Re: endpoint liveness (RE: Do ATM-based Exchange Points make sensean ymore?)

[Petri Helenius <pete () he iki fi>]

Mike Hughes wrote:

> But, how does that work when you may be delivering multiple q-tags on a
> single GigE port (for example)? If only one tag is affected, you don't
> want to drop link, right?
>
> So, we're back to detection at layer 3, can I ping it, do I have
> adjacency, etc.
>
> Some sort of lower-level heartbeat (maybe like OAM), not dependent on IP
> reachability, would be a bonus - and it's probably low in the tax stakes,
> if it can be made simple enough.
I think pseudowire liveness (in case of ethernet pseudowires which are 
by nature multipoint and multi-vlan) does not really make sense but as you
conclude L3 liveness does. Obviously one can repeat the exercise for everything
that needs liveness but it would make more sense to have a generic way to 
determine L3 reachability in a robust manner.

Pete