Interior Gateway Routing Protocol (IGRP)
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2501A(config-router)#netw 172.16.0.0
2501A(config-router)#^Z
2501A#
2501B
To configure 2501B, you need, once again, to turn on IGRP using AS 10.
2501B#config t
Enter configuration commands, one per line.
End with CNTL/Z.
2501B(config)#router igrp 10
2501B(config-router)#netw 172.16.0.0
2501B(config-router)#^Z
2501B#
2501C
The last router is 2501C; you need to use AS 10 here as well.
2501C#config t
Enter configuration commands, one per line.
End with CNTL/Z.
2501C(config)#router igrp 10
2501C(config-router)#netw 172.16.0.0
2501C(config-router)#^Z
RouterC#
Verifying the IGRP Routing Tables
Once the routers are configured, you need to verify the configuration with
the show ip route command.
In all of the following router outputs, notice that the only routes to net-
works are either directly connected or IGRP-injected routes. Since we did not
turn off RIP, it is still running in the background and taking up both router
CPU cycles and bandwidth. However, the routing tables will never use a RIP-
found route because IGRP has a better administrative distance than RIP does.
The router output below is from the 2621A router. Notice that all routes
are in the routing table.
2621A#sh ip route
[output cut]
172.16.0.0/24 is subnetted, 5 subnets
I 172.16.50.0 [100/160360] via 172.16.10.2,
FastEthernet0/0
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