RIP/IGRP routes

barryn13087

sometimes when i apply rip or igrp xx, my problem is that, the networks i apply it to do not broad cast it, i do show run and show ip proto and it shows they are running and updating on thier regular intervals but when i do show ip route, the routes are not there. only thing i see is C for connected, i assign the protocols on both routers and make sure ipclassless is enabled but still to no avail, what could i be doing wrong? ill update with a show run in near future...

shadown7

Check your ethernet interfaces to see if your status is up. You stating that "sometimes" you have trouble could be a bad cable. I've had a similar problem which was caused by a bad cat5 cable.

keenon

barryn13087 wrote:

sometimes when i apply rip or igrp xx, my problem is that, the networks i apply it to do not broad cast it, i do show run and show ip proto and it shows they are running and updating on thier regular intervals but when i do show ip route, the routes are not there. only thing i see is C for connected, i assign the protocols on both routers and make sure ipclassless is enabled but still to no avail, what could i be doing wrong? ill update with a show run in near future...

1. are both routers on the same subnet?
2. if using serial connections are both routers using same WAN protocol?
if frame make sure your using same sub interfaces and dlci numbers
3. when using igrp verify both using same AS
4. verify status of interfaces connected to make sure there up

tunerX

Sounds like a problem rooted in RIP and IGRP being classful protocols. A classful protocol sends the entire network address address minus the mask. The router that recieves the update will use its own subnet mask for the network if it has an interface that is also in the within the classful boundary. This works good, you can use subnets, and the routers will exchange routes only when the advertised routes all have the same subnet masks. If the recieving router does not have an interface within the same classful network then it will apply the default classful mask to the route and inject it into the routing table.

mojomuchmojo

It's not clear from your question if I have an answer, but here is my comment fwiw...

Remember that you won't see the routes advertised by a router in its own routing table as anything other than a "C" connection. You would have to go to the next hop router to see those routes in the table as "R" or "I".

In other words, if Router A is advertising 10.1.0.0 (network 10.000) under RIP, you will still see : C 10.0.0.0 in router A's routing table, but you will see : R 10.0.0.0 in, say, router C's routing table.

Put another way, if a subnet is directly connected to an interface on the Router, it will be a "C" route in the router's table, even though that router is indeed advertising it using a dynamic routing protocol.