On Sat, May 18, 2002 at 04:51:27PM -0400, Ralph Doncaster wrote:
One BGP session instead of dozens is more convenient. Maybe not more useful for engineering, but certainly less work than negotiating and configuring a bunch of sessions for bilateral peering.
For smaller ISPs like mine, knowing in advance that you won't get snubbed for peering after connecting to an exchange is the big attraction. Given the dozens of signatories on the AADS MLPA, it looks like they can be quite popular.
Strictly speaking, I don't think a route-server is required to multilaterally peer, but they certainly help. However, there are a couple of big catches, particularly on an ATM or similar switching fabric: 1) One or two sessions, one or two VCs...if they go down, you will lose all your peering at that site. 2) The possibility of blackholing traffic to a peer who you have a downed VC to, but who is still advertising their prefixes to the route server. Additionally, quality of peering does not necessarily correlate to quantity of peering. I'm not going to claim that it's a bad thing to peer with a large number of typically smaller providers, but they don't always account for a statistically signifigant portion of your traffic. If you're going to have to negotiate bilateral agreements to cover the bulk of your peering traffic, why not consistantly negotiate bilateral agreements? --msa