[c-nsp] BFD on ME3600/ME3800/7600s

[Adam Vitkovsky]

> James Bensley
> Sent: Friday, May 27, 2016 7:27 PM
>
> > On 27 May 2016 at 18:07, Adam Vitkovsky
> <Adam.Vitkovsky at gamma.co.uk> wrote:
> >> Also I would have thought that in echo mode since each side is
> responsible for checking its own packets independently of the remote end
> then each side can also run its own timers -though I'm not sure if also in echo
> mode there's timers negotiation that makes sure one doesn't shoot himself
> in the foot.
>
> Yeah in both echo mode and no echo mode, initially control packets are sent
> to negotiate timers. Whilst technically in echo mode it would be possible to
> have both nodes using different interval timers (for the fast echo packets),
> as long as the slow control packet timers match edso the BFD session
> wouldn't drop, everything should work, however in the RFC it does state that
> the timers shall be aligned (I can't remember exactly how it works, but if one
> has higher or lower timers the other adjusts to match so this should never
> happen).
>
Yeah I've noticed the cli saying min-rx -suggesting that one defines a bottom limit for the timers negotiation, something like minimum hold time in BGP. So there indeed is timers negotiation going on during session initiation.
Since I haven't tested this specifically I was just wondering if in echo mode the negotiation is taking place as well and if timers don't match the session is not formed.



adam




        Adam Vitkovsky
        IP Engineer

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