BFD on back-to-back connected BGP-speakers

Tue Nov 29 19:13:13 UTC 2016

Hugo, I think those are all valid potential reasons to use BFD. I use it
for some of the same reasons even on direct connect peers.

Only time I ever recall actively avoiding it if I had the capability was if
I had NSF/SSO, since they didn't used to (still don't?) play very well
together.

On Tue, Nov 29, 2016 at 1:23 PM, Hugo Slabbert <hugo at slabnet.com> wrote:

> Good morning, nanog,
>
> Is there any/sufficient benefit in adding BFD onto BGP sessions between
> directly-connected routers?  If we have intermediate L2 devices such that
> we can't reliably detect link failures BFD can help us quickly detect peers
> going away even when link remains up, but what about sessions with:
>
> - eBGP with peering to interface addresses (not loopback)
> - no multi-hop
> - direct back-to-back connections (no intermediate devices except patch
>  panels)
>
> Possible failure scenarios where I could see this helping would be fat
> fingering (filters implemented on one or the other side drops traffic from
> the peer) or e.g. something catastrophic that causes the control plane to
> go away without any last gasp to the peer.
>
> Or is adding BFD into the mix in this type of setup getting into
> increasing effort/complexity (an additional protocol) for dimishing returns?
>
> --
> Hugo Slabbert       | email, xmpp/jabber: hugo at slabnet.com
> pgp key: B178313E   | also on Signal
>
>