Why does DWDM imply need of BFD? DWDM has no problem propagating loss-of-signal and asserting remote failure.
It is of course possible to configure DWDM so that this does not happen, particularly if you buy protected circuit you might not want it to happen. But as per usual, you should test that vendor delivers what you buy. I think the problem probability of not detecting failure on waves, dark fibres and copper connections are smaller than the probability of having issue caused by presence of BFD. I think you need very unreliably failing link to capitalise on BFD. Radio is good candidate, switch masked liveliness is good candidate. Of course you also need to be sure you don't kill your BGP's fast external failover, by using eBGP multihop on your point-to-point circuit. On 21 March 2018 at 18:37, Luke Guillory <lguill...@reservetele.com> wrote: > He's asking because if it was dark the interface would go down when the link > was lost and the router would pull routes. But PA to FL would lead me to > believe it'll be a wave from some type of DWDM gear which brings us to BFD. > > > > > > > Luke Guillory > Vice President – Technology and Innovation > > Tel: 985.536.1212 > Fax: 985.536.0300 > Email: lguill...@reservetele.com > > Reserve Telecommunications > 100 RTC Dr > Reserve, LA 70084 > > _________________________________________________________________________________________________ > > Disclaimer: > The information transmitted, including attachments, is intended only for the > person(s) or entity to which it is addressed and may contain confidential > and/or privileged material which should not disseminate, distribute or be > copied. Please notify Luke Guillory immediately by e-mail if you have > received this e-mail by mistake and delete this e-mail from your system. > E-mail transmission cannot be guaranteed to be secure or error-free as > information could be intercepted, corrupted, lost, destroyed, arrive late or > incomplete, or contain viruses. Luke Guillory therefore does not accept > liability for any errors or omissions in the contents of this message, which > arise as a result of e-mail transmission. . > > -----Original Message----- > From: NANOG [mailto:nanog-boun...@nanog.org] On Behalf Of Alex Lembesis > Sent: Wednesday, March 21, 2018 11:31 AM > To: Job Snijders (External); Youssef Bengelloun-Zahr > Cc: NANOG > Subject: RE: How are you configuring BFD timers? > > 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:j...@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. -- ++ytti
