[j-nsp] Problems with MPLS

[Dermot Williams]

Hi,

 

OK, another MPLS problem. This one is pretty serious and is affecting
rollout on our network, so it would be great if someone could give me a
dig out. 

 

The gist of the problem is this: I've a core router, let's call it
Core_A. I've also got three edge routers, let's call these Edge_A,
Edge_B and Edge_C. Edge_A and Edge_B both connect to the same logical
interface on Core_A. Both Edge_A and Edge_B need to have an LSP built to
Edge_C. Unfortunately only of one of these LSPs works in both
directions. For the purpose of this example, let's assume that this is
Edge_A-to-Edge_C. For Edge_B-to-Edge_C, the LSP only comes up in one
direction (Egress from the point of view of Edge_B).

 

I am using the same configuration for these LSPs that I have used in
various other places on the network. The only difference in this
instance is the fact that Core_A has two neighbours on the same logical
interface.

 

This is probably a little confusing, so I've attached a diagram that I
hope explains things a little better. Any help that anyone can give me
on this would be hugely appreciated.

 

Regards,

 

Dermot Williams

Senior Network Engineer

Irish Broadband Internet Services Ltd.