BGP Advertise-map with dual ISP

Haris P · ‎05-10-2008

I have two upstream on my BGP and I want to make failover when either of them goes down . The attached diagram will explain my scenario and the config I did .

I want to acheive the following this

Advertise my Prefix_A thru ISP_A and Prefix_B thru ISP_B in normal condition

Advertise both Prefixes thru ISP_A when ISP_B is down and vice versa

I did the config. as attached on the diagram . Please tell me if I'nm wrong

andrew.prince · ‎05-12-2008

Haris,

To be honest -I think that would be really tricky. What I would do - is just prepend my AS to one of the upstream peers.

That way I can send my AS to both peers, and all my subnets - and just make one peer better than the other.

set as-path prepend 65003 65003 65003

Place the above in with ever route map you want for the secondary peer - and that peer with receve your subnets with an AS cost of 3.

HTH.