I think the argument is not about route filtering - it is the implementation method. Genuity uses ip extended access-lists. Everyone else uses prefix-lists. To a purist, the former is more granular, but performs poorly because it is a linked list implementation. The later, while less granular, performs faster by using a trie. It also allows insertion without list rebuilding. Does this matter much? I'm sure there are some that have tested convergence between the two technologies, so I'd welcome comments out of curiosity. They are somewhat anal with their lists as well. If you have a /19, but you want to deaggregate for inbound BGP TE, you will need to send them EVERY route you will send. That can be 64 subnets. For a /16, it is waaayyy worse. Then again, it allows them to know exactly how many prefixes MAY be announced from their customers, which I suppose has its merits. chris
-----Original Message----- From: neil@DOMINO.ORG [mailto:neil@DOMINO.ORG] Sent: Friday, April 12, 2002 2:08 PM To: garlic@garlic.com Cc: matthew@velvet.org; nanog@merit.edu Subject: Re: genuity - any good?
1) Their BGP polices are not as good as others. They force you to register each route you want to advertise rather than allowing you to advertise any reasonable route for your prefixes. According to one of their top people, prefix-lists were unreliable new technology. We gave up and canceled the circuit.
Man I don't know of a provider that doesn't do this - but the fact is this is a good thing.