BGP graceful restart for software update only?

[Vincent Bernat]

 ❦ 17 octobre 2019 11:29 +01, Neil Jerram <neil at tigera.io>:

> In my setup, an instance of BIRD runs all the time, except for when it
> needs to be restarted for a software update.
>
> For that update scenario, I'd like BGP graceful restart to apply, so that
> the stop-update-restart process does not cause the routes advertised by
> this BIRD to be withdrawn from the rest of the BGP network.
>
> For all other scenarios, however, I don't want any graceful restart.
> Specifically, if there's a break in connectivity to a BGP peer, I want to
> detect that as quickly as possible (with BFD), locally to remove the routes
> learned from that peer, and for that peer to remove routes learned from me,
> all immediately.
>
> Is there some combination of configuration and procedure that can provide
> both of those desires?

You should look at the long lived graceful restart alternative. It will
enable you to do software upgrades without impact without keeping routes
around when a BGP session is cut unexpectedly, as long as you have
alternative routes available.
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