nanog mailing list archives
Re: BFD for routes learned trough Route-servers in IXPs
From: Zbyněk Pospíchal <zbynek () dialtelecom cz>
Date: Wed, 16 Sep 2020 10:14:21 +0200
Hi, In some IXPs, getting a BFD protected BGP sessions with their route-servers is possible. However, it is usualy optional, so there is no way how to discover know who of your MLPA peering partners has their sessions protected the same way and who don't. You can also ask peers you have a session with to enable BFD there. If they run carrier-grade border routes connected to IXP switches just with fibers, it works pretty well. So just try to talk with your peers about BFD. -- S pozdravem/Best Regards, Zbyněk Pospíchal Dne 16.09.20 v 2:55 Douglas Fischer napsal(a):
Time-to-time, in some IXP in the world some issue on the forwarding plane occurs. When it occurs, this topic comes back. The failures are not big enough to drop the BGP sessions between IXP participants and route-servers. But are enough to prejudice traffic between participants. And then the problem comes: "How can I check if my communication against the NextHop of the routes that I learn from the route-servers are OK? If it is not OK, how can I remove it from my FIB?" Some other possible causes of this feeling are: - ARP Resolution issues (CPU protection and lunatic Mikrotiks with 30 seconds ARP timeout is a bombastic recipe) - MAC-Address Learning limitations on the transport link of the participants can be a pain in the a..rm. So, I was searching on how to solve that and I found a draft (8th release) with the intention to solve that... https://tools.ietf.org/html/draft-ietf-idr-rs-bfd-08 If understood correctly, the effective implementation of it will depend on new code on any BGP engine that will want to do that check. It is kind of frustrating... At least 10 years after the release of RFC until the refresh os every router involved in IXPs in the world. Some questions come: A) There is anything that we can do to rush this? B) There is any other alternative to that? P.S.1: I gave up of inventing crazy BGP filter polices to test reachability of NextHop. The effectiveness of it can't even be compared to BFD, and almost kill de processing capacity of my router. P.S.2: IMHO, the biggest downside of those problems is the evasion of route-servers from some participants when issues described above occurs.
Current thread:
- Re: BFD for routes learned trough Route-servers in IXPs, (continued)
- Re: BFD for routes learned trough Route-servers in IXPs Randy Bush (Sep 17)
- Re: BFD for routes learned trough Route-servers in IXPs Ryan Hamel (Sep 15)
- Re: BFD for routes learned trough Route-servers in IXPs Nick Hilliard (Sep 16)
- BFD for routes learned trough Route-servers in IXPs Chriztoffer Hansen (Sep 16)
- Re: BFD for routes learned trough Route-servers in IXPs Saku Ytti (Sep 16)
- Re: BFD for routes learned trough Route-servers in IXPs Douglas Fischer (Sep 17)
- Re: BFD for routes learned trough Route-servers in IXPs Saku Ytti (Sep 17)
- Re: BFD for routes learned trough Route-servers in IXPs Douglas Fischer (Sep 17)
- Re: BFD for routes learned trough Route-servers in IXPs Paul Timmins (Sep 17)
- Re: BFD for routes learned trough Route-servers in IXPs Baldur Norddahl (Sep 20)
- Re: BFD for routes learned trough Route-servers in IXPs Robert Raszuk (Sep 17)
- Re: BFD for routes learned trough Route-servers in IXPs Jared Mauch (Sep 22)