On Wed, 18 Feb 2009 22:12:02 GMT, Rod Beck said:
From the fine article:
"In greedy routing, a node passes information to the neighboring node that is closest to the final destination in an abstract space called hidden metric space." Sounds suspiciously like "throw the packet at the router that's got the shortest AS path to the destination" doesn't it? You don't need to know the entire topology to know router X is 2 AS's closer to the dest than router Y once X and Y have been loaded with the "hidden metric space" known as a BGP update ;) I'm not sure this article is actually telling us anything we didn't already know. Now if there was a way to compute those distance metrics without global knowledge - if there was only an algorithm that only cared about what was "upstream" from a locally connected link and whether it was connected. Say, we could call it a link-state routing protocol.... Now if they were able to actually develop a link-state protocol that involved *only* local adjacency announcements and not flooded announcements, *that* would be something... But what I see here is "if somebody developed that, we'd be able to route more efficiently". Maybe there's some critical insight in the paper that Physorg managed to totally not mention, I dunno.