Split horizon with poison reverse

auosdavid2000 · ‎05-11-2009

Hi,

I have below network

R1 ------ R2 (Fa0/1) -- (172.30.22.1/24)

The network connected to interface (Fa0/1) on Router2 was down; therefore R2 triggered partial update about this network as poison to R1.

My question is why R1 is advertised the poison reverse back to R2 about this network, what the benefit for that.

BR,

Auos.

Jon Marshall · ‎05-11-2009

Auos

The benefit is that R2 does not then try to find a route to 172.30.22.0/24 via R1. In a large network with a lot of routers this can save a certain amount of convergence time.

Jon

davy.timmermans · ‎05-12-2009

I can be wrong but isn't it R1 which will send a poison reverse update to R2?

edit:

ignore ;-)