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@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@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 This message is intended solely for the designated recipient(s). It may contain confidential or proprietary information and may be subject to attorney-client privilege or other confidentiality protections. If you are not a designated recipient you may not review, copy or distribute this message. If you receive this in error, please notify the sender by reply e-mail and delete this message. Thank you.