RIP Scenario

[rivanfrank]

Hi Everyone,

I have here a configured RIP scenario.

It was configured using RIP version 1. In my understanding RIP v1 supports classful network, but when i check the route of Router 1, the RIP acknowledge the network 10.0.20.0 and network 10.0.10.0.

Router1 sh ip route

     10.0.0.0/24 is subnetted, 3 subnets

R       10.0.10.0 [120/2] via 10.0.30.2, 00:00:17, FastEthernet0/1

R       10.0.20.0 [120/1] via 10.0.30.2, 00:00:17, FastEthernet0/1

C       10.0.30.0 is directly connected, FastEthernet0/1

C    192.168.10.0/24 is directly connected, FastEthernet0/0

R    192.168.20.0/24 [120/1] via 192.168.10.2, 00:00:21, FastEthernet0/0

How come it reads classless networks and did not summarize to 10.0.0.0 network?

Thanks

[Mohamed Sobair · Accepted solution]

Hello,

RIPv1 is indded classful routing protocol, however , take the below note when considering RIPv1 advertisement:

(( Check to see if the Network to be advertised is part of the major Network Interface of te router, IF IT IS, Then Advertise! IF IT IS NOT, then Summarize the Network to its Classful Network Boundary And then Advertise))!

The Fact About your example, If you look at the Topology, You find that Network 10.0.20.0/24 & 10.0.10.0/24 Are Part of their Major Network Interfaces and therfore, they are advertised to R1 without being Summarized.

However, If you need to examine Summarization in Place, Shutdown R1's F0/1 Interface, and Look at its routing table again, you should see that R1 now recieves 10.0.0.0/8 Classful Network instead of 10.0.0.20/24 & 10.0.10.0/24. and the reason is because the 10 Network are no Longer Part of the Major Network Interface of R3!

Regards,

Mohamed

[rivanfrank]

Thank You!

After I read your reply i tried different scenario on my own, and i fully understand now.

Thanks.