How are you configuring BFD timers?

Wed Mar 21 19:09:13 UTC 2018

They were ME3600s.  AFAIR it was two of these things in a lab connected back to back with two links between them, one metric higher than the other.  Some sort of traffic generator running between the two that would generate fixed size UDP frames at some tens of milliseconds interval, yanking the preferred link, counting how many packets were lost and doing some math, correlating with various logs debugs on the boxes.

> On Mar 21, 2018, at 1:34 PM, Youssef Bengelloun-Zahr <bengelly at gmail.com> wrote:
> 
> Which platform ? What context ?
> 
> Best regards.
> 
> 
> 
>> Le 21 mars 2018 à 18:10, Jason Lixfeld <jason+nanog at lixfeld.ca> a écrit :
>> 
>> A few years ago I did some testing and found that the time between the transceiver detecting LOS and the routing protocol (ISIS in this case) being informed that the link was down (triggering the recalculation) took longer than it took BFD to signal ISIS to recalculate.
>> 
>>> On Mar 21, 2018, at 12:35 PM, Bryan Holloway <bryan at shout.net> wrote:
>>> 
>>> Wouldn't any tangible problem on a dark-fiber link result in an interface shutdown, ostensibly creating the trigger one would need to begin re-convergence?
>>> 
>>> 
>>>> On 3/21/18 11:31 AM, Alex Lembesis wrote:
>>>> To speed up BGP routing convergence.  The (2x) dark fiber links from PA to FL are being used as Layer3 datacenter interconnects, where each datacenter has its own AS.  The DF is also carrying FCIP traffic, so we need failover to be as fast as possible.
>>>> Best regards,
>>>> Alex
>>>> -----Original Message-----
>>>> From: Job Snijders (External) [mailto:job at instituut.net]
>>>> Sent: Wednesday, March 21, 2018 12:25 PM
>>>> To: Youssef Bengelloun-Zahr
>>>> Cc: Alex Lembesis; NANOG
>>>> Subject: Re: How are you configuring BFD timers?
>>>> Silly question perhaps, but why would you do BFD on dark fiber?
>>>> Kind regards,
>>>> Job
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>> 