Randy Bush wrote (on Nov 03):
if you don't, then traffic from cust2 to customers of exchange peers will trombone across the expensive link.
and back again, and back again, and ...
Only if you're mad enough to try to run BGP across a network with forwarding devices in the middle that don't. Even a monetary argument for this weak. Routing decisions in a routing domain need to be deterministic otherwise you risk the loops you mention. In a small network you may be able to get away with it. I personally have better things to worry about and I am sure most people do too. IGP's rarely make the same decisions as EGP's. They don't have the same data to base their decisions on. Chris. -- == chris@easynet.net T: +44 845 333 0122 == Global IP Network Engineering, Easynet Group PLC F: +44 845 333 0122