Ondrej Zajicek <[email protected]> writes:

> I have two questions w.r.t. this sequence of events:
>
> 1) How is router restart and seqnos supposed to be handled without
> waiting for route timeout?

This is indeed a problem. Babeld sends a wildcard retraction before
shutting down (which I just taught Bird to handle; will send off the
patch tonight after testing it properly). I can add in sending such
retractions when an interface goes away as well.

But this problem can still occur on a crash, or if the retraction was
lost for whatever reason. In that case, waiting for things to expire is
the only option.

> 2) If a route is selected, then becomes unreachable/retracted, and
> there is no other route to be selected, is it still considered
> selected? I would say that no as the selection process (3.6) forbids
> retracted routes to be selected, but the BIRD implementation keeps the
> old selected route (now unreachable) in this case.

It is kept for a while (and installed as unreachable) to avoid transient
routing loops. This is described in section 2.8 of the RFC.

-Toke

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