Routers updating each other

[emilieiifo]

Is it possible for routers on the same network to update each other about the network they are both connected to?

Attached is a piece of question paper that I am going through for exam preparation.

I think router A will not update router B about the network between them because they are both connected to it. 

Is this right?

[Georg Pauwen]

Hello,

I am not sure what exactly they are asking, but both routers need to know about the 10.0.0.0/8 network (by means of adding the network under the RIP process). So even when you configure static RIP neighbors (neighbor x.x.x.x), you still need to announce the network, even if both routers are directly connected. That is unlike BGP, where you don't need to announce a network where two BGP neighbors are directly connected to.

So both routers need the below, and hence update each other of that network. You can easily check that by displaying the contents of the RIP database: without announcing the network, the database is empty.

Router_A

router rip

version 2

network 10.0.0.0

Router_B

router rip

version 2

network 10.0.0.0

[Jon Marshall · Accepted solution]

You are correct routers A and B will not send updates to each other for the 10.0.0.0/8 network because they are both directly connected to it so there is no need. 

If you have access to physical kit or a simulator you can easily see this by running a "debug ip rip" on either router and you would not see any updates being sent for that network.

Jon

[Georg Pauwen]

Hello,

obviously Jon's answer is completely right, and my answer completely missed the point. I thought the question was about the need to announce the 10.0.0.0/8 network under the RIP process, so the neighbors can see each other. That as opposed to BGP, where announcing the network for directly connected neighbors is NOT necessary...

[emilieiifo]

Thank you for your the correction

[emilieiifo]

Thank you Jon