[c-nsp] BGP Fast-external-fallover

[Oliver Boehmer (oboehmer)]

John Neiberger <> wrote on Friday, March 11, 2005 10:21 PM:

> We're migrating from a frame relay environment to an MPLS-based VPN
> using BGP for routing. Our provider does have BGP dampening
> configured. In that sort of environment, would it be beneficial or
> not to use bgp fast-external-fallover? I can see that in the case of
> the circuit that is bouncing often that it might cause our routes to
> be dampened. On the other hand, if a circuit just takes a quick hit,
> which is probably more likely, the BGP session will re-establish
> quicker. 
> 
> I'm leaning toward using this feature but I'd like to get your
> opinions.

I see customers using fast-external failover to react more quickly to
failures, but this is usually accompanied by IP event dampening
("dampening" on the interface) to avoid churns during interface flaps
(i.e. then the interface dampening code takes down the lineprotocol
during periods of instability). I wouldn't use it without interface
dampening..

	oli