[c-nsp] BFD on customer-facing interfaces - experiences

[Adam Vitkovsky]

> Eric Louie
> Sent: Wednesday, October 05, 2016 10:48 PM
>
> We're looking for any ISPs who have experience with BFD configured on
> customer-facing interfaces (OSPF or BGP).  Was it reliable?  Did it cause too
> many false positives for down routing sessions?  What about re-establishing
> the routing protocol when BGD recovers?  Did you have issue with root cause
> analysis when the sessions dropped (as in explaining to the customers why
> their routing session went down or flapped)?
>
Regarding false positives,
Might want to check whether on your platform of choice the BFD is offloaded to HW (i.e. not being handled by the CPU on RE).
Might want to run some scaling testing to see how many BFD sessions and with what timers can be run concurrently in your specific setup (note the scaling numbers provided by vendors are unidimensional).

Regarding flapping,
Might want to use interface state dampening (i.e. wait 0s to transition interface to down state and wait e.g. 60s so see if the link is stable and only then transition to protocol up state).

adam









        Adam Vitkovsky
        IP Engineer

T:      0333 006 5936
E:      Adam.Vitkovsky at gamma.co.uk
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