Route matching filter not exported

[Alexander Zubkov]

Say you have router A having routes with localpref 50, and router B with
localpref 100. When A receives a prefix from B, it will be the best in A's
table. Router A will not try to propagate routes with localpref 50, because
only the best route are propagated (usually). And as the best route is that
was received from B, then B will get nothing back.

On Fri, May 17, 2024, 19:16 Nico Schottelius <nico.schottelius at ungleich.ch>
wrote:

>
> I've a question to the list in regards to iBGP behaviour:
>
> - the router in question imports all routes with a bgp_local_pref of 50 [A]
> - the other routers import eBGP routes with a bgp_local_pref of 100 [B]
> - my assumption would be that the lower preference route would
>    propagated via iBGP, however that is not the case
> - the above router also receive the higher preference routes via iBGP
>
> Is the default iBGP behaviour to *not* export routes with lower
> preference to other routers? That would explain the behaviour I see.
>
> Best regards,
>
> Nico
>
> --
> Sustainable and modern Infrastructures by ungleich.ch
>
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