Getting a "portable" /19 or /20

Patrick Evans pre at
Tue Apr 10 17:21:44 UTC 2001

On Tue, 10 Apr 2001, Majdi S. Abbas wrote:

> On Tue, Apr 10, 2001 at 08:27:54AM -0400, Greg Maxwell wrote:
> > The reason they don't allocate /24's is because without aggregation the
> > Internet is not scalable. Perhaps they are being too agressive, but the
> > reasoning is sound.
> Aggregation buys time, that's it.  Aggregation does not make
> the current routing methods any more scalable.
I'd be inclined to think that anything which allows a system to
stretch further without fundamental change implies increased
scalability. That's not to say that it makes it infinitely scaleable,
but is anything?

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-?

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?

Curious (and thinking aloud),


Patrick Evans - Net bloke, indie kid and lemonade drinker
pre at pre dot org              tompaulin dot pre dot org

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