route withdraws on BGP route-refresh

[Stefan Jakob]

I dont know the bird internals exactly, but iirc this is implemented to
save tracking as you mentioned in the code.

According to

RFC 2918

Otherwise, the BGP speaker shall re-
advertise to that peer the Adj-RIB-Out of the <AFI, SAFI> carried in
the message, based on its outbound route filtering policy.

--> No withdraw mentioned

I think in some situations it makes sense to withdraw all known routes, but
the still active ones to create a consistent table on the receiver side.

What is the peer device btw?

Rgds, SJ

P.S.: Sorry for TOFU

Christos Trochalakis <yatiohi at ideopolis.gr> schrieb am Mo., 28. Dez. 2015
09:46:

> On Thu, Dec 10, 2015 at 12:10:35PM +0200, Christos Trochalakis wrote:
> >Hello all,
> >
> >While debugging a route-refresh issue we discovered that when a
> route-refresh
> >is received, bird, instead of just sending an update containing the
> exported
> >routes, also withdraws **all known routes** from its peer. In our case, it
> >withdraws the whole FIRT sending multiple BGP updates. Is this the
> expected
> >behaviour? We are using bird 1.4.5.
> >
> >We believe that the opposite router has trouble processing all those
> withdrawed
> >routes which leads to other connectivity issues.
> >
>
> Any comments on that?
>
> Let me restate the issue, bird withdraws every route in its routing
> table despite the fact that those routes were never exported to that
> protocol. I am not familiar with bird internals so I don't know if bird
> keeps track of the exported routes per protocol.
>
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