Re: Getting a "portable" /19 or /20

[John Fraizer <nanog () Overkill EnterZone Net>]

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