[j-nsp] Route redistribution

[Jonathan Lassoff]

On Tue, May 22, 2012 at 12:24 PM, Cyn D. <cynthia_dal at yahoo.ca> wrote:
> Network connections:
>
> We have router A(M120, 10.4), B(MX240, 11.4) and C(M7i, 10.4) connected as a triangle. Router A and B are in OSPF area 0 and also run IBGP between them. Router C is connected to A and B via OSPF area 5.
>
> Problem:
>
> Router A has a lot of EBGP learned routes. These routes are redistributed to router B using IBGP and OSPF. My intension is to redistribute these routes to Router C with OSPF from BOTH A and B. Therefore if A-C link fail, Router C will learn all routes from B. The problem is now Router C only learned these routes from A but can not learn from router B.  Did I miss anything or is it Router B not working properly?

Assuming that B and C are both in the same AS and speaking iBGP, B
wont re-announce the NLRIs back into itself without being set as a
route reflector.

However, I'd recommend making a full-mesh of BGP sessions over
OSPF-learned loopback addresses. Whether that's hauled over MPLS or
some other L2 transport mechanism, or using routing and multi-hop BGP
is up to you.

That way, C will still learn the routes coming into A, even if the
path is via B to get to the next-hops.

Cheers,
jof