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