[c-nsp] Inter-AS L2VPN redundancy, option B (Ruzhanskaya Olga)

[Ольга Ружанская]

Thank You for reply.

> Basically, L2VPN Pseudowire Switching and Back-to-Back 
> VLAN's are a single point of failure. You may add redundancy 
> by replicating NNI sessions, but this may not be scalable 
> from a management perspective.
I just want to add little comment this statement (maybe I'm wrong..). 
Talking about the Cisco equipment, for option B we cannot build a redundant scheme even replicating NNI;
because point-to-point VFIs have not ability to check, is the neighbor down.
But for back-to-back we still can use redundant links (maybe there will be questions for intervendor compatibility, Phil re:).

> Option C. I can't say we've looked at that yet.
The main question is security - each AS will have reachability to all the internal next-hops in the other AS. Otherwise, this is the most scalable and flexible option.

Best regards,
Olga