  
example to avoid redundancy.  
router iso-igrp B  
net 47.0006.0200.0004.0102.0104.0506.00  
redistribute iso-igrp C  
router iso-igrp C  
net 47.0008.0200.0005.0102.01040.506.00  
redistribute iso-igrp B  
interface serial 0  
clns router iso-igrp B  
interface serial 1  
clns router iso-igrp C  
Chicago injects a prefix route for domain A into domai nB. Domai nB  
injects this prefix route and a prefix route for doma inB into do mainC.  
You also can configure a border router between d o mainA and  
domai nC.  
Configure ISO IGRP Parameters  
Cisco's ISO IGRP implementation allows you to customize certain  
ISO IGRP parameters:  
z
z
z
Adjust ISO IGRP Metrics  
Adjust ISO IGRP Metrics  
You have the option of altering the default behavior of ISO IGRP rout-  
ing and metric computations. This allows, for example, the tuning of  
system behavior to allow for transmissions via satellite. Although ISO  
IGRP metric defaults were carefully selected to provide excellent op-  
eration in most networks, you can adjust the metric.  
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Warning: Adjusting the ISO IGRP metric can dramatically affect  
network performance, so ensure that all metric adjust-  
ments are made carefully. Because of the complexity of  
this task, it is not recommended unless it is done with  
guidance from an experienced system designer.  
You can use different metrics for the ISO IGRP routing protocol on  
CLNS. In router configuration mode, configure the metric constants  
used in the ISO IGRP composite metric calculation of reliability and  
load:  
metric weights qos k1 k2 k3 k4 k5  
Two additional ISO IGRP metrics can be configured: the bandwidth  
and delay associated with an interface.  
Warning: Using the bandwidthand delaycommands to change  
the values of the ISO IGRP metrics also changes the val-  
ues of IP IGRP metrics.  
Adjust ISO IGRP Timers  
The basic timing parameters for ISO IGRP are adjustable. Because the  
ISO IGRP routing protocol executes a distributed, asynchronous rout-  
ing algorithm, it is important that these timers be the same for all rout-  
ers in the network.  
In router configuration mode, adjust ISO IGRP timing parameters:  
timers basic update-interval holddown-  
interval invalidinterval  
Enable or Disable Split Horizon  
Split horizon blocks information about routes from being advertised  
out the interface from which that information originated. This feature  
usually optimizes communication among multiple routers, particularly  
when links are broken.  
In interface configuration mode, either enable or disable split horizon  
for ISO IGRP updates:  
z
Enable split horizon for ISO IGRP updates.  
clns split-horizon  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
z
Disable split horizon for ISO IGRP updates.  
no clns split-horizon  
The default for all LAN interfaces is for split horizon to be enabled;  
the default for WAN interfaces on X.25, Frame Relay, or SMDS net-  
works is for split horizon to be disabled.  
Configure IS-IS  
Dynamic Routing  
IS-IS is a dynamic routing specification described in ISO 10589.  
Cisco's implementation of IS-IS allows you to configure IS-IS as an  
ISO CLNS routing protocol.  
To configure IS-IS, complete these tasks. Only enabling IS-IS is re  
quired; the remainder of the tasks are optional, although you might b  
required to perform them depending upon your specific application.  
z
z
z
z
Enable IS-IS  
In addition, you can also configure these miscellaneous features:  
z
z
z
Filter routing information (refer to Create Packet-Forwarding Fil-  
Redistribute routing information from one routing process to an-  
Configure administrative distances (refer to Specify Preferred  
Routes)  
Enable IS-IS  
To configure IS-IS dynamic routing, you must enable the IS-IS routing  
process, identify the address for the router, and specify the interfaces  
that are to route IS-IS. CLNS routing is enabled by default when you  
configure IS-IS dynamic routing. You can specify only one IS-IS pro-  
cess per router.  
In global configuration mode, configure IS-IS dynamic routing on the  
router:  
1. Enable IS-IS routing and enter router configuration mode.  
router isis [tag]  
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2. Configure the NET for the routing process.  
net network-entity-title  
You can assign a meaningful name for the routing process by using the  
tag option. You can also specify a name for a NET in addition to an  
address. For information on how to assign a name, see Specify Short-  
In interface configuration mode, specify the interfaces that should be  
actively routing IS-IS:  
clns router isis [tag]  
Warning: For IS-IS, multiple NETs per router are allowed, with a  
maximum of three. However, only one ISIS process is al-  
lowed, whether you run it in integrated mode, ISO CLNS  
only, or IP only.  
Examples: IS-IS Routing Configuration  
These examples illustrate the basic syntax and configuration command  
sequence for IS-IS routing.  
Level1 and Level2 Routing  
This example illustrates using the IS-IS protocol to configure a single  
area address for Lev el1 and Le vel2 routing:  
1. Route dynamically using the IS-IS protocol:  
router isis  
2. Configure the NET for the process in area 47.0004.004d.0001:  
net 47.0004.004d.0001.0000.0c00.1111.00  
3. Enable IS-IS routing on ethernet 0:  
interface ethernet 0 clns router isis  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
4. Enable IS-IS routing on ethernet 1:  
interface ethernet 1  
clns router isis  
5. Enable IS-IS routing on serial 0:  
interface serial 0  
clns router isis  
Level2 Routing Only  
This example illustrates a similar configuration, featuring a single area  
address being used for specification of Level 1 and Level2 routing.  
However, in this case, interface serial interface 0 is configured for  
Level 2 routing only. Most comment lines have been eliminated from  
this example to avoid redundancy.  
router isis  
net 47.0004.004d.0001.0000.0c00.1111.00  
interface ethernet 0  
clns router isis  
interface ethernet 1  
clns router isis  
interface serial 0  
clns router isis  
1. Configure a level 2 adjacency only for interface serial 0:  
isis circuit-type level-2-only  
OSI Configuration  
This example illustrates an OSI configuration example. In this exam-  
ple, IS-IS runs with two area addresses, metrics tailored, and different  
circuit types specified for each interface. Most comment lines have  
been eliminated from this example to avoid redundancy.  
1. Enable IS-IS routing in area 1:  
router isis area1  
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2. Router is in areas 47.0004.004d.0001 and 47.0004.004d.0011:  
net 47.0004.004d.0001.0000.0c11.1111.00  
net 47.0004.004d.0011.0000.0c11.1111.00  
3. Enable the router to operate as a station router and an interare  
router:  
is-type level-1-2  
!
interface ethernet 0  
clns router isis area1  
4. Specify a cost of 5 for the level-1 routes:  
5. Establish a level-1 adjacency:  
isis metric 5 level-1  
isis circuit-type level-1  
!
interface ethernet 1  
clns router isis area1  
isis metric 2 level-2  
isis circuit-type level-2-only  
!
interface serial 0  
clns router isis area1  
isis circuit-type level-1-2  
6. Set the priority for serial 0 to 3 for a level-1 adjacency:  
isis priority 3 level-  
isis priority 1 level-  
ISO CLNS Dynamic Route Redistribution  
This example illustrates route redistribution between IS-IS and ISO  
IGRP domains. In this case, the IS-IS domain is on Ethernet interface  
0; the ISO IGRP doma inis on serial interface 0. The IS-IS routing pro-  
cess is assigned a null tag; the ISO IGRP routing process is assigned a  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
tag of remote-domain. Most comment lines have been eliminated from  
this example to avoid redundancy.  
router isis  
net 39.0001.0001.0000.0c00.1111.00  
1. Redistribute iso-igrp routing information throughout remote-do-  
main:  
redistribute iso-igrp remote-domai n  
!
router iso-igrp remote-domain  
net 39.0002.0001.0000.0c00.1111.00  
2. Redistribute IS-IS routing information:  
redistribute isis  
!
interface ethernet 0  
clns router isis  
!
interface serial 0  
clns router iso-igrp remote  
Assign Multiple Area Addresses to IS-IS Areas  
IS-IS routing supports the assignment of multiple area addresses on  
the same router. This concept is referred to as multihoming. Multi-  
homing provides a mechanism for smoothly migrating network ad-  
dresses as:  
z
Splitting up an area. Nodes within a given area can accumulate to  
a point that they are difficult to manage, cause excessive traffic, or  
threaten to exceed the usable address space for an area. Multiple  
area addresses can be assigned so that you can smoothly partition  
a network into separate areas without disrupting service.  
z
z
Merging areas. Use transitional area addresses to merge as many  
as three separate areas into a single area that share a common area  
address.  
Transition to a different address. You may need to change an are  
address for a particular group of nodes. Use multiple area address-  
es to allow incoming traffic intended for an old area address to  
continue being routed to associated nodes.  
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You must statically assign the multiple area addresses on the router.  
You can assign up to three area addresses on the AI2524. The number  
of areas allowed in a doma inis unlimited.  
All the addresses must have the same system ID. For example, you can  
assign one address (area1 plus system ID), and two additional ad-  
dresses in different areas (area2 plus system ID and area3 plus system  
ID) where the system ID is the same.  
A router can dynamically learn about any adjacent router. As part o  
this process, the routers inform each other of their area addresses. If  
two routers share at least one area address, the set of area addresses of  
the two routers are merged. The merged set cannot contain more than  
three addresses. If there are more than three, the three addresses with  
the lowest numerical values are kept, and all others are dropped.  
Beginning in global configuration mode, configure multiple area ad  
dresses in IS-IS areas:  
1. Enable IS-IS routing and enter router configuration mode.  
router isis [tag]  
2. Configure NETs for the routing process. The router can have up to  
three NETs. Enter each command separately.  
Examples: NETs Configuration  
These are examples of configuring NETs for both ISO IGRP and  
IS-IS.  
ISO IGRP  
This example illustrates specifying a NET:  
router iso-igrp Finance  
net 47.0004.004d.0001.0000.0c11.1111.00  
This example illustrates using a name for a NET:  
clns host NAME 39.0001.0000.0c00.1111.00  
router iso-igrp Marketing  
net NAME  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
The use of this netrouter configuration command configures the sys-  
tem ID, area address, and d omainaddress. Only a single NET per rout-  
ing process is allowed.  
router iso-igrp local  
net 49.0001.0000.0c00.1111.00  
IS-IS  
This example illustrates specifying a single NET:  
router isis Pieinthesky  
net 47.0004.004d.0001.0000.0c11.1111.00  
This example illustrates using a name for a NET:  
clns host NAME 39.0001.0000.0c00.1111.00  
router isis  
net NAME  
IS-IS Multihoming  
This example illustrates the assignment of three separate area ad  
dresses for a single router using net commands. Traffic received that  
includes an area address of 47.0004.004d.0001, 47.0004.004d.0002,  
or 47.0004.004d.0003, and that has the same system ID, is forwarded  
to this router.  
router isis eng-area1  
! | IS-IS Area|  
System ID| S|  
net 47.0004.004d.0001.0000.0C00.1111.00  
net 47.0004.004d.0002.0000.0C00.1111.00  
net 47.0004.004d.0003.0000.0C00.1111.00  
Example: Router in Two Areas  
These two examples show how to configure a router in two areas. The  
first example configures ISO IGRP; the second configures IS-IS.  
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ISO IGRP  
In this example, the router is in domai n49.0001 and has a system ID  
of aaaa.aaaa.aaaa. The router is in two areas: 31 and 40 (decimal).Fig-  
ure 9-8 illustrates this configuration.  
Figure 9-8:ISO IGRP Configuration  
router iso-igrp test-proc1  
001F in this example net is the hex value for area 31:  
net 49.0001.001F.aaaa.aaaa.aaaa.00  
router iso-igrp test-proc2  
0028 in this example net is the hex value for area 40:  
net 49.0001.0028.aaaa.aaaa.aaaa.00  
!
interface ethernet 1  
clns router iso-igrp test-proc1  
!
interface serial 2  
clns router iso-igrp test-proc1  
!
interface ethernet 2  
clns router iso-igrp test-proc2  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
IS-IS  
To run IS-IS instead of ISO IGRP, use this configuration. The illustra-  
tion in Figure 9- still applies. Ethernet interface 2 is configured for  
IS-IS routing and is assigned the tag of test-proc2.  
router iso-igrp test-proc1  
net 49.0002.0002.bbbb.bbbb.bbbb.00  
router isis test-proc2  
net 49.0001.0002.aaaa.aaaa.aaaa.00  
!
interface ethernet 1  
clns router iso-igrp test-proc1  
!
interface serial 2  
clns router iso-igrp test-proc1  
!
interface ethernet 2  
clns router IS-IS test-proc2  
To allow CLNS packets only to blindly pass through an interface with-  
out routing updates, you could use a simple configuration. This exam-  
ple shows such a configuration:  
clns routing  
interface serial 2  
This permits serial 2 to pass CLNS packets without having CLNS rout-  
ing turned on:  
clns enable  
Configure IS-IS Parameters  
Cisco's IS-IS implementation allows you to customize certain IS-IS  
parameters. You can perform the optional tasks:  
z
z
z
z
z
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Specify Router-Lev elSupport  
It is seldom necessary to configure the IS type because the IS-IS pro-  
tocol will automatically establish this. However, you can configure th  
AI2524 to act as a Le vel1 (intra-area) router, as both a Level1 router  
and a Leve l2 (interarea) router, or as an interarea router only.  
In router configuration mode, configure the IS-IS level at which the  
router is to operate:  
is-type {level-1 | level-1-2 | level-2-  
only}  
Configure IS-IS Authentication Passwords  
You can assign authentication passwords to areas and domains. An  
area password is inserted in Level 1 (station router) link-state PDUs  
(LSPs), complete sequence number PDUs (CSNPs), and partial se-  
quence number PDUs (PSNPs). A routi ng domainauthentication  
password is inserted in Leve l2 (area router) LSP, CSNP, and PSNP.  
In router configuration mode, configure area or domain passwords:  
1. Configure the area authentication password.  
area-password password  
2. Configure the routin g domainauthentication password.  
domain-password password  
Ignore IS-IS Link-State Packet (LSP) Errors  
You can configure the router to ignore IS-IS LSPs that are received  
with internal checksum errors, rather than purging the LSPs. LSPs are  
used by the receiving routers to maintain their routing tables.  
The IS-IS protocol definition requires that a received LSP with an in-  
correct data-link checksum be purged by the receiver, which causes  
the initiator of the LSP to regenerate it. However, if a network has a  
link that causes data corruption while still delivering LSPs with correct  
data-link checksums, a continuous cycle of purging and regenerating  
large numbers of LSPs can occur, rendering the network nonfunc-  
tional.  
In router configuration mode, allow the router to ignore LSPs with an  
internal checksum error:  
ignore-lsp-errors  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
Log Adjacency State Changes  
You can configure IS-IS to generate a log message when an IS-IS ad  
jacency changes state (up or down). This may be useful when monitor-  
ing large networks. Messages are logged using the system error  
message facility. Messages are in this form:  
%CLNS-5-ADJCHANGE: ISIS: Adjacency to 0000.0000.0034 (Serial0) Up, new adjacency  
%CLNS-5-ADJCHANGE: ISIS: Adjacency to 0000.0000.0034 (Serial0) Down, hold time  
expired  
In router configuration mode, generate log messages when an IS-IS  
adjacency changes state:  
log-adjacency-changes  
Change IS-IS LSP MTU Size  
Under normal conditions, the default maximum transmission unit  
(MTU) size should be sufficient. However, if the MTU of a link is low-  
ered to less than 1500 bytes, the LSP MTU must be lowered accord-  
ingly on each router in the network. If this is not done, routing will  
become unpredictable.  
The MTU size must be less than or equal to the smallest MTU of any  
link in the network. The default size is 1497 bytes.  
Caution: The CLNS MTU of a link (which is the applicable value  
for IS-IS, even if it is being used to route IP) may differ  
from the IP MTU. To be certain about a link MTU as it  
pertainsto IS-IS, use the show clnsinterface command  
to display the value.  
In router configuration mode, change the MTU size of IS-IS link state  
packets:  
lsp-mtu size  
Warning: This rule applies for all routers in a network. If any link  
in the network has a reduced MTU, all routers must b  
changed, not just the routers directly connected to th  
link.  
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Configure IS-IS Interface Parameters  
Cisco's IS-IS implementation allows you to customize certain inter-  
face-specific IS-IS parameters:  
z
z
z
z
z
z
z
You are not required to alter any of these parameters, but some inter  
face parameters must be consistent across all routers in the network.  
Therefore, if you do configure any of these parameters, be sure the  
configurations for all routers on the network have compatible values.  
Adjust IS-IS Link-State Metrics  
You can configure a cost for a specified interface. The default metric  
is used as a value for the IS-IS metric. This is the value assigned when  
there is no quality of service (QOS) routing performed. The only met-  
ric that is supported by the Cisco IOS software and that you can con-  
figure is the default-metric, which you can configure for L evel1 or  
Level 2 routing or both.  
In interface configuration mode, configure the link state metric:  
isis metric default-metric {level-1 |  
level-2}  
Set the Advertised Hello Interval and Hello Multiplier  
You can specify the length of time (in seconds) between hello packets  
that the Cisco IOS software sends on the interface. You can also  
change the default hello packet multiplier used on the interface to de-  
termine the hold time transmitted in IS-IS hello packets (the default is  
3).  
The hold time determines how long a neighbor waits for another hello  
packet before declaring the neighbor down. This time determines how  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
quickly a failed link or neighbor is detected so that routes can be recal-  
culated.  
In interface configuration mode, set the advertised hello interval and  
multiplier:  
1. Specify the length of time, in seconds, between hello packets th  
software sends on the specified interface.  
isis hello-interval seconds {level-1 |  
level-2}  
2. Specify the number used to multiply the hello interval seconds by  
to determine the total holding time transmitted in the IS-IS hello  
packet. If not specified, a multiplier of 3 is used.  
isis hello-multiplier multiplier [{level-1  
| level-2}]  
The hello interval can be configured independently for Level1 and  
Level 2, except on serial point-to-point interfaces. (Because there is  
only a single type of hello packet sent on serial links, the hello packet  
is independent of Lev el1 or Lev el2.) Specify an optional level for  
X.25, SMDS, and Frame Relay multiaccess networks.  
Use the isis hello-multiplier command in circumstances  
where hello packets are lost frequently and IS-IS adjacencies are fail-  
ing unnecessarily. You can raise the hello multiplier and lower th  
hello interval (isis hello-interval command) correspond  
ingly to make the hello protocol more reliable without increasing th  
time required to detect a link failure.  
Set the Advertised CSNP Interval  
CSNPs are sent by the designated router to maintain database synchro-  
nization.  
In interface configuration mode, configure the IS-IS CSNP interval fo  
the interface:  
isis csnp-interval seconds {level-1 |  
level-2}  
This feature does not apply to serial point-to-point interfaces. It does  
apply to WAN connections if the WAN is viewed as a multiaccess  
meshed network.  
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Set the Retransmission Interval  
In interface configuration mode, configure the number of seconds be  
tween retransmission of LSPs for point-to-point links.  
isis retransmit-interval seconds  
The value you specify should be an integer greater than the expected  
round-trip delay between any two routers on the network. The setting  
of this parameter should be conservative, or needless retransmission  
will result. The value you determine should be larger for serial lines  
and virtual links.  
Specify Designated Router Election  
You can configure the priority to use for designated router election.  
Priorities can be configured for Level1 an d Level2 individually. Th  
designated router enables a reduction in the number of adjacencies re-  
quired on a multiaccess network, which in turn reduces the amount of  
routing protocol traffic and the size of the topology database.  
In interface configuration mode, configure the priority to use for des-  
ignated router election:  
isis priority value {level-1 | level-2}  
Specify the Interface Circuit Type  
It is normally not necessary to configure this feature because the IS-IS  
protocol automatically determines area boundaries and keeps L evel1  
and Leve l2 routing separate. However, you can specify the adjacency  
levels on a specified interface.  
In interface configuration mode, configure the adjacency for neigh-  
bors on the specified interface:  
isis circuit-type {level-1 | level-1-2 |  
level-2-only}  
If you specify Level 1, a Level 1 adjacency is established if there is at  
least one area address common to both this node and its neighbors.  
If you specify both Le vel1 and L evel2 (the default value), a Level1  
and 2 adjacency is established if the neighbor is also configured as  
both Leve l1 and Lev el2 and there is at least one area in common. If  
there is no area in common, a Leve l2 adjacency is established.  
If you specify Leve l2 only, a Le vel2 adjacency is established. If the  
neighbor router is a Leve l1 router, no adjacency is established.  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
Configure IS-IS Password Authentication  
You can assign different authentication passwords for different rout-  
ing levels. By default, authentication is disabled. Specifying Lev el1 or  
Level 2 enables the password only for Le vel1 or L evel2 routing, re-  
spectively. If you do not specify a level, the default is Le vel1.  
In interface configuration mode, configure an authentication password  
for an interface:  
isis password password {level-1 | level-2}  
Configure CLNS  
Static Routing  
You do not need to explicitly specify a routing process to use stati  
routing facilities. You can enter a specific static route and apply it glo-  
bally, even if you have configured the router for ISO IGRP or IS-IS dy-  
namic routing.  
To configure a static route, complete the tasks in the following sec-  
tions. Only enabling static routes is required; the remaining tasks may  
be necessary for certain applications, but are otherwise optional.  
z
z
z
Enable Static Routes  
Enable Static Routes  
To configure static routing, you must enable CLNS on the router and  
on the interface. CLNS routing is enabled on the router by default  
when you configure ISO IGRP or IS-IS routing protocols. NSAP ad-  
dresses that start with the NSAP prefix you specify are forwarded to  
the next-hop node.  
In global configuration mode, configure CLNS on the router:  
1. Configure CLNS.  
clns routing  
2. Assign an NSAP address to the router if the router has not been  
configured to route CLNS packets dynamically using ISO IGRP  
or IS-IS.  
clns net {net-address | name}  
3. Enter a specific static route.  
clns route nsap-prefix {next-hop-net |  
name}  
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Warning: If you have not configured the router to route CLNS pack-  
ets dynamically using ISO IGRP or IS-IS, you must as  
sign an address to the router.  
You also must enable ISO CLNS for each interface you want to pass  
ISO CLNS packet traffic to end systems, but for which you do not  
want to perform any dynamic routing on the interface. This is done au-  
tomatically when you configure IS-IS or ISO IGRP routing on an in-  
terface; however, if you do not intend to perform any dynamic routing  
on an interface, you must manually enable CLNS. You can assign an  
NSAP address for a specific interface. This allows the Cisco IOS soft-  
ware to advertise different addresses on each interface. This is useful  
if you are doing static routing and need to control the source NET used  
by the router on each interface.  
In interface configuration mode, configure CLNS on an interface:  
1. Enable ISO CLNS for each interface.  
clns enable  
2. Optionally, assign an NSAP address to a specific interface.  
clns net {nsap-address | name}  
Examples: Basic Static Routing  
Configuring FDDI, Ethernets, Token Rings, and serial lines for CLNS  
can be as simple as enabling CLNS on the interfaces. This is all that is  
ever required on serial lines using HDLC encapsulation. If all systems  
on an Ethernet or Token Ring support ISO 9542 ES-IS, then nothing  
else is required.  
Example 1  
This example illustrates how an Ethernet and a serial line can be con-  
figured:  
1. Enable clns packets to be routed:  
clns routing  
2. Configure this network entity title for the routing process:  
clns net 47.0004.004d.0055.0000.0C00.BF3B.00  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
3. Pass ISO CLNS traffic on ethernet 0 to end systems without rout-  
ing:  
interface ethernet 0  
clns enable  
4. Pass ISO CLNS traffic on serial 0 to end systems without routing:  
interface serial 0  
clns enable  
5. Create a static route for the interface:  
clns route 47.0004.004d.0099 serial 0  
clns route 47.0005 serial 0  
Example 2  
This is a more complete example of CLNS static routing on a system  
with two Ethernet interfaces. After configuring routing, you define  
NET and enable CLNS on the Ethernet 0 and Ethernet 1 interfaces.  
You must then define an ES neighbor and define a staticroute with the  
clns route global configuration command, as shown. In this situ-  
ation, there is an ES on Ethernet 1 that does not support ES-IS.Figur  
9-9 illustrates this network.  
Figure 9-9:Static Routing  
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clns host sid 39.0001.1111.1111.1111.00  
clns host bar 39.0002.2222.2222.2222.00  
1. Assign a static address for the router:  
clns net sid  
clns routing  
2. Enable CLNS packets to be routed:  
3. Pass ISO CLNS packet traffic to end systems without routing  
them:  
interface ethernet 0  
clns enable  
4. Pass ISO CLNS packet traffic to end systems without routing  
them:  
interface ethernet 1  
clns enable  
5. Specify end system for static routing:  
clns es-neighbor bar 0000.0C00.62e7  
6. Create an interface-static route to bar for packets with the this  
NSAP address:  
clns route 47.0004.000c bar  
Example: Static Intradomain Routing  
Figure 9-10, and the configurations demonstrate how to use static rout-  
ing inside of a domain. Imagine a company with branch offices in De-  
troit and Chicago, connected with an X.25 link. These offices are both  
in the domai nnamed Sales.  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
Figure 9-10:CLNS X.25 Intradomain Routing  
This example shows one way to configure the router in Chicago:  
1. Define the name chicago to be used in place of this NSAP:  
clns host chicago 47.0004.0050.0001.0000.0c00.243b.00  
2. Define the name detroit to be used in place of this NSAP:  
clns host detroit 47.0004.0050.0002.0000.0c00.1e12.00  
3. Enable ISO IGRP routing of CLNS packets:  
router iso-igrp sales  
4. Configure net chicago, as shown in steps 1-3:  
net chicago  
5. Specify iso-igrp routing using the specified tag sales:  
interface ethernet 0  
clns router iso-igrp sales  
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6. Set the interface up as a DTE with X.25 encapsulation:  
interface serial 0  
encapsulation x25  
x25 address 1111  
x25 nvc 4  
7. Specify iso-igrp routing using the specified tag sales:  
clns router iso-igrp sales  
8. Define a static mapping between Detroit's nsap and its X.121 ad-  
dress:  
x25 map clns 2222 broadcast  
This configuration brings up an X.25 virtual circuit between the router  
in Chicago and the router in Detroit. Routing updates will be sent  
across this link. This implies that the virtual circuit could be up contin-  
uously.  
If the Chicago office should grow to contain multiple routers, it would  
be appropriate for each of those routers to know how to get to Detroit.  
Add the following command to redistribute information between rout-  
ers in Chicago:  
router iso-igrp sales  
redistribute static  
Example: Static InterdomainRo uting  
Figure 9-11 and the example configurations illustrate how to configure  
two routers that distribute information across domains. In this exam-  
ple, Router A (in dom ainOrion) and Router B (i n domainPleiades)  
communicate across a serial link.  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
Figure 9-11:CLNS Interdomain S tatic Routing  
Router A  
This configuration shows how to configure Router A for stati  
interdomainrouting:  
1. Define tag orion for net 47.0006.0200.0100.0102.0304.0506.00:  
router iso-igrp orion  
2. Configure this network entity title for the routing process:  
net 47.0006.0200.0100.0102.0304.0506.00  
3. Define the tag bar to be used in place of Router B's NSAP:  
clns host bar 47.0007.0200.0200.1112.1314.1516.00  
4. Specify iso-igrp routing using the specified tag orion:  
interface ethernet 0  
clns router iso-igrp orion  
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5. Pass ISO CLNS traffic to end systems without routing:  
interface serial 1  
clns enable  
6. Configure a static route to Router B:  
clns route 39.0001 bar  
Router B  
This configuration shows how to configure Router B for static  
interdomainrouting:  
router iso-igrp pleiades  
1. Configure the network entity title for the routing process:  
net 47.0007.0200.0200.1112.1314.1516.00  
2. Define the name sid to be used in place of Router A's NSAP:  
clns host sid 47.0006.0200.0100.0001.0102.0304.0506.00  
3. Specify iso-igrp routing using the specified tag pleiades:  
interface ethernet 0  
clns router iso-igrp pleiades  
4. Pass ISO CLNS traffic to end systems without routing:  
interface serial 0 clns enable  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
5. Pass packets bound for sid in dom ain47.0006.0200 through serial  
0:  
clns route 47.0006.0200 sid  
CLNS routing updates will not be sent on the serial link; however,  
CLNS packets will be sent and received over the serial link.  
Configure Variations of the Static Route  
These tasks include variations of the clns routeglobal configura-  
tion command:  
z
Bind the next hop to a specified interface and media address when  
you do not know the NSAP address of your neighbor. Note that  
this version of the clns route command is not literally applied to a  
specific interface.  
clns route nsap-prefix type number [snpa-  
address]  
z
z
Tell the Cisco IOS software to discard packets with the specified  
NSAP prefix.  
clns route nsap-prefix discard  
Specify a default prefix.  
clns route default nsap-prefix type number  
Map NSAP Addresses to Media Addresses  
Conceptually, each ES lives in one area. It discovers the nearest IS by  
listening to ES-IS packets. Each ES must be able to communicate di  
rectly with an IS in its area.  
When an ES wants to communicate with another ES, it sends the  
packet to any IS on the same medium. The IS looks up the destination  
NSAP address and forwards the packet along the best route. If the des-  
tination NSAP address is for an ES in another area, the Level1 IS  
sends the packet to the nearest Lev el2 IS. The Lev el2 IS forwards the  
packet along the best path for the destination area until it gets to a  
Level 2 IS that is in the destination area. This IS then forwards the  
packet along the best path inside the area until it is delivered to the des-  
tination ES.  
ESs need to know how to get to a Level1 IS for their area, a nd Level1  
ISs need to know all of the ESs that are directly reachablethrough each  
of their interfaces. To provide this information, the routers support the  
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ES-IS protocol. The router dynamically discovers all ESs running the  
ES-IS protocol. ESs that are not running the ES-IS protocol must be  
configured statically.  
It is sometimes desirable for a router to have a neighbor configured  
statically rather than learned through ES-IS, ISO IGRP, or IS-IS.  
Warning: It is necessary to use static mapping only for ESs that do  
not support ES-IS. The Cisco IOS software continues to  
dynamically discover ESs that do support ES-IS. If you  
have configured interfaces for ISO IGRP or IS-IS, the  
ES-IS routing software automatically turns on ES-IS for  
those interfaces.  
In interface configuration mode, enter static mapping information be-  
tween the NSAP protocol addresses and the subnetwork point of at  
tachment (SNPA) addresses (media) for ESs or ISs, as needed:  
z
Configure all end systems that will be used when you manually  
specify the NSAP-to-SNPA mapping.  
clns es-neighbor nsap snpa  
z
Configure all intermediate systems that will be used when you  
manually specify the NSAP-to-SNPA mapping.  
clns is-neighbor nsap snpa  
For more information, refer to Configure CLNS over WANs.  
Warning: The SNPA is a data link layer address (such as an Ether-  
net address, X.25 address, or Frame Relay DLCI address)  
used to configure a CLNS route for an interface.  
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Configure  
Miscellaneous  
Features  
Perform these optional tasks to configure miscellaneous features of an  
ISO CLNS network:  
z
z
Specify Shortcut NSAP Addresses  
z
z
z
z
Specify Shortcut NSAP Addresses  
You can define a name-to-NSAP address mapping. This name can  
then be used in place of typing the long set of numbers associated with  
an NSAP address.  
In global configuration mode, define a name-to-NSAP address map-  
ping:  
clns host name nsap  
The assigned NSAP name is displayed, where applicable, inshowand  
debugEXEC commands. However, some effects and requirements  
are associated with using names to represent NETs and NSAP ad  
dresses.  
The clns hostglobal configuration command is generated after all  
other CLNS commands when the configuration file is parsed. As a re-  
sult, you cannot edit the nonvolatile random access memory  
(NVRAM) version of the configuration to specifically change the ad-  
dress defined in the original clns hostcommand. You must spe-  
cifically change any commands that refer to the original address. This  
affects all commands that accept names.  
The commands that are affected by these requirements include:  
z net(router configuration command  
z clns is-neighbor (interface configuration command)  
z clns es-neighbor (interface configuration command)  
z clns route (global configuration command)  
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Use the IP DomainNa me System to Discover ISO CLNS  
Addresses  
If your router has both ISO CLNS and IP enabled, you can use the  
Domain Naming System (DNS) to query ISO CLNS addresses by  
using the NSAP address type, as documented in RFC 1348. This fea-  
ture is useful for the ISO CLNS pingEXEC command and when  
making Telnet connections. This feature is enabled by default.  
In global configuration mode, enable or disable DNS queries for IS  
CLNS addresses:  
z
Enable DNS queries for CLNS addresses.  
ip domain-lookup nsap  
z
Disable DNS queries for CLNS addresses.  
no ip domain-lookup nsap  
Create Packet-Forwarding Filters and Establish  
Adjacencies  
You can build powerful CLNS filter expressions, or access lists. These  
can be used to control either the forwarding of frames through route  
interfaces, or the establishment of adjacencies with, or the application  
of filters to, any combination of ES or IS neighbors, ISO IGRP neigh-  
bors, or IS-IS neighbors.  
CLNS filter expressions are complex logical combinations of CLNS  
filter sets. CLNS filter sets are lists of address templates against which  
CLNS addresses are matched. Address templates are CLNS address  
patterns that are either simple CLNS addresses that match just one ad-  
dress, or match multiple CLNS addresses through the use of wildcard  
characters, prefixes, and suffixes. Frequently used address templates  
can be given aliases for easier reference.  
1. In global configuration mode, establish CLNS filters:  
z
z
Create aliases for frequently used address templates.  
clns template-alias name template  
Build filter sets of multiple address template permit and deny con-  
ditions.  
clns filter-set sname [permit | deny]  
template  
z
Build filter expressions, using one or more filter sets.  
clns filter-expr ename term  
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2. In interface configuration mode, apply filter expressions to an in-  
terface:  
z
Apply a filter expression to frames forwarded in or out of an inter-  
face.  
clns access-group name [in | out]  
z
z
z
Apply a filter expression to ISIS adjacencies.  
isis adjacency-filter name [match-all]  
Apply a filter expression to ISO IGRP adjacencies.  
iso-igrp adjacency-filter name  
Apply a filter expression to ES or IS adjacencies.  
clns adjacency-filter {es | is} name  
Examples: CLNS Filter  
This example allows packets if the address starts with either 47.0005  
or 47.0023. It implicitly denies any other address.  
clns filter-set US-OR-NORDUNET permit 47.0005...  
clns filter-set US-OR-NORDUNET permit 47.0023...  
Redistribute Routing Information  
In addition to running multiple routing protocols simultaneously, the  
Cisco IOS software can redistribute information from one routing pro-  
cess to another.  
You can also configure the Cisco IOS software to do  
interdomain d ynamic routing by configuring two routing processes  
and two NETs (thereby putting the router into two domains) and redis-  
tributing the routing information between the domains. Routers con-  
figured this way are referred to as border routers. If you have a router  
that is in two routing domains, you might want to redistribute routing  
information between the two domains.  
Warning: It is not necessary to use redistribution between areas. Re-  
distribution only occurs for Le vel2 routing.  
1. In global configuration mode, configure the router to redistribute  
routing information into the ISO IGRP domain:  
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z
z
Specify the routing protocol and tag (if applicable) into which you  
want to distribute routing information.  
router iso-igrp [tag]  
Specify one or more ISO IGRP routing protocol and tag (if appli-  
cable) you want to redistribute.  
redistribute iso-igrp [tag] [route-map map-  
tag]  
z
z
Specify the IS-IS routing protocol and tag (if applicable) you want  
to redistribute.  
redistribute isis [tag] [route-map map-tag]  
Specify the static routes you want to redistribute.  
redistribute static [clns | ip]  
2. Beginning in global configuration mode, configure the router to  
redistribute routing information into the IS-IS domains:  
z
Specify the routing protocol and tag (if applicable) into which you  
want to distribute routing information.  
router isis [tag]  
z
Specify the IS-IS routing protocol and tag (if applicable) you want  
to redistribute.  
redistribute isis [tag] [route-map map-tag]  
Warning: By default, static routes are redistributed into IS-IS.  
You can conditionally control the redistribution of routes between  
routing domains by defining route maps between the two domains.  
Route maps allow you to use tags in routes to influence route redistri-  
bution.  
3. In global configuration mode, conditionally control the redistribu-  
tion of routes between domains:  
route-map map-tag {permit | deny} sequence-  
number  
One or more matchcommand and one or more setcommands typ-  
ically follow a route-mapcommand to define the conditions for re-  
distributing routes from one routing protocol into another. If there are  
no matchcommands, everything matches. If there are no setcom-  
mands, nothing is done (other than the match).  
Each route-mapcommand has a list of matchand setcommands  
associated with it. The matchcommands specify the match criteria—  
the conditions under which redistribution is allowed for the current  
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route-mapcommand. The setcommands specify the redistribu-  
tion set actions—the particular redistribution actions to perform if th  
criteria enforced by th matchcommands are met. When all matc  
criteria are met, all setactions are performed  
The match route-map configuration command has multiple for-  
mats. The matchcommands may be given in any order, and all de-  
fined match criteria must be satisfied to cause the route to be  
redistributed according to th setactions given with the setcom-  
mands.  
In route-map configuration mode, define the match criteria for redis-  
tribution of routes from one routing protocol into another by perform-  
ing at least one of these  
z
z
z
z
Match routes that have a network address matching one or more of  
the specified names (the names can be a standard access list, filter  
set, or expression).  
match clns address name [name...name]  
Match routes that have a next hop address matching one or more  
of the specified names (the names can be a standard access list, fil-  
ter set, or expression).  
match clns next-hop name [name...name]  
Match routes that have been advertised by routers matching one or  
more of the specified names (the names can be a standard access  
list, filter set, or expression).  
match clns route-source name [name...name]  
Match routes that have the next hop out matching one or more o  
the specified interfaces.  
match clns interface type number [type  
number...type number]  
z
z
Match routes that have the specified metric.  
match metric metric-value  
Match routes that have the specified route type.  
match route-type {level-1 | level-2}  
In route-map configuration mode, define setactions for redistribu-  
tion of routes from one routing protocol into another by performing at  
least one of these:  
z
Set the routing level of the routes to be advertised into a specified  
are of the routing domain.  
set level {level-1 | level-2 | level-1-2}  
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z
z
z
Set the metric value to give the redistributed routes.  
set metric metric-value  
Set the metric type to give the redistributed routes.  
set metric-type {internal | external}  
Set the tag value to associate with the redistributed routes.  
set tag tag-value  
Examples: Route Map  
This example redistributes two types of routes into the integrated IS-IS  
routing table (supporting both IP and CLNS). The first routes are  
OSPF external IP routes with tag 5, and these are inserted into level-2  
IS-IS LSPs with a metric of 5. The second routes are ISO IGRP de  
rived CLNS prefix routes that match CLNS filter expression osifilter.  
These are redistributed into IS-IS as level-2 LSPs with a metric of 30.  
router isis  
redistribute ospf 109 route-map ipmap  
redistribute iso-igrp nsfnet route-map osimap  
!
route-map ipmap permit  
match route-type external  
match tag 5  
set metric 5  
set level level-2  
!
route-map osimap permit  
match clns address osifilter  
set metric 30  
clns filter-set osifilter permit 47.0005.80FF.FF00  
Given this configuration, a RIP learned route for network 160.89.0.0  
and an ISO IGRP learned route with prefix 49.0001.0002 will be re  
distributed into an IS-IS level-2 LSP with a metric of 5. For example:  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
router isis  
redistribute rip route-map ourmap  
redistribute iso-igrp remote route-map ourmap  
!
route-map ourmap permit  
match ip address 1  
match clns address ourprefix  
set metric 5  
set level level-2  
!
access-list 1 permit 160.89.0.0 0.0.255.255  
clns filter-set ourprefix permit 49.0001.0002...  
Specify Preferred Routes  
When multiple routing processes are running in the same router for  
CLNS, it is possible for the same route to be advertised by more than  
one routing process. The Cisco IOS software always picks the route  
whose routing protocol has the lowest administrative distance. The  
lower the value of the distance, the more preferred the route.  
By default, these administrative distances are assigned:  
z
z
z
Static routes—10  
ISO IGRP routes—100  
IS-IS routes—110  
In router configuration mode, change an administrative distance for a  
route:  
distance value [clns]  
If you want an ISO IGRP prefix route to override a static route, you  
must set the distance for the routing process to be lower than 10.  
Configure ES-IS Hello Packet Parameters  
You can configure ES-IS parameters for communication between end  
systems and routers. In general, you should leave these parameters at  
their default values.  
When configuring an ES-IS router, be aware of these items:  
z
ES-IS does not run over X.25 links unless the broadcast facility is  
enabled.  
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z
ES hello packets and IS hello packets are sent without options. Op-  
tions in received packets are ignored.  
ISs and ESs periodically send out hello packets to advertise their avail-  
ability. The frequency of these hello packets can be configured.  
The recipient of a hello packet creates an adjacency entry for the sys-  
tem that sent it. If the next hello packet is not received within the in-  
terval specified, the adjacency times out and the adjacent node is  
considered unreachable. A default rate has been set for hello packets  
and packet validity, but it can be changed.  
In global configuration mode, change the defaults:  
z
z
Specify the rate at which ES hello and IS hello packets are sent.  
clns configuration-time seconds  
Allow the sender of an ES hello or IS hello packet to specify the  
length of time you consider the information in these packets to be  
valid.  
clns holding-time seconds  
A default rate has been set for the ES Configuration Timer (ESCT) op-  
tion, but it can be changed.  
In interface configuration mode, specify how often the end system  
should transmit ES hello packet PDUs:  
clns esct-time seconds  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
Configure CLNS  
over WANs  
This section provides general information about running ISO CLNS  
over WANs.  
You can use CLNS routing on serial interfaces with HDLC, PPP,  
LAPB, X.25, Frame Relay, DDR, or SMDS encapsulation. To use  
HDLC encapsulation, you must have a router at both ends of the link.  
If you use X.25 encapsulation, and if IS-IS or ISO IGRP is not used on  
an interface, you must manually enter the NSAP-to-X.121 address  
mapping. The LAPB, SMDS, Frame Relay, and X.25 encapsulations  
interoperate with other vendors.  
Both ISO IGRP and IS-IS can be configured over WANs.  
X.25 is not a broadcast medium and, therefore, does not broadcast pro-  
tocols (such as ES-IS) that automatically advertise and record map-  
pings between NSAP/NET (protocol addresses) and SNPA (media  
addresses). (With X.25, the SNPAs are the X.25 network addresses, or  
the X.121 addresses. These are usually assigned by the X.25 network  
provider.) If you use static routing, you must configure the NSAP-to  
X.121 address mapping with th x25 mapcommand.  
Configuring a serial line to use CLNS over X.25 requires configuring  
the general X.25 information and the CLNS-specific information.  
First, configure the general X.25 information. Then, enter the CLNS  
static mapping information.  
You can specify X.25 nondefault packet and window sizes, reverse  
charge information, and so on. The X.25 facilities information that can  
be specified is exactly the same as in the x25 mapinterface configu-  
ration command.  
Example: ISO CLNS over X.25  
In this example, serial interface 1 on Router A acts as a DTE for X.25.  
It permits broadcasts to pass through. Router B is an IS, which has  
CLNS address of 49.0001.bbbb.bbbb.bbbb.00 and an X.121 address of  
31102. Router A has a CLNS address of 49.0001.aaaa.aaaa.aaaa.00  
and an address of 31101. Figure 9-12 illustrates this configuration.  
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Figure 9-12:Routers Acting as DTEs and DCEs  
Router A  
router iso-igrp test-proc  
net 49.0001.aaaa.aaaa.aaaa.00  
!
interface serial 1  
clns router iso-igrp test-proc  
1. Assume the host is a DTE and encapsulates x.25:  
encapsulation x25  
X25 address 31101  
2. Define the X.121 address of 31101 for serial 1:  
3. Set up an entry for the other side of the X.25 link (Router B):  
x25 map clns 31101 broadcast  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
Router B  
router iso-igrp test-proc  
net 49.0001.bbbb.bbbb.bbbb.00  
!
interface serial 2  
clns router iso-igrp test-proc  
1. Configure this side as a DCE:  
encapsulation x25-dce  
X25 address 31102  
2. Define the X.121 address of 31102 for serial 2:  
3. Configure the NSAP of Router A and accept reverse charges:  
x25 map clns 31101 broadcast accept-reverse  
Enhance ISO  
CLNS  
Performance  
Generally, you do not need to change the router's default settings for  
CLNS packet switching, but there are some modifications you can  
make when you decide to make changes in your network's perfor  
mance. The following sections describe ISO CLNS parameters that  
you can change:  
z
z
z
z
z
z
z
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Specify the MTU Size  
All interfaces have a default maximum packet size. However to reduc  
fragmentation, you can set the MTU size of the packets sent on the in-  
terface. The minimum value is 512; the default and maximum packet  
size depends on the interface type.  
Changing the MTU value with the mtuinterface configuration com-  
mand can affect the CLNS MTU value. If the CLNS MTU is at its  
maximum given the interface MTU, the CLNS MTU will change with  
the interface MTU. However, the reverse is not true; changing th  
CLNS MTU value has no effect on thevalue for themtuinterface con-  
figuration command.  
In interface configuration mode, set the CLNS MTU packet size for a  
specified interface:  
clns mtu size  
Warning: The CTR card does not support the switching of frames  
larger than 4472 bytes. Interoperability problems might  
occur if CTR cards are intermixed with other Token Ring  
cards on the same network. These problems can be mini  
mized by lowering the CLNS MTU sizes to be the same on  
all routers on the network.  
Disable Checksums  
When the ISO CLNS routing software originates a CLNS packet, by  
default it generates checksums. In interface configuration mode, dis-  
able checksum generation:  
no clns checksum  
Warning: Enabling checksum generation has no effect on routing  
packets (ES-IS, ISO IGRP, and IS-IS) originated by th  
router; it applies to pings and traceroute packets.  
Disable Fast Switching Through the Cache  
Fast switching through the cache is enabled by default for all sup-  
ported interfaces. In interface configuration mode, disable fast switch-  
ing:  
no clns route-cache  
Warning: The cache still exists and is used after the no clns  
route-cache interface configuration command is  
used; the software just does not do fast switching through  
the cache.  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
Set the Congestion Threshold  
If a router configured for CLNS experiences congestion, it sets the  
congestion-experienced bit. You can set the congestion threshold on a  
per-interface basis. By setting this threshold, you cause the system to  
set the congestion-experienced bit if the output queue has more than  
the specified number of packets in it.  
In interface configuration mode, set the congestion threshold:  
clns congestion-threshold number  
Transmit Error Protocol Data Units (ERPDUs)  
When a CLNS packet is received, the routing software looks in the  
routing table for the next hop. If it does not find one, the packet is dis-  
carded and an error protocol data unit (ERPDU) is sent.  
You can set an interval between ERPDUs. Doing so reduces band-  
width if this feature is disabled. When you set the minimum interval  
between ERPDUs, the Cisco IOS software does not send ERPDUs  
more frequently than one per interface per ten milliseconds.  
In interface configuration mode, transmit ERPDUs:  
1. Send an ERPDU when the routing software detects an error in  
data PDU; this is enabled by default.  
clns send-erpdu  
2. Set the minimum interval, in milliseconds, between ERPDUs.  
clns erpdu-interval milliseconds  
Control Redirect Protocol Data Units (RDPDUs)  
If a packet is sent out the same interface it came in on, a redirect pro-  
tocol data unit (RDPDU) also can be sent to the sender of the packet.  
You can control RDPDUs with one of these actions:  
z
By default, CLNS sends RDPDUs when a better route for a given  
host is known. You can disable this feature. Disabling this feature  
reduces bandwidth because packets may continue to unnecessarily  
go through the router.  
clns send-rdpdu  
z
You can set the interval times between RDPDUs.  
clns rdpdu-interval milliseconds  
Warning: SNPA masks are never sent, and RDPDUs are ignored by  
the Cisco IOS software when the router is acting as an IS.  
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Configure Parameters for Locally Sourced Packets  
In global configuration mode, configure parameters for packets origi-  
nated by a specified router:  
z
z
Specify in seconds the initial lifetime for locally generated pack-  
ets.  
clns packet-lifetime seconds  
Specify whether to request ERPDUs on packets originated by the  
router.  
clns want-erpdu  
You should set the packet lifetime low in an internetwork that has fre-  
quent loops.  
Warning: The clns want-erpduglobal configuration command  
has no effect on routing packets (ES-IS, ISO IGRP, and  
ISIS) originated by the router; it applies to pings and trac-  
eroute packets.  
Example: Performance Parameters  
This example shows how to set ES hello packet and IS hello packet pa-  
rameters in a simple ISO IGRP configuration, as well as the MTU for  
a serial interface:  
router iso-igrp xavier  
net 49.0001.004d.0002.0000.0C00.0506.00  
1. Send IS/ES hellos every 45 seconds:  
clns configuration-time 45  
2. Recipients of the hello packets keep information in the hellos for  
2 minutes:  
clns holding-time 120  
3. Specify an mtu of 978 bytes; generally, do not alter the default:  
mtu value interface serial 2  
clns mtu 978  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
Monitor and  
Maintain the ISO  
CLNS Network  
Use these EXEC commands to monitor and maintain the ISO CLNS  
caches, tables, and databases:  
z
z
z
z
Clear and reinitialize the CLNS routing cache.  
clear clns cache  
Remove ES neighbor information from the adjacency database.  
clear clns es-neighbors  
Remove IS neighbor information from the adjacency database.  
clear clns is-neighbors  
Remove CLNS neighbor information from the adjacency data-  
base.  
clear clns neighbors  
z
z
z
z
z
Remove dynamically derived CLNS routing information.  
clear clns route  
Invoke a diagnostic tool for testing connectivity.  
ping clns {host | address}  
Display information about the CLNS network.  
show clns  
Display the entries in the CLNS routing cache.  
show clns cache  
Display ES neighbor entries, including the associated areas.  
show clns es-neighbors [type number]  
[detail]  
z
z
z
z
Display filter expressions.  
show clns filter-expr [name] [detail]  
Display filter sets.  
show clns filter-set [name]  
List the CLNS-specific or ES-IS information about each interface.  
show clns interface [type number]  
Display IS neighbor entries, according to the area in which they  
are located.  
show clns is-neighbors [type number]  
[detail]  
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z
z
Display both ES and IS neighbors.  
show clns neighbors [type number] [detail]  
List the protocol-specific information for each IS-IS or ISO IGRP  
routing process in this router.  
show clns protocol [domain | area-tag]  
z
Display all the destinations to which this router knows how to  
route packets.  
show clns route [nsap]  
z
z
Display information about the CLNS packets this router has seen.  
show clns traffic  
Display the IS-IS link state database.  
show isis database [level-1] [level-2] [l1]  
[l2] [detail] [lspid]  
z
z
z
z
Display the IS-IS Leve l1 routing table.  
show isis routes  
Display a history of the SPF calculations for IS-IS.  
show isis spf-log  
Display all route maps configured or only the one specified.  
show route-map [map-name]  
Discover the paths taken to a specified destination by packets in  
the network.  
trace clns destination  
z
Display the routing table in which the specified CLNS destination  
is found.  
which-route {nsap-address | clns-name}  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
Configure TARP  
on ISO CLNS  
Some applications (typically used by telephone companies) running  
on Synchronous Optical Network (SONET) devices identify these de-  
vices by a target identifier (TID). Therefore, it is necessary for the  
router to cache TID-to-network address mappings. Because these ap  
plications usually run over OSI, the network addresses involved in the  
mapping are OSI NSAPs.  
When a device must send a packet to another device it does not know  
about (that is, it does not have information about the NSAP address  
corresponding to the remote device's TID), the device needs a way to  
request this information directly from the device, or from an interme-  
diate device in the network. This functionality is provided by an ad-  
dress resolution protocol called Target Identifier Address Resolution  
Protocol (TARP).  
Requests for information and associated responses are sent as TARP  
protocol data units (PDUs), which are sent as CLNP data packets.  
TARP PDUs are distinguished by a unique N-selector in the NSAP ad-  
dress. Here are the five types of TARP PDUs:  
z
Type 1—Sent when a device has a TID for which it has no match-  
ing NSAP. Type 1 PDUs are sent to all Le vel1 (IS-IS and ES-IS)  
neighbors. If no response is received within the specified time lim-  
it, a Type 2 PDU is sent. To prevent packet looping, a loop detec-  
tion buffer is maintained on the router. A Type 1 PDU is sent when  
you use the tarp resolve command.  
z
Type 2—Sent when a device has a TID for which it has no match-  
ing NSAP and no response was received from a Type 1 PDU.  
Type 2 PDUs are sent to all Le vel1 and Lev el2 neighbors. A time  
limit for Type 2 PDUs can also be specified. A Type 2 PDU is sent  
when you use the tarp resolvecommand and specify the op-  
tion 2.  
z
z
Type 3—Sent as a response to a Type 1, Type 2, or Type 5 PDU.  
Type 3 PDUs are sent directly to the originator of the request.  
Type 4—Sent as a notification when a change occurs locally (fo  
example, a TID or NSAP change). A Type 4 PDU is sent when you  
use the tarp query command.  
z
Type 5—Sent when a device needs a TID that corresponds to a  
specific NSAP. Unlike Type 1 and Type 2 PDUs that are sent to  
all Leve l1 and Level 2 neighbors, a Type 5 PDU is sent only to a  
particular router.  
In addition to the type, TARP PDUs contain the sender's NSAP, th  
sender's TID, and the target's TID (if the PDU is a Type 1 or Type 2).  
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TARP Configuration Task List  
To configure TARP on the router, complete these tasks (only the first  
task is required, all other tasks are optional):  
z
z
z
z
z
z
z
z
z
Enable TARP and Configure a TARP TID  
Enable TARP and Configure a TARP TID  
TARP must be explicitly enabled before the TARP functionality be  
comes available and the router must have a TID assigned. Also, before  
TARP packets can be sent out on an interface, each interface must  
have TARP enabled and the interface must be able to propagate TARP  
PDUs.  
The router will use the CLNS capability to send and receive TARP  
PDUs. If the router is configured as an IS, the router must be running  
IS-IS. If the router is configured as an ES, the router must be running  
ES-IS.  
1. In global configuration mode, turn on the TARP functionality:  
z
z
Turn on the TARP functionality.  
tarp run  
Assign a TID to the router.  
tarp tid tid  
2. In interface configuration mode, enable TARP on one or more in-  
terfaces:  
tarp enable  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
Disable TARP Caching  
By default, TID-to-NSAP address mappings are stored in the TID  
cache. Disabling this capability clears the TID cache. Re-enabling this  
capability restores any previously cleared local entry and all static en-  
tries.  
In global configuration mode, disable TID-to-NSAP address mapping  
in the TID cache:  
no tarp allow-caching  
Disable TARP PDU Origination and Propagation  
By default, the router originates TARP PDUs and propagates TARP  
PDUs to its neighbors, and the interface propagates TARP PDUs to its  
neighbor. Disabling these capabilities means that the router no longer  
originates TARP PDUs. Also, the router and the specific interface no  
longer propagate TARP PDUs received from other routers.  
z
In global configuration mode, disable origination of TARP PDUs:  
no tarp originate  
z
In global configuration mode, disable global propagation of TARP  
PDUs.  
no tarp global-propagate  
z
In interface configuration mode, disable propagation of TARP  
PDUs on a specific interface:  
no tarp propagate  
Configure Multiple NSAP Addresses  
A router may have more than one NSAP address. When a request for  
an NSAP is sent (Type 1 or Type 2 PDU), the first NSAP address is  
returned. To receive all NSAP addresses associated with the router,  
enter a TID-to-NSAP static route in the TID cache for each NSAP ad-  
dress.  
In global configuration mode, create a TID-to-NSAP static route:  
tarp map tid nsap  
Configure Static TARP Adjacency and Blacklist Adjacency  
In addition to all its IS-IS/ES-IS adjacencies, a TARP router propa-  
gates PDUs to all its static TARP adjacencies. If a router is not running  
TARP, the router discards TARP PDUs rather than propagating the  
PDUs to all its adjacencies. To allow TARP to bypass routers enroute  
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that may not have TARP running, TARP provides a static TARP adja-  
cency capability. Static adjacencies are maintained in a special queue.  
In global configuration mode, create a static TARP adjacency:  
tarp route-static nsap  
To stop TARP from propagating PDUs to an IS-IS/ES-IS adjacency  
that may not have TARP running, TARP provides a blacklist adja-  
cency capability. The router will not propagate TARP PDUs to black-  
listed routers.  
In global configuration mode, bypass a router not running TARP.  
tarp blacklist-adjacency nsap  
Determine TIDs and NSAPs  
In EXEC mode, determine an NSAP address for a TID or a TID for an  
NSAP address:  
1. Get the TID associated with a specific NSAP.  
tarp query nsap  
2. Get the NSAP associated with a specific TID.  
tarp resolve tid [1 | 2]  
To determine the TID, the router first checks the local TID cache. I  
there is a TID entry in the local TID cache, the requested information  
is displayed. If there is no TID entry in the local TID cache, a TARP  
Type 5 PDU is sent out to the specified NSAP address.  
To determine the NSAP address, the router first checks the local TID  
cache. If there is an NSAP entry in the local TID cache, the requested  
information is displayed. If there is no NSAP entry in the local TID  
cache, a TARP Type 1 or Type 2 PDU is sent out. By default, a Typ  
1 PDU is sent to all Lev el1 (IS-IS and ES-IS) neighbors. If a response  
is received, the requested information is displayed. If a response is not  
received within the response time, a Type 2 PDU is sent to all L evel1  
and Leve l2 neighbors. Specifying the EXEC command tarp re-  
solvetid2causes only a Type 2 PDU to be sent.  
You can configure the length of time that the router will wait for a re-  
sponse (in the form of a Type 3 PDU).  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
Configure TARP Timers  
TARP timers provide default values and typically do not need to be  
changed.  
The amount of time that the router waits to receive a response from a  
Type 1 PDU, a Type 2 PDU, and a Type 5 PDU can be configured. In  
addition, you can also configure the PDU's lifetime based on the num-  
ber of hops.  
Timers can also be set to control how long dynamically created TARP  
entries remain in the TID cache, and how long the system ID-to-se-  
quence number mapping entry remains in the loop detection buffer ta-  
ble. The loop detection buffer table prevents TARP PDUs from  
looping.  
In global configuration mode, configure TARP PDU timers, control  
PDU lifetime, and set how long entries remain in cache:  
1. Configure the number of seconds that the router will wait for a re-  
sponse from a TARP Type 1 PDU.  
tarp t1-response-timer seconds  
2. Configure the number of seconds that the router will wait for a re-  
sponse from a TARP Type 2 PDU.  
tarp t2-response-timer seconds  
3. Configure the number of seconds that the router will wait for a re-  
sponse from a TARP Type 2 PDU after the default timer has ex  
pired.  
tarp post-t2-response-timer seconds  
4. Configure the number of seconds that the router will wait for a re-  
sponse from a TARP Type 5 PDU.  
tarp arp-request-timer seconds  
5. Configure the number of routers that a TARP PDU can traverse  
before it is discarded.  
tarp lifetime hops  
6. Configure the number of seconds a dynamically-created TARP  
entry remains in the TID cache.  
tarp cache-timer seconds  
7. Configure the number of seconds that a system ID-to-sequence  
number mapping entry remains in the loop detection buffer table.  
tarp ldb-timer seconds  
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Configure Miscellaneous TARP PDU Information  
TARP default PDU values typically do not need to be changed.  
You can configure the sequence number of the TARP PDU, set the up-  
date remote cache bit used to control whether the remote router up  
dates its cache, specify the N-selector used in the PDU to indicate  
TARP PDU, and specify the network protocol type used in outgoing  
PDUs.  
In global configuration mode, configure miscellaneous PDU informa-  
tion:  
1. Change the sequence number in the next outgoing TARP PDU.  
tarp sequence-number number  
2. Set the update remote cache bit in all subsequent outgoing TARP  
PDUs so that the remote router does or does not update the cache.  
tarp urc [0 | 1]  
3. Specify the N-selector used to identify TARP PDUs.  
tarp selector hex-digit  
4. Specify the protocol type used in outgoing TARP PDUs. Only FE  
(to indicate CLNP) is supported.  
tarp protocol hex-digit  
Monitor and Maintain the TARP Protocol  
Use these EXEC commands to monitor and maintain the TARP  
caches, tables, and databases:  
z
z
z
z
Reset the TARP counters that are shown with th show tarp  
trafficcommand.  
clear tarp counters  
Remove all system ID-to-sequence number mapping entries in the  
TARP loop detection buffer table.  
clear tarp ldb-table  
Remove all dynamically created TARP TID-to-NSAP address  
mapping entries in the TID cache.  
clear tarp tid-table  
Display all global TARP parameters.  
show tarp  
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Chapter 9: AI2524 OSI/CLNP Configuration Steps  
z
z
List all adjacencies that are blacklisted (that is, adjacencies that  
will not receive propagated TARP PDUs).  
show tarp blacklisted-adjacencies  
Display information about a specific TARP router stored in the lo-  
cal TID cache.  
show tarp host tid  
z
z
z
z
z
z
List all interfaces on the router that have TARP enabled.  
show tarp interface [type number]  
Display the contents of the loop detection buffer table.  
show tarp ldb  
List all the static entries in the TID cache.  
show tarp map  
List all static TARP adjacencies.  
show tarp static-adjacencies  
Display information about the entries in the TID cache.  
show tarp tid-cache  
Display statistics about TARP PDUs.  
show tarp traffic  
Examples: TARP Configuration  
This section provides both basic and complex examples of TARP con-  
figuration.  
Basic TARP Configuration Example  
This example enables TARP on the router and interface Ethernet 0.  
The router is assigned the TID myname.  
clns routing  
tarp run  
tarp tid myname  
interface ethernet 0  
tarp enable  
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AI2524 Router Card User’s Manual  
Complex TARP Configuration Example  
Figure 9-13 and this example show how to enable TARP on Router A  
and on interface Ethernet 0 and assign the TID myname. A static rout  
is created from Router A (49.0001.1111.1111.00) to Router D  
(49.0004.1234.1234.1234.00) so that Router D can receive TARP  
PDUs because Router C in not TARP capable. A blacklist adjacency  
isalso created on Router A for Router B (49.0001.7777.7777.7777.00  
so that Router A does not send any TARP PDUs to Router B.  
Figure 9-13:Sample TARP Configuration  
clns routing  
tarp run  
tarp cache-timer 300  
tarp route-static 49.0004.1234.1234.1234.00  
tarp blacklist-adjacency 49.0001.7777.7777.7777.00  
tarp tid myname  
interface ethernet 0  
tarp enable  
!=  
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Chapter 10: Serial Interface Configuration Steps  
Chapter 10: Serial Interface  
Configuration Steps  
Introduction  
This chapter describes how to configure synchronous serial interfaces.  
Configure the  
Synchronous  
Serial Interfaces  
The synchronous serial interfaces are configured to allow connection  
to WANs. Once the Ethernet or Token Ting port on your router has  
been configured, complete these steps to configure the synchronous  
serial interfaces:  
1. Press <Enter> or type yes to configure serial port 0:  
Configuring interface Serial0:  
Is this interface in use? [yes]:  
2. Determine which protocols you want on the synchronous serial  
interface and enter the appropriate responses:  
Configure IP on this interface? [yes]:  
Configure IP unnumbered on this interface? [no]:  
IP address for this interface: 172.16.73.1  
Number of bits in subnet field [8]:  
Class B network is 172.16.0.0, 8 subnet bits; mask is  
255.255.255.0  
Configure AppleTalk on this interface? [no]: yes  
Extended AppleTalk network? [yes]:  
AppleTalk starting cable range [2]: 4  
AppleTalk ending cable range [3]: 4  
AppleTalk zone name [myzone]: ZZ Serial  
AppleTalk additional zone name:  
Configure IPX on this interface? [no]: yes  
IPX network number [2]: B002  
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AI2524 Router Card User’s Manual  
3. Configure the second synchronous serial interface, for example:  
Configuring interface Serial 1:  
Is this interface in use? [yes]:  
Configure IP on this interface? [yes]:  
Configure IP unnumbered on this interface? [no]:  
IP address for this interface: 172.16.74.2  
Number of bits in subnet field [8]:  
Class B network is 172.16.0.0, 8 subnet bits; mask is  
255.255.255.0  
Configure AppleTalk on this interface? [no]: yes  
AppleTalk starting cable range [3]: 5  
AppleTalk ending cable range [4]: 5  
AppleTalk zone name [myzone]: ZZ Serial  
AppleTalk additional zone name:  
Configure IPX on this interface? [no]: yes  
IPX network number [3]: B003  
4. The configuration you entered now displays and you are asked if  
you want to use the displayed configuration. If you enter no, you  
will lose the configuration information you just entered and you  
can begin the configuration again. If you type yes, the configura-  
tion will be entered and saved in the startup configuration:  
Use this configuration? [yes/no]: yes  
Building configuration...  
Use the enabled mode 'configure' command to modify this configuration.  
Press RETURN to get started!  
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Chapter 11: AI2524 Sync PPP Configuration Steps  
Chapter 11: AI2524 Sync PPP  
Configuration Steps  
Introduction  
This chapter describes how to enable PPP encapsulation and perform  
a variety of PPP configuration tasks.  
Configuration  
Overview  
The Point-to-Point Protocol (PPP), described in RFCs 1661 and 1332,  
encapsulates network layer protocol information over point-to-point  
links. You can configure PPP on these physical interfaces:  
z
z
z
z
Asynchronous serial  
HSSI  
ISDN  
Synchronous serial  
The software provides PPP as an encapsulation method. It also pro-  
vides the Challenge Handshake Authentication Protocol (CHAP) and  
Password Authentication Protocol (PAP) on serial interfaces running  
PPP encapsulation. By enabling PPP encapsulation on physical inter  
faces, PPP can also be used on calls placed by dialer interfaces that use  
physical interfaces.  
The current implementation of PPP supports option 3, authentication  
using CHAP or PAP, option 4, Link Quality Monitoring, and option 5,  
Magic Number configuration options. The software always sends op-  
tion 5 and negotiates for options 3 and 4 if so configured. All other op-  
tions are rejected.  
Magic Number support is available on all serial interfaces. PPP always  
attempts to negotiate for Magic Numbers, which are used to detect  
looped-back lines. Depending on how th down-when-looped  
command is configured, the router might shut down a link if it detects  
a loop.  
The AI2524 supports the following upper-layer protocols: Bridging,  
CLNS, IP, and IPX.  
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PPP Configuration Task List  
To configure PPP on a serial interface, you must enable PPP encapsu-  
lation.  
You can also complete these tasks; these tasks are optional but offer  
variety of uses and enhancements for PPP on your systems and net-  
works:  
z
z
z
z
z
z
z
z
z
z
z
z
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Chapter 11: AI2524 Sync PPP Configuration Steps  
Enable PPP  
Encapsulation  
You can enable PPP on serial lines to encapsulate IP and other network  
protocol datagrams in interface configuration mode:  
encapsulation ppp  
PPP echo requests are used as keepalives to minimize disruptions to  
the end users of your network. Theno keepalivecommand can be  
used to disable echo requests.  
Enable CHAP or  
PAP  
Authentication  
The Point-to-Point Protocol (PPP) with Challenge Handshake Authen-  
tication Protocol (CHAP) authentication or Password Authentication  
Protocol (PAP) is often used to inform the central site about which re-  
mote routers are connected to it.  
With this authentication information, if the router or access server re-  
ceives another packet for a destination to which it is already con-  
nected, it does not place an additional call. However, if the router or  
access server is using rotaries, it sends the packet out the correct port.  
CHAP and PAP are specified in RFC 1334. These protocols are sup  
ported on synchronous and asynchronous serial interfaces. When  
using CHAP or PAP authentication, each router or access server iden-  
tifies itself by a name. This identification process prevents a route  
from placing another call to a router to which it is already connected  
and prevents unauthorized access.  
Access control using CHAP or PAP is available on all serial interfaces  
that use PPP encapsulation. The authentication feature reduces the risk  
of security violations on your router or access server. You can config-  
ure either CHAP or PAP for the interface.  
Note:  
To use CHAP or PAP, you must be running PPP  
encapsulation.  
When CHAP is enabled on an interface and a remote device attempts  
to connect to it, the local router or access server sends a CHAP packet  
to the remote device. The CHAP packet requests or challenges the re-  
mote device to respond. The challenge packet consists of an ID, a ran-  
dom number, and the host name of the local router.  
The required response consists of two parts:  
z
An encrypted version of the ID, a secret password (or secret), and  
the random number  
z
Either the host name of the remote device or the name of the user  
on the remote device  
When the local router or access server receives theresponse, it verifies  
the secret by performing the same encryption operation as indicated in  
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AI2524 Router Card User’s Manual  
the response and looking up the required host name or username. The  
secret passwords must be identical on the remote device and the local  
router.  
By transmitting this response, the secret is never transmitted in clear  
text, preventing other devices from stealing it and gaining illegal ac-  
cess to the system. Without the proper response, the remote device  
cannot connect to the local router.  
CHAP transactions occur only at the time a link is established. The  
local router or access server does not request a password during the  
rest of the call. The local device can, however, respond to such re-  
quests from other devices during a call.  
When PAP is enabled, the remote router attempting to connect to the  
local router or access server is required to send an authentication re-  
quest. If the username and password specified in the authentication re-  
quest are accepted, the Cisco IOS software sends an authentication  
acknowledgment.  
After you have enabled CHAP or PAP, the local router or access server  
requires authentication from remotedevices. If theremote device does  
not support the enabled protocol, no traffic will be passed to that de-  
vice.  
1. In interface configuration mode, enable PPP encapsulation:  
encapsulation ppp  
2. In interface configuration mode, enable CHAP or PAP authentica-  
tion on an interface configured for PPP encapsulation:  
ppp authentication {chap | chap pap | pap  
chap | pap} [if-needed] [list-name |  
default] [callin]  
The ppp authentication chap optional keyword, is used  
only with TACACS or extended TACACS. The optional keyword  
list-name is used only with AAA/TACACS+.  
Note:  
If you use a list-namethat has not been configured  
with the aaa authentication ppp command, you  
disable PPP on the line.  
3. Add a username entry for each remote system from which the  
local router or access server requires authentication.  
In global configuration mode, specify the password to be used in  
CHAP or PAP caller identification:  
username name password secret  
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Chapter 11: AI2524 Sync PPP Configuration Steps  
4. In interface configuration mode, configure Terminal Access Con-  
troller Access Control System (TACACS) on a specific interface  
as an alternative to global host authentication:  
ppp use-tacacs [single-line]  
or  
aaa authentication ppp  
Use the ppp use-tacacs command with TACACS and Ex-  
tended TACACS. Use the aaa authentication ppp com-  
mand with Authentication, Authorization, and Accounting  
(AAA)/TACACS+.  
Example: CHAP with an Encrypted Password  
These configuration examples enable CHAP on interface serial 0 of  
three devices.  
1. Configure Router yyy.  
hostname yyy  
interface serial 0  
encapsulation ppp  
ppp authentication chap  
username xxx password secretxy  
username zzz password secretzy  
2. Configure Router xxx.  
hostname xxx  
interface serial 0  
encapsulation ppp  
ppp authentication chap  
username yyy password secretxy  
username zzz password secretxz  
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AI2524 Router Card User’s Manual  
3. Configure Router zzz.  
hostname zzz  
interface serial 0  
encapsulation ppp  
ppp authentication chap  
username xxx password secretxz  
username yyy password secretzy  
When you look at the configuration file, the passwords will be en  
crypted and the display will look similar to:  
hostname xxx  
interface serial 0  
encapsulation ppp  
ppp authentication chap  
username yyy password 7 121F0A  
username zzz password 7 1329A05  
Enable Link  
Quality  
Monitoring  
(LQM)  
Link Quality Monitoring (LQM) is available on all serial interfaces  
running PPP. LQM will monitor the link quality, and if the quality  
drops below a configured percentage, the router shuts down the link.  
The percentages are calculated for both the incoming and outgoing di-  
rections. The outgoing quality is calculated by comparing the total  
number of packets and bytes sent to the total number of packets and  
bytes received by the destination node. The incoming quality is calcu-  
lated by comparing the total number of packets and bytes received to  
the total number of packets and bytes sent by the destination peer.  
When LQM is enabled, Link Quality Reports (LQRs) are sent every  
keepalive period. LQRs are sent in place of keepalives. All incoming  
keepalives are responded to properly. If LQM is not configured, kee-  
palives are sent every keepalive period and all incoming LQRs are re-  
sponded to with an LQR.  
In interface configuration mode, enable LQM on the interface:  
ppp quality percentage  
The percentage argument specifies the link quality threshold. That per-  
centage must be maintained, or the link is deemed to be of poor quality  
and taken down.  
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Chapter 11: AI2524 Sync PPP Configuration Steps  
Configure  
Automatic  
Detection of  
Encapsulation  
Type  
You can enable a serial or ISDN interface to accept calls and dynami-  
cally change the encapsulation on the interface when the remote de-  
vice does not signal the call type. For example, if an ISDN call does  
not identify the call type in the Lower Layer Compatibility fields and  
is using an encapsulation that is different from the one configured on  
the interface, the interface can change its encapsulation type on the fly.  
This feature enables interoperation with ISDN terminal adapters that  
use V.120 encapsulation but do not signal V.120 in the call setup mes-  
sage. An ISDN interface that, by default, answers a call as synchro-  
nous serial with PPP encapsulation can change its encapsulation and  
answer such calls.  
Automatic detection is attempted for the first 10 seconds after the link  
is established or for the first 5 packets exchanged over the link, which-  
ever is first.  
In interface configuration mode, enable automatic detection of encap-  
sulation type:  
autodetect encapsulation encapsulation-type  
You can specify one or more encapsulations to detect. Cisco IOS soft-  
ware currently supports automatic detection of PPP and V.120 encap-  
sulations.  
Configure  
Compression of  
PPP Data  
You can configure point-to-point software compression on serial inter-  
faces that use PPP encapsulation. Compression reduces the size of a  
PPP frame via lossless data compression. The compression algorithm  
used is a predictor algorithm (the RAND algorithm), which uses a  
compression dictionary to predict the next character in the frame.  
PPP encapsulations support both predictor and Stacker compression  
algorithms.  
Compression is performed in software and might significantly affect  
system performance. Disable compression if the router CPU load ex  
ceeds 65%. To display the CPU load, use th show process cpu  
EXEC command.  
If the majority of your traffic is already compressed files, do not us  
compression.  
In interface configuration mode, configure compression over PPP:  
1. Enable encapsulation of a single protocol on the serial line.  
encapsulation ppp  
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2. Enable compression.  
ppp compress [predictor | stac]  
Configure IP  
Address Pooling  
Point-to-point interfaces must be able to provide a remote node with  
its IP address through the IP Control Protocol (IPCP) address negotia-  
tion process. The IP address can be:  
z
z
z
Configured through the command lin  
Entered with an EXEC-level command  
Provided by TACACS+, DHCP, or from a locally administered  
pool  
IP address pooling consists of a pool of IP addresses from which an in-  
coming interface can provide an IP address to a remote node through  
the IP Control Protocol (IPCP) address negotiation process. It also en-  
hances the flexibility of configuration by allowing multiple types of  
pooling to be active simultaneously.  
IP address pooling allows the configuration of a global default address  
pooling mechanism, per-interface configuration of the mechanism,  
and per-interface configuration of a specific address or pool name.  
Peer Address Allocation  
A peer IP address can be allocated to an interface through several  
methods:  
z
Dialer map lookup. This method is used only if the peer requests  
an IP address, if no other peer IP address has been assigned, and if  
the interface is a member of a dialer group.  
z
PPP or SLIP EXEC command. An asynchronous dial-up user can  
enter a peer IP address or host name when PPP or SLIP is invoked  
from the command line. The address is used for the current session  
and then discarded.  
z
IPCP negotiation. If the peer presents a peer IP address during  
IPCP address negotiation and if no other peer address is assigned,  
the presented address is acknowledged and used in the current ses-  
sion.  
z
z
Chat script. The IP address in the dialer mapcommand entry  
that started the script is assigned to the interface and overrides any  
previously assigned peer IP address.  
VTY/Protocol translation. Th translatecommand can defin  
the peer IP address for a VTY (pseudo async interface).  
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Chapter 11: AI2524 Sync PPP Configuration Steps  
z
z
Default IP address. The peer default ip address com-  
mand and the member peer default ip address com-  
mand can be used to define default peer IP addresses.  
TACACS+ assigned IP address. During the authorization phase of  
IPCP address negotiation, TACACS+ can return an IP address that  
can be used by the user being authenticated on a dial-up interface.  
This address overrides any default IP address and prevents pooling  
from taking place.  
z
z
DHCP retrieved IP address. If configured, the routers acts as a  
proxy client for the dial-up user and retrieves an IP address from a  
DHCP server. That address is returned to the DHCP server when  
the timer expires or when the interface goes down.  
Local address pool. The local address pool contains a set of con-  
tiguous IP addresses (a maximum of 256 addresses) stored in two  
queues. The free queue contains addresses available to be as-  
signed. The used queue contains addresses that are in use. Ad-  
dresses are stored in the free queue in First-In First-Out (FIFO  
order to minimize the chance the address will be reused and to al-  
low a peer to reconnect using the same address that it used in the  
last connection. If the address is available, it is assigned; if not, an-  
other address from the free queue is assigned.  
The pool configured for the interface is used, unless TACACS+  
returns a pool name as part of authentication, authorization, and  
accounting (AAA). If no pool is associated with a given interface,  
the global pool named default is used.  
Precedence Rules  
These precedence rules of peer IP address support determine which  
address is used. Precedence is listed from most likely to least likely:  
1. AAA/TACACS+ provided address or addresses from the pool  
named by AAA/TACACS+  
2. An address from a local IP address pool or DHCP (typically not  
allocated unless no other address exists)  
3. Dialer map lookup address (not done unless no other address ex  
ists)  
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4. Address from an EXEC-level PPP or SLIP command or from a  
chat script  
5. Configured address from the peer default ip address  
command or address from the protocol translatecommand  
6. Peer provided address from IPCP negotiation (not accepted unless  
no other address exists)  
Interfaces Affected  
IP address pooling is available on all asynchronous serial, synchro  
nous serial, ISDN BRI, and ISDN PRI interfaces running the Point-to-  
Point Protocol (PPP) or Serial Line Internet Protocol (SLIP).  
Choose the IP Address Assignment Method  
IP address pooling allows configuration of a global default address  
pooling mechanism, per-interface configuration of the mechanism,  
and per-interface configuration of a specific address or pool name.  
You can define the type of IP address pooling mechanism used on  
router interfaces by completing these actions:  
z
z
Define the Global Default Mechanism  
Configure Per-Interface IP Address Assignment  
Define the Global Default Mechanism  
The Global Default Mechanism applies to all point-to-point interfaces  
(asynchronous, synchronous, ISDN BRI, ISDN PRI, and dialer inter-  
faces) that support PPP encapsulation and that have not otherwise been  
configured for IP address pooling. You can define the Global Default  
Mechanism to be either DHCP or local address pooling.  
To configure the global default mechanism for IP address pooling, per-  
form one of these tasks:  
z
z
Define DHCP as the Global Default Mechanism  
Define Local Address Pooling as the Global Default Mechanism  
After you have defined a global default mechanism, you can disable it  
on a specific interface by configuring the interface for some other  
pooling mechanism. You can define a local pool other than the default  
pool for the interface, or you can configure the interface with a specifi  
IP address to be used for dial-in peers.  
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Chapter 11: AI2524 Sync PPP Configuration Steps  
Define DHCP as the Global Default Mechanism  
The Dynamic Host Configuration Protocol (DHCP) specifies these  
components:  
z
A DHCP server. A host-based DHCP server configured to accept  
and process requests for temporary IP addresses.  
z
A DHCP proxy-client. An access server configured to arbitrate  
DHCP calls between the DHCP server and the DHCP client. Th  
DHCP client-proxy feature manages a pool of IP addresses avail-  
able to dial-in clients without a known IP address.  
In global configuration mode, enable DHCP as the global default  
mechanism:  
1. Specify DHCP client-proxy as the global default mechanism.  
ip address-pool dhcp-proxy-client  
2. (Optional) Specify the IP address of a DHCP server for the proxy  
client to use.  
ip dhcp-server [ip-address | name]  
You can provide up to ten DHCP servers for the proxy-client (the  
router or access server)to use. DHCP servers provide temporary IP ad-  
dresses.  
Define Local Address Pooling as the Global Default Mechanism  
In global configuration mode, define local pooling as the global de-  
fault mechanism:  
1. Specify local pooling as the global default mechanism.  
ip address-pool local  
2. Create one or more local IP address pools.  
ip local pool {default | poolname} low-ip-  
address [high-ip-address]  
If no other pool is defined, the local pool called default is used.  
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Configure Per-Interface IP Address Assignment  
When you have defined a global default mechanism for assigning IP  
addresses to dial-in peers, you can then configure the few interfaces  
for which it is important to have a nondefault configuration. You can  
do any of these:  
1. In global configuration mode, define a nondefault address pool for  
use on an interface:  
z
Create one or more local IP address pools.  
ip local pool poolname {low-ip-address  
[high-ip-address]}  
z
z
Specify the interface and enter interface configuration mode.  
interface type number  
Specify the pool for the interface to use.  
peer default ip address pool poolname  
2. In global configuration mode, define DHCP as the IP address  
mechanism for an interface:  
z
Specify the interface and enter interface configuration mode.  
interface type number  
z
Specify DHCP as the IP address mechanism on this interface.  
peer default ip address pool dhcp  
3. Beginning in global configuration mode, define a specific IP ad  
dress to be assigned to all dial-in peers on an interface:  
z
Specify the interface and enter interface configuration mode.  
interface type number  
z
Specify the IP address to assign.  
peer default ip address ip-address  
4. Beginning in global configuration mode, make temporary IP ad-  
dresses available on a per-interface basis for dial-in asynchronous  
clients using Serial Line Internet Protocol (SLIP) or Point-to-Point  
Protocol (PPP):  
z
Specify that the access server use a local IP address pool on all  
asynchronous interfaces.  
ip address-pool local  
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Chapter 11: AI2524 Sync PPP Configuration Steps  
z
Create one or more local IP address pools.  
ip local pool {default | poolname { begin-  
ip-address-range [end-ip-address-range]}}  
z
z
(Optional) Enter interface configuration mode.  
interface async number  
(Optional) If you want an interface to use an address pool other  
than default, specify which pool each interface uses.  
peer default ip address pool poolname  
Configure PPP  
Callback  
PPP callback provides a client-server relationship between the end  
points of a point-to-point connection. PPP callback allows a router to  
request that a dial-up peer router call back. The callback feature can be  
used to control access and toll costs between the routers.  
When PPP callback is configured on the participating routers, the call-  
ing router (the callback client) passes authentication information to th  
remote router (the callback server), which uses the host name and dial  
string authentication information to determine whether to place a re-  
turn call. If the authentication is successful, the callback server discon-  
nects and then places a return call. The remote username of the return  
call is used to associate it with the initial call so that packets can b  
transmitted.  
Both routers on a point-to-point link must be configured for PPP call-  
back; one must function as a callback client and one must be config-  
ured as a callback server. The callback client must be configured to  
initiate PPP callback, and the callback server must be configured to ac-  
cept PPP callback.  
This feature implements these callback specifications of RFC 1570:  
z
For the client. Option 0, location is determined by user authentica-  
tion  
z
For the server. Option 0, location is determined by user authenti-  
cation; Option 1, dialing string; and Option 3, E.164 number.  
Return calls are made through the same dialer rotary group but not  
necessarily the same line as the initial call.  
Note:  
If the return call fails (because the line is not answered or  
the line is busy), no retry occurs. If the callback server has  
no interface available when attempting the return call, it  
does not retry.  
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AI2524 Router Card User’s Manual  
Configure a Router as a Callback Client  
Beginning in global configuration mode, configure a router interface  
as a callback client:  
1. Specify the interface.  
interface serial number  
2. Enable DDR. Set parity on synchronous serial interfaces and asyn-  
chronous interfaces.  
dialer in-band [no-parity | odd-parity]  
3. Enable PPP encapsulation.  
encapsulation ppp  
4. Enable CHAP or PAP authentication.  
ppp authentication {chap | pap}  
5. Map the next hop address to the host name and phone number.  
dialer map protocol next-hop-address name  
hostname dial-string  
6. Enable the interface to request PPP callback for this callback map  
class.  
ppp callback request  
7. (Optional) Configure a dialer hold queue to store packets for this  
callback map class.  
dialer hold-queue packets timeout seconds  
Example: PPP Callback Client  
The PPP callback client is configured on an ISDN BRI interface in a  
router in Dallas. The callback client does not require an enable timeout  
and a map class to be defined.  
interface BRI0  
ip address 7.1.1.8 255.255.255.0  
encapsulation ppp  
dialer map ip 7.1.1.7 name dallas 81012345678902  
dialer-group 1  
ppp callback request  
ppp authentication chap  
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Chapter 11: AI2524 Sync PPP Configuration Steps  
Configure a Router as a Callback Server  
Beginning in global configuration mode, configure a router as a call  
back server:  
1. Specify the interface and enter interface configuration mode.  
interface serial number  
2. Enable DDR. Set parity on synchronous serial interfaces and asyn-  
chronous interfaces.  
dialer in-band [no-parity | odd-parity]  
3. Enable PPP encapsulation.  
encapsulation ppp  
4. Enable CHAP or PAP authentication.  
ppp authentication {chap | pap}  
5. Map the next hop address to the host name and phone number,  
using the name of the map class established for PPP callback on  
this interface.  
dialer map protocol address name hostname  
class classname dial-string  
6. (Optional) Configure a dialer hold queue to store packets to be  
transferred when the callback connection is established.  
dialer hold-queue number timeout seconds  
7. (Optional) Configure a timeout period between calls.  
dialer enable-timeout seconds  
8. Configure the interface to accept PPP callback.  
ppp callback accept  
9. (Optional) Enable callback security, if desired.  
dialer callback-secure  
10. Return to global configuration mode.  
exit  
11. Configure a dialer map class for PPP callback.  
map-class dialer classname  
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AI2524 Router Card User’s Manual  
12. Configure a dialer map class as a callback server.  
dialer callback-server [username]  
The enable timer default is 15 seconds. The time between the initial  
call and the return call can be improved by reducing this number, but  
care should be taken to ensure that the initial call is completely discon-  
nected before the timer expires.  
Note:  
On the PPP callback server, the dialer enable-timeout  
functions as the timer for returning calls to the callback  
client.  
Example: PPP Callback Server  
The PPP callback server is configured on an ISDN BRI interface in  
router in Atlanta. The callback server requires an enable timeout and  
map class to be defined.  
interface BRI0  
ip address 7.1.1.7 255.255.255.0  
encapsulation ppp  
dialer callback-secure  
dialer enable-timeout 2  
dialer map ip 7.1.1.8 name atlanta class dial1 81012345678901  
dialer-group 1  
ppp callback accept  
ppp authentication chap  
!
map-class dialer dial1  
dialer callback-server username  
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Chapter 11: AI2524 Sync PPP Configuration Steps  
Disable or  
Reenable Peer  
Neighbor Routes  
The Cisco IOS software automatically creates neighbor routes by de-  
fault; that is, it automatically sets up a route to the peer address on  
point-to-point interface when the PPP IPCP negotiation is completed.  
In interface configuration mode, disable this default behavior o  
reenable it once it has been disabled:  
z
Disable creation of neighbor routes.  
no peer neighbor-route  
z
Reenable creation of neighbor routes.  
peer neighbor-route  
Note:  
If entered on a dialer or async-group interface, this  
command affects all member interfaces.  
Configure PPP  
Half-Bridging  
For situations in which a routed network needs connectivity to a re-  
mote bridged Ethernet network, a serial or ISDN interface can be con-  
figured to function as a PPP half-bridge. The line to the remote bridge  
functions as a virtual Ethernet interface. The router's serial or ISDN in-  
terface functions as a node on the same Ethernet subnetwork as the re-  
mote network.  
The bridge sends bridge packets to the PPP half-bridge, which con-  
verts them to routed packets and forwards them to other router pro  
cesses. Likewise, the PPP half-bridge converts routed packets to  
Ethernet bridge packets and sends them to the bridge on the sam  
Ethernet subnetwork.  
Note:  
An interface cannot function as both a half-bridge and a  
bridge.  
Figure 11-1 shows a router with a serial interface configured as a PPP  
half-bridge. The interface functions as a node on the Ethernet subnet-  
work with the bridge. Note that the serial interface has an IP address  
on the same Ethernet subnetwork as the bridge.  
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Figure11-1: Router Serial Interface Configured as a Half-  
Bridge  
Note:  
The Cisco IOS software supports no more than one PPP  
half-bridge per Ethernet subnetwork.  
Beginning in global configuration mode, configure a serial interface to  
function as a half-bridge:  
1. Specify the interface and enter interface configuration mode.  
interface serial number  
2. Enable PPP half-bridging for one or more routed protocols:  
ppp bridge ip  
ppp bridge ipx [novell-ether | arpa | sap |  
snap]  
3. Provide a protocol address on the same subnetwork as the remote  
network.  
ip address n.n.n.n  
ipx network network  
Note:  
You must enter the ppp bridgecommand either when  
the interface is shut down or before you provide a protocol  
address for the interface.  
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Chapter 11: AI2524 Sync PPP Configuration Steps  
Configure  
Multilink PPP  
Multilink PPP (MLP) provides load balancing over multiple WAN  
links, while providing multivendor interoperability, packet fragmenta-  
tion and proper sequencing, and load calculation on both inbound and  
outbound traffic.  
Multilink PPP allows packets to be fragmented and the fragments to  
be sent at the same time over multiple point-to-point links to the sam  
remote address. The multiple links come up in response to a dialer load  
threshold that you define. The load can be calculated on inbound traf-  
fic, outbound traffic, or on either. MLP provides bandwidth on de-  
mand and reduces transmission latency across WAN links.  
Multilink PPP is designed to work over single or multiple interfaces  
that are configured to support both dial-on-demand rotary groups and  
PPP encapsulation:  
z
z
z
Asynchronous serial interfaces  
Basic Rate Interfaces (BRIs)  
Primary Rate Interfaces (PRIs)  
Configure Multilink PPP on Asynchronous Interfaces  
Beginning in global configuration mode, configure an asynchronous  
interface to support DDR and PPP encapsulation:  
1. Specify an asynchronous interface.  
interface async number  
2. Specify no IP address for the interface.  
no ip address  
3. Enable PPP encapsulation.  
encapsulation ppp  
4. Enable DDR on the interface.  
dialer in-band  
5. Include the interface in a specific dialer rotary group.  
dialer rotary-group number  
Repeat these steps for additional asynchronous interfaces, as needed.  
At some point, adding more asynchronous interfaces does not improve  
performance. With the default maximum transmission unit (MTU)  
size, Multilink PPP should support three asynchronous interfaces  
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AI2524 Router Card User’s Manual  
using V.34 modems. However, packets might be dropped occasionally  
if the MTU is small or if large bursts of short frames occur.  
Beginning in global configuration mode, configure a dialer interface  
to support PPP encapsulation and Multilink PPP:  
1. Define a dialer rotary group.  
interface dialer number  
2. Specify no IP address for the interface.  
no ip address  
3. Enable PPP encapsulation.  
encapsulation ppp  
4. Enable DDR on the interface.  
dialer in-band  
5. Configure bandwidth on demand by specifying the maximum load  
before the dialer places another call to a destination.  
dialer load-threshold load [inbound |  
outbound | either]  
6. Enable Multilink PPP.  
ppp multilink  
Configure Multilink PPP on a Single ISDN BRI Interface  
To enable Multilink PPP on a single Integrated Services Digital Net  
work (ISDN) BRI interface, you are not required to define a dialer ro-  
tary group separately because ISDN interfaces aredialerrotary groups  
by default.  
Beginning in global configuration mode, enable PPP on an ISDN BRI  
interface:  
1. Specify an interface.  
interface bri number  
2. Provide an appropriate protocol address for the interface.  
ip address ip-address mask  
3. Enable PPP encapsulation.  
encapsulation ppp  
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Chapter 11: AI2524 Sync PPP Configuration Steps  
4. (Optional) Specify a dialer idle timeout.  
dialer idle-timeout seconds  
5. Specify the dialer load threshold for bringing up additional WAN  
links.  
dialer load-threshold load  
6. Configure the ISDN interface to call the remote site.  
dialer map protocol next-hop-address [name  
hostname] [spc] [speed 56 | 64] [broadcast]  
[dial-string[:isdn-subaddress]]  
7. Add the interface to a dialer rotary group.  
dialer-group group-number  
8. (Optional) Enable PPP authentication.  
ppp authentication pap  
9. Enable Multilink PPP on the dialer rotary group.  
ppp multilink  
If you do not use PPP authentication procedures, your telephone ser-  
vice must pass caller ID information. The load threshold number is re-  
quired.  
When Multilink PPP is configured and you want a multilink bundle to  
be connected indefinitely, use the dialer idle-timeout com-  
mand to set a very high idle timer.  
The dialer-load threshold 1command does not keep a mul-  
tilink bundle of n links connected indefinitely, and the dialer-  
load threshold 2command does not keep a multilink bundle of  
two links connected indefinitely.  
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Example: Multilink PPP on One ISDN Interface  
This example enables Multilink PPP on the BRI 0 interface. Because  
an ISDN interface is a rotary group by default, when one BRI is con-  
figured, no dialer rotary group configuration is required.  
interface bri 0  
description connected to ntt 81012345678902  
ip address 7.1.1.7 255.255.255.0  
encapsulation ppp  
dialer idle-timeout 30  
dialer load-threshold 40 either  
dialer map ip 7.1.1.8 name atlanta 81012345678901  
dialer-group 1  
ppp authentication pap  
ppp multilink  
Configure Multilink PPP on Multiple ISDN BRI Interfaces  
To enable Multilink PPP on multiple ISDN BRI interfaces, set up a di-  
aler rotary interface and configure it for Multilink PPP and then con  
figure the BRIs separately and add them each to the same rotary group.  
Beginning in global configuration mode, set up the dialer rotary inter-  
face for the BRI interfaces:  
1. Specify the dialer rotary interface.  
interface dialer number  
2. Specify the protocol address for the dialer rotary interface.  
ip address address mask  
3. Enable PPP encapsulation.  
encapsulation ppp  
4. Specify in-band dialing.  
dialer in-band  
5. Specify the dialer idle timeout period, using the same timeout pe-  
riod as the individual BRI interfaces.  
dialer idle-timeout seconds  
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Chapter 11: AI2524 Sync PPP Configuration Steps  
6. Map the next-hop protocol address and name to the dial string  
needed to reach it.  
dialer map protocol next-hop-address [name  
hostname] [spc] [speed 56 | 64] [broadcast]  
[dial-string[:isdn-subaddress]]  
7. Specify the dialer load threshold, using the same threshold as the  
individual BRI interfaces.  
dialer load-threshold load  
8. Control access to this interface by adding it to a dialer access  
group.  
dialer-group group-number  
9. (Optional) Enable PPP CHAP authentication.  
ppp authentication chap  
10. Enable Multilink PPP.  
ppp multilink  
If you do not use PPP authentication procedures, your telephone ser-  
vice must pass caller ID information.  
Beginning in global configuration mode, configure each of the BRIs to  
belong to the same rotary group:  
1. Specify one of the BRI interfaces.  
interface bri number  
2. Specify that it does not have an individual protocol address.  
no ip address  
3. Enable PPP encapsulation.  
encapsulation ppp  
4. Set the dialer idle timeout period, using the same timeout for each  
of the BRI interfaces you configure.  
dialer idle-timeout seconds  
5. Add the interface to the rotary group.  
dialer rotary-group group-number  
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AI2524 Router Card User’s Manual  
6. Specify the dialer load threshold for bringing up additional WAN  
links.  
dialer load-threshold load  
Repeat Steps 1 through 6 for each BRI you want to belong to the same  
dialer rotary group.  
When Multilink PPP is configured and you want a multilink bundle to  
be connected indefinitely, use the dialer idle-timeout com-  
mand to set a very high idle timer.  
The dialer load-threshold 1 command does not keep a mul-  
tilink bundle of n links connected indefinitely, and the dialer  
load-threshold 2command does not keep a multilink bundle of  
two links connected indefinitely.  
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Chapter 11: AI2524 Sync PPP Configuration Steps  
Example: Multilink PPP on Multiple ISDN Interfaces  
This example configures multiple ISDN BRIs to belong to the same di-  
aler rotary group for Multilink PPP. Th dialer rotary-group  
command is used to assign each of the ISDN BRIs to that dialer rotary  
group.  
interface BRI0  
no ip address  
encapsulation ppp  
dialer idle-timeout 500  
dialer rotary-group 0  
dialer load-threshold 255 balanced  
!
interface BRI1  
no ip address  
encapsulation ppp  
dialer idle-timeout 500  
dialer rotary-group 0  
dialer load-threshold 255 balanced  
!
interface BRI2  
no ip address  
encapsulation ppp  
dialer idle-timeout 500  
dialer rotary-group 0  
dialer load-threshold 255 balanced  
!
interface Dialer0  
ip address 99.0.0.2 255.0.0.0  
encapsulation ppp  
dialer in-band  
dialer idle-timeout 500  
dialer map ip 99.0.0.1 name atlanta broadcast 81012345678901  
dialer load-threshold 255 balanced  
dialer-group 1  
ppp authentication chap  
ppp multilink  
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AI2524 Router Card User’s Manual  
ConfigureVirtual  
Private Dial-up  
Networks  
Virtual private dial-up networks (VDPN) allow separate and autono-  
mous protocol domains to share common access infrastructure includ-  
ing modems, access servers, and ISDN routers. VPDN uses the Level  
2 Forwarding protocol (L2F) which permits the tunneling of link level  
frames.  
Using L2F tunneling, an Internet Service Provider (ISP) or other ac  
cess service can create a virtual tunnel to link a customer's remote sites  
or remote users with corporate home networks. In particular, a net-  
work access server at the ISP's Point of Presence (POP) exchanges  
PPP messages with the remote users and communicates by L2F re-  
quests and responses with the customer's home gateway to set up tun-  
nels.  
L2F passes protocol-level packets through the virtual tunnel between  
endpoints of a point-to-point connection.  
Frames from the remote users are accepted by the ISP POP, stripped  
of any linked framing or transparency bytes, encapsulated in L2F, and  
forwarded over the appropriate tunnel. The customer's home gateway  
accepts these L2F frames, strips the L2F encapsulation, and processes  
the incoming frames for the appropriate interface.  
Note:  
This implementation of VPDN supports PPP dial-up only.  
To configure virtual private dial-up networks, complete these tasks:  
z
z
Understand VPDNs  
z
z
Understand Virtual Private Dial-up Networks  
VPDN enables users to configure secure networks that take advantag  
of internet service providers that tunnel the company's remote access  
traffic through the ISP cloud.  
Remote offices or mobile users can connect to their home network  
using local dial-up services of third parties. The dial-up service pro-  
vider agrees to forward the company's traffic from the ISP POP to a  
company-run home gateway. Network configuration and security re-  
main in the control of the client. The dial-up service provider provides  
a virtual pipe between the company's sites.  
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Chapter 11: AI2524 Sync PPP Configuration Steps  
Note:  
The MMP feature uses VPDN to connect multiple PPP  
sessions for which individual dial-in calls have arrived on  
different stack group members. VPDN provides speed and  
reliability for the setup and shutdown of Multilink PPP.  
Complete these steps to create a a VPDN connection between a remote  
user and the home LAN:  
1. The remote user initiates a PPP connection to the ISP using the an-  
alog telephone system or ISDN.  
2. The ISP network access server accepts the connection.  
3. The ISP network access server authenticates the end user with  
CHAP or PAP. The username is used to determine whether the  
user is a VPDN client. If the user is not a VPDN client, the client  
accesses the Internet or other contacted service.  
4. The tunnel endpoints—the network access server and the home  
gateway—authenticate each other before any sessions are at  
tempted within a tunnel.  
5. If no L2F tunnel exists between the network access server and the  
remote user’s home gateway, a tunnel is created. Once the tunnel  
exists, an unused slot within the tunnel is allocated.  
6. The home gateway accepts or rejects the connection. Initial setup  
can include authentication information required to allow the home  
gateway to authenticate the user.  
7. The home gateway sets up a virtual interface. Link-level frames  
can now pass through this virtual interface through the L2F tunnel.  
Figure 11-2 illustrates a VPDN connection from a remote user, who  
makes a local call, to the corporate network, through an end-to-end  
L2F tunnel (shown by the dotted line).  
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Figure 11-2: Configure a Virtual Template and Create a Vir-  
tual Template Interface on the Home Gateway  
Beginning in global configuration mode, configure a virtual templat  
for interfaces on a home gateway access server:  
1. Specify a default local IP address pool.  
ip local pool default ip-address  
2. Create a virtual template interface, and enter interface configura-  
tion mode.  
interface virtual-template number  
3. Identify the virtual template interface type and number on the  
LAN.  
ip unnumbered ethernet 0  
4. Enable PPP encapsulation on the virtual template interface.  
encapsulation ppp  
5. Enable PPP authentication on the virtual template interface.  
ppp authentication chap  
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Chapter 11: AI2524 Sync PPP Configuration Steps  
Configure Incoming VPDN Connections on the Home  
Gateway  
In global configuration mode, configure virtual private dialup net-  
working on a home gateway router or access server:  
1. Enable virtual private networking.  
vpdn enable  
2. Specify the remote host, the local name to use for authenticating,  
and the virtual template to use.  
vpdn incoming remote-name local-name  
virtual-template number  
Configure Outgoing VPDN Connections on the Network  
Access Server  
In global configuration mode, configure a network access server to  
make outgoing L2F connections to a home gateway for VPDN:  
1. Enable virtual private networking.  
vpdn enable  
2. Specify the remote host that is to accept L2F connections.  
vpdn outgoing domain-name local-name ip ip-  
address  
Example: Network Access Server Servicing Multiple  
Domains  
This example provides VDPN configurations for a single NAS and  
two different gateways. The two gateways are presumably located at  
two entirely separate companies. The NAS decides which company to  
forward to based on the domain name that is passed by the user.  
The commands also illustrate where toconfigure the commandsvpdn  
outgoing(on the network access server) and vpdn incoming  
(on a home gateway).  
NAS1  
vpdn enable  
vpdn outgoing domain1.com nas1 ip 1.1.1.1  
vpdn outgoing domain2.com nas2 ip 2.2.2.2  
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Gateway1—Domain1  
vpdn enable  
vpdn incoming nas1 gateway1 virtual-template 1  
interface virtual-template 1  
ip unnumbered Ethernet0  
ppp authentication chap  
Gateway2—Domain2  
vpdn enable  
vpdn incoming nas2 gateway2 virtual-template 1  
int virtual-template 1  
ip unnumbered Ethernet0  
ppp authentication chap  
Example: NAS Servicing Multiple Domains to the Same  
Gateway  
This example provides configurations for one NAS and one Gateway  
that might have two parallel tunnels between them. Two different do-  
main names are associated with two different virtual interface config-  
urations.  
Users dialing in with domain name domain1.com will be forwarded to  
the home gateway and be given a virtual-access interface based on vir-  
tual template 1. Users dialing in with the domain2.com will be for-  
warded to the same home gateway and be given a virtual-access  
interface based on virtual template 2.  
NAS 1  
vpdn enable  
vpdn outgoing domain1.com nas1 ip 1.1.1.1  
vpdn outgoing domain2.com nas2 ip 1.1.1.1  
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Chapter 11: AI2524 Sync PPP Configuration Steps  
Gateway 1  
vpdn incoming nas1 gateway virtual-template 1  
vpdn incoming nas2 gateway virtual-template 2  
interface virtual-template 1  
ip unnumbered Ethernet0  
peer default ip address pool domain1-pool  
ppp authentication chap  
interface virtual-template 2  
ip unnumbered Ethernet0  
peer default ip address pool domain2-pool  
ppp authentication chap  
Example: Using TACACS+ for Forwarding from the NAS  
This example provides configurations for an NAS and a public domain  
TACACS+ server. On the NAS it is only necessary to enable AAA and  
to use the vpdn enable command.  
Users with structured logins ([email protected]) will have their do-  
main authorized on the TACACS server and will be forwarded if there  
is a VPDN entry there. If there is no VPDN entry on the TACACS  
server, the login process will continue as normal.  
NAS  
aaa new-model  
vpdn enable  
TACACS+ Server  
vpdn outgoing domain.com nas ip 172.21.9.18  
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AI2524 Router Card User’s Manual  
Enable PPP on  
VTY Lines for  
Asynchronous  
Access over ISDN  
You can configure a router to support asynchronous access over ISDN  
by globally enabling PPP on VTY lines. PPP is typically enabled on  
synchronous or asynchronous serial interfaces; however, the Cisco  
IOS software permits you to configure PPP on VTY lines. This con-  
figures the VTY line to support asynchronous access over ISDN from  
an ISDN terminal to a VTY session on the router.  
In global configuration mode, enable asynchronous protocol features  
on all the router's VTY lines:  
vty-async  
This task enables PPP on VTY lines on a global basis on the router. To  
configure PPP on a per-VTY basis, use th translatecommand.  
Monitor and  
To monitor and maintain virtual interfaces, you can perform any of  
these tasks:  
Maintain MLP,  
MMP, and VPDN  
Virtual Interfaces  
z
Display MLP and MMP bundle information.  
show ppp multilink  
z
Display information about the active L2F tunnels and the L2F  
message identifiers.  
show vpdn  
z
z
Display the status of the stack group members.  
show sgbp  
Display the current seed bid value.  
show sgbp queries  
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Chapter 12: AI2524 X.25 Configuration Steps  
Chapter 12: AI2524 X.25 Configuration  
Steps  
Introduction  
This chapter describes how to configure connections through X.25  
networks and Link Access Procedure Balanced (LAPB) connections.  
This section also describes how to create X.29 access lists and profile  
scripts. For users who only want to configure a simple, reliable serial  
encapsulation method, se Configure LAPB.  
X.25  
X.25 Configuration Task List  
Configuration  
To configure X.25, complete the tasks in one or more of these sections,  
depending upon the X.25 application or task required for your net-  
work. The interface, datagram transport, and routing tasks are divided  
into sections based generally on how common the feature is and how  
often it is used.  
z
z
z
z
z
z
z
z
z
z
All these features can coexist on an X.25 interface.  
Default parameters are provided for X.25 operation; however, you can  
change the settings to meet the needs of your X.25 network or as de-  
fined by your X.25 service supplier. The AI2524 also provides addi-  
tional configuration settings to optimize your X.25 usage.  
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Note:  
If you connect a router to an X.25 network, use the  
parameters set by your network administrator for th  
connection; these parameters will typically be thos  
Protocol Parameters sections. Also, note that the X.25  
Level 2 parameters described in the Modify LAPB  
Protocol Parameters section affect X.25 Level 3  
operations.  
Configure  
Interface  
To configure an X.25 interface, perform these tasks:  
z
z
z
z
z
Set the X.25 Mode  
These tasks describe the parameters that are essential for correct X.25  
behavior. The first task is required. The others might be required or op-  
tional, depending on what the router is expected to do and on the X.25  
network.  
Set the X.25 Mode  
A router using X.25 Level 3 encapsulation can:  
z
Act as a DTE or DCE protocol device (according to the needs of  
your X.25 service supplier)  
z
Use the Internet Engineering Task Force (IETF) standard encap-  
sulation, as specified by RFC 1356.  
Because the default serial encapsulation is High-level Data Link Con-  
trol (HDLC), you must explicitly configure an X.25 encapsulation  
method.  
In interface configuration mode, configure the mode of operation and  
one of these encapsulation types for a specified interface:  
encapsulation x25 [dte | dce] [ietf]]  
Typically, a Public Data Network (PDN) will require attachment as  
DTE. This requirement is distinct from the hardware interface DTE or  
DCE identity.  
The default mode of operation is DTE, and the default encapsulation  
method is Cisco's pre-IETF method.  
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Chapter 12: AI2524 X.25 Configuration Steps  
Set the Virtual Circuit Ranges  
The X.25 protocol maintains multiple connections over one physical  
link between a DTE and a DCE. These connections are called virtual  
circuits or Logical Channels (LCs). X.25 can maintain up to 4095 vir-  
tual circuits numbered 1 through 4095. You identify an individual vir-  
tual circuit by giving its Logical Channel Identifier (LCI) or Virtual  
Circuit Number (VCN). Many documents use the terms virtual circuit  
and LC, VCN, LCN, and LCI interchangeably. Each of these terms re-  
fers to the virtual circuit number  
An important part of X.25 operation is the range of VCNs. VCNs are  
broken into four ranges (listed here in numerically increasing order):  
1. Permanent virtual circuits (PVCs)  
2. Incoming-only circuits  
3. Two-way circuits  
4. Outgoing-only circuits  
The incoming-only, two-way, and outgoing-only ranges define the  
VCNs over which a Switched Virtual Circuit (SVC) can be established  
by the placement of an X.25 call, much like a telephone network es-  
tablishes a switched voice circuit when a call is placed.  
The rules about DCE and DTE devices initiating calls are:  
z
Only the DCE device can initiate a call in the incoming-only  
range.  
z
z
Only the DTE device can initiate a call in the outgoing-only range.  
Both the DCE device and the DTE device can initiate a call in the  
two-way range.  
The ITU-T Recommendation for X.25 defines incoming and outgoing  
in relation to the DTE or DCE interface role; this documentation uses  
the more intuitive sense. Unless the ITU-T sense is explicitly refer-  
enced, a call received from the interface is an incoming call and a call  
sent out the interface is an outgoing call.  
Note:  
The ITU-T carries out the functions of the former  
Consultative Committee for International Telegraph and  
Telephone (CCITT).  
There is no difference in the operation of the SVCs ranges except th  
restrictions on which device can initiate a call. These ranges can be  
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AI2524 Router Card User’s Manual  
used to prevent one side from monopolizing the virtual circuits, and is  
useful for X.25 interfaces with a small total number of SVCs available.  
Six X.25 parameters define the upper and lower limit of each of th  
three SVC ranges. A PVC must be assigned a number less than the  
numbers assigned to the SVC ranges. An SVC range is not allowed to  
overlap another range.  
Note:  
Because the X.25 protocol requires the DTE and DCE to  
have identical virtual circuit ranges, changes you make to  
the virtual circuit range limits when the interface is up are  
held until the X.25 protocol restarts the packet service.  
To configure X.25 virtual circuit ranges, complete these tasks as ap-  
propriate for your configuration:  
1. Set the lowest incoming-only circuit number (default is 0).  
x25 lic circuit-number  
2. Set the highest incoming-only circuit number (default is 0).  
x25 hic circuit-number  
3. Set the lowest two-way circuit number (default is 1).  
x25 ltc circuit-number  
4. Set the highest two-way circuit number (default is1024 for X.25  
and 4095 for CMNS).  
x25 htc circuit-number  
5. Set the lowest outgoing-only circuit number (default is 0).  
x25 loc circuit-number  
6. Set the highest outgoing-only circuit number (default is 0).  
x25 hoc circuit-number  
Each of these parameters can range from 1 to 4095, inclusive. The val-  
ues for these parameters must be the same on both ends of an X.25  
link. For connection to a PDN, these values must be set to the values  
assigned by the network. Virtual circuit 0 is not available except for  
marking unused ranges (by setting the lower and upper limits to 0).  
Example: Virtual Circuit Ranges  
This example sets the virtual circuit ranges of 5 to 20 for incoming  
calls only (from the DCE to the DTE) and 25 to 1024 for either incom-  
ing or outgoing calls. It also specifies no virtual circuits for outgoing  
calls (from the DTE to the DCE). Up to 4 permanent virtual circuits  
can be defined on virtual circuits 1 through 4.  
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Chapter 12: AI2524 X.25 Configuration Steps  
x25 lic 5  
x25 hic 20  
x25 ltc 25  
Set the Packet Numbering Modulo  
The AI2524 implementation of X.25 supports both modulo 8 and mod-  
ulo 128 packet sequence numbering; module 8 is the default.  
In interface configuration mode, set the packet numbering modulo:  
x25 modulo {8 | 128}  
Note:  
Because the X.25 protocol requires the DTE and DCE to  
have identical modulos, changes you make to the modulo  
when the interface is up are held until the X.25 protocol  
restarts the packet service.  
The X.25 modulo and the LAPB modulo are distinct and serve differ-  
ent purposes. LAPB modulo 128 (or extended mode) can be used to  
achieve higher throughput across the DTE or DCE interface; it affects  
only the local point of attachment. X.25 Packet-Level Protocol (PLP)  
modulo 128 can be used to achieve higher end-to-end throughput for  
virtual circuits by allowing more data packets to be in transit through  
the X.25 network.  
Set the X.121 Address  
If your router does not originate or terminate calls but only participates  
in X.25 switching, this task is optional. However, if the router is at  
tached to a PDN, you must set the interface X.121 address assigned by  
the X.25 network service provider.  
In interface configuration mode, set the X.121 address:  
x25 address x121-address  
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Set the Default Flow Control Values  
Because X.25 is a strongly flow-controlled protocol, setting correct  
default flow control parameters for window size and packet size is es-  
sential. Mismatched default flow control values will cause X.25 local  
procedure errors, evidenced by Clear and Reset events.  
To configure flow control parameters, complete these tasks. Thes  
tasks are optional if your X.25 attachment uses the standard default  
values for maximum packet sizes (128 bytes incoming and outgoing  
and window sizes (2 packets incoming and outgoing).  
z
z
Note:  
Because the X.25 protocol requires the DTE and DCE to  
have identical default maximum packet sizes and default  
window sizes, changes made to the window and packet  
sizes when the interface is up are held until the X.25 pro-  
tocol restarts the packet service.  
Set Default Window Sizes  
X.25 networks have a default input and output window size (the preset  
value is 2) that is defined by your network administrator. You must set  
the Cisco IOS software default input and output window sizes to match  
those of the network. These defaults are the values that an SVC uses if  
it is set up without explicitly negotiating its window sizes. PVCs also  
use these default values unless different values are configured.  
In interface configuration mode, set the default window sizes:  
1. Set the default virtual circuit receive window size.  
x25 win packets  
2. Set the default virtual circuit transmit window size.  
x25 wout packets  
Set Default Packet Sizes  
X.25 networks have a default maximum input and output packet siz  
(the preset value is 128) that is defined by your network administrator.  
You must set the Cisco IOS software default input and output maxi-  
mum packet sizes to match those of the network. These defaults are the  
values that an SVC uses if it is set up without explicitly negotiating its  
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Chapter 12: AI2524 X.25 Configuration Steps  
maximum packet sizes. PVCs also use these default values unless dif-  
ferent values are configured.  
In interface configuration mode, set the default input and output max-  
imum packet sizes:  
1. Set the default input maximum packet size.  
x25 ips bytes  
2. Set the default output maximum packet size.  
x25 ops bytes  
To send a packet larger than the agreed on X.25 packet size over an  
X.25 virtual circuit, the Cisco IOS software must break the packet into  
two or more X.25 packets with the M-bit (More data bit) set. The re-  
ceiving device collects all packets in the M-bit sequence and reassem-  
bles them into the original packet.  
It is possible to define default packet sizes that cannot be supported by  
the lower layer (see the LAPB N1 parameter). However, the router will  
negotiate lower maximum packet sizes for all SVCs so the agreed on  
sizes can be carried. The Cisco IOS software will also refuse a PVC  
configuration if the resulting maximum packet sizes cannot be sup-  
ported by the lower layer.  
Example: Typical X.25 Configuration  
This example shows the complete configuration for a serial interface  
connected to a commercial X.25 PDN for routing the IP protocol. The  
IP subnetwork address 172.25.9.0 has been assigned for the X.25 net-  
work.  
Note:  
When you are routing IP over X.25, you must treat the  
X.25 network as a single IP network or subnetwork. Map  
entries for routers with addresses on subnetworks other  
than the one on which the interface's IP address is stored  
are ignored by the routing software. All routers using the  
subnet number must have map entries for all others  
routers. Using the broadcast option with dynamic routing  
can result in larger traffic loads, requiring a larger hold  
queue, larger window sizes, or multiple virtual circuits.  
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AI2524 Router Card User’s Manual  
interface serial 2  
ip address 172.25.9.1 255.255.255.0  
!
encapsulation X25  
!
The bandwidth command is not part of the X.25 configuration; it is es-  
pecially important to understand that it does not have any connection  
with the X.25 entity of the same name. bandwidth commands are used  
by IP routing processes (currently only IGRP) to determine which  
lines are the best choices for traffic. Since the default is 1544 Kbaud,  
and X.25 service at that rate is not generally available, most X.25 in  
terfaces that are being used with IGRP in a real environment will have  
bandwidth settings.  
This is a 9.6 Kbaud line:  
bandwidth 10  
These Level 3 parameters are default flow control values; they need to  
match the PDN defaults. The values used by an SVC are negotiable on  
a per-call basis:  
x25 win 7  
x25 wout 7  
x25 ips 512  
x25 ops 512  
You must specify an X.121 address to be assigned to the X.25 inter-  
face by the PDN.  
x25 address 31370054065  
These Level 3 parameters have been set to match the network. You  
generally need to change some Level 3 parameters, most often those  
listed below. You might not need to change any Level 2 parameters,  
however.  
x25 htc 32  
x25 idle 5  
x25 nvc 2  
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Chapter 12: AI2524 X.25 Configuration Steps  
These commands configure the X.25 map. If you want to exchange  
routing updates with any of the routers, they would need broadcast  
flags. If the X.25 network is the only path to the routers, static routes  
are generally used to save on packet charges. If there is a redundant  
path, it might be desirable to run a dynamic routing protocol.  
x25 map IP 172.25.9.3 31370019134 ACCEPT-REVERSE  
x25 map IP 172.25.9.2 31370053087  
ACCEPT-REVERSE allows collect calls.  
If the PDN cannot handle fast back-to-back frames, use the trans-  
mitter-delay command to slow down the interface.  
transmitter-delay 1000  
Configure  
Additional X.25  
Interface  
Some X.25 applications have less common, or special, needs. Several  
X.25 parameters are available to modify the X.25 protocol behavior  
for these applications.  
To configure less common X.25 interface parameters for these special  
needs, perform these tasks, as needed:  
Parameters  
z
z
z
z
Configure the X.25 Level 3 Timers  
Configure the X.25 Level 3 Timers  
The X.25 Level 3 retransmission timers determine how long the Cisco  
IOS software waits for acknowledgment of control packets. You can  
set these timers independently. Only those timers that apply to the in-  
terface are able to be configured. (A DTE interface does not have the  
T1x timers, and a DCE interface does not have the T2x timers.)  
To set the retransmission timers, perform any of these tasks in inter-  
face configuration mode:  
z
Set DTE T20 Restart Request.  
x25 t20 seconds  
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z
z
z
z
z
z
z
Set DCE T10 Restart Indication.  
x25 t10 seconds  
Set DTE T21 Call Request.  
x25 t21 seconds  
Set DCE T11 Incoming Call.  
x25 t11 seconds  
Set DTE T22 Reset Request.  
x25 t22 seconds  
Set DCE T12 Reset Indication.  
x25 t12 seconds  
Set DTE T23 Clear Request.  
x25 t23 seconds  
Set DCE T13 Clear Indication.  
x25 t13 seconds  
Configure X.25 Addresses  
When establishing SVCs, X.25 uses addresses in the form defined by  
the ITU-T Recommendation for X.121. An X.121 address has from  
zero to 15 digits. Because of the importance of addressing to call setup,  
several interface addressing features are available for X.25.  
To configure X.25 addresses, perform these tasks:  
z
z
z
z
z
Understand Normal X.25 Addressing  
Understand Normal X.25 Addressing  
An X.25 interface's X.121 address is used when it is the source or des-  
tination of an X.25 call. The X.25 call setup procedure identifies both  
the calling (source) and the called (destination) X.121 addresses.  
When an interface is the source of a call, it encodes the interface X.121  
address as the source address. An interface determines that it is th  
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Chapter 12: AI2524 X.25 Configuration Steps  
destination of a received call if the destination address matches the in-  
terface's address.  
The AI2524 X.25 software can also route X.25 calls, which involves  
placing and accepting calls, but the router is neither the source nor the  
destination for these calls. Routing X.25 does not modify the source or  
destination addresses, thus preserving the addresses specified by the  
source host. Routed (switched) X.25 simply connects two logical X.25  
channels to complete an X.25 virtual circuit. An X.25 virtual circuit,  
is a connection between two hosts (the source host and the destination  
host) that is switched between routed X.25 links.  
The null X.121 address (the X.121 address that has zero digits) is a  
special case. The router acts as the destination host for any call it re-  
ceives that has the null destination address.  
Understand X.25 Subaddresses  
A subaddress is an X.121 address that matches the digits defined for  
the interface's X.121 address, but has additional digit(s) after the base  
address. X.25 acts as the destination host for an incoming Packet As-  
sembler/Disassembler (PAD) call with a destination that is a subad-  
dress of the interface's address; the trailing digits specify which line a  
PAD connection is requesting. Other calls that use a subaddress can be  
accepted if the trailing digit(s) are zeros; otherwise, the router will not  
act as the call's destination host.  
Configure an Interface Alias Address  
You can supply alias X.121 addresses for an interface. This allows the  
interface to act as the destination host for calls having a destination ad-  
dress that is neither the interface's address, an allowed subaddress o  
the interface, nor the null address.  
Local processing (for example, IP encapsulation) can be performed  
only for incoming calls whose destination X.121 address matches the  
serial interface or alias of the interface.  
In global configuration mode, configure an alias:  
x25 route [#position] x121-address-pattern  
[cud pattern] alias type number  
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Suppress or Replace the Calling Address  
Some attachments require thatno calling (source) address be presented  
in outgoing calls. The requirement is called suppressing the calling ad-  
dress.  
When attached to a PDN, X.25 may need to ensure that outgoing calls  
only use the assigned X.121 address for the calling (source) address.  
Routed X.25 normally uses the original source address. Although in-  
dividual X.25 route configurations can modify the source address,  
Cisco provides a simple command to force the use of the interface ad-  
dress in all calls sent; this requirement is called replacing the calling  
address.  
To suppress or replace the calling address, perform the appropriat  
task in interface configuration mode:  
z
Suppress the calling (source) X.121 address in outgoing calls.  
x25 suppress-calling-address  
z
Replace the calling (source) X.121 address in switched calls.  
x25 use-source-address  
Suppress the Called Address  
Some attachments require that no called (destination) address be pre-  
sented in outgoing calls; this requirement is called suppressing the  
called address.  
In interface configuration mode, suppress the called address:  
x25 suppress-called-address  
Establish a Default Virtual Circuit Protocol  
The Call Request packet that sets up a virtual circuit can encode a field  
called the Call User Data (CUD) field. Typically, the first few bytes of  
the CUD field identify which high-level protocol is carried by the vir-  
tual circuit. The router, when acting as a destination host, normally re-  
fuses a call if the CUD is absent or if the protocol identification isn't  
recognized. The PAD protocol, however, specifies that unidentified  
calls be treated as PAD connection requests. Other applications re-  
quire that they be treated as IP encapsulation connection requests, per  
RFC 877.  
In interface configuration mode, configure either PAD or IP encapsu  
lation treatment of unidentified calls:  
x25 default {ip | pad}  
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Chapter 12: AI2524 X.25 Configuration Steps  
Disable Packet-Level Protocol (PLP) Restarts  
By default, a PLP restart is performed when the link level resets (for  
example, when LAPB reconnects). Although PLP restarts can be dis-  
abled for those few networks that do not allow restarts, do not disable  
these restarts because doing so can cause anomalous packet layer be-  
havior.  
In interface configuration mode, disable PLP restarts:  
no x25 linkrestart  
Configure an  
X.25 Datagram  
Transport  
X.25 support is most commonly configured as a transport for data  
grams across an X.25 network. Datagram transport (or encapsulation)  
is a cooperative effort between two hosts communicating across an  
X.25 network. You configure datagram transport by establishing a  
mapping on the encapsulating interface between the far host's protocol  
address (for example, IP) and its X.121 address. Because the call iden-  
tifies the protocol that the virtual circuit will carry (in the CUD field),  
the terminating host can accept the call if it is configured to exchange  
the identified traffic with the source host.  
Figure 12-1 illustrates two routers sending datagrams across an X.25  
public data network (PDN).  
Figure 12-1: Transporting LAN Protocols across an X.25  
Public Data Network (PDN)  
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Perform these tasks, as necessary, to complete the X.25 configuration  
for your network needs:  
z
z
z
z
z
Configure Subinterfaces  
These sections describe how to perform these configuration tasks.  
Configure Subinterfaces  
Subinterfaces are virtual interfaces that can be used to connect several  
networks to each other through a single physical interface. Subinter-  
faces are made available on AI2524 routers because routing protocols,  
especially those using the split horizon principle, may need help to de-  
termine which hosts need a routing update. The split horizon principle  
allows routing updates to be distributed to other routed interfaces ex  
cept the interface on which the routing update was received. It works  
well in a LAN environment in which other routers reached by the in-  
terface have already received the routing update.  
However, in a WAN environment using connection-oriented inter-  
faces (like X.25 and Frame Relay), other routers reached by the same  
physical interface might not have received the routing update. Rathe  
than forcing you to connect routers by separate physical interfaces, the  
AI2524 provides subinterfaces that are treated as separate interfaces.  
You can separate hosts into subinterfaces on a physical interface. Sep-  
aration does not affect the X.25 protocol, and routing processes recog-  
nize each subinterface as a separate source of routing updates,  
enabling all subinterfaces to receive routing updates.  
Understand Point-to-Point and Multipoint Subinterfaces  
There are two types of subinterfaces: point-to-point and multipoint.  
Subinterfaces are implicitly multipoint unless configured as point-to-  
point.  
A point-to-point subinterface is used to encapsulate protocols between  
two hosts. An X.25 point-to-point subinterface will accept only a sin-  
gle encapsulation command (such as x25 mapor x25 pvc) for a  
given protocol, so there can be only one destination for the protocol.  
However, you can use multiple encapsulation commands, one for each  
protocol, or multiple protocols for one map or PVC. All protocol traf-  
fic routed to a point-to-point subinterface is forwarded to the one des-  
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Chapter 12: AI2524 X.25 Configuration Steps  
tination host defined for the protocol. Because only one destination is  
defined for the interface, the routing process need not consult the des-  
tination address in the datagrams.  
A multipoint subinterface is used to connect hosts for a given protocol.  
There is no restriction on the number of encapsulation commands that  
can be configured on a multipoint subinterface. Because the hosts ap-  
pear on the same subinterface, they are not relying on the router to dis-  
tribute routing updates between them. When a routing process  
forwards a datagram to a multipoint subinterface, the X.25 encapsula-  
tion process must be able to map the datagram's destination address to  
a configured encapsulation command. If the routing process cannot  
find a map for the datagram destination address, the encapsulation will  
fail.  
Note:  
Because of the complex operations dependent on a sub-  
interface and its type, the router will not allow a subinter-  
face type to be changed, nor can a subinterface with the  
same number be re-established once it has been deleted.  
After a subinterface has been deleted, you must reload the  
Cisco IOS software (by using the reloadcommand) to  
remove all internal references. However, you can easily  
reconstitute the deleted subinterface by using a different  
subinterface number.  
Create and Configure X.25 Subinterfaces  
In interface configuration mode, create and configure a subinterface  
by completing the first task and one or both of the second tasks:  
1. Create a point-to-point or multipoint subinterface.  
interface serial number.subinterface-number  
[point-to-point | multipoint]  
2. Configure an X.25 encapsulation map for the subinterface:  
x25 map protocol address [protocol2  
address2 [... [protocol9 address9]]] x121-  
address [option]  
And/or establish an encapsulation PVC for the subinterface:  
x25 pvc circuit protocol address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address [option]  
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Note:  
When configuring IP routing over X.25, you might need  
tomake adjustments to accommodate splithorizon effects.  
Refer to the Configuring IP Routing Protocols chapter in  
the Network Protocols Configuration Guide, Part 1 for  
details about how the Cisco IOS software handles possible  
split horizon conflicts. By default, split horizon is enabled  
for X.25 networks.  
Example: Point-to-Point Subinterface Configuration  
This example creates a point-to-point subinterface and maps IP to a re-  
mote host:  
interface Serial0.1 point-to-point  
x25 map ip 172.20.170.90 170090 broadcast  
Map Protocol Addresses to X.121 Addresses  
This section describes the X.25 single-protocol and multiprotocol en-  
capsulation options that are available and describes how to map proto-  
col addresses to an X.121 address for a remote host. This section also  
includes reference information about how protocols are identified.  
Understand Protocol Encapsulation for Single-Protocol and  
Multiprotocol Virtual Circuits  
The AI2524 supports encapsulation of a number of datagram protocols  
across X.25, using a standard method when available, or a proprietary  
method when necessary. These traditional methods assign a protocol  
to each virtual circuit. If more than one protocol is carried between th  
router and a given host, each active protocol will have at least one vir-  
tual circuit dedicated to carrying its datagrams.  
The AI2524 also supports RFC 1356, a standardized method for en  
capsulating most datagram protocols over X.25. It also specifies ho  
one virtual circuit can carry datagrams from more than one protocol.  
The Cisco IOS software can be configured to use any of the available  
encapsulation methods with a particular host.  
After you establish an encapsulation virtual circuit, the Cisco IOS soft-  
ware sends and receives a datagram by simply fragmenting it from and  
reassembling it into an X.25 complete packet sequence. An X.25 com-  
plete packet sequence is one or more X.25 data packets that have the  
M-bit set in all but the last packet. A virtual circuit that can carry mul-  
tiple protocols includes protocol identification data as well as the pro-  
tocol data at the start of each complete packet sequence.  
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Chapter 12: AI2524 X.25 Configuration Steps  
Understand Protocol Identification  
The various methods and protocols used in X.25 SVC encapsulation  
are identified in a specific field of the call packet; this field is defined  
by X.25 to carry CUD. Since PVCs do not use the X.25 call setup pro-  
cedures, only PVCs do not use CUD to identify their encapsulation.  
The primary difference between the available AI2524 and IETF en-  
capsulation methods is the specific value used to identify a protocol.  
When any of the methods establishes a virtual circuit for carrying  
single protocol, the protocol is identified in the call packet by the  
CUD. When a virtual circuit is established to carry more than one pro-  
tocol (only available using the RFC 1356 methodology), a protocol  
identification field precedes the datagram encapsulated in the X.25  
data packet; every datagram exchanged over that virtual circuit has its  
protocol identified.  
This table summarizes the values used in the CUD field to identify  
protocols.  
AI2524  
Protocol  
Identifier  
IETF RFC 1356  
Protocol Identifier  
Protocol  
Apollo Domain  
0xD4  
0x80 (5-byte SNAP  
1
encoding )  
Bridging  
0xD5  
0x81  
(Not implemented)  
2
ISO CLNS  
0x81  
Compressed TCP  
IP  
0xD8  
0xCC  
0xD3  
0x00 (5-byte SNAP  
3
encoding)  
4
0xCC or 0x80 (5-byte  
SNAP encoding)  
Novell IPX  
PAD  
0x80 (5-byte SNAP  
encoding)  
5
5
0x01  
0x01  
QLLC  
0xC3  
(Not available)  
0x00  
Multiprotocol  
(Not available)  
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AI2524 Router Card User’s Manual  
1. Subnetwork Access Protocol (SNAP) encoding is defined from  
the Assigned Numbers RFC. The AI2524 implementation recog-  
nizes only the IETF organizational unique identifier (OUI)  
0x0000 00 followed by a 2-byte Ethernet protocol type.  
2. The use of 0x81 for CLNS is compatible with ISO/IEC 8473-  
3:1994.  
3. Compressed TCP traffic has two types of datagrams, so IETF en-  
capsulation requires a multiprotocol virtual circuit.  
4. The use of 0xCC for IP is backwards-compatible with RFC 877.  
5. The use of 0x01 for PAD is defined by ITU-T Recommendation  
X.29.  
Once a multiprotocol virtual circuit has been established, datagrams  
on the virtual circuit have protocol identification data before the actual  
protocol data; the protocol identification values are the same used by  
RFC 1356 in the CUD field for an individual protocol.  
Note:  
IP datagrams can be identified with a 1-byte identification  
(0xCC) or a 6-byte identification (0x80 followed by the 5-  
byte SNAP encoding). The 1-byte encoding is used b  
default, although the SNAP encoding can be configured.  
Map Datagram Addresses to X.25 Hosts  
Encapsulation is a cooperative process between the router and anothe  
X.25 host. Because X.25 hosts are reached with an X.121 address (an  
X.121 address has up to15 decimal digits), the router must have  
means to map a host's protocols and addresses to its X.121 address.  
Each encapsulating X.25 interface must be configured with the rele-  
vant datagram parameters. For example, an interface that encapsulates  
IP will typically have an IP address.  
You must also establish the X.121 address of an encapsulating X.25  
interface using the x25 address interface configuration com-  
mand. The X.121 address is the address where encapsulation calls ar  
directed. This is also the source X.121 address used for originating an  
encapsulation call and is used by the destination host to map the sourc  
host and protocol to the protocol address. An encapsulation virtual cir-  
cuit must be a mapped at both the source and destination host inter  
faces.  
For each X.25 interface, you must explicitly map each destination  
host's protocols and addresses to its X.121 address. If needed and if the  
destination host has the capability, one host map can be configured to  
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Chapter 12: AI2524 X.25 Configuration Steps  
support several protocols; alternatively, you can define one map for  
each supported protocol.  
In interface configuration mode, establish a map:  
x25 map protocol address [protocol2  
address2[...[protocol9 address9]]] x121-  
address [option]  
For example, if you are encapsulating IP over a given X.25 interface,  
you must define an IP address for the interface and, for each of the de-  
sired destination hosts, map the host's IP address to its X.121 address.  
Note:  
You can map an X.121 address to as many as nine  
protocol addresses, but each protocol can be mapped only  
once in the command line.  
An individual host map can use these keywords to specify these pro-  
tocols:  
z apollo—Apollo Domain  
z bridge—Bridging  
z clns—OSI Connectionless Network Servic  
z compressedtcp—TCP/IP header compression  
z ip—IP  
z ipx—Novell IPX  
z pad—Packet Assembler/Disassemble  
z qllc—IBM's QLLC  
Each mapped protocol, except bridging and CLNS, takes a datagram  
address. All bridged datagrams are sent to all bridge maps on an inter-  
face. CLNS uses the mapped X.121 address as the SNPA, which is ref-  
erenced by a clns neighbor command. The configured datagram  
protocol(s) and relevant addresses are mapped to the destination host's  
X.121 address. All protocols that are supported for RFC 1356 opera  
tion can be specified in a single map. Bridging and QLLC are not sup-  
ported for RFC 1356 encapsulation. If IP and TCP/IP header  
compression are both specified, the same IP address must be given for  
both protocols.  
When setting up the address map, you can include options such as en-  
abling broadcasts, specifying the number of virtual circuits allowed,  
and defining various user facility settings.  
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AI2524 Router Card User’s Manual  
Note:  
Multiprotocol maps, especially those configured to carr  
broadcast traffic, can result in significantly larger traffi  
loads, requiring a larger hold queue, larger window sizes,  
or multiple virtual circuits.  
You can simplify the configuration for the Open Shortest Path First  
(OSPF) protocol by adding the optional broadcastkeyword.  
Configure PAD Access  
By default, PAD connection attempts are processed for session cre  
ation or protocol translation from all hosts. In interface configuration  
mode, restrict PAD connections to only statically mapped X.25 hosts:  
1. Restrict PAD access.  
x25 pad-access  
2. Configure a host for PAD access.  
x25 map pad x121-address [option]  
You can configure outgoing PAD access using the optional features of  
the x25 map padcommand without restricting incoming PAD con-  
nections to the configured hosts.  
Establish an Encapsulation PVC  
Permanent Virtual Circuits (PVCs) are the X.25 equivalent of leased  
lines; they are never disconnected. You do not need to configure an ad-  
dress map before defining a PVC; an encapsulation PVC implicitly de-  
fines a map.  
In interface configuration mode, establish a PVC:  
x25 pvc circuit protocol address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address [option]  
The x25 pvccommand uses the same protocol keywords as the x25  
mapcommand. Encapsulation PVCs also use a subset of the options  
defined for the x25 mapcommand.  
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Chapter 12: AI2524 X.25 Configuration Steps  
Example: PVC Used to Exchange IP Traffic  
This example, illustrated in Figure 12-2, demonstrates how to use the  
PVC to exchange IP traffic between Router X and Router Y.  
Figure 12-2:Establishing an IP Encapsulation PVC through  
an X.25 Network  
Configuration for Router X  
interface serial 2  
ip address 172.20.1.3 255.255.255.0  
x25 map ip 172.20.1.4 0  
x25 pvc 4 ip 172.20.1.4  
Configuration for Router Y  
interface serial 3  
ip address 172.20.1.4 255.255.255.0  
x25 map ip 172.20.1.3 0  
x25 pvc 3 ip 172.20.1.3  
In this example, the PDN has established a PVC through its network  
connecting PVC number 3 of access point A to PVC number 4 of ac-  
cess point B. On Router X, a connection is established between Router  
X and Router Y's IP address, 172.20.1.4. On Router Y, a connection is  
established between Router Y and Router X's IP address, 172.20.1.3.  
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AI2524 Router Card User’s Manual  
Set X.25 TCP/IP Header Compression  
The AI2524 supports RFC 1144 TCP/IP header compression (THC)  
on serial lines using HDLC and X.25 encapsulation. THC encapsula-  
tion is different from other encapsulation traffic. The implementation  
of compressed TCP over X.25 uses one virtual circuit to pass the com-  
pressed packets. Any IP traffic (including standard TCP) is separate  
from TCH traffic; it is carried over separate IP encapsulation virtual  
circuits or identified separately in a multiprotocol virtual circuit.  
Note:  
If you specify both ipand compressedtcpin the same  
x25 map compressedtcp command, they must both  
specify the same IP address.  
In interface configuration mode, set up a separate virtual circuit for  
X.25 TCP/IP header compression:  
x25 map compressedtcp ip-address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address [option]  
Configure X.25 Bridging  
The AI2524 transparent bridging software supports bridging ove  
X.25 virtual circuits. Bridging is not supported for RFC 1356 opera-  
tion. Bridge maps must include the broadcast option for correct oper-  
ation.  
In interface configuration mode, enable the X.25 bridging capability:  
x25 map bridge x121-address broadcast  
[option]  
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Chapter 12: AI2524 X.25 Configuration Steps  
Configure  
Additional X.25  
Datagram  
Transport  
Features  
The Cisco IOS software allows you to configure additional X.25 dat-  
agram transport features, including various user facilities defined for  
X.25 call setup.  
This section describes the X.25 datagram transport features you can  
configure by using the options in the x25 mapor x25 pvc en-  
capsulation command (or by setting an interface default). Th  
tasks you perform depend upon your needs, the structure of your net-  
work, and the requirements of the service provider.  
To configure the optional parameters, user facilities, and special fea-  
tures, perform one or more of these tasks:  
z
z
z
z
z
z
z
z
Configure X.25 Payload Compression  
Configure X.25 Payload Compression  
For increased efficiency on relatively slow networks, the Cisco IOS  
software supports X.25 payload compression of outgoing encapsula-  
tion traffic.  
Several restrictions apply to X.25 payload compression:  
z
The compressed virtual circuit must connect two Cisco routers,  
because X.25 payload compression is not standardized.  
The data packets conform to the X.25 protocol rules, so a com-  
pressed virtual circuit can be switched through standard X.25  
equipment. However, only Cisco routers can compress and de-  
compress the data.  
z
Only datagram traffic can be compressed, although all the encap-  
sulation methods supported by Cisco routers are available. For ex-  
ample, an IETF multiprotocol virtual circuit can be compressed.  
SVCs cannot be translated between compressed and uncom  
pressed data, nor can PAD data be compressed.  
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AI2524 Router Card User’s Manual  
z
X.25 payload compression must be applied carefully.  
Each compressed virtual circuit requires significant memory re-  
sources (for a dictionary of learned data patterns) and computation  
resources (every data packet received is decompressed and every  
data packet sentis compressed). Excessive use of compression can  
cause unacceptable overall performance.  
z
X.25 compression must be explicitly configured for mapcom-  
mand.  
A received call that specifies compression will be rejected if the  
corresponding host map does not specify the compress option. An  
incoming call that does not specify compression can, however, be  
accepted by a map that specifies compression.  
In interface configuration mode, enable payload compression over  
X.25:  
x25 map protocol address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address compress  
This command specifies that X.25 compression is to be used between  
the two hosts. Because each virtual circuit established for compressed  
traffic uses significant amounts of memory, compression should be  
used with careful consideration of its impact on performance.  
The compressoption may be specified for an encapsulation PVC.  
Configure the Encapsulation Virtual Circuit Idle Time  
The Cisco IOS software can clear a datagram transport SVC after a set  
period of inactivity. Routed SVCs are not timed for inactivity.  
In interface configuration mode, set the time:  
1. Set an idle time for clearing encapsulation.  
x25 idle minutes  
2. Specify an idle time for clearing a map's SVCs.  
x25 map protocol address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address idle minutes  
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Chapter 12: AI2524 X.25 Configuration Steps  
Increase the Number of Virtual Circuits Allowed  
For X.25 datagram transport, you can establish up to eight SVCs to  
one host for each map.  
To increase the number of virtual circuits allowed, perform one or both  
of these tasks in interface configuration mode:  
z
z
Specify the default maximum number of SVCs that can be open  
simultaneously to one host for each map.  
x25 nvc count  
Specify the maximum number of SVCs allowed for a map.  
x25 map protocol address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address nvc count  
Configure the Ignore Destination Time  
Upon receiving a Clear Request for an outstanding datagram transport  
Call Request, the X.25 encapsulation code immediately tries another  
Call Request if it has more traffic to send. This action can overrun  
some X.25 switches.  
To define the number of minutes the Cisco IOS software will prevent  
calls from going to a previously failed destination, type this command  
in interface configuration mode. Incoming calls will still be accepted.  
x25 hold-vc-timer minutes  
Establish the Packet Acknowledgment Policy  
You can instruct the Cisco IOS software to send an acknowledgment  
packet when it has received a threshold of data packets it has not ac-  
knowledged, instead of waiting until its input window is full. A value  
of 1 sends an acknowledgment for each data packet received if it can-  
not be acknowledged in an outgoing data packet. This approach im-  
proves line responsiveness at the expense of bandwidth. A value of 0  
restores the default behavior of waiting until the input window is full.  
To establish the acknowledgment threshold, type (in interface config-  
uration mode):  
x25 th delay-count  
The packet acknowledgment threshold also applies to encapsulation  
PVCs.  
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AI2524 Router Card User’s Manual  
Configure X.25 User Facilities  
The X.25 software provides commands to support X.25 user facilities  
(options specified by the creators of the X.25 Recommendation) that  
allow you to implement features such as accounting, user identifica-  
tion, and flow control negotiation. You can choose to configure facil-  
ities on a per-map basis or on a per-interface basis. In the following  
list, the x25 mapcommands configure facilities on a per-map basis;  
the x25 facilitycommands specify the values sent for all encap-  
sulation calls originated by the interface. Routed calls are not affected  
by the facilities specified for the outgoing interface.  
To set the supported X.25 user facilities, perform one or more of these  
tasks in interface configuration mode:  
z
Select the closed user group.  
x25 facility cug group-number  
or  
x25 map protocol address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address cug number  
z
Set flow control parameter negotiation values to request on outgo-  
ing calls.  
x25 facility packetsize in-size out-size  
or  
x25 map protocol address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address packetsize in-size out-size  
x25 facility windowsize in-size out-size  
or  
x25 map protocol address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address windowsize in-size outsize  
z
Set reverse charging.  
x25 facility reverse  
or  
x25 map protocol address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address reverse  
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Chapter 12: AI2524 X.25 Configuration Steps  
z
z
z
z
Allow reverse charging acceptance.  
x25 accept-reverse  
or  
x25 map protocol address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address accept-reverse  
Select throughput class negotiation.  
x25 facility throughput in out  
or  
x25 map protocol address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address throughput in out  
Select transit delay.  
x25 facility transit-delay value  
or  
x25 map protocol address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address transit-delay milliseconds  
Set the Recognized Private Operation Agency (RPOA) to use.  
x25 facility rpoa name  
or  
x25 map protocol address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address rpoa name  
z
z
Set the AI2524 standard network user identification.  
x25 map protocol address [protocol2  
address2 [...[ protocol9 address9]]] x121-  
address nuid username password  
Set a user-defined network user identification allowing the format  
to be determined by your network administrator.  
x25 map protocol address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address nudata string  
The windowsizeand packetsize options are supported for  
PVCs, although they have a slightly different meaning because PVCs  
do not use the call setup procedure. If the PVC does not use the inter-  
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AI2524 Router Card User’s Manual  
face defaults for the flow control parameters, these options must b  
used to specify the values. Not all networks will allow a PVC to be de-  
fined with arbitrary flow control values.  
Additionally, the Data bit (D-bit) is supported, if negotiated. PVCs  
allow the D-bit procedure because there is no call setup to negotiate its  
use. Both restricted and unrestricted fast select are also supported and  
are transparently handled by the software. No configuration is required  
for use of the D-bit or fast select facilities.  
Define the Virtual Circuit Packet Hold Queue Size  
To define the maximum number of packets that can be held whil  
virtual circuit is unable to send data, type (in interface configuration  
mode):  
x25 hold-queue queue-size  
An encapsulation virtual circuit's hold queue size is determined when  
it is created; the x25 hold-queue command does not affect ex-  
isting virtual circuits. This command also defines the hold queue siz  
of encapsulation PVCs.  
Restrict Map Usage  
An X.25 map can be restricted so that it will not be used to place calls  
or so that it will not be considered when incoming calls are mapped.  
To restrict X.25 map usage, use the following map options as needed:  
z
z
Restrict incoming calls from a map.  
x25 map protocol address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address no-incoming  
Restrict outgoing calls from a map.  
x25 map protocol address [protocol2  
address2 [...[protocol9 address9]]] x121-  
address no-outgoing  
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Chapter 12: AI2524 X.25 Configuration Steps  
Configure X.25  
Routing  
The X.25 software implementation allows virtual circuits to be routed  
from one X.25 interface to another and from one router to another. The  
routing behavior can be controlled with switching and X.25-over-TCP  
(XOT) configuration commands, based on a locally built table.  
X.25 encapsulation can share an X.25 serial interface with the X.25  
switching support. Switching or forwarding of X.25 virtual circuits  
can be completed two ways:  
z
Incoming calls received from a local serial interface running X.25  
can be forwarded to another local serial interface running X.25.  
This is known as local X.25 switching because the router handles  
the complete path. It does not matter whether the interfaces are  
configured as DTE or DCE device because the software takes the  
appropriate actions.  
z
An incoming call also can be forwarded to another Cisco router  
over a LAN using the TCP/IP protocols. Upon receipt of an in-  
coming call, a TCP connection is established to the router that is  
acting as the switch for the destination. All X.25 packets are sent  
and received over this reliable data stream. Flow control is main-  
tained end-to-end. This is known as X.25-over-TCP or XOT.  
(XOT was previously called remote switching or tunneling.) It  
does not matter whether the interfaces are configured as DTE or  
DCE, because the software takes the appropriate actions.  
Running X.25 over TCP/IP provides a number of benefits. The data-  
gram containing the X.25 packet can be switched by other routers  
using their high-speed switching abilities. X.25 connections can be  
sent over networks running only the TCP/IP protocols. The TCP/IP  
protocol suite runs over many different networking technologies, in-  
cluding Ethernet, Token Ring, T1 serial, and FDDI. Thus X.25 data  
can be forwarded over these media to another router where it can b  
output to an X.25 interface.  
When the connection is made locally, the switching configuration is  
used; when the connection is across a LAN, the XOT configuration is  
used. The basic function is the same for both types of connections, but  
different configuration commands are required for each type of con-  
nection.  
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AI2524 Router Card User’s Manual  
The X.25 switching subsystem supports these facilities and parame  
ters:  
z
D-bit negotiation—Data packets with the D-bit set are passed  
through transparently  
z
z
z
z
Variable-length interrupt data  
Flow control parameter negotiation  
Window size up to 7, or 127 for modulo 128 operation  
Packet size up to 4096, if the LAPB layers used are capable of han-  
dling the requested siz  
z
z
z
Basic closed user group selection  
Throughput class negotiation  
Reverse charging and fast select  
To configure X.25 routing, perform these tasks:  
z
z
z
z
z
Enable X.25 Routing  
You may also need to configure additional X.25 routing features, as re-  
quired for your network.  
Enable X.25 Routing  
In global configuration mode, enable X.25 routing to use local switch-  
ing or XOT by typing:  
x25 routing [use-tcp-if-defs]  
The use-tcp-if-defs keyword is used by some routers that re  
ceive remote routed calls from older versions of XOT; it might be  
needed if the originating router cannot be migrated to a new softwar  
release.  
Example: X.25 Route Address Pattern Matching  
This example shows how to route X.25 calls with addresses whos  
first four Data Network Identification Code (DNIC) digits are 1111 to  
interface serial 3, and to change the DNIC field in the addresses pre  
sented to the equipment connected to that interface to 2222. The \1 in  
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Chapter 12: AI2524 X.25 Configuration Steps  
the rewrite pattern indicates the portion of the original address  
matched by the digits following the 1111 DNIC.  
x25 route ^1111(.*) substitute-dest 2222\1 interface serial 3  
Figure 12-3 shows a more contrived command intended to illustrate  
the power of the rewriting scheme.  
Figure 12-3:X.25 Route Address Pattern Matching  
The command in Figure 12-3 causes all X.25 calls with 14-digit called  
addresses to be routed through interface serial 0. The incoming DNIC  
field is moved to the end of the address. The fifth, sixth, ninth, and  
tenth digits are deleted, and the thirteenth and fourteenth are moved  
before the eleventh and twelfth.  
Configure a Local X.25 Route  
When an incoming call needs to be forwarded, two fields in the X.25  
routing table are consulted to determine a local X.25 route:  
z
z
Destination X.121 address  
X.25 packet's CUD field (optional)  
When the destination address and the CUD of the incoming packet fit  
the X.121 and CUD patterns in the routing table, the call is forwarded.  
Forwarding to a specified interface is called local routing or local  
switching.  
To configure a local X.25 route, thus adding the local route to the rout-  
ing table, type (in global configuration mode):  
x25 route [#position] x121-address [cud  
pattern] interface type number  
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AI2524 Router Card User’s Manual  
Example: X.25 Routing  
This example shows how to enable X.25 switching, as well as how to  
enter routes into the X.25 routing table:  
Enable X.25 forwarding:  
x25 routing  
Enter routes into the table. Without a positional parameter, entries ar  
appended to the end of the table.  
x25 route ^100$ interface serial 0  
x25 route 100 cud ^pad$ interface serial 2  
x25 route 100 interface serial 1  
x25 route ^3306 interface serial 3  
x25 route .* ip 10.2.0.2  
The routing table forwards calls for X.121 address 100 out interface  
serial 0. Otherwise, calls are forwarded onto serial 1 if the X.121 ad-  
dress contains 100 anywhere within it and contains no CUD. Also, if  
the CUD is not the string pad, calls are forwarded to serial 1. If the  
X.121 address contains the digits 100 and the CUD is the string pad,  
the call is forwarded onto serial 2. All X.121 addresses that do not  
match the first 3 routes are checked for a DNIC of 3306 as the first 4  
digits. If they do match, they are forwarded over serial 3. All other  
X.121 addresses will match the fifth entry, which is a match-all pattern  
and will have a TCP connection established to the IP address 10.2.0.2.  
The router at 10.2.0.2 will then route the call according to its X.25  
routing table.  
This example configures a router that sits on a Tymnet/PAD switch to  
accept calls and have them forwarded to a DEC VAX system. This fea-  
ture permits running an X.25 network over a generalized existing IP  
network, thereby making another physical line for one protocol unnec-  
essary. The router positioned next to the DEC VAX system is config-  
ured with X.25 routes.  
x25 route vax-x121-address interface serial 0  
x25 route .* ip cisco-on-tymnet-ipaddress  
These commands route all calls to the DEC VAX X.121 address out to  
serial 0, where the VAX is connected running PSI. All other X.121 ad-  
dresses are forwarded to thecisco-on-tymnet address through its IP ad-  
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Chapter 12: AI2524 X.25 Configuration Steps  
dress. As a result, all outgoing calls from the VAX are sent to cisco  
on-tymnet for further processing.  
On the router named cisco-on-tymnet, you enter these commands:  
x25 route vax-x121-address ip cisco-on-vax  
x25 route .* interface serial 0  
These commands force all calls with the VAX X.121 address to be sent  
to the router with the VAX connected to it. All other calls with X.121  
addresses are forwarded out to Tymnet. If Tymnet can route them, a  
Call Accepted packet is returned, and everything proceeds normally.  
If Tymnet cannot handle the calls, it clears each call and the Clear Re-  
quest packet is forwarded back toward the VAX.  
Configure XOT (Remote) X.25 Route  
A remote X.25 route is one that crosses a TCP connection. Such routes  
are called X.25-over-TCP, or XOT, routes. (XOT was previously  
called remote routes or tunneled routes.  
When an incoming call needs to be forwarded, two fields in the X.25  
routing table are consulted to determine a remote X.25 route:  
z
z
Destination X.121 address  
X.25 packet's Call User Data (CUD) field (optional)  
When the destination address and the CUD of the incoming packet fit  
the X.121 and CUD patterns in the routing table, the call is forwarded.  
You can also specify an XOT source that causes the XOT TCP con  
nection to use the IP address of a specified interface as the source ad-  
dress of the TCP connection. If, for instance, a loopback interface is  
specified for the XOT connection's source address, TCP can use a pri-  
mary interface or any backup interface to reach the other end of th  
connection. However, if a physical interface address is specified as the  
source address, the XOT connection is terminated if that interface goes  
down.  
In global configuration mode, configure an XOT route (thus adding it  
to the X.25 routing table):  
x25 route [#position] x121-address [cud  
pattern] ip ip-address [xot-source type  
number]  
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Configure a Locally Switched PVC  
You can configure an X.25 PVC in the X.25 switching software. As a  
result, DTEs that require permanent circuits can be connected to  
router acting as an X.25 switch and have a properly functioning con-  
nection. X.25 resets will be sent to indicate when the circuit comes up  
or goes down. Both interfaces must define complementary locally  
switched PVCs.  
To configure a locally switched PVC, type (in interface configuration  
mode):  
x25 pvc number1 interface type number pvc  
number2 [option]  
The command options ar packetsize in outand window-  
size in out; they allow a PVC's flow control values to be defined  
if they differ from the interface defaults.  
Example: PVC Switching on the Same Router  
In this example, a PVC is connected between two serial interfaces on  
the same router. In this type of interconnection configuration, the des-  
tination interface must be specified along with the PVC number on that  
interface. To make a working PVC connection, two commands must  
be specified, each pointing to the other.  
interface serial 0  
encapsulation x25  
x25 ltc 5  
x25 pvc 1 interface serial 1 pvc 4  
!
interface serial 1  
encapsulation x25  
x25 ltc 5  
x25 pvc 4 interface serial 0 pvc  
1
In global configuration mode, ensure that these TCP sessions remain  
connected in the absence of XOT traffic by enabling keepalives:  
service tcp-keepalives-in  
service tcp-keepalives-out  
TCP keepalives also inform a router when an XOT SVCs session is not  
active, thus freeing router resources.  
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Chapter 12: AI2524 X.25 Configuration Steps  
Example: Simple Remote PVC Tunneling  
In this example, a connection is established between two PVCs across  
a LAN. Because the connection is remote (across the LAN), the tun  
neling command is used. This example establishes a PVC between  
Router X, Serial 0, PVC 1 and Router Y, Serial 1, PVC 2. Keepalives  
are enabled to maintain connection notification. Figure 12-4 provides  
a visual representation of the configuration.  
Figure 12-4:X.25 Tunneling Connection  
Configuration for Router X  
service tcp-keepalives-in  
service tcp-keepalives-out  
interface serial 0  
x25 pvc 1 tunnel 172.20.1.2 interface serial 1 pvc 2  
Configuration for Router Y  
service tcp-keepalives-in  
service tcp-keepalives-out  
interface serial 1  
x25 pvc 2 tunnel 172.20.1.1 interface serial 0 pvc 1  
Configure an XOT (Remote) PVC  
A PVC can be connected to another router over a LAN with the XOT  
protocol. When the interfaces come up, a TCP connection is estab-  
lished to the router that is acting as the switch for the destination. All  
X.25 packets will be sent and received over this reliable data stream.  
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AI2524 Router Card User’s Manual  
Flow control is maintained end-to-end. This was previously called re-  
mote switching or tunneling.  
Running X.25 over TCP/IP provides a number of benefits. Other rout-  
ers can switch IP datagrams containing the X.25 packets using the  
router's high-speed switching abilities. X.25 data can be sent over net-  
works running only TCP/IP protocols. The TCP/IP protocol suite runs  
over many different networking technologies, including Ethernet,  
Token Ring, T1 serial, and FDDI. Thus X.25 data can be forwarded  
over these media to another XOT host where it can be output to an  
X.25 interface. Both interfaces must define complementary tunneled  
PVCs.  
To configure a remote PVC to connect across a TCP/IP LAN, type (in  
interface configuration mode):  
x25 pvc number1 tunnel address interface  
serial string pvc number2 [option]  
The command options ar packetsize in outand window-  
size in out; they allow a PVC's flow control values to be defined  
if they differ from the interface defaults.  
Each XOT connection relies on a TCP session to carry traffic. If you  
do not enable TCP keepalives, XOT PVCs might encounter problems  
if one end of the connection is reloaded. When the reloaded host at-  
tempts to establish a new connection, the other host refuses the new  
connection because it has not been informed that the old session is no  
longer active. Recovery from this state requires the other host to be in-  
formed that its TCP session is no longer viable so that it attempts to  
reconnect the PVC.  
Example: Remote PVC Tunneling  
In the more complex example shown in Figure 12-5, the connection  
between points A and B is switched, and the connections between  
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Chapter 12: AI2524 X.25 Configuration Steps  
point C and points A and B are tunneled. Keepalives are enabled to  
maintain connection notification.  
Figure 12-5:Local Switching and Remote Tunneling PVCs  
Configuration for Router X  
service tcp-keepalives-in  
service tcp-keepalives-out  
interface ethernet 0  
ip address 172.20.1.1 255.255.255.0  
!
interface serial 0  
x25 ltc 5  
x25 pvc 1 interface serial 1 pvc 1  
x25 pvc 2 tunnel 172.20.1.2 interface serial 0 pvc 1  
!
interface serial 1  
x25 ltc 5  
x25 pvc 1 interface serial 0 pvc 1  
x25 pvc 2 tunnel 172.20.1.2 interface serial 0 pvc 2  
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Configuration for Router Y  
service tcp-keepalives-in  
service tcp-keepalives-out  
interface ethernet 0  
ip address 172.20.1.2 255.255.255.0  
!
interface serial 0  
x25 ltc 5  
x25 pvc 1 tunnel 172.20.1.1 interface serial 0 pvc 2  
x25 pvc 2 tunnel 172.20.1.1 interface serial 1 pvc 2  
Configure  
Additional X.25  
Routing Features  
To configure other, less common X.25 routing features, perform these  
tasks:  
z
z
z
Configure XOT to Use Interface Default Flow Control Values  
Configure XOT to Use Interface Default Flow Control  
Values  
When setting up a connection, the source and destination XOT imple-  
mentations need to cooperate to determine the flow control values that  
apply to the SVC. The source XOT ensures cooperation by encoding  
the X.25 flow control facilities (the window sizes and maximum  
packet sizes) in the X.25 Call packet. The far host's XOT implementa-  
tion can then correctly negotiate the flow control values at the destina-  
tion interface and, if needed, indicate the final values in the X.25 Call  
Confirm packet.  
The versions of XOT prior to Release 9.1(4.1) software will not, how-  
ever, ensure that these flow control values are encoded in the X.25 Call  
packet. When XOT receives a call that leaves one or both flow control  
values unspecified, it supplies the values. The values supplied are a  
window size of 2 packets and maximum packet size of 128 bytes; ac  
cording to the standards, any SVC can be negotiated to use these val-  
ues. Thus, when XOT receives a call from an older XOT  
implementation, it can specify in the Call Confirm packet that thes  
flow control values must revert to the lowest common denominator.  
What the older XOT implementations required was that the source and  
destination XOT router use the same default flow control values on the  
two X.25 interfaces that connect the SVC. Consequently, connections  
with mismatched flow control values were created when this assump-  
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Chapter 12: AI2524 X.25 Configuration Steps  
tion was not true, resulting in mysterious problems. The current imple-  
mentation's practice of signaling the values in the Call Confirm packet  
avoids these problems.  
Occasionally the older XOT implementation will be connected to a  
piece of X.25 equipment that cannot handle modification of the flow  
control parameters in the Call Confirm packet. These configurations  
should be upgraded to use a more recent version of XOT; when up  
grade is not possible, XOT's behavior causes a migration problem. In  
this situation, you may configure the Cisco IOS software to cause  
XOT to obtain unspecified flow control facility values from the desti-  
nation interface's default values.  
Modify XOT's source of unencoded flow control values by adding the  
option use-tcp-if-defs when enabling X.25 routing in global  
configuration mode:  
x25 routing [use-tcp-if-defs]  
Substitute Addresses in a Local X.25 Route  
When interconnecting two separate X.25 networks, you must some-  
times provide for address translation for local routes. Your X.25  
switch supports translation of X.25 source and destination addresses  
for local switching.  
To translate addresses, perform one or both of these tasks in global  
configuration mode:  
z
Translate the X.25 source address for local switching.  
x25 route [#position] x121-address  
[substitute-source pattern] [cud pattern]  
interface interface number  
z
Translate the X.25 destination address for local switching.  
x25 route [#position] x121-address  
[substitute-dest pattern] [cud pattern]  
interface interface number  
Address substitution is not available for XOT routes.  
Configure XOT Alternate Destinations  
XOT routes can be configured with alternate addresses. On routing  
call, XOT will try each XOT destination host in sequence; if the TCP  
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AI2524 Router Card User’s Manual  
connection establishment fails, the next destination will be tried. Up to  
six XOT destination addresses can be entered.  
To configure an XOT route with alternate addresses, thus adding it to  
the X.25 routing table, type (in global configuration mode):  
x25 route [#position] x121-address [cud  
pattern]  
ip ip-address [ip-address2... [ip-  
address6]]  
The sequence of alternate destination XOT host addresses is simply  
added to the normal XOT route configuration command.  
Note:  
It can take up to 50 seconds to try an alternate route due  
to TCP timings.  
Configure CMNS  
Routing  
The Connection-Mode Network Service (CMNS) provides a mecha  
nism through which local X.25 switching can be extended to nonserial  
media through the use of OSI-based NSAP addresses. This implemen-  
tation runs packet-level X.25 over frame-level LLC2.  
The AI2524 CMNS implementation allows LAN-based OSI re  
sources, such as a DTE host and a Sun workstation, to be intercon-  
nected to each other via the router's LAN interfaces and to a remot  
OSI-based DTE through a WAN interface using, for example, an X.25  
Packet-Switched Network (PSN).  
Note:  
CMNS is implicitly enabled whenever an X.25  
encapsulation is included with a serial interfac  
configuration.  
All local mapping is performed by the static mapping of MAC ad-  
dresses and X.121 addresses to NSAP addresses.  
Implementing CMNS routing involves completing these tasks:  
z
z
Enable CMNS on an Interface  
Specify a CMNS Static Map of Addresses  
Enable CMNS on an Interface  
In interface configuration mode, enable CMNS on a nonserial inter-  
face:  
cmns enable  
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Chapter 12: AI2524 X.25 Configuration Steps  
Specify a CMNS Static Map of Addresses  
After enabling CMNS on a nonserial interface (or specifying X.25 en-  
capsulation on a serial interface), you must map NSAP addresses to ei-  
ther MAC-layer addresses or X.121 addresses, depending on th  
application.  
For CMNS support over dedicated serial links (such as leased lines),  
an X.121 address is not needed, but can be included. You must specify  
the X.121 address for CMNS connections over a packet-switched net-  
work, and you must specify a MAC address for CMNS connections  
over a nonserial medium (Ethernet, FDDI, or Token Ring).  
To map the NSAP addresses to either a MAC address or X.121 ad  
dress, perform one of these tasks in interface configuration mode:  
z
z
Statically map an NSAP address to a nonserial MAC-layer ad-  
dress.  
x25 map cmns nsap mac-address  
Statically map an NSAP address to X.25, with an optional X.121  
destination address.  
x25 map cmns nsap x121-address  
Example: CMNS Configured for X.121 and MAC Addresses  
This example illustrates enabling CMNS and configuring X.121 and  
MAC address mappings. Map NSAP to MAC-address on Ethernet0:  
interface ethernet 0  
cmns enable  
x25 map cmns 38.8261.1000.0150.1000.17 0000.0c00.ff89  
Map NSAP to X.121-address on Serial0 assuming the link is over  
PDN:  
interface serial 0  
encapsulation x25  
x25 map cmns 38.8261.1000.0150.1000.18 3110451  
Specify cmns support for Serial1 assuming that the link is over  
leased line:  
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interface serial 1  
encapsulation x25  
x25 map cmns 38.8261.1000.0150.1000.20  
Example: CMNS Switched over a PDN  
This example depicts switching CMNS over a packet-switched PDN.  
Figure 12-6 illustrates the general network topology for a CMNS  
switching application where calls are being made between resources  
on opposite sides of a remote link to Host A (on an Ethernet) and Host  
B (on a Token Ring), with a PDN providing the connection.  
Figure 12-6:Example Network Topology for Switching  
CMNS over a PDN  
This configuration listing allows resources on either side of the PD  
to call Host A or Host B. This configuration allows traffic intended for  
the remote NSAP address specified in the x25 map cmns com-  
mands (for the serial ports) to be switched through the serial interface  
for which CMNS is configured.  
Configuration for Router C2  
This configuration specifies that any traffic from any other interface  
intended for any NSAP address with NSAP prefix 38.8261.17 will be  
switched to MAC address 0800.4e02.1f9f through Token Ring 0.  
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Chapter 12: AI2524 X.25 Configuration Steps  
interface token 0  
cmns enable  
x25 map cmns 38.8261.17 0800.4e02.1f9f  
This configuration specifies that traffic from any other interface on  
Cisco Router C2 that is intended for any NSAP address with NSAP-  
prefix 38.8261.18 will be switched to X.121 address 2095551000  
through Serial 0.  
interface serial 0  
encapsulation x25  
x25 address 4085551234  
x25 map cmns 38.8261.18 2095551000  
Configuration for Router C1  
This configuration specifies that any traffic from any other interface  
intended for any NSAP address with NSAP 38.8261.18 will be  
switched to MAC address 0800.4e02.2abc through Ethernet 0.  
interface ethernet 0  
cmns enable  
x25 map cmns 38.8261.18 0800.4e02.2abc  
This configuration specifies that traffic from any other interface on  
Cisco Router C1 that is intended for any NSAP address with NSAP-  
prefix 38.8261.17 will be switched to X.121 address 4085551234  
through Serial 1.  
interface serial 1  
encapsulation x25  
x25 address 2095551000  
x25 map cmns 38.8261.17 4085551234  
Example: CMNS Switched over Leased Lines  
This example illustrates switching CMNS over a leased line. Figur  
12-7, illustrates the general network topology for a CMNS switching  
application where calls are being made by resources on the opposit  
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AI2524 Router Card User’s Manual  
sides of a remote link to Host C (on an Ethernet) and Host B (on a  
Token Ring), with a dedicated leased line providing the connection.  
This configuration listing allows resources on either side of the leased  
line to call Host C or Host B. This configuration allows traffic intended  
for the remote NSAP address specified in the x25 map cmns com-  
mands (for the serial ports) to be switched through the serial interface  
for which CMNS is configured.  
Figure 12-7:Example Network Topology for Switching  
CMNS over a Leased Line  
A key difference for this configuration compared with the previous ex-  
ample is that with no PDN, the specification ofan X.121 address in the  
x25 map cmns command is not necessary. The specification of an  
X.25 address also is not needed, but is included for symmetry with the  
previous example.  
Configuration for Router C4  
This configuration specifies that any traffic from any other interface  
intended for any NSAP address with NSAP 38.8261.21 will be  
switched to MAC address 0800.4e02.bcd0 through Token Ring 0.  
interface token 0  
cmns enable  
x25 map cmns 38.8261.21 0800.4e02.bcd0  
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Chapter 12: AI2524 X.25 Configuration Steps  
This configuration specifies that traffic from any other interface on  
Cisco Router C4 that is intended for any NSAP address with NSAP-  
prefix 38.8261.20 will be switched through Serial 0.  
interface serial 0  
encapsulation x25  
x25 address 00002  
x25 map cmns 38.8261.20  
Configuration for Router C3  
This configuration specifies that any traffic from any other interface  
intended for any NSAP address with NSAP 38.8261.20 will be  
switched to MAC address 0800.4e02.123f through Ethernet 0.  
interface ethernet 0  
cmns enable  
x25 map cmns 38.8261.20 0800.4e02.123f  
This configuration specifies that traffic from any other interface on  
Router C3 that is intended for any NSAP address with NSAP-prefix  
38.8261.21 will be switched through Serial 1.  
interface serial 1  
encapsulation x25  
x25 address 00001  
x25 map cmns 38.8261.21  
Create X.29  
Access Lists  
Protocol translation software supports access lists, which make it pos-  
sible to limit access to the access server from X.25 hosts. Access lists  
take advantage of the message field defined by Recommendation  
X.29, which describes procedures for exchanging data between two  
PADs or between a PAD and a DTE device.  
To define X.29 access lists, perform these tasks:  
z
z
Create an Access List  
When configuring protocol translation, you can specify an access list  
number with each translatecommand. When translation sessions  
result from incoming PAD connections, the corresponding X.29 ac  
cess list is used.  
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Create an Access List  
To specify the access conditions, restrict incoming and outgoing con-  
nections between a particular Virtual Terminal (VTY) line (into a  
Cisco access server) and the addresses in an access list by typing (in  
global configuration mode):  
x29 access-list access-list-number {deny |  
permit} x121-address  
An access list can contain any number of lines. The lists are processed  
in the order in which you type the entries. The first match causes the  
permit or deny condition. If an X.121 address does not match any of  
the entries in the access list, access is denied.  
Example: X.29 Access List  
This example illustrates an X.29 access list. Incoming permit condi-  
tions are set for all IP hosts that have specific characters in their names.  
All X.25 connections to a printer are denied. Outgoing connections are  
list restricted.  
Permit all IP hosts beginning with VMS. Deny X.25 connections to th  
printer on line 5.  
access-list 1 permit 0.0.0.0 255.255.255.255  
lat access-list 1 permit ^VMS.*  
x29 access-list 1 deny .*  
!
line vty 5  
access-class 1 i  
Permit outgoing connections for other lines. Permit IP access with the  
network 172.30.  
access-list 2 permit 172.30.0.0 0.0.255.255  
Permit X.25 connections to Infonet hosts only.  
x29 access-list 2 permit ^31370  
!
line vty 0 16  
access-class 2 ou  
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Chapter 12: AI2524 X.25 Configuration Steps  
Apply an Access List to a Line  
In line configuration mode, apply an access list to a virtual line by re-  
stricting incoming and outgoing connections between a particular vir-  
tual terminal line (into a Cisco access server) and the addresses in an  
access list:  
access-class access-list-number in  
The access list number is used for incoming TCP access and for in-  
coming PAD access. For TCP access, the protocol translator uses the  
defined IP access lists. For incoming PAD connections, the protocol  
translator uses the defined X.29 access list. If you want to have access  
restrictions only on one of the protocols, create an access list that per-  
mits all addresses for the other protocols.  
Create an X.29  
Profile Script  
You can create an X.29 profile script for th translatecommand.  
When an X.25 connection is established, the protocol translator acts as  
if an X.29 Set Parameter packet had been sent containing the parame-  
ters and values set by this command.  
In global configuration mode, create an X.29 profile script:  
x29 profile name parameter:value  
[parameter:value]  
Example: X.29 Profile Script  
This profile script turns local edit mode on when the connection is  
made and establishes local echo and line termination upon receipt of a  
Return. The name linemode is used with the translatecommand  
to activate this script.  
x29 profile linemode 2:1 3:2 15:1  
translate tcp 172.30.1.26 x25 55551234 profile linemode  
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AI2524 Router Card User’s Manual  
Configure LAPB  
You can use only LAPB as a serial encapsulation method if you hav  
a private serial line. You must use one of the X.25 packet-level encap-  
sulations when attaching to an X.25 network.  
The LAPB standards distinguish between two types of hosts: Data  
Terminal Equipment (DTE), and Data Circuit-terminating Equipment  
(DCE). At Level 2, or the data link layer in the OSI model, LAPB al-  
lows for orderly and reliable exchange of data between a DTE and a  
DCE. A router using LAPB encapsulation can act as a DTE or DCE  
device at the protocol level, which is distinct from the hardware DTE  
or DCE identity.  
Using LAPB under noisy conditions can result in greater throughput  
than HDLC encapsulation. When LAPB detects a missing frame, th  
router retransmits the frame instead of waiting for the higher layers to  
recover the lost information. This behavior is good only if the host tim-  
ers are relatively slow. In the case of quickly expiring host timers,  
however, you will discover that LAPB is spending much of its tim  
transmitting host retransmissions. If the line is not noisy, the lower  
overhead of HDLC encapsulation is more efficient than LAPB. When  
you are using long-delay satellite links, for example, the lock-step be-  
havior of LAPB makes HDLC encapsulation the better choice.  
To configure LAPB, complete these tasks. The tasks in the first section  
are required; the remaining are optional.  
z
z
z
z
z
Configure a LAPB Datagram Transport  
Configure a LAPB Datagram Transport  
Set the appropriate LAPB encapsulation to run datagrams over a serial  
interface. One end of the link must be DTE, the other must be DCE.  
1. Specify a serial interface.  
interface serial number  
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Chapter 12: AI2524 X.25 Configuration Steps  
2. In interface configuration mode, select an encapsulation and pro-  
tocol if using a single protocol or select the multiple protocol op-  
eration by performing one or more of these tasks:  
zEnable encapsulation of a single protocol on the line using DCE  
operation.  
encapsulation lapb dce [protocol]  
zEnable encapsulation of a single protocol on the line using DTE  
operation.  
encapsulation lapb [dte] [protocol]  
zEnable use of multiple protocols on the line using DCE opera  
tion.  
encapsulation lapb dce multi  
zEnable use of multiple protocols on the line using DTE opera-  
tion.  
encapsulation lapb [dte] multi  
Single protocol LAPB defaults to IP encapsulation. Multiprotocol  
LAPB does not support source-route bridging or TCP/IP header com-  
pression, but does support transparent bridging. Only protocols sup-  
ported by a single protocol encapsulation are supported by  
multiprotocol LAPB encapsulation.  
Example: Typical LAPB Configuration  
In this example, the frame size (N1), window size (k), and maximum  
retransmission (N2) parameters retain their default values. The en-  
capsulation interface configuration command sets DCE opera-  
tion to carry a single protocol, IP by default. The lapb t1 interfac  
configuration command sets the retransmission timer to 4,000 milli-  
seconds (4 seconds) for a link with a long delay or slow connecting  
DTE device.  
interface serial 3  
encapsulation lapb dce  
lapb t1 4000  
Modify LAPB Protocol Parameters  
X.25 Level 2 or LAPB operates at the data link layer of the OSI refer-  
ence model. LAPB specifies methods for exchanging data (in units  
called frames), detecting out-of-sequence or missing frames, retrans  
mitting frames, and acknowledging frames. Several protocol parame-  
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AI2524 Router Card User’s Manual  
ters can be modified to change LAPB protocol performance on  
particular link. Because X.25 operates the PLP on top of the LAPB  
protocol, these tasks apply to both X.25 links and LAPB links. The pa-  
rameters and their default values are summarized in this table.  
Values  
or  
Ranges  
Task (LAPB  
Parameter)  
Command  
Default  
Set the modulo. lapb modulo  
8 or 128  
8
modulus  
Set the window lapb k window- 1- (mod-  
7
size (K).  
size  
ulo minus  
1) frames  
Set the maxi-  
mum bits per  
frame (N1).  
lapb n1bits  
Bits(must Based on  
be a mul- hardware  
tiple of 8) MTU and  
protocol  
overhead  
Set the count for lapb n2tries  
sending frames  
(N2).  
1--255  
tries  
20  
Set the retrans- lapb t1milli-  
1--64000  
millisec-  
onds  
3000  
mission timer  
(T1).  
seconds  
Set the hard  
ware outage  
period.  
lapb inter-  
face-outage  
milliseconds  
0 (dis-  
abled)  
Set the idle link lapb t4seconds  
period (T4).  
0 (dis-  
abled)  
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Chapter 12: AI2524 X.25 Configuration Steps  
z
LAPB Modulo and LAPB K. The LAPB modulo determines the  
operating mode. Modulo 8 (basic mode) is widely available, be-  
cause it is required for all standard LAPB implementations and is  
sufficient for most links. Modulo 128 (extended mode) can  
achieve greater throughput on high-speed links that have a low er-  
ror rate (some satellite links, for example) by increasing the num-  
ber of frames that can be transmitted before waiting for  
acknowledgment (as configured by the LAPB window parameter,  
k). By its design, LAPB's k parameter can be at most one less than  
the operating modulo. Modulo 8 links can typically send seven  
frames before an acknowledgment must be received; modulo 128  
links can set k to a value as large as 127. By default, LAPB links  
use the basic mode with a window of 7.  
z
LAPB N1. When connecting to an X.25 network, use the N1 pa-  
rameter value set by the network administrator. This value is the  
maximum number of bits in an LAPB frame, which determines the  
maximum size of an X.25 packet. When you are using LAPB over  
leased lines, the N1 parameter should be eight times the hardwar  
Maximum Transmission Unit (MTU) size plus any protocol over-  
head.  
The LAPB N1 range is dynamically calculated by the Cisco IOS  
software whenever an MTU change, an L2/L3 modulo change, o  
a compression change occurs on a LAPB interface.  
Caution: The LAPB N1 parameter provides little benefit beyond the  
interface MTU and can easily cause link failures if  
misconfigured. This parameter should be left at its default  
value.  
z
LAPB N2. The transmit counter (N2) is the number of unsuccess-  
ful transmit attempts made before the link is declared down.  
z
LABP T1. The retransmission timer (T1) determines how long  
transmitted frame can remain unacknowledged before the Cisco  
IOS software polls for an acknowledgment. For X.25 networks,  
the retransmission timer setting should match that of the network.  
For leased-line circuits, the T1 timer setting is critical because the  
design of LAPB assumes that a frame has been lost if it is not ac-  
knowledged within period T1. The timer setting must be larg  
enough to permit a maximum-sized frame to complete one round  
trip on the link. If the timer setting is too small, the software will  
poll before the acknowledgment frame can return, which may re-  
sult in duplicated frames and severe protocol problems. If the tim-  
er setting is too large, the software waits longer than necessary  
before requesting an acknowledgment, which reduces bandwidth.  
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z
LAPB T4. The LAPB standards define a timer to detect unsig-  
naled link failures (T4). The T4 timer is reset every time a frame  
is received from the partner on the link. If the T4 timer expires,  
Receiver Ready frame with the Poll bit set is sent to the partner,  
which is required to respond. If the partner does not respond, the  
standard polling mechanism is used to determine whether the link  
is down. The period of T4 must be greater than the period of T1.  
Another LAPB timer function allows brief hardware failures  
while the protocol is up, without requiring a protocol reset. When  
a brief hardware outage occurs, the link will continue uninterrupt-  
ed if the outage is corrected before the specified hardware outage  
period expires.  
Configure LAPB Priority and Custom Queuing  
AI2524 priority queuing and custom queuing are available for LAPB  
to allow you to improve link responsiveness to a given type of traffic  
by specifying the priority of that type of traffic for transmission on the  
link.  
Priority queuing is a mechanism that classifies packets based on cer-  
tain criteria and then assigns the packets to 1of 4 output queues, with  
high, medium, normal, or low priority. Custom queuing similarly clas-  
sifies packets, assigns them to 1 of 10 output queues, and controls the  
percentage of an interface's available bandwidth that is used for a  
queue.  
For example, you can use priority queuing to ensure that all Telnet  
traffic is processed promptly and that Simple Mail Transfer Protocol  
(SMTP) traffic is sent only when there is no other traffic to send. Pri  
ority queuing in this example can starve the non-Telnet traffic; custom  
queuing can be used instead to ensure that some traffic of all categories  
is sent.  
Both priority queuing and custom queuing can be defined, but only  
one method can be assigned to a given interface.  
To configure priority and custom queuing for LAPB, perform thes  
tasks:  
1. Perform the standard priority and custom queuing tasks except the  
task of assigning a priority or custom group to the interface.  
2. Perform the standard LAPB encapsulation tasks, as specified in  
the Configure a LAPB Datagram Transport section of this chapter.  
3. Assign either a priority group or a custom queue to the interface.  
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Chapter 12: AI2524 X.25 Configuration Steps  
Note:  
The lapb hold-queue command is no longer  
supported, but the same functionality is provided by the  
hold-queue size outstandard queue control  
command.  
Configure Transparent Bridging over Multiprotocol LAPB  
To configure transparent bridging over multiprotocol LAPB, perform  
these tasks beginning in global configuration mode:  
1. Specify the serial interface, and enter interface configuration  
mode.  
interface serial number  
2. Assign no IP address to the interface.  
no ip address  
3. Configure multiprotocol LAPB encapsulation.  
encapsulation lapb multi  
4. Assign the interface to a bridge group.  
bridge-group bridge-group  
5. Define the type of spanning tree protocol.  
bridge bridge-group protocol {ieee|dec}  
Note:  
This feature requires use of theencapsulation lapb  
multicommand. You cannot use theencapsulation  
lapb protocolcommand with a bridgekeyword to  
configure this feature.  
Monitor and Maintain LAPB and X.25  
To monitor and maintain X.25 and LAPB, perform any of these tasks  
in EXEC mode:  
z
Clear all virtual circuits at once (everything—encapsulation, rout-  
ed calls, and PAD calls—is cleared), or clear the single virtual cir-  
cuit specified.  
clear x25-vc type number [lcn]  
z
z
Display CMNS information.  
show cmns [type number]  
Display operation statistics for an interface.  
show interfaces serial number  
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z
z
z
z
Display CMNS connections over LLC2.  
show llc2  
Display the protocol-to-X.121 address map.  
show x25 map  
Display routes assigned by the x25 route command.  
show x25 route  
Display details of active virtual circuits.  
show x25 vc [lcn]  
Example: Transparent Bridging for Multiprotocol LAPB  
Encapsulation  
This example configures transparent bridging for multiprotocol LAPB  
encapsulation:  
no ip routing  
!
interface Ethernet 1  
no ip address  
no mop enabled  
bridge-group 1  
!
interface serial 0  
no ip address  
encapsulation lapb multi  
bridge-group 1  
!
bridge 1 protocol ieee  
Example: X.25 Configured to Allow Ping Support over  
Multiple Lines  
For pingcommands to work in an X.25 environment (when load  
sharing over multiple serial lines), you must include entries for all ad-  
jacent interface IP addresses in the x25 mapcommand for each serial  
interface. This example illustrates this point.  
Consider two routers, Router A and Router B, communicating with  
each other over two serial lines via an X.25 PDN (seeFigure 12-8) or  
over leased lines. In either case, all serial lines must be configured fo  
the same IP subnet address space. The configuration that follows al-  
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Chapter 12: AI2524 X.25 Configuration Steps  
lows for successful pingcommands. A similar configuration is re  
quired for the same subnet IP addresses to work across X.25.  
Figure 12-8:Parallel Serial Lines to an X.25 Network  
Note:  
All four serial ports configured for the two routers in the  
following configuration example must be assigned to the  
same IP subnet address space. In this case, the subnet is  
172.20.170.0.  
Configuration for Router A  
interface serial 1  
ip 172.20.170.1 255.255.255.0  
x25 address 31370054068  
x25 map ip 172.20.170.3 31370054065  
x25 map ip 172.20.170.4 31370054065  
!
interface serial 2  
ip 172.20.170.2 255.255.255.0  
x25 address 31370054069  
x25 map ip 172.20.170.4 31370054067  
x25 map ip 171.20.170.3 31370054067  
(allow either destination address)  
x25 31370054068 alias serial2  
x25 31370054069 alias serial1  
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AI2524 Router Card User’s Manual  
Configuration for Router B  
interface serial 0  
ip 172.20.170.3 255.255.255.0  
x25 address 31370054065  
x25 map ip 172.20.170.1 31370054068  
x25 map ip 172.20.170.2 31370054068  
!
interface serial 3  
ip 172.20.170.4 255.255.255.0  
x25 address 31370054067  
x25 map ip 172.20.170.2 31370054069  
x25 map ip 172.20.170.1 31370054069  
(allow either destination address)  
x25 31370054065 alias serial3  
x25 31370054067 alias serial0  
Example: Booting from a Network Server over X.25  
Over X.25, you cannot boot the router from a network server via a  
broadcast. Instead, you must boot from a specific host. Also, anx25  
mapcommand must exist for the host that you boot from. The x25  
mapcommand is used to map an IP address into an X.121 address.  
There must be an x25 mapcommand that matches the IP address  
given on the boot system command line.  
boot system gs3-k.100 172.18.126.111  
interface Serial 1  
ip address 172.18.126.200 255.255.255.0  
encapsulation X25  
x25 address 10004  
x25 map IP 172.18.126.111 10002 broadcast  
lapb n1 12040  
clockrate 56000  
In this case, 10002 is the X.121 address of the remote router that can  
get to host 172.18.126.111.  
The remote router must have this x25 mapentry:  
x25 map IP 172.18.126.200 10004 broadcast  
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Chapter 12: AI2524 X.25 Configuration Steps  
This entry allows the remote router to return a boot image from the  
host to the router booting over X.25.  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Chapter 13: AI2524 Frame Relay  
Configuration Steps  
Introduction  
This chapter describes how to perform a variety of frame relay config-  
uration tasks and enable frame relay encapsulation.  
Frame Relay  
Hardware  
Configuration  
Routers and access servers can connect directly to:  
z
z
The Frame Relay switch  
A channel service unit/digital service unit (CSU/DSU), which  
then connects to a remote Frame Relay switch  
A Frame Relay network is not required to support only routers that are  
connected directly or only routers connected via CSU/DSUs. Within  
network, some routers can connect to a Frame Relay switch through  
direct connection and others through connections via CSU/DSUs.  
However, a single router interface configured for Frame Relay can be  
only one or the other.  
The CSU/DSU converts V.35 or RS-449 signals to the properly coded  
T1 transmission signal for successful reception by the Frame Relay  
network. Figure 13-1 illustrates the connections between the different  
components.  
Figure 13-1:Typical Frame Relay Configuration  
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AI2524 Router Card User’s Manual  
The Frame Relay interface actually consists of one physical  
connection between the network server and the switch that provides  
the service. This single physical connection provides direct  
connectivity to each device on a network, such as a StrataCom  
FastPacket wide-area network (WAN).  
Frame Relay  
Configuration  
Task List  
There are required, basic steps you must follow to enable Frame Relay  
for your network. In addition, you can customize Frame Relay for you  
particular network needs and monitor Frame Relay connections. These  
sections outline these tasks. The tasks in the first two sections are re-  
quired.  
z
z
z
z
z
z
z
Enable Frame  
Relay  
Beginning in global configuration mode, set Frame Relay encapsula-  
tion at the interface level:  
Encapsulation on  
an Interface  
1. Specify the serial interface, and enter interface configuration  
mode.  
interface serial number  
2. Enable Frame Relay, and specify the encapsulation method.  
encapsulation frame-relay [ietf]  
Frame Relay supports encapsulation of all supported protocols in con-  
formance with RFC 1490, allowing interoperability between multiple  
vendors. Use the Internet Engineering Task Force (IETF) form of  
Frame Relay encapsulation if your router or access server is connected  
to another vendor's equipment across a Frame Relay network. IETF  
encapsulation is supported either at the interface level or on a per-vir-  
tual circuit basis.  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Examples: IETF Encapsulation  
The first example sets IETF encapsulation at the interface level. The  
second example sets IETF encapsulation on a per-DLCI basis. In the  
first example, the keyword ietf sets the default encapsulation method  
for all maps to IETF.  
encapsulation frame-relay IETF  
frame-relay map ip 131.108.123.2 48 broadcast  
frame-relay map ip 131.108.123.3 49 broadcast  
In this example, IETF encapsulation is configured on a per-DLCI ba-  
sis. This configuration has the same result as the configuration in th  
first example.  
encapsulation frame-relay  
frame-relay map ip 131.108.123.2 48 broadcast ietf  
frame-relay map ip 131.108.123.3 49 broadcast ietf  
Configure  
Dynamic or Static  
Address Mapping  
Dynamic address mapping uses Frame Relay Inverse ARP to request  
the next hop protocol address for a specific connection, given its  
known DLCI. Inverse ARP is enabled by default for all protocols it  
supports, but can be disabled for specific protocol-DLCI pairs. As a re-  
sult, you can use dynamic mapping for some protocols and static map-  
ping for other protocols on the same DLCI.  
Configure Dynamic Mapping  
Inverse ARP is enabled by default for all protocols enabled on the  
physical interface. Packets are not sent out for protocols that are not  
enabled on the interface.  
Because Inverse ARP is enabled by default, no additional command is  
required to configure dynamic mapping on an interface.  
Configure Static Mapping  
A static map links a specified next hop protocol address to a specified  
DLCI. Static mapping removes the need for Inverse ARP requests;  
when you supply a static map, Inverse ARP is automatically disabled  
for the specified protocol on the specified DLCI.  
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To establish static mapping according to your network needs, perform  
one of these tasks in interface configuration mode:  
z
z
z
Define the mapping between a next hop protocol address and the  
DLCI used to connect to the address.  
frame-relay map protocol protocol-address  
dlci [broadcast] [ietf] [cisco]  
Define a DLCI used to send International Organization for Stan-  
dardization (ISO) Connectionless Network Service (CLNS)  
frames.  
frame-relay map clns dlci [broadcast]  
Define a DLCI used to connect to a bridge.  
frame-relay map bridge dlci [broadcast]  
[ietf]  
Use these keywords to specify the protocols:  
z ip—IP  
z ipx—Novell IPX  
z clns—ISO CLNS  
Examples: Static Address Mapping  
These sections provide examples of static address mapping for the IP  
and IPX protocols.  
Two Routers in Static Mode Example  
This example illustrates how to configure two routers for static mode.  
Configuration for Router 1  
interface serial 0  
ip address 131.108.64.2 255.255.255.0  
encapsulation frame-relay  
keepalive 10  
frame-relay map ip 131.108.64.1 43  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Configuration for Router 2  
interface serial 0  
ip address 131.108.64.1 255.255.255.0  
encapsulation frame-relay  
keepalive 10  
frame-relay map ip 131.108.64.2 43  
IPX Routing Example  
This example illustrates how to send packets destined for IPX address  
200.0000.0c00.7b21 out on DLCI 102:  
ipx routing 000.0c00.7b3b  
!
interface ethernet 0  
ipx network 2abc  
!
interface serial 0  
ipx network 200  
encapsulation frame-relay  
frame-relay map ipx 200.0000.0c00.7b21 102 broadcast  
Configure the  
LMI  
Local Management Interface (LMI) autosense enables the interface to  
determine the LMI type supported by the switch and eliminates the  
need to configure the Local Management Interface (LMI) explicitly.  
Allow LMI Autosense to Operate  
LMI autosense is active in these situations:  
z
z
z
z
The router is powered up or the interface changes state to up.  
The line protocol is down but the line is up.  
The interface is a Frame Relay DTE.  
The LMI type is not explicitly configured.  
The LMI Autosense Process  
When LMI autosense is active, it sends out a full status request, in all  
3 LMI options (ANSI, ITU, Cisco) to the switch.  
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The router decodes the reply and configures itself automatically. If  
more than one reply is received, the router configures itself according  
to the most recent reply, accommodating intelligent switches that can  
handle multiple formats simultaneously.  
Using an intelligent retry scheme, LMI autosense attempts to deter  
mine the LMI type every N391 interval if initially unsuccessful. De-  
fault is 60 seconds, which is 6 keep exchanges at 10 seconds each.  
To make the typically transparent LMI autosense process visible to the  
user, turn on "debug frame lmi.” Every N391 interval, the user will se  
three rapid status queries coming from the serial interface.  
Configuring LMI Autosense  
No configuration options are provided. You can turn off LMI au  
tosense by explicitly configuring an LMI type. When the LMI type is  
written into NVRAM, the next time the router powers up, LMI au  
tosense is inactive.  
Explicitly Configure the LMI  
If you want to configure the LMI and thus deactivate LMI autosense,  
complete the tasks. The tasks in the first two sections are required if  
you choose to configure the LMI.  
z
z
z
Set the LMI Typ  
Set the LMI Keepalive Interval  
Set the LMI Polling and Timer Intervals  
Set the LMI Type  
If the router or access server is attached to a public data network  
(PDN), the LMI type must match the type used on the public network.  
Otherwise, the LMI type can be set to suit the needs of your privat  
Frame Relay network.  
In interface configuration mode, set one of three types of LMIs—  
ANSI T1.617 Annex D, Cisco, or ITU-T Q.933 Annex A:  
1. Set the LMI type.  
frame-relay lmi-type {ansi | cisco | q933a}  
2. Write the LMI type to NVRAM. Use the command form that is  
appropriate to your router platform.  
copy running-config destination  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Set the LMI Keepalive Interval  
A keepalive interval must be set to configure the LMI. By default, this  
interval is 10 seconds and, per the LMI protocol, must be less than the  
corresponding interval on the switch.  
z
To set the keepalive interval, type (in interface configuration  
mode):  
keepalive number  
z
To turn off keepalives on networks without an LMI.  
no keepalive  
Set the LMI Polling and Timer Intervals  
You can set various optional counters, intervals, and thresholds to  
fine-tune the operation of your LMI DTE and DCE devices. Set these  
attributes by performing one or more of these tasks in interface config-  
uration mode  
z
Set the DCE and Network-to-Network Interface (NNI) error  
threshold.  
frame-relay lmi-n392dce threshold  
z
z
z
z
z
Set the DCE and NNI monitored events count.  
frame-relay lmi-n393dce events  
Set the polling verification timer on a DCE or NNI interface.  
frame-relay lmi-t392dce timer  
Set a full status polling interval on a DTE or NNI interface.  
frame-relay lmi-n391dte keep-exchanges  
Set the DTE or NNI error threshold.  
frame-relay lmi-n392dte threshold  
Set the DTE and NNI monitored events count.  
frame-relay lmi-n393dte events  
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Configure Frame  
Relay Switched  
Virtual Circuits  
Currently, access to Frame Relay networks is made through private  
leased lines at speeds ranging from 56 kbps to 45 Mbps. Frame Relay  
is a connection-oriented, packet-transfer mechanism that establishes  
virtual circuits between endpoints.  
Switched virtual circuits (SVCs) allow access through a Frame Relay  
network by setting up a path to thedestination endpoints only when th  
need arises and tearing down the path when it is no longer needed.  
You must have these services before Frame Relay SVCs can operate:  
z
Frame Relay SVC support by the service provider—The service  
provider's switch must be capable of supporting SVC operation.  
z
Physical loop connection—A leased line or dedicated line must  
exist between the router (DTE) and the local Frame Relay switch.  
You must enable SVC operation at the interface level. Once it is en-  
abled at the interface level, it is enabled on any subinterface on that in-  
terface. One signaling channel, DLCI 0, is set up for the interface, and  
all SVCs are controlled from the physical interface.  
To enable Frame Relay SVC service and set up SVCs, complete these  
tasks. The subinterface tasks are not required, but offer additional flex-  
ibility for SVC configuration and operation. The LAPF tasks are not  
required and not recommended unless you understand thoroughly the  
impacts on your network.  
z
z
z
z
z
z
Configure SVCs on a Physical Interface  
Configure SVCs on a Physical Interface  
To enable SVC operation on a Frame Relay interface, perform these  
tasks beginning in global configuration mode:  
1. Specify the physical interface.  
interface serial number  
2. Specify the interface IP address, if needed.  
ip address ip-address mask  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
3. Enable Frame Relay encapsulation on the interface.  
encapsulation frame-relay  
4. Assign a map group to the interface.  
map-group group-name  
5. Enable Frame Relay SVC support on the interface.  
frame-relay svc  
Map-group details are specified with the map-listcommand.  
Example: SVCs on an Interface  
This example configures a physical interface, applies a map-group to  
the physical interface, and then defines the map-group.  
interface serial 0  
ip address 172.10.8.6  
encapsulation frame-relay  
map-group bermuda  
frame-relay lmi-type q933a  
frame-relay svc  
map-list bermuda source-addr E164 123456 dest-addr E164 654321  
ip 131.108.177.100 class hawaii  
appletalk 1000.2 class rainbow  
map-class frame-relay rainbow  
frame-relay idle-timer 60  
map-class frame-relay hawaii  
frame-relay cir in 64000  
frame-relay cir out 64000  
Configure SVCs on a Subinterface (optional)  
To configure Frame Relay SVCs on a subinterface, perform all th  
tasks in the previous section, except assigning a map group. Then, be-  
ginning in global configuration mode, complete these tasks:  
1. Specify a subinterface of the main interface configured for SVC  
operation.  
interface serial number.subinterface-  
number {multipoint | point-to-point}  
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2. Specify the subinterface IP address, if needed.  
ip address ip-address mask  
3. Assign a map group to the subinterface.  
map-group group-name  
Example: SVCs on a Subinterface  
This example configures a point-to-point interface for SVC operation.  
This example assumes that the main serial 0 interface has been config-  
ured for signalling, and that SVC operation has been enabled on th  
main interface.  
int s 0.1 point-point  
Define the map-group; details are specified under the map-list  
holidaycommand:  
map-group holiday  
Associate the map-group with a specific source and destination:  
map-list holiday local-addr X121 <X121-addr> dest-addr E164 <E164-addr>  
Specify destination protocol addresses for a map-class:  
ip 131.108.177.100 class hawaii IETF  
appletalk 1000.2 class rainbow IETF broadcast  
Define a map class and its QOS settings:  
map-class hawaii  
frame-relay cir in 2000000  
frame-relay cir out 56000  
frame-relay be 9000  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Define another map class and its QOS settings:  
map-class rainbow  
frame-relay cir in 64000  
frame-relay idle-timer 2000  
Configure a Map Class  
Beginning in global configuration mode, configure a map class:  
1. Specify the Frame Relay map class name and enter map class con-  
figuration mode.  
map-class frame-relay map-class-name  
2. Specify a custom queue list to be used for the map class.  
frame-relay custom-queue-list list-number  
3. Assign a priority queue to virtual circuits associated with the map  
class.  
frame-relay priority-group list-number  
4. Enable BECN feedback to throttle the frame-transmission rate.  
frame-relay becn-response-enable  
5. Specify the inbound committed information rate (CIR).  
frame-relay cir in bps  
6. Specify the outbound committed information rate (CIR).  
frame-relay cir out bps  
7. Set the minimum acceptable incoming CIR.  
frame-relay mincir in bps  
8. Set the minimum acceptable outgoing CIR.  
frame-relay mincir out bps  
9. Set the incoming committed burst size (Bc).  
frame-relay bc in bits  
10. Set the outgoing committed burst size (Bc).  
frame-relay bc out bits  
11. Set the incoming excess burst size (Be).  
frame-relay be in bits  
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12. Set the outgoing excess burst size (Be).  
frame-relay be out bits  
13. Set the idle timeout interval.  
frame-relay idle-timer duration  
You can define multiple map classes. A map class is associated with a  
static map, not with the interface or subinterface. Because of the flex-  
ibility this association allows, you can define different map classes fo  
different destinations.  
Configure a Map Group with E.164 or X.121 Addresses  
After you have defined a map group for an interface, you can associate  
the map group with a specific source and destination address, such as  
E.164 or X.121 addresses. In global configuration mode, specify th  
map group for a specific interface:  
map-list group-name source-addr {e164 |  
x121} source-address dest-addr {e164 |  
x121} destination-address  
Associate the Map Class with Static Protocol Address Maps  
To define the protocol addresses under a map-listcommand and  
associate each protocol address with a specified map class, use the  
classcommand for each protocol address. In map class configura-  
tion mode, associate a map class with a protocol address:  
protocol protocol-address class class-name  
[ietf] [broadcast [trigger]]  
The ietfkeyword specifies RFC 1490 encapsulation; th broad-  
castkeyword specifies that broadcasts must be carried. Thetrig-  
gerkeyword, which can be configured only if broadcastis also  
configured, enables a broadcast packet to trigger an SVC. If an SVC  
already exists that uses this map class, the SVC will carry the broad  
cast.  
Configure LAPF Parameters  
Frame Relay Link Access Procedure for Frame Relay (LAPF) com-  
mands are used to tune Layer 2 system parameters to work well with  
the Frame Relay switch. Normally, you do not need to change the de-  
fault settings. However, if the Frame Relay network indicates that it  
does not support the Frame Reject frame (FRMR) at the LAPF Fram  
In interface configuration mode, reject procedure:  
no frame-relay lapf frmr  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
By default, the Frame Reject frame is sent at the LAPF Frame Reject  
procedure.  
Note:  
Manipulation of Layer 2 parameters is not recommended  
if you do not know well the resulting functional change.  
For more information, refer to the ITU-T Q.922  
specification for LAPF.  
If you must change Layer 2 parameters for your network environment  
and if you know the resulting functional change, complete these tasks  
as needed:  
z
z
z
Set the LAPF window size k.  
frame-relay lapf k number  
Set the LAPF maximum retransmission count N200.  
frame-relay lapf n200 retries  
Set the maximum length of the Information field of the LAPF I  
frame N201.  
frame-relay lapf n201 number  
z
z
Set the LAPF retransmission timer value T200.  
frame-relay lapf t200 tenths-of-a-second  
Set the LAPF link idle timer value T203 of DLCI 0.  
frame-relay lapf t203 seconds  
Configure Frame  
Relay Traffic  
Shaping  
Beginning with Release 11.2, AI2524 supports Frame Relay traffic  
shaping, which provides:  
z
Rate enforcement on a per-virtual circuit basis—The peak rate for  
outbound traffic can be set to the CIR or some other user-config  
ured rate.  
z
Dynamic traffic throttling on a per-virtual circuit basis—When  
BECN packets indicate congestion on the network, the outbound  
traffic rate is automatically stepped down; when congestion eases,  
the outbound traffic rate is stepped up again. This feature is en-  
abled by default.  
z
Enhanced queuing support on a per-virtual circuit basis—Either  
custom queuing or priority queuing can be configured for individ-  
ual virtual circuits.  
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By defining separate virtual circuits for different types of traffic and  
specifying queuing and an outbound trafficrate foreach virtual circuit,  
you can provide guaranteed bandwidth for each type of traffic. By  
specifying different traffic rates for different virtual circuits over the  
same line, you can perform virtual time division multiplexing. By  
throttling outbound traffic from high-speed lines in central offices to  
lower-speed lines in remote locations, you can ease congestion and  
data loss in the network; enhanced queuing also prevents congestion-  
caused data loss.  
Traffic shaping applies to both PVCs and SVCs.  
To configure Frame Relay traffic shaping, perform these tasks:  
z
z
z
z
z
z
Enable Frame Relay Traffic Shaping on the Interface  
Enable Frame Relay Traffic Shaping on the Interface  
In interface configuration mode, enable Frame Relay traffic shaping  
on an interface to enable both traffic shaping and per-virtual circuit  
queuing on all the interface's PVCs and SVCs:  
frame-relay traffic-shaping  
Specify a Traffic-Shaping Map Class for the Interface  
If you specify a Frame Relay map class for a main interface, all the vir-  
tual circuits on its subinterfaces inherit all the traffic shaping parame  
ters defined for the class.  
In interface configuration mode, specify a map class for the specified  
interface:  
frame-relay class map-class-name  
You can override the default for a specific DLCI on a specific sub-  
interface by using the class virtual circuit configuration  
command to assign the DLCI explicitly to a different class.  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Define a Map Class with Queuing and Traffic Shaping  
Parameters  
When you define a map class for Frame Relay, you can define the av-  
erage and peak rates (in bits per second) allowed on virtual circuits as-  
sociated with the map class. You can also specify either a custom  
queue-list or a priority queue-group to use on virtual circuits associ-  
ated with the map class (optional).  
Beginning in global configuration mode, define a map class:  
1. Specify a map class to define.  
map-class frame-relay map-class-name  
2. Define the traffic rate for the map class.  
frame-relay traffic-rate average [peak]  
3. Specify a custom queue-list.  
frame-relay custom-queue-list number  
4. Specify a priority queue-list.  
frame-relay priority-group number  
Define Access Lists  
You can specify access lists and associate them with the custom  
queue-list defined for any map class. The list number specified in th  
access list and the custom queue list tie them together.  
See the appropriate protocol chapters for information about defining  
access lists for the protocols you want to transmit on the Frame Relay  
network.  
Define Priority Queue Lists for the Map Class  
You can define a priority list for a protocol and a default priority list.  
The number used for a specific priority list ties the list to the Frame  
Relay priority group defined for a specified map class.  
For example, if you enter th frame relay priority-group  
2command for the map class fast_vcs and then you enter th prior-  
ity-list 2 protocol decnet highcommand, that priority  
list is used for the fast_vcs map class. The average and peak traffic  
rates defined for the fast_vcs map class are used for traffic.  
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Define Custom Queue Lists for the Map Class  
You can define a queue list for a protocol and a default queue list. You  
can also specify the maximum number of bytes to be transmitted in  
any cycle. The number used for a specific queue list ties the list to the  
Frame Relay custom-queue list defined for a specified map class.  
For example, if you enter the frame relay custom-queue-  
list 1command for the map class slow_vcs and then you enter th  
queue-list 1 protocol ip list 100command, that queue  
list is used for the slow_vcs map class; access-list 100 defini-  
tion is also used for that map class and queue. The average and peak  
traffic rates defined for the slow_vcs map class are used for IP traffi  
that meets the access list 100 criteria.  
Example: Frame Relay Traffic Shaping  
This example illustrates a Frame Relay interface with three point-to  
point subinterfaces.  
In this example, the virtual circuits on subinterfaces Serial0.1 a  
Serial0.2 inherit class parameters from the main interface, namely  
those defined in slow_vcs. However, the virtual circuit defined on sub-  
interface Serial0.2 (DLCI 102) is specifically configured to use map  
class fast_vcs.  
Map class slow_vcs uses a peak rate of 9600 and average rate of 4800  
bps. Because BECN feedback is enabled by default, the output rate  
will be cut back as low as 4800bps in response to received BECNs.  
This map class is configured to use custom queuing using queue-list 1.  
In this example, queue-list 1 has 3 queues, with the first two being con-  
trolled by access lists 100 and 115.  
Map class fast_vcs uses a peak rate of 64000 and average rate of 16000  
bps. Because BECN feedback is enabled by default, the output rate  
will be cut back as low as 4800bps in response to received BECNs.  
This map class is configured to use priority-queuing using priority-  
group 2.  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
interface Serial0  
no ip address  
encapsulation frame-relay  
frame-relay lmi-type ansi  
frame-relay traffic-shaping  
frame-relay class slow_vcs  
!
interface Serial0.1 point-to-point  
ip address 10.128.30.1 255.255.255.248  
ip ospf cost 200  
bandwidth 10  
frame-relay interface-dlci 101  
!
interface Serial0.2 point-to-point  
ip address 10.128.30.9 255.255.255.248  
ip ospf cost 400  
bandwidth 10  
frame-relay interface-dlci 102  
class fast_vcs  
!
interface Serial0.3 point-to-point  
ip address 10.128.30.17 255.255.255.248  
ip ospf cost 200  
bandwidth 10  
frame-relay interface-dlci 103  
!
map-class frame-relay slow_vcs  
frame-relay traffic-rate 4800 9600  
frame-relay custom-queue-list 1  
!
map-class frame-relay fast_vcs  
frame-relay traffic-rate 16000 64000  
frame-relay priority-group 2  
!
access-list 100 permit tcp any any eq 2065  
access-list 115 permit tcp any any eq 256  
!
priority-list 2 protocol decnet hig  
priority-list 2 ip nor  
priority-list 2 default mediu  
!
queue-list 1 protocol ip 1 list 100  
queue-list 1 protocol ip 2 list 115  
queue-list 1 default 3  
queue-list 1 queue 1 byte-count 1600 limit 200  
queue-list 1 queue 2 byte-count 600 limit 200  
queue-list 1 queue 3 byte-count 500 limit 200  
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Customize Frame  
Relay for Your  
Network  
Perform these tasks to customize Frame Relay:  
z
z
z
z
z
z
z
z
Configure Frame Relay Subinterfaces  
Configure Frame Relay Subinterfaces  
To understand and define Frame Relay Subinterfaces, perform these  
tasks:  
z
z
z
Understand Frame Relay Subinterfaces  
After these tasks are completed, you can also perform these optional  
tasks:  
z
z
Understand Frame Relay Subinterfaces  
Frame Relay subinterfaces provide a mechanism for supporting par-  
tially meshed Frame Relay networks. Most protocols assume transitiv-  
ity on a logical network; that is, if station A can talk to station B, and  
station B can talk to station C, then station A should be able to talk to  
station C directly. Transitivity is true on LANs, but not on Fram  
Relay networks unless A is directly connected to C.  
Additionally, certain protocols such as transparent bridging cannot b  
supported on partially meshed networks because they require "split  
horizon," in which a packet received on an interface cannot be trans  
mitted out the same interface even if the packet is received and trans  
mitted on different virtual circuits.  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Configuring Frame Relay subinterfaces ensures that a singlephysical  
interface istreated as multiple virtual interfaces. This capability allows  
us to overcome split horizon rules. Packets received on one virtual in-  
terface can now be forwarded out another virtual interface, even if they  
are configured on the same physical interface.  
Subinterfaces address the limitations of Frame Relay networks by pro-  
viding a way to subdivide a partially meshed Frame Relay network  
into a number of smaller, fully meshed (or point-to-point) subnet  
works. Each subnetwork is assigned its own network number and ap-  
pears to the protocols as if it is reachable through a separate interface.  
Note:  
Point-to-point subinterfaces can be unnumbered for us  
with IP, reducing the addressing burden that might  
otherwise result.  
For example, suppose you have a 5-node Frame Relay network (see  
Figure 13-2) that is partially meshed (Network A). If the entire net-  
work is viewed as a single subnetwork (with a single network number  
assigned), most protocols assume that node A can transmit a packet di-  
rectly to node E, when in fact it must be relayed through nodes C and  
D. This network can be made to work with certain protocols (for ex-  
ample, IP) but will not work at all with other protocols because nodes  
C and D will not relay the packet out the same interface on which it  
was received. One way to make this network function fully is to creat  
a fully meshed network (Network B), but doing so requires a larg  
number of PVCs, which may not be economically feasible.  
Using subinterfaces, you can subdivide the Frame Relay network into  
three smaller subnetworks (Network C) with separate network num-  
bers. Nodes A, B, and C are connected to a fully meshed network, and  
nodes C and D, as well as nodes D and E are connected via point-to  
point networks. In this configuration, nodes C and D can access two  
subinterfaces and can therefore forward packets without violating split  
horizon rules. If transparent bridging is being used, each subinterfac  
is viewed as a separate bridge port.  
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Figure 13-2:Using Subinterfaces to Provide Full Connectiv-  
ity on a Partially Meshed Frame Relay Network  
Define Frame Relay Subinterfaces  
Configure subinterfaces on a Frame Relay network:  
1. Specify a serial interface.  
interface serial number  
2. Configure Frame Relay encapsulation on the serial interface.  
encapsulation frame-relay  
3. Specify a subinterface.  
interface serial number.subinterface-number  
{multipoint | point-to-point}  
Subinterfaces can be configured for multipoint or point-to-point com-  
munication. There is no default.  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Define Subinterface Addressing  
For point-to-point subinterfaces, the destination is presumed to be  
known and is identified or implied in the frame-relay inter-  
face-dlcicommand. For multipointsubinterfaces, the destinations  
can be dynamically resolved through the use of Frame Relay Inverse  
ARP or can be statically mapped through the use of the frame-  
relay mapcommand.  
Addressing on Point-to-Point Subinterfaces  
If you specified a point-to-point subinterface in Step 3 unde Define  
Frame Relay Subinterfaces, type (in interface configuration mode):  
frame-relay interface-dlci dlci [option]  
If you define a subinterface for point-to-point communication, you  
cannot reassign the same subinterface number to be used for multi-  
point communication without first rebooting the router or access  
server. Instead, you can simply avoid using that subinterface numbe  
and use a different subinterface number instead.  
Examples: Basic Subinterface  
In this example, subinterface 1 models apoint-to-point subnet and sub-  
interface 2 models a broadcast subnet. For emphasis, the multipoint  
keyword is used for serial subinterface 2, even though a subinterface  
is multipoint by default.  
interface serial 0  
encapsulation frame-relay  
interface serial 0.1 point-to-point  
ip address 10.0.1.1 255.255.255.0  
frame-relay interface-dlci 42  
interface serial 0.2 multipoint  
ip address 10.0.2.1 255.255.255.0  
frame-relay map 10.0.2.2 18  
Addressing on Multipoint Subinterfaces  
If you specified a multipoint subinterface in Step 3 under Define  
Frame Relay Subinterfaces, perform the tasks in one or both of the  
these sections:  
z
z
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You can configure some protocols for dynamic address mapping and  
others for static address mapping.  
Accept Inverse ARP for Dynamic Address Mapping on Multipoint  
Subinterfaces  
Dynamic address mapping uses Frame Relay Inverse ARP to request  
the next hop protocol address for a specific connection, given a DLCI.  
Responses to Inverse ARP requests are entered in an address-to-DLC  
mapping table on the router or access server; the table is then used to  
supply the next hop protocol address or the DLCI for outgoing traffic.  
Since the physical interface is now configured as multiple subinter-  
faces, you must provide information that distinguishes a subinterface  
from the physical interface and associates a specific subinterface with  
a specific DLCI.  
In interface configuration mode, associate a specific multipoint sub-  
interface with a specific DLCI:  
frame-relay interface-dlci dlci  
Inverse ARP is enabled by default for all protocols it supports, but can  
be disabled for specific protocol-DLCI pairs. As a result, you can use  
dynamic mapping for some protocols and static mapping for other pro-  
tocols on the same DLCI. You can explicitly disable Inverse ARP for  
a protocol-DLCI pair if you know the protocol is not supported on th  
other end of the connection.  
Because Inverse ARP is enabled by default for all protocols that it sup-  
ports, no additional command is required to configure dynamic ad-  
dress mapping on a subinterface.  
Example: Frame Relay Multipoint Subinterface with  
Dynamic Addressing  
This example configures two multipoint subinterfaces for dynamic ad-  
dress resolution. Each subinterface is provided with an individual pro-  
tocol address and subnet mask, and the interface-dlci  
command associates the subinterface with a specified DLCI. Ad-  
dresses of remote destinations for each multipoint subinterface will b  
resolved dynamically.  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
interface Serial0  
no ip address  
encapsulation frame-relay  
frame-relay lmi-type ansi  
!
interface Serial0.103 multipoint  
ip address 172.21.177.18 255.255.255.0  
frame-relay interface-dlci 300  
!
interface Serial0.104 multipoint  
ip address 172.21.178.18 255.255.255.0  
frame-relay interface-dlci 400  
Configure Static Address Mapping on Multipoint Subinterfaces  
A static map links a specified next hop protocol address to a specified  
DLCI. Static mapping removes the need for Inverse ARP requests;  
when you supply a static map, Inverse ARP is automatically disabled  
for the specified protocol on the specified DLCI.  
You must use static mapping if the router at the other end either does  
not support Inverse ARP at all or does not support Inverse ARP for a  
specific protocol that you want to use over Frame Relay.  
To establish static mapping according to your network needs, perform  
one of these tasks in interface configuration mode:  
z
Define the mapping between a next hop protocol address and the  
DLCI used to connect to the address.  
frame-relay map protocol protocol-address  
dlci [broadcast] [ietf] [cisco]  
z
z
Define a DLCI used to send ISO CLNS frames.  
frame-relay map clns dlci [broadcast]  
Define a DLCI used to connect to a bridge.  
frame-relay map bridge dlci [ietf]  
broadcast  
Use these keywords to specify the protocols:  
z ip—IP  
z ipx—Novell IPX  
z clns—ISO CLNS  
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AI2524 Router Card User’s Manual  
The broadcastkeyword is required for routing protocols such as  
OSI protocols and the Open Shortest Path First (OSPF) protocol. Se  
the frame-relay map command description in the Wide-Area  
Networking Command Reference for more information about using  
the broadcastkeyword.  
Example: IPX Routes over Frame Relay Subinterfaces  
This example configures a serial interface for Frame Relay encapsula-  
tion and sets up multiple IPX virtual networks corresponding to Frame  
Relay subinterfaces:  
ipx routing 0000.0c02.5f4f  
!
interface serial 0  
encapsulation frame-relay  
interface serial 0.1 multipoint  
ipx network 1  
frame-relay map ipx 1.000.0c07.d530 200 broadcast  
ipx network 2  
frame-relay map ipx 2.000.0c07.d530 300 broadcast  
For subinterface serial 0.1, the router at the other end might be config-  
ured as:  
ipx routing  
interface serial 2 multipoint  
ipx network 1  
frame-relay map ipx 1.000.0c02.5f4f 200 broadcast  
Configure Transparent Bridging for Frame Relay  
Transparent bridging for Frame Relay encapsulated serial and HSSI  
interfaces is supported on the AI2524 router. Transparent bridging for  
Frame Relay encapsulated serial interfaces is supported on our access  
servers.  
You can configure transparent bridging for point-to-point or point-to-  
multipoint subinterfaces.  
Note:  
All PVCs configured on a subinterface belong to the same  
bridge group.  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Point-to-Point Subinterfaces  
In interface configuration mode, configure transparent bridging for  
point-to-point subinterfaces:  
1. Specify a serial interface.  
interface serial number  
2. Configure Frame Relay encapsulation on the serial interface.  
encapsulation frame-relay  
3. Specify a subinterface.  
interface serial number.subinterface-number  
point-to-point  
4. Associate a DLCI with the subinterface.  
frame-relay interface-dlci dlci [option]  
5. Associate the subinterface with a bridge group.  
bridge-group bridge-group  
Example: Unnumbered IP over a Point-to-Point  
Subinterface  
This example sets up unnumbered IP over subinterfaces at both ends  
of a point-to-point connection. In this example, Router A functions as  
the DTE, and Router B functions as the DCE. Routers A and B are both  
attached to Token Ring networks.  
Configuration for Router A  
frame-relay switching  
!
interface token-ring 0  
ip address 131.108.177.1 255.255.255.0  
!
interface serial 0  
no ip address  
encapsulation frame-relay IETF  
!
interface Serial0.2 point-to-point  
ip unnumbered TokenRing0  
ip pim sparse-mode  
frame-relay interface-dlci 20  
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Configuration for Router B  
frame-relay switching  
!
interface token-ring 0  
ip address 131.108.178.1 255.255.255.0  
!
interface serial 0  
no ip address  
encapsulation frame-relay IETF  
bandwidth 384  
clockrate 4000000  
frame-relay intf-type dce  
!
interface serial 0.2 point-to-point  
ip unnumbered TokenRing1  
ip pim sparse-mode  
bandwidth 384  
frame-relay interface-dlci 20  
Point-to-Multipoint Interfaces  
In interface configuration mode, configure transparent bridging for  
point-to-multipoint subinterfaces:  
1. Specify a serial interface.  
interface serial number  
2. Configure Frame Relay encapsulation on the serial interface.  
encapsulation frame-relay  
3. Specify a subinterface.  
interface serial number.subinterface-number  
multipoint  
4. Define the mapping between a next hop protocol address and the  
DLCI used to connect to the address.  
frame-relay map bridge dlci [broadcast]  
[ietf]  
5. Associate the subinterface with a bridge group.  
bridge-group bridge-group  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Example: Transparent Bridging Using Subinterfaces  
In this example, Frame Relay DLCIs 42, 64, and 73 are to be used as  
separate point-to-point links with transparent bridging running over  
them. The bridging spanning tree algorithm views each PVC as a sep-  
arate bridge port, and a frame arriving on the PVC can be relayed back  
out a separate PVC. Be sure that routing is not enabled when config-  
uring transparent bridging using subinterfaces.  
interface serial 0  
encapsulation frame-relay  
interface serial 0.1 point-to-point  
bridge-group 1  
frame-relay interface-dlci 42  
interface serial 0.2 point-to-point  
bridge-group 1  
frame-relay interface-dlci 64  
interface serial 0.3 point-to-point  
bridge-group 1  
frame-relay interface-dlci 73  
Configure a Backup Interface for a Subinterface  
Both point-to-point and multipoint Frame Relay subinterfaces can be  
configured with a backup interface. This approach allows individual  
PVCs to be backed up in case of failure rather than depending on th  
entire Frame Relay connection to fail before the backup takes over.  
You can configure a subinterface for backup on failure only, not for  
backup based on loading of the line.  
If the serial interface has a backup interface, it will have precedenc  
over the subinterface's backup interface in the case of complete loss o  
connectivity with the Frame Relay network. As a result, a subinterface  
backup is activated only if the serial interface is up, or if the serial in-  
terface is down and does not have a backup interface defined. If a sub-  
interface has failed while its backup is in use, and then the serial  
interface goes down, the subinterface backup stays connected.  
Beginning in global configuration mode, configure a backup interface  
for a Frame Relay subinterface:  
1. Specify the interface.  
interface serial number  
2. Configure Frame Relay encapsulation.  
encapsulation frame-relay  
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3. Configure the subinterface.  
interface serial number.subinterface-number  
point-to-point  
4. Specify a DLCI for the subinterface.  
frame-relay interface-dlci dlci  
5. Specify a backup interface for the subinterface.  
backup interface serial number  
6. Specify backup enable and disable delay.  
backup delay {enable-delay | disable-delay}  
Configure Frame Relay Switching  
Frame Relay switching is a means of switching packets based upon the  
DLCI, which can be looked upon as the Frame Relay equivalent of a  
MAC address. You perform the switching by configuring your router  
or access server as a Frame Relay network. There are two parts to a  
Frame Relay network: a Frame Relay DTE (the router or access  
server) and a Frame Relay DCE switch. Figure 13-3 illustrates this  
concept.  
Figure 13-3:Frame Relay Switched Network  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
In Figure 13-3, Routers A, B, and C are Frame Relay DTEs connected  
to each other via a Frame Relay network. Our implementation of  
Frame Relay switching allows our devices to be used as depicted in  
this Frame Relay network.  
Perform the tasks in these sections, as necessary, to configure Frame  
Relay switching:  
z
z
Enable Frame Relay Switching  
z
Enable Frame Relay Switching  
In global configuration mode, enable packet switching before config-  
uring it on a Frame Relay DTE or DCE or with Network-to-Network  
Interface (NNI) support:  
frame-relay switching  
Configure a Frame Relay DTE Device, DCE Switch, or NNI  
Support  
In interface configuration mode, configure an interface as a DTE de-  
vice or a DCE switch or as a switch connected to a switch to support  
NNI connections:  
frame-relay intf-type [dce | dte | nni]  
DCE is the default.  
Specify the Static Route  
In interface configuration mode, specify a static route for PVC switch-  
ing:  
frame-relay route in-dlci out-interface  
out-dlci  
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Example: PVC Switching Configuration  
You can configure your router as a dedicated, DCE-only Frame Relay  
switch. Switching is based on DLCIs. The incoming DLCI is exam-  
ined, and the outgoing interface and DLCI are determined. Switching  
takes place when the incoming DLCI in the packet is replaced by the  
outgoing DLCI, and the packet is sent out the outgoing interface.  
In this example, the router switches two PVCs between interface serial  
1 and 2. Frames with DLCI 100 received on serial 1 will be transmitted  
with DLCI 200 on serial 2 (see Figure 13-4).  
Figure 13-4:PVC Switching Configuration  
Configuration for Router A  
frame-relay switching  
!
interface Ethernet0  
ip address 131.108.160.58 255.255.255.0  
!
interface Serial1  
no ip address  
encapsulation frame-relay  
keepalive 15  
frame-relay lmi-type ansi  
frame-relay intf-type dce  
frame-relay route 100 interface Serial2 200  
frame-relay route 101 interface Serial2 201  
clockrate 2000000  
!
interface Serial2  
encapsulation frame-relay keepalive 15  
frame-relay intf-type dce  
frame-relay route 200 interface Serial1 100  
frame-relay route 201 interface Serial1 101  
clockrate 64000  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Example: Pure Frame Relay DCE  
Using the PVC switching feature, it is possible to buildan entire Frame  
Relay network using our routers. In this example, Router A and Router  
C act as Frame Relay switches implementing a two-node network. Th  
standard Network-to-Network Interface (NNI) signaling protocol is  
used between Router A and Router C (see Figure 13-5).  
Figure 13-5:Frame Relay DCE Configuration  
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Configuration for Router A  
frame-relay switching  
!
interface ethernet 0  
no ip address  
shutdown  
!
interface ethernet 1  
no ip address  
shutdown  
!
interface ethernet 2  
no ip address  
shutdown  
!
interface ethernet 3  
no ip address  
shutdown  
!
interface serial 0  
ip address 131.108.178.48 255.255.255.0  
shutdown  
!
interface serial 1  
no ip address  
encapsulation frame-relay  
frame-relay intf-type dce  
frame-relay lmi-type ansi  
frame-relay route 100 interface serial 2 200  
!
interface serial 2  
no ip address  
encapsulation frame-relay  
frame-relay intf-type nni  
frame-relay lmi-type q933a  
frame-relay route 200 interface serial 1 100  
clockrate 2048000  
!
interface serial 3  
no ip address  
shutdown  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Configuration for Router C  
frame-relay switching  
!
interface ethernet 0  
no ip address  
shutdown  
!
interface ethernet1  
no ip address  
shutdown  
!
interface ethernet 2  
no ip address  
shutdown  
!
interface ethernet 3  
no ip address  
shutdown  
!
interface serial 0  
ip address 131.108.187.84 255.255.255.0  
shutdown  
!
interface serial 1  
no ip address  
encapsulation frame-relay  
frame-relay intf-type dce  
frame-relay route 300 interface serial 2 200  
!
interface serial 2  
no ip address  
encapsulation frame-relay  
frame-relay intf-type nni  
frame-relay lmi-type q933a  
frame-relay route 200 interface serial 1 300  
!
interface serial 3  
no ip address  
shutdown  
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Example: Hybrid DTE/DCE PVC Switching  
Routers can also be configured as hybrid DTE/DCE Frame Relay  
switches (see Figure 13-6).  
Figure 13-6:Hybrid DTE/DCE PVC Switching  
In this example, Router B acts as a hybrid DTE/DCE Frame Relay  
switch. It can switch frames between the two DCE ports and between  
a DCE port and a DTE port. Traffic from the Frame Relay network can  
also be terminated locally. In the example, three PVCs are defined as:  
z
z
z
Serial 1, DLCI 102 to serial 2, DLCI 201—DCE switching  
Serial 1, DLCI 103 to serial 3, DLCI 301—DCE/DTE switching  
Serial 2, DLCI 203 to serial 3, DLCI 302—DCE/DTE switching  
DLCI 400 is also defined for locally terminated traffic.  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Configuration for Router B  
frame-relay switching  
!
interface ethernet 0  
ip address 131.108.123.231 255.255.255.0  
!
interface ethernet 1  
ip address 131.108.5.231 255.255.255.0  
!
interface serial 0  
no ip address  
shutdown  
!
interface serial 1  
no ip address  
encapsulation frame-relay  
frame-relay intf-type dce  
frame-relay route 102 interface serial 2 201  
frame-relay route 103 interface serial 3 301  
!
interface serial 2  
no ip address  
encapsulation frame-relay  
frame-relay intf-type dce  
frame-relay route 201 interface serial 1 102  
frame-relay route 203 interface serial 3 302  
!
interface serial 3  
ip address 131.108.111.231  
encapsulation frame-relay  
frame-relay lmi-type ansi  
frame-relay route 301 interface serial 1 103  
frame-relay route 302 interface serial 1 203  
frame-relay map ip 131.108.111.4 400 broadcast  
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Example: Switching over an IP Tunnel  
You can switch over an IP tunnel by creating a point-to-point tunnel  
across the internetwork over which PVC switching can take place (se  
Figure 13-7:Frame Relay Switch over IP Tunnel  
The following configurations illustrate how to create the IP network  
depicted in Figure 13-7.  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Configuration for Router A  
frame-relay switching  
!
interface Ethernet0  
ip address 108.131.123.231 255.255.255.0  
!
interface Ethernet1  
ip address 131.108.5.231 255.255.255.0  
!
interface Serial0  
no ip address  
shutdown  
!
interface Serial1  
ip address 131.108.222.231 255.255.255.0  
encapsulation frame-relay  
frame-relay map ip 131.108.222.4 400 broadcast  
frame-relay route 100 interface Tunnel1 200  
!
interface Tunnel1  
tunnel source Ethernet0  
tunnel destination 150.150.150.123  
Configuration for Router D  
frame-relay switching  
!
interface Ethernet0  
ip address 131.108.231.123 255.255.255.0  
!
interface Ethernet1  
ip address 131.108.6.123 255.255.255.0  
!
interface Serial0  
ip address 150.150.150.123 255.255.255.0  
encapsulation ppp  
interface Tunnel1  
tunnel source Serial0  
tunnel destination 108.131.123.231  
!
interface Serial1  
ip address 131.108.7.123 255.255.255.0  
encapsulation frame-relay  
frame-relay intf-type dce  
frame-relay route 300 interface Tunnel1 200  
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Disable or Reenable Frame Relay Inverse ARP  
Frame Relay Inverse ARP is a method of building dynamic address  
mappings in Frame Relay networks running IP and Novell IPX. In-  
verse ARP allows the router or access server to discover the protocol  
address of a device associated with the virtual circuit.  
Inverse ARP creates dynamic address mappings, as contrasted with  
the frame-relay map command, which defines static mappings  
between a specific protocol address and a specific DLCI.  
Inverse ARP is enabled by default but can be disabled explicitly for a  
given protocol and DLCI pair. Disable or reenable Inverse ARP under  
these conditions:  
z
Disable Inverse ARP for a selected protocol and DLCI pair when  
you know that the protocol is not supported on the other end of th  
connection.  
z
Reenable Inverse ARP for a protocol and DLCI pair if conditions  
or equipment change and the protocol is then supported on the oth-  
er end of the connection.  
Note:  
If you change from a point-to-point subinterface to a  
multipoint subinterface, then change the subinterface  
number. Frame Relay Inverse ARP will be on by default,  
and no further action is required.  
You do not need to enable or disable Inverse ARP if you have a point-  
to-point interface, because there is only a single destination and dis-  
covery is not required.  
To select Inverse ARP or disable it, perform one of these tasks in in-  
terface configuration mode:  
z
z
Enable Frame Relay Inverse ARP for a specific protocol and  
DLCI pair, only if it was previously disabled.  
frame-relay inverse-arp protocol dlci  
Disable Frame Relay Inverse ARP for a specific protocol and  
DLCI pair.  
no frame relay inverse-arp protocol dlci  
Create a Broadcast Queue for an Interface  
Very large Frame Relay networks might have performance problems  
when many DLCIs terminate in a single router or access server that  
must replicate routing updates and service advertising updates on each  
DLCI. The updates can consume access-link bandwidth and cause sig-  
nificant latency variations in user traffic; the updates can also consum  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
interface buffers and lead to higher packet rate loss for both user dat  
and routing updates.  
To avoid such problems, you can create a special broadcast queue for  
an interface. The broadcast queue is managed independently of th  
normal interface queue, has its own buffers, and has a configurable  
size and service rate.  
A broadcast queue is given a maximum transmission rate (throughput)  
limit measured in both bytes per second and packets per second. The  
queue is serviced to ensure that no more than this maximum is pro  
vided. The broadcast queue has priority when transmitting at a rate  
below the configured maximum, and hence has a guaranteed minimum  
bandwidth allocation. The two transmission rate limits are intended to  
avoid flooding the interface with broadcasts. The actual transmission  
rate limit in any second is the first of the two rate limits that is reached.  
In interface configuration mode, create a broadcast queue:  
frame-relay broadcast-queue size byte-rate  
packet-rate  
Configure Payload Compression  
You can configure payload compression on point-to-point or multi  
point interfaces or subinterfaces. Payload compression uses the stac  
method to predict what the next character in the frame will be. Becaus  
the prediction is done packet-by-packet, the dictionary is not con  
served across packet boundaries.  
Payload compression on each virtual circuit consumes approximately  
40 kilobytes for dictionary memory.  
z
Configure payload compression on a specified multipoint inter-  
face or subinterface:  
frame-relay map protocol protocol-address  
dlci  
payload-compress packet-by-packet  
z
Configure payload compression on a specified point-to-point in-  
terface or subinterface:  
frame-relay payload-compress packet-by-  
packet  
Configure TCP/IP Header Compression  
TCP/IP header compression, as described by RFC 1144, is designed to  
improve the efficiency of bandwidth use over low-speed serial links.  
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A typical TCP/IP packet includes a 40-byte datagram header. Once a  
connection is established, the header information need not be repeated  
in every packet that is sent. Reconstructing a smaller header that iden-  
tifies the connection and indicates the fields that changed and the  
amount of change reduces the number of bytes transmitted. The aver-  
age compressed header is 10 bytes long.  
For this algorithm to function, packets must arrive in order. If packets  
arrive out of order, the reconstruction will appear to create regular  
TCP/IP packets but the packets will not match the original.  
Note:  
Because priority queuing changes the order in which  
packets are transmitted, enabling priority queueing on th  
interface is not recommended.  
You can configure TCP/IP header compression in either of two ways:  
z
z
Configure an Individual IP Map for TCP/IP Header Compression  
Note:  
If you configure an interface with Cisco encapsulation  
and TCP/IP header compression, Frame Relay IP maps  
inherit the compression characteristics of the interface.  
However, if you configure the interface with IETF  
encapsulation, the interface cannot be configured for  
compression. Frame Relay maps will have to b  
configured individually to support TCP/IP header  
compression.  
Configure an Individual IP Map for TCP/IP Header  
Compression  
TCP/IP header compression requires Cisco encapsulation. If you need  
to have IETF encapsulation on an interface as a whole, you can still  
configure a specific IP map to use Cisco encapsulation and TCP  
header compression.  
In addition, even if you configure the interface to perform TCP/IP  
header compression, you can still configure a specific IP map not to  
compress TCP/IP headers.  
You can specify whether TCP/IP header compression is active or pas-  
sive. Active compression subjects every outgoing packet to TCP/IP  
header compression. Passive compression subjects an outgoing TCP/  
IP packet to header compression only if the packet had a compressed  
TCP/IP header when it was received.  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
In interface configuration mode, configure an IP map to use Cisco  
encapsulation and TCP/IP header compression:  
frame-relay map ip ip-address dlci  
[broadcast] cisco tcp headercompression  
{active | passive}  
The default encapsulation is cisco.  
Note:  
An interface that is configured to support TCP/IP header  
compression cannot also support priority queuing or  
custom queuing.  
Configure an Interface for TCP/IP Header Compression  
You can configure the interface with active or passive TCP/IP header  
compression. Active compression, the default, subjects all outgoing  
TCP/IP packets to header compression. Passive compression subjects  
an outgoing packet to header compression only if the packet had a  
compressed TCP/IP header when it was received on that interface.  
In interface configuration mode, apply TCP/IP header compression to  
an interface:  
1. Configure Cisco encapsulation on the interface.  
encapsulation frame-relay  
2. Enable TCP/IP header compression on the interface.  
frame-relay ip tcp header-compression  
[passive]  
Note:  
If an interface configured with Cisco encapsulation is  
later configured with IETF encapsulation, all TCP/IP  
header compression characteristics are lost. To appl  
TCP/IP header compression over an interface configured  
with IETF encapsulation, you must configure individual  
IP maps, as described in the sectionConfigure an  
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Example: IP Map with Inherited TCP/IP Header  
Compression  
This example shows an interface configured for TCP/IP header com-  
pression and an IP map that inherits the compression characteristics.  
Note that the Frame Relay IP map is not explicitly configured for  
header compression.  
interface serial 1  
encapsulation frame-relay  
ip address 131.108.177.178 255.255.255.0  
frame-relay map ip 131.108.177.177 177 broadcast  
frame-relay ip tcp header-compression passive  
Use the show frame-relay map command to display the result-  
ing compression and encapsulation characteristics; the IP map has in-  
herited passive TCP/IP header compression:  
Router> show frame-relay map  
Serial 1(administratively down): ip 131.108.177.177  
dlci 177 (0xB1,0x2C10), static,  
broadcast,  
CISCO  
TCP/IP Header Compression (inherited), passive (inherited  
)
Example: Using an IP Map to Override TCP/IP Header  
Compression  
This example shows the use of a Frame Relay IP map to override the  
compression set on the interface:  
interface serial 1  
encapsulation frame-relay  
ip address 131.108.177.178 255.255.255.0  
frame-relay map ip 131.108.177.177 177 broadcast nocompress  
frame-relay ip tcp header-compression passive  
Use the show frame-relay map command to display the result-  
ing compression and encapsulation characteristics; the IP map has not  
inherited TCP header compression:  
Serial 1 (administratively down): ip 131.108.177.177  
dlci 177 (0xB1,0x2C10), static,  
broadcast, CISCO  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Disable TCP/IP Header Compression  
You can disable TCP/IP header compression by using either of two  
commands that have different effects, depending on whether Fram  
Relay IP maps have been explicitly configured for TCP/IP header  
compression or have inherited their compression characteristics from  
the interface.  
Frame Relay IP maps that have explicitly configured TCP/IP heade  
compression must also have TCP/IP header compression explicitly  
disabled.  
To disable TCP/IP header compression, perform one of these tasks in  
interface configuration mode:  
z
Disable TCP/IP header compression on all Frame Relay IP maps  
that are not explicitly configured for TCP header compression.  
no frame-relay ip tcp header-compression  
frame-relay map ip ip-address dlci  
z
Disable TCP/IP header compression on a specified Frame Relay  
IP map.  
nocompress tcp header-compression  
Example: Disabling Inherited TCP/IP Header Compression  
In this first example, the initial configuration is:  
interface serial 1  
encapsulation frame-relay  
ip address 131.108.177.179 255.255.255.0  
frame-relay ip tcp header-compression passive  
frame-relay map ip 131.108.177.177 177 broadcast  
frame-relay map ip 131.108.177.178 178 broadcast tcp header-compression  
Enter these commands:  
serial interface 1  
no frame-relay ip tcp header-compression  
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Use the show frame-relay map command to display the  
resulting compression and encapsulation characteristics:  
Router> show frame-relay map  
Serial 1 (administratively down): ip 131.108.177.177 177  
dlci 177(0xB1, 0x2C10), static,  
broadcast  
CISCO  
Serial 1 (administratively down): ip 131.108.177.178 178  
dlci 178(0xB2,0x2C20), static  
broadcast  
CISCO  
TCP/IP Header Compression (enabled)  
As a result, header compression is disabled for the first map (with  
DLCI 177), which inherited its header compression characteristics  
from the interface. However, header compression is not disabled for  
the second map (DLCI 178), which is explicitly configured for header  
compression.  
Example: Disabling Explicit TCP/IP Header Compression  
In this second example, the initial configuration is the same as the pre-  
vious example, but you enter these commands:  
serial interface 1  
no frame-relay ip tcp header-compression  
frame-relay map ip 131.108.177.178 178 nocompress  
Use the show frame-relay map command display the resulting  
compression and encapsulation characteristics:  
Router> show frame-relay map  
Serial 1 (administratively down): ip 131.108.177.177 177  
dlci 177(0xB1,0x2C10), static,  
broadcast  
CISCO  
Serial 1 (administratively down): ip 131.108.177.178 178  
dlci 178(0xB2,0x2C20), static  
broadcast ISCO  
The result of the commands is to disable header compression for th  
first map (with DLCI 177), which inherited its header compression  
characteristics from the interface, and also explicitly to disable header  
compression for the second map (with DLCI 178), which was explic-  
itly configured for header compression.  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Configure Discard Eligibility  
You can specify which Frame Relay packets have low priority or low  
time sensitivity and will be the first to be dropped when a Frame Relay  
switch is congested. The mechanism that allows a Frame Relay switch  
to identify such packets is the discard eligibility (DE) bit.  
This feature requires that the Frame Relay network be able to interpret  
the DE bit. Some networks take no action when the DE bit is set. Other  
networks use the DE bit to determine which packets to discard. The  
most desirable interpretation is to use the DE bit to determine which  
packets should be dropped first and also which packets have lower  
time sensitivity.  
You can define DE lists that identify the characteristics of packets to  
be eligible for discarding, and you can also specify DE groups to iden-  
tify the DLCI that is affected.  
z
In global configuration mode, define a DE list specifying which  
packets can be dropped when the Frame Relay switch is congest-  
ed:  
frame-relay de-list list-number {protocol  
protocol | interface type number}  
characteristic  
You can specify DE lists based on the protocol or the interface, and on  
characteristics such as fragmentation of the packet, a specific TCP o  
User Datagram Protocol (UDP) port, an access list number, or a packet  
size.  
z
In interface configuration mode, define a DE group specifying th  
DE list and DLCI affected:  
frame-relay de-group group-number dlci  
Configure DLCI Priority Levels  
DLCI priority levels allow you to separatedifferent types of traffic and  
can provide a traffic management tool for congestion problems caused  
by these situations:  
z
z
Mixing batch and interactive traffic over the same DLC  
Traffic from sites with high-speed access being queued at destina-  
tion sites with lower speed access  
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AI2524 Router Card User’s Manual  
Before you configure the DLCI priority levels, complete these tasks:  
1. Define a global priority list.  
2. Enable Frame Relay encapsulation, as described earlier in this sec-  
tion.  
3. Define static or dynamic address mapping, as described earlier in  
this section.  
4. Make sure that you define each of the DLCIs to which you intend  
to apply levels. You can associate priority-level DLCIs with sub-  
interfaces.  
5. Configure the LMI, as described earlier in this section.  
Note:  
DLCI priority levels provide a way to define multiple  
parallel DLCIs for different types of traffic. DLCI priority  
levels do not assign priority queues within the router or  
access server; in fact, they are independent of the device's  
priority queues. However, if you enable queuing and use  
the same DLCIs for queuing, then high-priority DLCIs  
can be put into high-priority queues.  
In interface configuration mode, configure DLCI priority levels by en-  
abling multiple parallel DLCIs for different types of Frame Relay traf-  
fic, associating specified DLCIs with the same group, and defining  
their levels:  
frame-relay priority-dlci-group group-  
number high-dlci medium-dlci normal-dlci  
low-dlci  
Note:  
If you do not explicitly specify a DLCI for each of the  
priority levels, the last DLCI specified in the command  
line is used as the value of the remaining arguments.  
However, you must provide at least the high-priority and  
the medium-priority DLCIs.  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
Monitor the  
Frame Relay  
Connections  
To monitor Frame Relay connections, perform any of these tasks in  
EXEC mode:  
z
Clear dynamically created Frame Relay maps, which are created  
by the use of Inverse ARP.  
clear frame-relay-inarp  
z
z
z
z
z
z
z
z
Display information about Frame Relay DLCIs and the LMI.  
show interfaces serial number  
Display LMI statistics.  
show frame-relay lmi [type number]  
Display the current Frame Relay map entries.  
show frame-relay map  
Display PVC statistics.  
show frame-relay pvc [type number [dlci]]  
Display configured static routes.  
show frame-relay route  
Display Frame Relay traffic statistics.  
show frame-relay traffic  
Display information about the status of LAPF.  
show frame-relay lapf  
Display all the SVCs under a specified map list.  
show frame-relay svc maplist  
Example: Configuration Providing Backward Compatibility  
This example configuration provides backward compatibility and in-  
teroperability with earlier versions that are not compliant with RFC  
1490. The ietf keyword is used to generate RFC 1490 traffic. This con-  
figuration is possible because of the flexibility provided by separately  
defining each map entry.  
encapsulation frame-relay  
frame-relay map ip 131.108.123.2 48 broadcast ietf  
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Interoperability is provided by IETF encapsulation.  
frame-relay map ip 131.108.123.3 49 broadcast ietf  
frame-relay map ip 131.108.123.7 58 broadcast  
This line allows the router to connect with a device running an older  
version of software.  
frame-relay map decnet 21.7 49 broadcast  
Configure IETF based on map entries and protocol for more flexibil-  
ity. Use this method of configuration for backward compatibility and  
interoperability.  
Example: Booting from a Network Server over Frame Relay  
When booting from a Trivial File Transfer Protocol (TFTP) serve  
over Frame Relay, you cannot boot from a network server via a broad-  
cast. You must boot from a specific TFTP host. Also, frame-  
relay mapcommand must exist for the host that you will boot from.  
For example, if file gs3-bfx is to be booted from a host with IP address  
131.108.126.2, these commands would need to be in the configuration:  
boot system gs3-bfx 131.108.126.2  
interface Serial 0  
encapsulation frame-relay  
frame-relay map IP 131.108.126.2 100 broadcast  
The frame-relay mapcommand is used to map an IP address into  
a DLCI address. To boot over Frame Relay, you must explicitly give  
the address of the network server to boot from, and a frame-relay map  
entry must exist for that site. For example, if fil gs3-bfx.83-2.0 is to  
be booted from a host with IP address 131.108.126.111, these com  
mands must be in the configuration:  
boot system gs3-bfx.83-2.0 131.108.13.111  
!
interface Serial 1  
ip address 131.108.126.200 255.255.255.0  
encapsulation frame-relay  
frame-relay map ip 131.108.126.111 100 broadcast  
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Chapter 13: AI2524 Frame Relay Configuration Steps  
In this case, 100 is the DLCI that can get to host 131.108.126.111.  
The remote router must have this frame-relay map entry:  
frame-relay map ip 131.108.126.200 101 broadcast  
This entry allows the remote router to return a boot image (from the  
network server) to the router booting over Frame Relay. Here, 101 is  
a DLCI of the router being booted.  
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Chapter 14: T1 Interface Configuration Steps  
Chapter 14: T1 Interface Configuration  
Steps  
Introduction  
This chapter describes how to configure the AI2524 for fractional T1.  
Configure  
Configuration Overview  
Fractional T1  
This section describes how to configure fractional T1 and T1 (FT1/T1  
service modules installed the AI2425 router. The tasks associated with  
configuring T1 include:  
z
z
z
z
z
z
z
z
Specify the Clock Source  
Enable Data Inversion Before Transmission  
Specify the Clock Source  
To specify the clock source for the FT1/T1 CSU/DSU internal clock  
or the line clock, type this in interface configuration mode:  
service-module t1 clock source {internal |  
line}  
Enable Data Inversion Before Transmission  
Data inversion is used to guarantee the T1s density requirement on an  
AMI line when using bit-oriented protocols such as High-Level Data  
Link Control (HDLC), Point-to-Point Protocol (PPP), X.25, and  
Frame Relay.  
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AI2524 Router Card User’s Manual  
To guarantee the ones density requirement on an AMI line using th  
FT1/T1 CSU/DSU module, type this in interface configuration mode:  
service-module t1 data-coding inverted  
This command inverts bit codes by changi ng all 1 bits to 0bits and all  
0 bits to 1 bits.  
If the timeslot speed is se t to 56kbps, this command is rejected be-  
cause line density is guaranteed when transmitti ng at 56kbps. Use this  
command with the 64 kbps line speed. If you transmit inverted bit  
codes, both CSU/DSUs must have this command configured for suc-  
cessful communication.  
To enable normal data transmission on a FT1/T1 network, type this in  
interface configuration mode:  
service-module tx1 data-coding normal  
or  
no service-module t1 data-coding inverted  
Specify the Frame Type of a FT/T1 Line  
To specify the frame type for a line using the FT1/T1 CSU/DSU mod-  
ule, type this in interface configuration mode:  
service-module t1 framing {sf | esf}  
Note:  
Choose either D4 Super Frame (sf) or Extended Super  
Frame (esf).  
In most cases, the service provider determines which framing type, ei-  
ther esfor sf, is required for your circuit.  
Specify the CSU Line Build Out  
To decrease the outgoing signal strength to an optimum value for the  
telecommunication carrier network, type this in interface configura-  
tion mode:  
service-module t1 lbo {-15 db | -7.5 db}  
This command decreases the outgoing signal strength in decibels.  
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Chapter 14: T1 Interface Configuration Steps  
To transmit packets without decreasing outgoing signal strength, typ  
this in interface configuration mode:  
service-module t1 lbo none  
The ideal signal strength should be between -15 dB and -22 dB, which  
is calculated by adding the phone company loss, cable length loss, and  
line build out.  
You may use this command in back-to-back configurations, but it is  
not needed on most actual T1 lines.  
Specify FT1/T1 Line-Code Type  
To configure the line code for the FT1/T1 CSU/DSU module, type this  
in interface configuration mode:  
service-module t1 linecode {ami | b8zs}  
Choose alternate mark inversion (AMI) or binary 8 zero substitution  
(B8ZS).  
Configuring B8ZS is a method of ensuring the T1s density require  
ment on a T1 line by substituting intentional bipolar violations in bit  
positions four and seven for a sequence of eight zero bits. When the  
CSU/DSU is configured for AMI, you must guarantee the T1s density  
requirement in your router configuration using the service-mod-  
ule t1 data-coding inverted command or the service-  
module t1 timeslots speed 56 command.  
In most cases, your T1 service provider determines which line-cod  
type, either amior b8zs, is required for your T1 circuit.  
Enable Remote Alarms  
To generate remote alarms (yellow alarms) at the local CSU/DSU or  
detect remote alarms sent from the remote CSU/DSU, type this in in-  
terface configuration mode:  
service-module t1 remote-alarm-enable  
Remote alarms are transmitted by the CSU/DSU when it detects an  
alarm condition, such as a red alarm (loss of signal) or blue alarm (un-  
framed 1's). The receiving CSU/DSU then knows there is an error con-  
dition on the line.  
With D4 super frame configured, a remote alarm condition is transmit-  
ted by setting the bit2 of each time slot to zero. For received user data  
that has the bit 2 of each time slot set to zero, the CSU/DSU will inter-  
pret the data as a remote alarm and interrupt data transmission, which  
explains why remote alarms are disabled by default. With Extended  
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AI2524 Router Card User’s Manual  
Super Frame configured, the remote alarm condition is signalled out  
of band in the facility data link.  
You can see if the FT1/T1 CSU/DSU is receiving a remote alarm (yel-  
low alarm) by issuing the show service-module command.  
To disable remote alarms, type this in interface configuration mode:  
no service-module t1 remote-alarm-enable  
Enable Loopcodes that Initiate Remote Loopbacks  
To configure the remote loopback code used to transmit or accept CSU  
loopback requests, and type this in interface configuration mode:  
service-module t1 remote-loopback full  
To configure the loopback code used by the local CSU/DSU to gener-  
ate or detect payload-loopback commands, type this in interface  
configuration mode:  
service-module t1 remote-loopback payload  
[alternate | v54]  
Note:  
By entering the service-module t1 remote-  
loopbackcommand without specifying any keywords,  
you enable the standard-loopup codes, which use a 1-in-5  
pattern for loopup and a 1-in-3 pattern for loopdown.  
You can simultaneously configure thefulland payloadloopback  
points. However, only one loopback payload code can be configured  
at a time. For example, if you configure the service-module t1  
remote-loopback payload alternate command, a pay-  
load v.54 request, which is the industry standard and default, cannot b  
transmitted or accepted. Full and payload loopbacks with standard-  
loopup codes are enabled by default.  
The noform of this command disables loopback requests. For exam-  
ple, the no service-module t1 remote-loopback full  
command ignores all full-bandwidth loopback transmissions and re-  
quests. Configuring the no form of the command may not prevent telco  
line providers from looping your router in esf mode, because fractional  
T1/T1 telcos use facilities data-link messages to initiate loopbacks.  
If you enable the service-module t1 remote-loopback  
command, the loopback remote commands on the FT1/T1 CSU/  
DSU module will not be successful.  
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Chapter 14: T1 Interface Configuration Steps  
Specify Timeslots  
To define timeslots for FT1/T1 module, type this in interface configu-  
ration mode:  
service-module t1 timeslots {range | all}  
[speed {56 | 64}]  
This command specifies which timeslots are used in fractional T1 op-  
eration and determines the amount of bandwidth available to the route  
in each timeslot.  
The range specifies the DS0 timeslots that constitute the FT1/T1 chan-  
nel. The range is from 1 to 24, where the first timeslot is numbered 1  
and the last timeslot is numbered 24. Specify this field by using a series  
of subranges separated by commas. The timeslot range must match the  
timeslots assigned to the channel group. In most cases, the service pro-  
vider defines the timeslots that comprise a channel group. Use th no  
form of this command to select all FT1/T1 timeslots transmitting at 64  
kbps, which is the default.  
To use the entire T1 line, enable the service-module T1  
timeslots all command.  
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AI2524 Router Card User’s Manual  
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Chapter 15: 56/64-kbps Switched and Digital Data Services (DDS) Interface  
Chapter 15: 56/64-kbps Switched and  
Digital Data Services (DDS) Interface  
Configuration Steps  
Introduction  
This chapter describes how to configure 2- and 4-wire 56/64 kbps ser-  
vice modules. These tasks are described:  
z
z
z
z
z
z
Set the Clock Source  
Set the Network Line Speed  
Enable Scrambled Data Coding  
Change Between DDS and Switched Dial-Up Modes  
Enable Acceptance of a Remote Loopback Request  
Select a Service Provider  
Set the Clock  
Source  
In most applications, the CSU/DSU should be configured with the  
service-module 56k clock source line command. Fo  
back-to-back configurations, use the internalkeyword to config-  
ure one CSU/DSU and use the linekeyword to configure the othe  
CSU/DSU.  
Configure the clock source for a 4-wire 56/64-kbps CSU/DSU mod-  
ule:  
service-module 56k clock source {line |  
internal}  
Do not use any form of this command to revert to the default clock  
source, which is the line clock.  
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Set the Network  
Line Speed  
In interface configuration mode, configure the network line speed for  
a 4-wire 56/64-kbps CSU/DSU module:  
service-module 56k clock rate line-speed  
You can use the following line speed settings: 2.4, 4.8, 9.6, 19.2, 38.4,  
56, 64 kpbs, and an auto setting.  
The 64-kbps line speed cannot be used with back-to-back digital data  
service (DDS) lines. The subrate line speeds are determined by the ser-  
vice provider  
Only the 56-kbps line speed is available in switched mode. Switched  
mode is the default on the 2-wire CSU/DSU and is enabled by the  
service-module 56k network-type interface configuration  
command on the 4-wire CSU/DSU.  
The auto linespeed setting enables the CSU/DSU to decipher current  
line speed from the sealing current running on the network. Becaus  
back-to-back DDS lines do not have sealing current, use the auto set-  
ting only when transmitting over telco DDS lines and using the line  
clock as the clock source.  
Do not use any form of this command to enable a network line speed  
of 56 kbps, which is the default.  
Warning: If the console line speed is changed and saved to NVRAM  
and the router is reloaded, the router displays this mes-  
sage  
The ne  
Failed to change line0’ speed.  
line speed is stored in the start-up configuration but not in  
the running configuration. In addition, changing the line  
speed on the router prevents connections to the console in-  
terface via the AI185DP (the line speed on the router and  
the AI185 must be set to 9600 bps). The default consol  
speed for the Cisco router is also set at 9600 bps.  
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Chapter 15: 56/64-kbps Switched and Digital Data Services (DDS) Interface  
Enable  
Scrambled Data  
Coding  
In interface configuration mode, prevent application data from repli  
cating loopback codes when operating at 64-kbps on a 4-wire CSU/  
DSU by scrambling bit codes before transmission:  
service-module 56k data-coding scrambled  
Enable the scrambled configuration only in 64-kbps digital data ser-  
vice (DDS) mode. If the network type is set to switched, the configu-  
ration is refused.  
If you transmit scrambled bit codes, both CSU/DSUs must have this  
command configured for successful communication.  
In interface configuration mode, enable normal data transmission fo  
the 4-wire 56/64-kbps module, which is the default:  
service-module 56k data-coding normal  
or  
no service-module 56k data-coding  
Change between  
DDS and  
Switched Dial-Up  
Modes  
In interface configuration mode, transmit packets in switched dial-up  
mode or DDS mode using the 4-wire 56/64-kbps CSU/DSU module:  
service-module 56k network-type dds  
or  
service-module 56k network-type switched  
Do not use any form of these commands to transmit from a dedicated  
leased line in DDS mode. DDS is enabled by default for the 4-wir  
CSU/DSU. Switched mode is enabled by default for the 2-wire CSU/  
DSU.  
In switched mode, you need additional dialer configuration commands  
to configure dial-out numbers. Before you enable the service-  
module 56k network-type switchedcommand, both CSU/  
DSUs must use a clock source coming from the line and the clock rate  
must be configured to auto or 56k kbps. If the clock rate is not set cor-  
rectly, this command will not be accepted.  
The 2-wire and 4-wire 56/64-kbps CSU/DSU modules use V.25 bis  
dial commands to interface with the router. Therefore, the interfac  
must be configured using the dialer in-band command. DTR  
dial is not supported.  
Warning: Any loopbacks in progress are terminated when switching  
between modes.  
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Enable  
Acceptance of a  
Remote  
In interface configuration mode, enable the acceptance of a remot  
loopback request on a 2- or 4-wire 56/64-kbps CSU/DSU module:  
service-module 56k remote-loopback  
Loopback  
Request  
The no service-module 56k remote-loopbackcommand  
prevents the local CSU/DSU from being placed into loopback by re-  
mote devices on the line. Unlike the T1 module, the 2- or 4-wire 56/  
64-kbps CSU/DSU module can still initiate remote loopbacks with the  
no form of this command.  
Select a Service  
Provider  
In interface configuration mode, select a service provider to use with  
a 2- or 4-wire 56/64 kbps dial-up line:  
service-module 56k switched-carrier {att |  
other | sprint}  
The attkeyword specifies AT&T or another digital network service  
provider as the line carrier, which is the default for the 4-wire 56/64  
kbps CSU/DSU module. Th sprintkeyword specifies Sprint or an-  
other service provider whose network carries mixed voice and data as  
the line carrier, which is the default for the 2-wire switched 56-kbps  
CSU/DSU module.  
In a Sprint network, echo-canceler tones are sent during call setup to  
prevent echo cancelers from damaging digital data. The transmission  
of these cancelers may increase call setup times by 8 seconds on the 4-  
wire module. Having echo cancellation enabled does not affect dat  
traffic.  
This configuration command is ignored if the network type is DDS.  
Use the noform of this command to enable the default service pro-  
vider. AT&T is enabled by default on the 4-wire 56/64 module. Sprint  
is enabled by default on the 2-wire switched 56 module.  
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Chapter 16: Basic Configuration  
Chapter 16: Basic Configuration  
Connecting to the  
Network  
Connecting to an Ethernet Network  
The AI2524 can be connected to an Ethernet network by:  
z
Using a straight-through 10BaseT cable to connect the 10BaseT  
port to a 10BaseT hub.  
z
Using a crossover 10BaseT cable to connect the 10BaseT port to  
a PC network interface card.  
Connecting to a WAN  
z
z
z
If you have a 4-wire 56K/64K DSU/CSU module, use a straight-  
through RJ-48S-to-RJ48S cable to connect the RJ-48S port to an  
RJ48S jack.  
If you have a FT1/T1 DSU/CSU module, use a straight-through  
RJ-48C-to-RJ48C cable to connect the RJ-48C port to an RJ48C  
jack.  
If you have a synchronous serial module, use a transition cable to  
connect the synchronous serial port to a modem or DSU/CSU.  
Configuring  
This chapter describes how to configure the AI2524 router and de-  
scribes the following:  
z
z
z
z
Booting the Router for the First Time  
Configuring the Router  
Specifying the Boot Method  
Checking the Configuration Settings  
This chapter provides just enough information to get the router up and  
running. Review the previous detailed configuration chapters for more  
information  
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AI2524 Router Card User’s Manual  
Booting the Router for the First Time  
Each time you power on the router, it goes through this boot sequence:  
1. The router goes through power-on self-test diagnostics to verify  
basic operation of the CPU, memory, and interfaces.  
2. The system bootstrap software (boot image) executes and searches  
for a valid Cisco IOS image (router operating system software).  
The source of the Cisco IOS image (Flash memory or a Trivial File  
Transfer Protocol [TFTP] server) is determined by the configura-  
tion register setting. The factory-default setting for the configura  
tion register is 0x2102, which indicates that the router should  
attempt to load a Cisco IOS image from Flash memory.  
3. If after five attempts a valid Cisco IOS image is not found in Flash  
memory, the router reverts to boot ROM mode (which is used to  
install or upgrade a Cisco IOS image).  
4. If a valid Cisco IOS image is found, then the router searches for a  
valid configuration file.  
5. If a valid configuration file is not found in NVRAM, the router  
runs the System Configuration Dialog so you can configure it  
manually. For normal router operation, there must be a valid Cisco  
IOS image in Flash memory and a configuration file in NVRAM.  
The first time you boot your router, you will need to configure the  
router interfaces and then save the configuration to a file in NVRAM.  
Proceed to the next section,Configuring the Router, for configuration  
instructions.  
Configuring the  
Router  
You can configure the router using one of these procedures:  
Configuration mode recommended if you are familiar with Cisco IOS  
commands.  
z
AutoInstall-Recommended for automatic installation if anothe  
router running Cisco IOS software is installed on the network.  
This configuration method must be set up by someone with expe-  
rience using Cisco IOS software.  
z
z
System Configuration Dialog-Recommended if you are not famil-  
iar with Cisco IOS commands.  
Use the procedure that best fits the needs of your network config-  
uration and level of Cisco IOS experience.  
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Chapter 16: Basic Configuration  
Warning: Acquire the correct network addresses from your system  
administrator or consult your network plan to determin  
correct addresses before you begin to configure the router.  
Using Configuration Mode  
You can configure the router manually if you prefer not to use Auto-  
Install or the System Configuration Dialog. Take these steps to config-  
ure the router manually:  
1. Connect a console terminal following the instructions in the sec-  
tion Connecting the Console Terminal and Modem in the chapter  
Installing the Cisco 2524 Router, and then power ON the router.  
2. When you are prompted to enter the initial dialog, enter no to go  
into the normal operating mode of the router:  
Would you like to enter the initial dialog? [yes]: no  
3. After a few seconds you will see the user EXEC prompt (Router).  
Enter the enablecommand to enter enable mode. You can only  
make configuration changes in enable mode.  
Router> enable  
The prompt changes to the privileged EXEC (enable) prompt:  
Router#  
4. Enter the configure terminal command at the enable  
prompt to enter configuration mode:  
Router# configure terminal  
You can now enter any changes you want to the configuration.  
5. Press <Ctrl-Z-Z> to exit configuration mode.  
To see the current operating configuration, enter the show run-  
ning-config command at the enable prompt:  
Router# show running-config  
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AI2524 Router Card User’s Manual  
6. To see the configuration in NVRAM, enter th show startup-  
configcommand at the enable prompt:  
Router# show startup-config  
The results of the show running-config and show star-  
tup-config commands will be different if you have mad  
changes to the configuration but have not yet written them to  
NVRAM.  
7. To make your changes permanent, enter the copy running-  
configstartup-config command at the enable prompt:  
Router# copy running-config startup-config  
*******  
The router is now configured and will boot with the configuration you  
entered.  
Using AutoInstall  
The AutoInstall process is designed to configure the router automati-  
cally after connection to your WAN. For AutoInstall to work properly,  
a Transmission Control Protocol Internet Protocol (TCP/IP) host on  
your network must be reconfigured to provide the required configura-  
tion files. The TCP/IP host may exist anywhere on the network as long  
as these conditions are maintained:  
1. The host must be on the remote side of the router's synchronous  
serial connection to the WAN.  
2. User Datagram Protocol (UDP) broadcasts to and from the router  
and the TCP/IP host must be enabled.  
This functionality is coordinated by your system administrator at th  
site where the TCP/IP host is located. You should not attempt to us  
AutoInstall unless the required files have been provided on the TCP/  
IP host.  
AutoInstall works on synchronous serial connections only.  
Take these steps to prepare your router for the AutoInstall process:  
3. Attach the WAN cable to the router.  
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Chapter 16: Basic Configuration  
4. Turn ON power to the router.  
The router will load the operating system image from Flash mem-  
ory. If the remote end of the WAN connection is connected and  
properly configured, the AutoInstall process will begin.  
If AutoInstall successfully completes, you can write the configu-  
ration data to the router's NVRAM.Perform this step to complete  
this task.  
5. Enter the copy running-config startup-config  
command:  
Router# copy running-config startup-config  
Taking this step saves the configuration settings that the AutoInstall  
process created in the router. If you do not do this, your configuration  
will be lost the next time you reload the router.  
Using the System Configuration Dialog  
If you do not plan to use AutoInstall, make sure all the WAN cables  
are disconnected from the router. This will prevent the router from at-  
tempting to the run the AutoInstall process. The router will attempt to  
run AutoInstall whenever you power it on if there is a WAN connec-  
tion on both ends and the router does not have a configuration fil  
stored in NVRAM. It can take several minutes for the router to deter-  
mine that AutoInstall is not set up to a remote TCP/IP host.  
If your router does not have a configuration (setup) file and you are not  
using AutoInstall, the router will automatically start the setup com  
mand facility. An interactive dialog called the System Configuration  
Dialog appears on the console screen. This dialog helps you navigat  
through the configuration process by prompting you for the configura-  
tion information necessary for the router to operate.  
Many prompts in the System Configuration Dialog include default an-  
swers, which are included in square brackets following the question.  
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AI2524 Router Card User’s Manual  
To accept the default answer, press <Enter>; otherwise enter your re-  
sponse.  
This section gives an example configuration using the System Config-  
uration Dialog. When you are configuring your router, respond as ap  
propriate for your network.  
At any time during the System Configuration Dialog, you can request  
help by typing a question mark (?) at a prompt.  
Before proceeding with the System Configuration Dialog, obtain from  
your system administrator the node addresses and the number of bits  
in the subnet field (if applicable) of the Ethernet and synchronous se-  
rial ports.  
Take these steps to configure the router using the System Configura  
tion Dialog:  
1. Connect a console terminal to the console connector on the rear  
panel of your router, and turn ON power to the router. (For mor  
information, refer to the section Connecting the Console Terminal  
and Modem in the chapter Installing the Cisco 2524 Routers.)  
The default parameters for the console port are 9600 baud, 8 data  
bits, no parity, and 2 stop bits.  
2. After about 30 seconds, information similar to this is displayed on  
the console screen.  
The messages displayed vary, depending on the Cisco IOS releas  
and feature set you selected. The screen displays in this section are  
for reference only and may not exactly reflect the screen displays  
on your console.  
When you see this information, you have successfully booted your  
router:  
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System Bootstrap, Version X.X(XXXX) [XXXXX XX], RELEASE SOFTWARE  
Copyright (c) 1986-1992 by Cisco Systems  
2500 processor with 4096 Kbytes of main memory  
Notice: NVRAM invalid, possibly due to write erase  
F3: 5797928+162396+258800 at 0x3000060  
Restricted Rights Legend  
Use, duplication, or disclosure by the Government is  
subject to restrictions as set forth in subparagraph  
(c) of the Commercial Computer Software - Restricted  
Rights clause at FAR sec. 52.227-19 and subparagraph  
(c) (1) (ii) of the Rights in Technical Data and Computer  
Software clause at DEARS. 252.227-7013.  
Cisco Systems, Inc.  
170 West Tasman Drive  
San Jose, California 95134-1706  
Cisco Internetwork Operating System Software  
IOS (to) X000 Software (IGS-J-L), Version XX.X(XXXX) [XXXXX XXX]  
Copyright (c) 1986-1996 by Cisco Systems, Inc.  
Compiled Fri 20-Oct-95 16:02 by XXXXX  
Image text-base: 0x03030FC0, data-base: 0x00001000  
Cisco 252X (68030) processor (revision A) with 4092K/2048K bytes of memory.  
Processor board ID 00000000  
Bridging software.  
SuperLAT software copyright 1990 by Meridian Technology Corp).  
X.25 software, Version X.X, NET2, 8FE and GOSIP compliant.  
TN3270 Emulation software (copyright 1994 by TGV Inc).  
Basic Rate ISDN software, Version X.X.  
1 Ethernet/IEEE 802.3 interface.  
2 Serial network interfaces.  
1 ISDN Basic Rate interface.  
32K bytes of non-volatile configuration memory.  
8192K bytes of processor board System flash (Read ONLY)  
Notice: NVRAM invalid, possibly due to write erase.  
--- System Configuration Dialog  
At any point you may enter a question mark '?' for help.  
Refer to the 'Getting Started' Guide for additional help.  
Use ctrl-c to abort configuration dialog at any prompt.  
Default settings are in square brackets '[]'.  
Would you like to enter the initial configuration dialog? [yes]:  
3. Press <Enter> or enter yes to begin the configuration process.  
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4. When the System Configuration Dialog asks whether you want to  
view the current interface summary, press< Return> or enter yes:  
First, would you like to see the current interface summary? [yes]:  
Any interface listed with OK? value “NO" does not have a valid configuration  
Interface IP-Address OK? Method Status  
Protocol  
down  
up  
EthernetO unassigned NO not set  
BRIO unassigned NO not set  
up  
up  
SerialO unassigned NO not set down  
Seriall unassigned NO not set down  
down  
down  
5. Configure the global parameters. Choose which protocols to sup  
port on the Ethernet interface. For IP installations, you can press  
<Enter> to accept the default values (in brackets) for most of the  
questions. A typical configuration is:  
Configuring global parameters:  
Enter host name {Router  
Next, you are prompted to enter an enable secret password. There are  
two types of privileged-level passwords:  
Enable secret password (a very secure, encrypted password  
Enable password (a less secure, nonencrypted password)  
The enable password is used when the enable secret password does not  
exist.  
For maximum security, be sure the passwords are different. If you  
enter the same password for both, the router will accept yourentry, but  
will display a warning message indicating that you should enter a dif-  
ferent password.  
6. Enter an enable secret password:  
The enable secret is a one-way cryptographic secret used instead  
of the enable password when it exists.  
Enter enable secret: pail  
The enable password is user when there is no enable secret and  
when using older software and some boot images.  
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7. Enter the enable and virtual terminal passwords:  
Enter enable password: shovel  
Enter virtual terminal password: vterml  
8. Press <Enter> to accept Simple Network Management Protocol  
(SNMP) management, or enter no to refuse it:  
Configure SNMP Network Management? [yes]: no  
9. In this example, the router is configured for AppleTalk, IP, and  
IPX. Configure the appropriate protocols for your router:  
Configure Vines? [no]:  
Configure LAT? [no]:  
Configure AppleTalk? [no]: yes  
Multizone networks? [no]: yes  
Configure DECnet? [no]:  
Configure IP? [yes]:  
Configure IGRP routing? [yes]:  
Your IGRP autonomous system number [l]: 15  
Configure CLNS? [No]:  
Configure bridging? [no]:  
Configure IPX? [no]: yes  
Configure XNS? [no]:  
Configure Apollo? [no]:  
10. Enter the ISDN BRI switch type for the router. The ISDN switch  
type appropriate for the router depends on the ISDN provider's  
equipment. This table lists the ISDN switch types:  
Enter ISDN BRI Switch Type [none]: besic-5ess  
Country  
ISDN Switch Type  
Description  
Australia  
basic-ts013  
Australian TS013 switches  
Europe  
basic-1tr6  
German 1TR6 ISDN switches  
basic-nwnet3  
Norwegian NET3 ISDN switches  
(phase 1)  
basic-net3  
vn2  
NET3 ISDN switches (UK and others)  
French VN2 ISDN switches  
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Country  
ISDN Switch Type  
Description  
vn3  
French VN3 ISDN switches  
Japanese NTT ISDN switches  
AT&T basic rate switches  
Japan  
ntt  
North America  
New Zealand  
basic-5ess  
basic-dms100  
basic-ni1  
basic-nznet3  
NT DMS-100 basic rate switches  
National ISDN-1 switches  
New Zealand NET3 switch  
Configuring the  
Ethernet or  
Token Ring  
Interfaces  
Take these steps to configure the Ethernet or Token Ring interface to  
allow communication over a LAN. To configure the interface param  
eters, you need to know your Ethernet or Token Ring interface net-  
work addresses. In this example, the system is being configured for an  
Ethernet LAN using IP.  
1. Respond (using your addresses and subnet mask) to the setup  
prompts, substituting the correct addresses and host names as ap-  
propriate:  
Configuring interface EthernetO:  
Is this interface in use? [yes]:  
Configure IP on this interface? [yes]:  
IP address for this interface: 172.16.72.1  
Number of bits in subset field [8]: 8  
Class s network is 172.16.0.0, 8 subnet bits; mask i  
255.255.255.0  
2. Enter yes if you will be using AppleTalk on the interface. Enter  
yes to configure the router for extended AppleTalk networks, and  
then enter the cable range. Enter the zone name, and any other ad-  
ditional zones that will be associated with your local zone:  
Configure AppleTalk on this interface? [no]: yes  
Extended AppleTalk network? [no]: yes  
AppleTalk starting cable range [0]: 3  
AppleTalk ending cable range [1]: 3  
AppleTalk zone name [myzone]:  
AppleTalk additional zone name: otherzone  
AppleTalk additional zone name:  
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Chapter 16: Basic Configuration  
3. Determine if you are going to enable IPX on the interface. If so,  
enter yes and then enter the unique IPX network number:  
Configure IPX on this interface? [no]: yes  
IPX network number [1]: B001  
Configuring the  
Synchronous  
Serial Interfaces  
The synchronous serial interfaces are configured to allow connection  
to WANs. Once the Ethernet or Token Ring port on your router has  
been configured, take these steps to configure the synchronous serial  
interfaces:  
1. Press <Enter> or enter yes to configure serial port 0:  
Configuring interface SerialO:  
Is this interface in use? [yes]:  
2. Determine which protocols you want on the synchronous serial in-  
terface and enter the appropriate responses. In this example, th  
system is being configured for IP, AppleTalk, and IPX:  
Configure IP on this interface? [yes:  
Configure IP unnumbered on this interface? Loo]:  
IP address for this interface: 172.16.73.1  
Number of bits in sunned field [8]:  
Class B network is 172.16.0.0, 8 subnet bits; mask is  
255.255.255.0  
Configure AppleTalk on this interface? [no]: yes  
Extended AppleTalk network? [yes]:  
AppleTalk starting cable range [2]: 4  
AppleTalk ending cable range [3]: 4  
AppleTalk zone name [myzone]: ZZ Serial  
AppleTalk additional zone name:  
Configure IPX on this interface? [no]: yes  
IPX network number [2]: B002  
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3. Configure the second synchronous serial interface, for example,  
as:  
Configuring interface Seriall:  
Is this interface in use? [yes]:  
Configure IP on this interface? ~yes;:  
Configure IP unnumbered on this interface? [no]:  
IP address for this interface: 172.16.74.2  
Number of bits in subset field [8]:  
Class B network is 172.16.0.0, 8 subset bits; mask is  
255.255.255.0  
Configure AppleTalk on this interface? [no]: yes  
AppleTalk starting cable range [3]: 5  
AppleTalk ending cable range [4]: 5  
AppleTalk zone name [myzone]: ZZ Serial  
AppleTalk additional zone name:  
Configure IPX on this interface? [no]: yes  
IPX network number [3]: B003  
4. The configuration you enter is now displayed and you are asked if  
you want to use the displayed configuration. If you enter no, you  
will lose the configuration information you just entered and you  
can begin the configuration again. If you enter yes, the configura-  
tion will be entered and saved in the startup configuration:  
Use this configuration? [yes/no]: yes  
Building configuration...  
Use the enabled mode 'configure' command to modify this configuration.  
Press RETURN to get started!  
Configuring  
ISDN  
If you have an ISDN BRI WAN module, configure the BRI port for  
ISDN. This section explains typical ISDN configurations for one or  
two B channels. In the examples, the BRI port is configured for IP  
routing and Point-to-Point Protocol (PPP) encapsulation.  
Complete these steps to configure the router for a basic ISDN PPP  
connection on a single B channel or two B channels, substituting th  
correct address and host names as appropriate for your network.  
1. Enter enable mode:  
Router> enable  
Password: enable password  
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Chapter 16: Basic Configuration  
2. Enter the configure terminal command.  
Router# config term  
3. If you have not already done so, enter the isdn switch-type  
command to configure the ISDN switch type:  
router (config) # ISDN switch-type switch-type  
4. Enter the BRI interface, encapsulation method (PPP), authentica  
tion type, target router’s IP address and ISDN number to dial, and  
the dialer group number:  
Router (config) # interface bri 0  
Router (config-if) # encapsulation ppp  
Router (config-if) #ppp authentication chap  
Router (config-if) # dial map ip targetrouter_ipaddress targetrouter_phonenumber  
Router (config-if) # dialer-group groupnumber  
Do not use periods or hyphens when you are entering dialing num-  
bers.  
Note:  
The ISDN/BRI interface provides dial backup for the  
AI2524 card. When a connection is requested, the system  
checks the username presented for validity, then dials  
back the number associated with the username.  
5. Some ISDN switch types, such as Basic NI1 or DMS-100 switch  
service, require you to configure a service profile identifie  
(SPID). Enter the SPID information substituting the appropriat  
entries for your installation:  
Router (config-if) # isdn spid1 SPID_no phone_number  
Router (config-if) # isdn spid2 SPID_no phone_number  
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6. To set up a second B channel for bandwidth on demand, enter the  
load-threshold command to set the ISDN load threshold. The load  
threshold determines the percentage of network loading at which  
the second ISDN B channel is triggered. The value ranges from 1  
to 255 (100 percent).  
Router (config-if) 3 dialer load-threshold 128  
In this example, the value of 128 means that when the first B chan-  
nel reaches 50 percent of its bandwidth capacity (128 equals 50  
percent of 255), the second B channel will be activated to assist  
with the bandwidth load.  
7. Enter the access-listcommand to configure the ISDN line to  
come up whenever IP packets are to be sent:  
Router (config-if) # access-list access-list-number permit-ip sourcerouter-  
ipnetwork sourcerouter-subnetmask targetrouter-ipnetwork targetrouter-subnetmask  
Router (config) # dialer-list groupnumber list access-list-number  
8. Configure a static route to allow connectivity to the target router’s  
local network. Enter the network number of the target router’s  
local IP network and subnet mask, and the IP address of the target  
router’s BRI port:  
Router (config) 3 ip route targetrouter_ipnetwork subnetmask  
targetBRIport_ipaddress  
9. Enter the exitcommand to exit configuration mode.  
10. Enter the copy running-config startup-config  
command to save the configuration to NVRAM.  
Configuring  
Switched 56  
This section explains how to configure the 4-wire 56/64-kbps DSU/  
CSU WAN modules for switched 56-kbps circuit-switched service  
The 4-wire 56/64-kbps DSU/CSU WAN module is configured for  
DDS as the factory default, but it can be configured for either switched  
56/64-kbps service or DDS.  
Take these steps to configure the 4-wire 56/64-kbps DSU/CSU WAN  
module for circuit-switched service, substituting the correct addresses  
and host names as appropriate for your network:  
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Chapter 16: Basic Configuration  
1. Enter enable mode:  
Router> enable  
password: enablepassword  
2. Enter configuration mode:  
Router# config term  
Router(config)#  
3. Assign an IP address to the serial port on the module:  
Router(config)# interface serial port_number  
Router(config-if)# ip address ipaddress suLnetmask  
Router(config-if)# no keepalive  
4. Set the network type to switched:  
Router(config-if)# service-module 56k network-type switched  
5. Set the carrier type, where carrier can be ttt, sprint, or other:  
Router(config-if)# service-module 56k switched-carrier carrier  
6. Enter the dialer information:  
Router(config-if)# dialer in-band  
Router(config-if)# dialer string targetrouter_phonenumber  
Router(config-if)# dialer-group~ groupnumber  
Router(config-if)# exit  
Router(config)# dialer-list groupnumber protocol protocol permit  
Router(config)#  
7. Return to user EXEC mode:  
Router(contlg)# exit  
Router# exit  
Router>  
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Configuring DDS  
The 4-wire 56/64-kbps DSU/CSU WAN module is configured for  
DDS (which are leased or dedicated lines) as the factory default, but it  
can be configured for either switched 56/64-kbps service or DDS. Th  
DDS configuration is described in this section. To configure the4-wire  
56/64-kbps DSU/CSU WAN module for circuit-switched service,  
follow the instructions in the previous section Configuring Switched  
56.  
Take these steps to configure the 4-wire 56/64-kbps DSU/CSU mod-  
ule for DDS, substituting the correct addresses and host names as ap-  
propriate for your network  
1. Enter enable mode:  
Router> enable  
password: enablepassword  
2. Enter configuration mode:  
Router# config term  
Router(config)#  
3. Assign an IP address to the serial port on the module:  
Router(config)# interface serial port _number  
Router(config-if)# ip address ipaddress subnet mask  
Router(config-if)# no keepalive  
4. Set the network type to DDS:  
Router(config-if)# service-module 56k network-type ads  
5. Return to user EXEC mode:  
Router(config-if)# exit  
Router(config)# exit  
Router# exit  
Router>  
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Chapter 16: Basic Configuration  
Configuring the  
Fractional T1/T1  
DSU/CSU WAN  
Module  
This section describes how to configure the fractional Tl/T1 DSU/  
CSU WAN module is configured for Extended Superframe Format  
(ESF) signal format, bipolar zero substitution (B8ZS), and full band-  
width as the factory default. Depending on networking environment,  
you might need to change these settings.  
Take these steps to configure the fractional Tl/T1 DSU/CSU WAN  
module for a typical leased-line connection, substituting the correct  
addresses and host names as appropriate for your network:  
1. Enter enable mode:  
Router> enable  
password: enablepassword  
2. Enter configuration mode:  
Router# config term  
Router(config)#  
3. Assign an IP address to the serial port on the module:  
Router(config)# interface serial port_number  
Router(config-if)# ip address ipaddress suLnetmask  
Router(config-if)# no keepalive  
4. Enter the framing type and line code type, substituting  
framing_type with sf(Superframe) o esf(Extended Super  
frame) and linecode_type with ami(alternate mark inversion) o  
b8zs(bipolar eight zero substitution):  
Router(config-if)# service-module tl framing framing_type  
Router(config-if)# service-module tl linecode linecode type  
5. If you are using fractional T1 service, enter the time slot range and  
speed. In this example, the time slot range is from 1 to 20 and the  
speed is 64-kbps:  
Router(config.f)# service-module tl timeslots 1-20 speed 64  
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6. Return to user EXEC mode:  
Router(config-if)# exit  
Router(config)# exit  
Router# exit  
Router>  
Specifying the  
Boot Method  
You can enter multiple boot commands in the configuration in  
NVRAM to provide a backup method for loading the Cisco IOS image  
onto the router. The router boots using the first boot command that  
succeeds. If you enter multiple boot commands, the router executes  
them in the order they are entered. There are two ways to load the  
Cisco IOS image: from Flash memory or from a TFTP server on the  
network.  
1. Flash memory  
Information stored in Flash memory is not vulnerable to network  
failures that might occur when you load system software from  
servers. In this example, replace filename with the filename of the  
Cisco IOS image:  
Router> enable  
Password: enablepassword  
Router# configure terminal  
Router (config)# boot system flash filename  
Router (config)# Ctrl-Z  
Router# copy running-config startup-config  
Building configuration...  
[OK]  
Router# exit  
Router>  
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Chapter 16: Basic Configuration  
2. TFTP server  
If Flash memory is not available, or if Flash memory does not con-  
tain a valid Cisco IOS image, you can specify that system software  
be loaded from a TFTP server on your network as a backup boot  
method for the router. In this example, replace filename with the  
filename of the Cisco IOS image, and replace IP address with the  
IP address of the TFTP server:  
Router> enable  
Password: enablepassword  
Router# configure terminal  
Router (config)# boot system tftp filename ipaddress  
Router (config)# Ctrl-Z  
Router# copy running -config startup-config  
Building configuration ...  
[OK]  
Router# exit  
Router>  
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Checking the  
Configuration  
Settings  
Enter the show version command to check the software version  
(third line from the top in this display) and configuration register set-  
ting (at the end of this display):  
Router> shovrsion  
Cisco Internetwork Operating System Software  
IOS (to) XX00 Software (XXX-X-X), RELEASE SOFTWARE XX.X(XXXX) [XXX]  
Copyright (c) 1986-1996 by Cisco Systems, Inc.  
Compiled Tue XX-XXX-XX 13:07 by XXXXX  
Image text-base: 0x03032810, data-base: 0x00001000  
ROM: System Bootstrap, Version X.X(XXXX) [XXXXX], RELEASE SOFTWARE  
ROM: XX00 Bootstrap Software (XXX-BOOT-X), Version XX.X(XXXXX) [XXXXX]  
Router uptime is 4 minutes  
System restarted by power-on  
System image file is Rflash:XXX/XXX-X-X.Novl4", booted via flash  
Cisco XXXX(68030) processor (revision X) with 4092K/2048K bytes of memory.  
Processor board ID 00000000  
Bridging software.  
SuperLAT software copyright l99X by Meridian Technology Cord).  
X.25 software, Version X.X, NET2, BEE and GOSIP compliant.  
TN3270 Emulation software (copyright l99X by TGV Inc).  
1 Ethernet/IEEE 802.3 interface.  
2 Serial network interfaces.  
No module installed for Serial Interface 0  
No module installed for Serial Interface 1  
32K bytes of non-volatile configuration memory.  
8192K bytes of processor board System flash (Read ONLY)  
Configuration register is 0x2102  
Router>  
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Chapter 17: Command References  
Chapter 17: Command References  
Introduction  
This chapter contains a link to the AI2524/Cisco IOS v. 11.2 documen-  
tation.  
Command References  
Refer to the Cisco Command Reference chapters on the AI2524/Cisco  
IOS v. 11.2 documentation CD.  
z
z
z
z
z
z
Security Command Referenc  
Wide-Area Networking Command Reference  
Network Protocols Command Reference Part 1  
Network Protocols Command Reference Part 2  
Network Protocols Command Reference Part 3  
Bridging and IBM Networking Command Reference  
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Chapter 18: System Error Messages  
Chapter 18: System Error Messages  
Introduction  
This chapter contains a link to the AI2524/Cisco IOS v. 11.2 documen-  
tation.  
System Error Messages  
Refer to the Cisco Command Reference chapters on the AI2524/Cisco  
IOS v. 11.2 documentation CD.  
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Chapter 19: Debug Command Reference  
Chapter 19: Debug Command Reference  
Introduction  
This chapter contains a link to the AI2524/Cisco IOS v. 11.2 documen-  
tation.  
Debug Command Reference  
Refer to the Cisco Command Reference chapters on the AI2524/Cisco  
IOS v. 11.2 documentation CD.  
August 1997  
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Appendix A: Release Notes  
Appendix A: Release Notes  
August 1997  
2524UM  
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AISwitch Release Notes  
AI2524, Version 1.00  
Router Card  
August 1997  
Applied Innovation, Inc.  
5800 Innovation Drive  
Dublin, Ohio 43016-3271  
(614) 798-2000  
(800) 247-9482  
FAX (614) 798-1770  
RN194  
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AI2524 Router Card, Version 1.00 Release Notes  
Copyright  
August 1997  
© Copyright 1983-1997 Applied Innovation Incorporated (AII).  
The material discussed in this manual is the proprietary property of  
AII and AII retains all rights to reproduction and distribution of this  
document.  
AISwitch, AISwitch Series 180 and AISwitch Series 130 are regis-  
tered trademarks of Applied Innovation Inc.  
Any other trademarks appearing in this documentation are regis  
tered trademarks of their respective companies.  
FCC Warning  
The Federal Communications Commission has set limits for emit-  
ted radio interference, and the AISwitch is constructed with this elec-  
tromagnetic interference (EMI) limitation in mind. The AISwitch is  
classified under FCC regulations as a Class A device, that is, a device  
for use in commercial environments and not in residential areas. This  
device has been tested and shown to comply with the following FCC  
rule: Part 15 Subpart J. Operation of this equipment in a residential  
area may cause interference to radio and TV reception, requiring the  
user to take whatever steps are necessary to correct the interference.  
Information is available from the FCC describing possible correc-  
tive actions. To maintain low EMI levels, we suggest that you use only  
metal connectors and shielded cable grounded to the frame.  
Electrostatic Discharge Warning  
The AISwitch and its peripherals contain electrostatic sensitive  
components. Proper handling, shipping, and storage precautions  
must be exercised:  
z
Removal and installation of circuit boards must be performed in a  
static-free environment. This means the technician should wear  
an anti-static wrist strip and stand on an anti-static mat. Both the  
wrist strap and mat must be grounded at the same point as th  
AISwitch enclosure.  
z
z
z
z
When not in use, circuit boards must be kept in their anti-static  
plastic bags.  
Circuit boards must only be removed from their anti-static plastic  
bags immediately prior to installation into the AISwitch enclosure.  
Immediately upon removal from the enclosure, circuit boards  
must be inserted into their anti-static bags.  
Do not ship or store the electronic circuit boards near strong elec-  
trostatic, electromagnetic, magnetic, or radioactive fields.  
Applied Innovation, Inc.  
5800 Innovation Drive  
Dublin, Ohio 43016-3271  
(614) 798-2000  
(800) 247-9482  
FAX (614) 798-1770  
RN194  
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August 1997  
AI2524 Router Card, Version 1.00 Release Notes  
AISwitch Release Notes  
AI2524, Version 1.00  
Router Card  
August 1997  
New Features  
These release notes document new or enhanced features and com  
mands, upgrade instructions, and problem resolutions for the AI2524  
Router card.  
z
Instructions for use of this product are detailed in the AI2524 Router  
Manual, document number 2524UM.  
RN194  
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AI2524 Router Card, Version 1.00 Release Notes  
August 1997  
ISDN/BRI  
Inferface  
The AI2524 ISDN/BRI module provides the digitalization of tele-  
phone network so that voice, data, text, graphics, music, video, and  
other source material can be provided to end users from a single end-  
user terminal over existing telephone wiring.  
ACT  
NT1  
Activity LED  
Flashing LED indicates normal opera  
tion. Transmitting and receiving dat  
normally.  
Network Termination 1 LED  
If the NT1 LED is on, the router detects  
the ISDN link integrity signal at the U  
interface and the internal S/T interface,  
indicating that an ISDN connection has  
been established.  
If the NT1 LED blinks once per second,  
the ISDN connection at the U interface  
is up and the internal S/T interface is  
coming up. If this condition persists, th  
ISDN port is either not configured o  
configured incorrectly.  
If the NT1 LED blinks 8 times per sec-  
ond, the ISDN connection at the internal  
S/T interface is up and the U interface is  
coming up.  
If the NT1 LED is off, the router is not  
detecting the ISDN link integrity signal.  
Check the BRI cable connection.  
ISDN-BRI with  
NT1  
RJ-45 connector  
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August 1997  
AI2524 Router Card, Version 1.00 Release Notes  
Configuring  
ISDN  
If you have an ISDN BRI WAN module, configure the BRI port for  
ISDN. This section explains typical ISDN configurations for one or  
two B channels. In the examples, the BRI port is configured for IP  
routing and Point-to-Point Protocol (PPP) encapsulation.  
Complete these steps to configure the router for a basic ISDN PPP  
connection on a single B channel or two B channels, substituting th  
correct address and host names as appropriate for your network.  
1. Enter enable mode:  
Router> enable  
Password: enable password  
2. Enter the configure terminal command.  
Router# config term  
3. If you have not already done so, enter the isdn switch-type  
command to configure the ISDN switch type:  
router (config) # ISDN switth-type switch-type  
4. Enter the BRI interface, encapsulation method (PPP), authentica  
tion type, target router’s IP address and ISDN number to dial, and  
the dialer group number:  
Router (config) # interface bri 0  
Router (config-if) # encapsulation ppp  
Router (config-if) #ppp authentication chap  
Router (config-if) # dial map ip targetrouter_ipaddress targetrouter_phonenumber  
Router (config-if) # dialer-group groupnumber  
Do not use periods or hyphens when you are entering dialing num-  
bers.  
Note:  
The ISDN/BRI interface provides dial backup for the  
AI2524 card. When a connection is requested, the system  
checks the username presented for validity, then dials  
back the number associated with the username.  
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AI2524 Router Card, Version 1.00 Release Notes  
August 1997  
5. Some ISDN switch types, such as Basic NI1 or DMS-100 switch  
service, require you to configure a service profile identifie  
(SPID). Enter the SPID information substituting the appropriat  
entries for your installation:  
Router (config-if) # isdn spid1 SPID_no phone_number  
Router (config-if) # isdn spid2 SPID_no phone_number  
6. To set up a second B channel for bandwidth on demand, enter the  
load-threshold command to set the ISDN load threshold. The load  
threshold determines the percentage of network loading at which  
the second ISDN B channel is triggered. The value ranges from 1  
to 255 (100 percent).  
Router (config-if) 3 dialer load-threshold 128  
In this example, the value of 128 means that when the first B chan-  
nel reaches 50 percent of its bandwidth capacity (128 equals 50  
percent of 255), the second B channel will be activated to assist  
with the bandwidth load.  
7. Enter the access-listcommand to configure the ISDN line to  
come up whenever IP packets are to be sent:  
Router (config-if) # access-list access-list-number permit-ip sourcerouter-  
ipnetwork sourcerouter-subnetmask targetrouter-ipnetwork targetrouter-subnetmask  
Router (config) # dialer-list groupnumber list access-list-number  
8. Configure a static route to allow connectivity to the target router’s  
local network. Enter the network number of the target router’s  
local IP network and subnet mask, and the IP address of the target  
router’s BRI port:  
Router (config) 3 ip route targetrouter_ipnetwork subnetmask  
targetBRIport_ipaddress  
9. Enter the exitcommand to exit configuration mode.  
10. Enter the copy running-config startup-config  
command to save the configuration to NVRAM.  
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Appendix B: Acronyms  
Appendix B: Acronyms  
Acronym Definition  
AAA  
Authentication, Authorization, and  
Accounting  
AMI  
Alternate Mark Inversion  
ANSI  
APPN  
ARA  
ARP  
American National Standards Institute  
Advanced Peer-to-Peer Networking  
AppleTalk Remote Access Protocol  
Address Resolution Protocol  
Advanced Research Projects Agency  
Asynchronous Transfer Mode  
Appletalk Update-based Routing Protocol  
Committed Burst Size  
ARPA  
ATM  
AURP  
Bc  
Be  
Excess Burst Size  
BECN  
BERT  
BFE  
Backward Explicit Congestion Notification  
Bit Error Rate Tester  
Blacker Front End  
BGP  
Border Gateway Protocol  
BRI  
Basic Rate Interface  
BSC  
Binary Synchronous Communications  
Block Serial Tunnel  
BSTUN  
CCITT  
Consultative Committee for International  
Telegraph & Telephone  
CHAP  
Challenge Handshake Authentication  
Protocol  
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CIP  
Channel Interface Protocol  
Committed Information Rate  
Command Line Interface  
Connectionless Network Services  
Connection-Mode Network Service  
Connection Mode Network Services  
Control Point  
CIR  
CLI  
CLNS  
CMNS  
CMNS  
CP  
CPU  
CSLIP  
CSNP  
CSU  
CUD  
D-bit  
DCA  
DCE  
DDN  
DDN  
DDR  
DDS  
DE  
Central Processor Unit  
Compressed Serial Line Internet Protocol  
Complete Sequence Numer PDU  
Channel Service Unit  
Call User Packet  
Data Bit  
Defense Communications Agency  
Data-Circuit Terminating Equipment  
Defense Data Network  
Defense Data Network  
Dial-on-Demand Routing  
Digital Data Service  
Discard Eligibility  
DHCP  
DLCI  
DLUR  
DNIC  
DS0  
Dynamic Host Configuration Protocol  
Data Link Connection Identifier  
Dependent LU Requester  
Data Network Identification Code  
Digital Signaling 0  
DSU  
Digital Service Unit  
Page B-2  
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Appendix B: Acronyms  
DTE  
Data Terminal Equipment  
Exterior Gateway Protocol  
Extended Superframe  
EGP  
ESF  
FDDI  
FIFO  
FRMR  
HDLC  
HDLC  
HSRP  
HSSI  
ICMP  
IETF  
IGRP  
IP  
Fiber Distributed Data Interface  
First-In First-Out  
Frame Reject Frame  
High-level Link Control  
High-Level Data Link Control  
Hot Standby Router Protocol  
High-Speed Serial Interface  
Internal Control Message Protocol  
Internet EngineeringTask Force  
Internet Gateway Routing Protocol  
Internet Protocol  
IPCP  
IPX  
IP Control Protocol  
Internet Packet Exchange  
ICMP Router Discovery Protocol  
Integrated Services Digital Network  
Intermediate System to Intermediate System  
IRDP  
ISDN  
IS-IS  
ISO  
International Organization for  
Standardization  
ISP  
Internet Service Provider  
InternationalTelecommunications  
Level 2 Forwarding  
ITU  
L2F  
LAN  
LANE  
Local Area Network  
LAN Emulation  
August 1997  
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AI2524 Router Card User’s Manual  
LAPB  
LAPB  
LAPF  
LAT  
Link Access Procedure Balanced  
Link Access Procedure Balanced  
Link Access Procedure for Frame Relay  
Local-Area Transport  
LC  
Logic Channel  
LCI  
Logic Channel Identifier  
Low-Entry Networking  
Station Router Level  
LEN  
Level1  
Level2  
LLC2  
LMI  
Area Router Level  
Logical Link Control type 2  
Local Management Interface  
Link Quality Monitoring  
Link Quality Reports  
LQM  
LQR  
LSP  
Link State PDU  
LU  
Logical Unit  
MAC  
M-bit  
MBRI  
MIP  
Media Access Control  
More Data Bit  
Multiport BRI  
MultiChannel Interface Processor  
Multilink PPP  
MLP  
MMP  
MOP  
MTU  
NAS  
NASI  
NCD  
Multichasis Multilink PPP  
Maintenance Operation Protocol  
Maximum Transmission Limit  
Network Access Server  
Netware Asynchronous Services Interface  
Network Control Device, Inc.  
Page B-4  
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Appendix B: Acronyms  
NCIA  
NET  
NETID  
NLSP  
NMP  
NNI  
Native Client Interface Architecture  
Network Entity Titles  
Network Identifier  
Netware Link Services Protocol  
Network Processor Module  
Network-to-Network Interface  
Network Service Access Point  
Nonvolatile Random Access Memory  
Open System Interconnection  
Open Shortest Path First  
Packet Assembler/Disassembler  
Password Authentication Protocol  
Public Data Network  
NSAP  
NVRAM  
OSI  
OSPF  
PAD  
PAP  
PDN  
PDU  
PLP  
Protocol Data Unit  
Packet Level Protocol  
POP  
Point of Presence  
POP  
Point of Presence  
PPP  
Point-to-point Protocol  
PRI  
Primary Rate Interface  
PSN  
Packet-Switched Network  
Partial Sequence Number PDU  
Physical Unit  
PSNP  
PU  
PVC  
QLLC  
QOS  
RIP  
Permanent Virtual Circuits  
Qualified Logical Link Control  
Quality of Service  
Routing Information Protocol  
August 1997  
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RIP  
Routing Information Protocol  
ROM  
RPOA  
RSRB  
RTMP  
SAP  
Read Only Memory  
Recognized Private Operation Agency  
Remote Source-Route Bridging  
Routing Table Maintenance Protocol  
Service Access Point  
SDLC  
SF  
Synchronous Data Link Control  
Superframe  
SGBP  
SLIP  
Stock Group Bidding  
Serial Line Internet Protocol  
Switched Multimegabit Data Service  
Simple Mail Transfer Protocol  
Systems Network Architecture  
Subnetwork Access Protocol  
Simple Network Management Protocol  
Source-Route Translational Bridge  
Source-Route Bridging  
SMDS  
SMTP  
SNA  
SNAP  
SNMP  
SR/TLB  
SRB  
SRT  
Source-Route Transport  
SVC  
Switched Virtual Circuit  
TAC  
Terminal Access Controller  
TACACS  
Terminal Access Controller Access Control  
System  
TCP  
TFTP  
THC  
TOS  
Transmission Control Protocol  
Trivial File Transfer Protocol  
TCP/IP Header Compression  
Type of Service  
Page B-6  
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Appendix B: Acronyms  
UDP  
UP  
User Datagram Protocol  
Usage Parameter  
URL  
VCN  
VPDN  
VTY  
WAN  
XNS  
XOT  
Universal Resource Locator  
Virtual Circuit Nember  
Virtual Private Dial-up Network  
Virtual Terminal  
Wide Area Network  
Xerox Network Systems  
X.25 Over TCP  
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