On Mon, Oct 17, 2005 at 09:03:45AM -1000, Randy Bush wrote:
Imagine a situation with no access to any means of direct communication (phone etc). You've got a message to deliver to some person, and have no idea where to find that person. Chances are there's a group of people nearby you can ask. They may know how to find the one you're looking for. If not they may know others they can ask on your behalf. Several iterations later the person is located and you've established a path through which you can pass the information you wanted.
Translated into cisco terms this mean that the FIB is just a partial routing database, enough to start the search and otherwise handle communications in the neighborhood (no more than X router-hops, maybe AS-hops away). When the destination is located you keep that information for a while in case there are more packets going to the same place, similar to what you do with traditional route-cache.
check out "The Landmark Hierarchy: A New Hierarchy for Routing in Very Large Networks"; Paul Tsuchiya; 1989.
great stuff... i have a hardcopy. is it online yet? --bill (checking citesear...)
randy