How are you configuring BFD timers?

Thu Mar 22 10:22:39 UTC 2018

RFI is corollary to LOS.

Both are essentially speed of light limited, there in no uncertainty
or detection margin. After one side sees LOS other side will see RFI,
if it's not seeing LOS as well.

I personally would consider BFD for: radio, pseudowire, L2 switch and
equivalent poorly failing links. But I wouldn't run it on dark,
copper or wave. Purely an anecdote, but I have far more BFD caused
problems than BFD solved problems, spanning multiple vendors.
(CAT7600, ASR9k, MX).

Regarding BFD echo and control mode, neither is guaranteed to be HW or
SW implementation, both can be both. Standard intends echo mode to be
HW, but does not guarantee.

On 22 March 2018 at 12:10, James Bensley <jwbensley at gmail.com> wrote:
> On 22 March 2018 at 09:59, Saku Ytti <saku at ytti.fi> wrote:
>> Ethernet handles unidirectional failure natively through autonego asserting RFI.
>
> I was thinking about this as I wrote that post. I've not had a chance
> to test this across our various devices types, I will have to try and
> find the time to test which devices support this and how effectively
> it works. For now we just use BFD because it's tested as working on
> all our device types. We've seen issues where LOS isn't working
> properly across third party DWDM platforms so for now, we have no BFD
> bugs and it catches these issues for us.
>
> I think it might also be worth testing Ethernet RFI to check the
> delays that Jason was talking about; which is quicker to signal link
> down and begin the re-convergence process, RFI / LOS / BFD?
>
> Cheers,
> James.

-- 
  ++ytti