On Fri, 2022-10-14 at 16:10 +0200, Ondrej Zajicek wrote: > On Fri, Oct 14, 2022 at 01:28:27AM +0200, Garri Djavadyan via Bird- > users wrote: > > Hello everyone, > > > > I noticed that the legacy Bird version behaves strangely while it > > is in > > an enhanced route-refreshing process, but I am not sure whether it > > is a > > known/expected behaviour for version 1.6.8. Namely, right after a > > 1.6.8 > > peers sends a BoRR message, it also sends withdrawals for the > > prefixes > > it received from that same peer. For example, below is the output > > from > > two Bird peers (1.6.8 and 2.0.10): > > > > So, I am just curious if it is a bug or some architectural > > limitation > > of Bird-1.6. If I understand correctly, there are two problems > > here: > > Hello > > Yes, it is expected, although unnecessary. The route feeding code > just > send updates or withdraws and does not consider whether it is initial > feed, regular route refresh, or enhanced route-refresh. > > In BIRD 2.0.10, we keep a bitmap of routes that were announced, so we > do > not send withdraws for ones that were not announced before, but we > would > AFAIK send unnecessary withdraws during enhanced route-refresh (for > routes > that were announced before). >
Indeed, BIRD 2.0.10 also sends redundant/explicit withdrawals for previously announced prefixes during ERR. Thank you for the details, Ondrej. Garri
