[c-nsp] bgp bestpath compare-routerid

Daniel Roesen dr at cluenet.de
Tue Oct 5 18:53:17 EDT 2004

On Tue, Oct 05, 2004 at 02:29:53PM -0500, Brian Feeny wrote:
> So by using compare-routerid, I can get somewhat of a 
> semi-deterministic way of how things will lay out, and make
> changes based on that (I realize AS_PATH's can change over time
> based on peering, etc).
> Any ideas of why this is good / bad?

Well, it is a trade-off thing. It buys you deterministic best
route selection, but costs you stability. As far as I remember,
NOT implementing the router-id check in the path decision process
was to avoid BGP updates.

If you are a stub AS, and are OK with the added volatility, then
there's no reason not to do it as far as I can see. If you are a
major transit ISP though, you should consider the effects on your
downstream customers.

Best regards,

CLUE-RIPE -- Jabber: dr at cluenet.de -- dr at IRCnet -- PGP: 0xA85C8AA0

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