Cisco Systems CCNA 2 Configuring Igrp, Migrating from RIP to Igrp, Verifying Igrp Configuration

The debug ip igrp events command can be used to verify that the timers affect routing updates. Have the students configure IGRP on the lab topology.

7.3.5 Configuring IGRP

To enable IGRP routing use the router igrp as-numberglobal configuration command. To disable IGRP routing use the no router igrp as-numbercommand.

RouterA(config)#router igrp as-number

RouterA(config-router)#

RouterA(config)#no router igrp as-number

RouterA(config)#

To identify which networks will participate in the IGRP routing process, use the network network-addressrouter configuration command. To remove a network from the IGRP routing process, use the no network network-addresscommand.

RouterA(config)#router igrp 101

RouterA(config-router)#network 192.168.1.0

RouterA(config)#router igrp 101

RouterA(config-router)#no network 192.168.1.0

The autonomous system number is used to identify the router to other IGRP routers and to tag routing information. Have the students configure IGRP on the lab topology.

7.3.6 Migrating from RIP to IGRP

With the creation of the IGRP in the early 80s, Cisco Systems was the first company to solve the problems associated with RIP. IGRP was designed to have a greater maximum hop count, which gave it more scalability for larger companies. IGRP uses multiple metrics to determine the best path, bandwidth, and delay, as opposed to the hop count metric used by RIP. As a result of these improvements, IGRP enabled many large, complex, and topologically diverse internetworks to be deployed. Have the students configure the lab topology with RIP and then migrate to IGRP. Make sure that students understand that RIP is still the most implemented routing protocol in smaller internetworks. Also, emphasize that IGRP can only be used in a fully Cisco environment.

7.3.7 Verifying IGRP Configuration

The following commands and available switches can be used to verify the configuration of IGRP:

•show interface

•show ip protocol

•show ip route

•show running-config

The show interface command can be used to verify issues that are specifically related to the interface configuration such as the ip address, physical connectivity, and keepalives. The show ip protocol command should be used to verify that routing protocols are correctly configured. This command can be used to view the routing protocols enabled on the router,

89 - 238 CCNA 2: Routers and Routing Basics v3.1 Instructor Guide – Module 7 Copyright ♥ 2004, Cisco Systems, Inc.