On Fri, 28 May 2004, Bruce Pinsky wrote:
But the "optimizing" device wouldn't be advertising multiple paths. It would be advertising its selected path from all viable paths based on the selection criteria/policy implemented by the user. The optimizing device can then keep track of what it has advertised and withdraw as appropriate/necessary.
But how do the edge routers, which are passing on all their paths, pass on withdraws? The edge routers would have resend all routes after a withdraw (which current implementations do not do, obviously). Also, the optimising device would not be BGP compliant, an update of a route is an implicit withdraw, so the optimising device could not know, if given additional UPDATE messages for additional prefixes, whether the edge device still had the previous route or not. Essentially, it's impossible to do right with BGP at the moment. If it is possible, I'd love to hear how having previously tried to implement this (and failed). regards, -- Paul Jakma paul@clubi.ie paul@jakma.org Key ID: 64A2FF6A warning: do not ever send email to spam@dishone.st Fortune: If you wish to succeed, consult three old people.