Leased Line: Dynamic IP Routing

Leased Line Sample Configuration Dynamic IP Routing	Cisco ConfigMaker Windows 95/NT 4.0 configuration tool

This sample configuration routes IP between two Cisco routers over a synchronous serial line. IP routes are dynamically resolved using RIP version 2 as the routing protocol.

The default encapsulation type used on leased lines between two Cisco routers is HDLC. However, when connecting to a non-Cisco router, PPP encapsulation must be used for third party compatability. This example also discusses how PPP encapsulation can be easily substituted in place of HDLC.

Info On IP Unnumbered
Faxback Doc #ip_unnum

Before you begin

Get The IOS Leased Line Command Glossary.
Faxback Doc #0553

Detailed descriptions of all IOS commands used in frame relay configurations. Also provides links to the IOS Command Reference if more information is required

Get The IOS Command Line Interface Tutorial
Faxback Doc #ios_tutorial

Instructions on configuring an IOS router using the command line interface

Preconfiguration Checklist

Leased Line Information
The following info must be gathered from the circuit provider

DSU/CSU Information
The circuit provider must provide clocking, data framing, and line encoding information to configure DSU/CSU successfully.

Network Information
The following info must be gathered from the network administrator

IP Address Information
An IP network design must be created. Separate IP network subnets are required at each site.

Note: Commands followed by a <*> are on by default and do not have to be configured. The "!" marks that appear in the configuration are automatically entered by the router and function as line separators for easier reading.

Atlanta Router Configuration
In IOS "show running-config" format

version 11.2 <*>
service udp-small-servers <*>
service tcp-small-servers <*>
!
hostname Atlanta
!
enable secret cisco
!
ip subnet-zero
no ip domain-lookup
!
interface Ethernet0
ip address 10.1.1.1 255.0.0.0
!
interface Serial0
description Leased Line to Boston
ip unnumbered Ethernet0
** add 'encapsulation ppp' here if communicating with third party routers **
!
router rip
version 2
network 10.0.0.0
no auto-summary
!
ip http server
ip classless
!
line con 0
password console
login
line aux 0 <*>
line vty 0 4
password telnet
login <*>
!
end <*>

Boston Router Configuration
In IOS "show running-config" format

version 11.2 <*>
service udp-small-servers <*>
service tcp-small-servers <*>
!
hostname Boston
!
enable secret cisco
!
ip subnet-zero
no ip domain-lookup
!
interface Ethernet0
ip address 20.1.1.1 255.0.0.0
!
interface Serial0
description Leased Line to Atlanta
ip unnumbered Ethernet0
!
router rip
version 2
network 20.0.0.0
no auto-summary
!
ip http server
ip classless
!
line con 0
password console
login
line aux 0 <*>
line vty 0 4
password telnet
login <*>
!
end <*>

After You've Tried

You've tried the configuration and it doesn't work. Help is available!

Get IOS Router Leased Line Troubleshooting Assistance
Faxback Doc #ll_ts