[c-nsp] BFD interval on a CRS3

Pshem Kowalczyk pshem.k at gmail.com
Wed Apr 3 17:12:58 EDT 2013

We were told that 20ms is probably the lowest safe value you should
run. For those reasons we're moving away from BFD and onto WanPhy and
OTU2e encoding on the fibre. I remember testing the actual
re-convergence time with BFD (on ASR9k) - with 20ms the actual
re-convergence time (measured by a tester/traffic generator sending
1Gb/s stream over L2VPN) was always ~120ms. With WanPhy and OTU2e we
could get around ~50ms. I suspect it has to do with the way error
detection work in those technologies - it's threshold based, so once
errors reach particular level switchover is triggered - whilst BFD has
to actually lose those packets first.

kind regards

On 3 April 2013 21:48, Adam Vitkovsky <adam.vitkovsky at swan.sk> wrote:
>> on a cisco CRS what is the lowest / shortest BFD interval that can be set
> It appears that on all XR platforms the lowest BFD interval is 15ms
> unfortunately.
> Combined with lowest multiplier of 2 it gives you 30ms detection time. We
> use multiplier 3 which only leaves 5ms for the IPFRR to do its magic.
> adam
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