[nsp] BGP question

[jlewis at lewis.org]

On Fri, 12 Sep 2003, Kevin wrote:

> A lot of routes from both providers have equal AS paths.
> If one bgp session gets reset all that traffic (the equal AS path
> routes) goes out to provider2 and does'nt reset back to provider1,
> providing that the bgp session to provider1 was the first one to come
> up. I don't have any metrics, weights or localpref on any routes.

At some point, cisco changed the default of bgp bestpath compare-routerid
to "bgp bestpath oldest-route" (AFAIK, that's not a valid command...just
what I think they might call it if it were).  You can go back to the old
behavior by adding bgp bestpath compare-routerid to your router bgp
config.  At least that way, you know how things will route when all your
connections are up...and you can play around with route-maps if you want
to shift some traffic off the best routerid.  With "bestpath oldest-route"
a BGP flap will screw up your balancing if you're just shifting traffic to
certain AS's.

----------------------------------------------------------------------
 Jon Lewis *jlewis at lewis.org*|  I route
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