Safeguarding BGP advertisments

[Alexander Zubkov]

Hi Lukasz,

How do you distinguish that the router loses connectivity to the rest of
the mesh? I mean if your mesh is split in parts because of connectivity
problems, which part is "the rest of the mesh"?

AFAIK, bird does not have conditional announces based on presense of other
announces. So I would think about some external daemon, that would monitor,
for example, availability of some route/s in bird or kernel table, and
enable/disable some pipe protocols based on that.

Regards,
Alexander Zubkov

On Mon, Jan 5, 2026 at 11:15 AM Lukasz Jarosz <lukasz at jarosz.in> wrote:

> Hello,
> I am currently working on handling edge cases of BGP advertisements
> malfunctions in my network. I am writing to this mailing list to confirm
> that I haven’t missed BIRD native solution.
> Issue in question is when BGP router loses its connectivity to rest of the
> internal mesh and still advertise routes to upstreams (I use manual
> aggregates, because my internal routes have very long prefixes and address
> space is non continuous).
> AFAIK (these were my ideas how to implement safeguards):
> - I can’t use BFD to guard advertisement of static blackhole route,
> - I can’t use BFD to guard pipe protocol.
> As I understand my only solutions are to use external monitoring tooling
> to disable advertisements to upstreams or restructure BGP configuration in
> a way that externally advertised prefixes come to BIRD routers through
> channel that is dependent on connection to internal mesh.
> Have I missed something?
>
> Best regards,
> Lukasz Jarosz
>
>
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