These are chat archives for Exa-Networks/exabgp

Oct 2018
Oct 19 2018 12:57
Hi! I'm testing a fairly simple case with exaBGP : Juste echoing "announce/withdraw route X.X.X.X" on fifo. When announcing an (already preaviously) announced route, exaBGP is smart enough to not really announce it (since neighbour knows it already). cool !
BUT when removing twice a route (after removing it once before), the "withdraw" command is still sent to neighbour...
it seems exaBGP is smart enough not to send twice the same "announce", but is not able to do the same thing for "withdraw" commands
is this by design? or is it a bug ?
@thomas-mangin I can open an issue in github if needed
Thomas Mangin
Oct 19 2018 17:34
Neither - it is the current behaviour. Yes, it could be improved by detecting that the prefix was not sent, but the idea is to let you do what you want. I know when the route was already announced on the session, but you could want to try to withdraw a prefix which was announced by another router. Not all vendor do check the session the prefix was learned from - or at least it was like that some time ago.
Changing it on 3.4 would be a change of behaviour so I would likely refuse the change without a configuration option (which would be confusing). On 4.x - the behaviour could be changed, but as withdrawing a route not present should be a NOP - it is not really bug.
Oct 19 2018 19:16
ok thanks for the answer