On Tue, 10 Apr 2001, Patrick Evans wrote:
Incidentally, how do people feel about the use of default routes to work around the problem of routing table size on tier-2 (!) networks and below? If all "small" edge networks pointed their default at one or more of their upstreams, and filtered their outbound traffic to remove things they wouldn't want to be able to get out anyway, it would be down to the larger NSPs to deal with the issue of routing table size for prefixes beyond a certain length. Doesn't really fix anything, as it reduces control over which path your outbound traffic takes, but I suppose at least it makes sure it'll go -somewhere-?
Pointing default is a stop-gap measure at best for the multi-homed entity on the edge. It does not reduce the size of the global table at all. It simply allows the edge entity to get by with using a less powerful router because they don't have to hold full views in their RIB.
On the flipside, who is actually less concerned about routing table size? The multihomed networks on the edges who can use a default if they want to, and are likely to be carrying less traffic and so have more resources to deal with routing, or the core networks who have capacity problems of their own?
Everyone _should_ be concerned about table size unless they just have money to throw at their routers for grins and giggles. --- John Fraizer EnterZone, Inc