Safeguarding BGP advertisments

[Alarig Le Lay]

On Mon 05 Jan 2026 23:44:25 GMT, Lukasz Jarosz wrote:
> I have N edge routers, which all of them announces exactly the same
> prefixes to different upstreams. They are interconnected to downstream
> segments and between each other with common switching fabric that
> backs up „edge router mesh” (in iBGP sense obviously). If edge router
> loses connectivity to upstreams it just stops advertising to
> downstreams and other neighbors. Case of losing connectivity to either
> downstreams or other neighbors only causes suboptimal routing, but
> when edge router loses connectivity to switching fabric it would
> become kind of zombie - advertising aggregated routes to prefixes that
> it does not have access. This is also condition in which router ends
> up when is sole survivor of failure, but I don’t think this would be
> recoverable remotely. Also I know this might seem far fetched for
> some, but jackasses with excavators already ruined many days of my
> life ;)

I avoid announcing the routes directly from the edge routers. I originate
them from RRs, so when the edge looses the connnection to the backbone,
the announcement is naturally withdrawn.

-- 
Alarig