On 8/18/13 6:33 PM, Christopher Karel wrote: > > I'm hoping you guys might be able to offer some advice or insight > into a BGP problem I've got. I've noticed some strange routes between > our network, AS27270, and AS22943. It looks like both our networks are > dual homed. One ISP as the primary, and the other used as a backup, > with path prepending to prevent it from actually being used except in an > outage. However, our route to 22943 appears to be using their backup > link. (27270 4323 7018 22943 22943 22943 22943 22943 22943 22943 22943 > 22943 22943 22943) Which is strange, because we can reach their primary > ISP without any such rigmarole.
It's not strange. AS path prepending like a typewriter monkey on crack doesn't mean anything and certainly does not a "backup" link make. Localpref can and will make it the best path anyway. ~Seth
