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Re: a radical proposal (Re: protocols that don't meet the need...)
From: Andre Oppermann <nanog-list () nrg4u com>
Date: Wed, 15 Feb 2006 21:41:53 +0100


Edward B. DREGER wrote:
CA> Date: Wed, 15 Feb 2006 14:04:24 -0600
CA> From: Chris Adams

CA> There's a difference: computers (routers) handle the O(N^2) routing
CA> problem, while people would have to handle the O(N^2) cooperative AS
CA> problem.

0.1 ^ 2 < 5000

One must also consider the scalar coefficient.

Err, the problem is not the number of AS numbers (other than having to
move to 32bit ones).  The 'problem' is the number of prefixes in the
routing system.  The control plane scales rather well and directly
benefits from Moore's law.  With todays CPU's there is no problem
handling 2 million routes and AS numbers.  Absolutely not.

Things get a bit more hairy with the forwarding plane though.  The
faster the link speed the less time it has per lookup and the larger
the routing table the more routes it has to search in that ever shrinking
amount of time.

You see, saving on AS numbers is not really going to help much where it
matters.

IMHO, and I have stated this before, the best way to handle the route
issue is to hand out IPv6 /32 for multihoming and make it the routeable
entity.  Perfect matches in hardware are pretty easy to do for large
numbers of them compared to longest match.  On the plus side perfect
match scales much better too and can be done in parallel or distributed
within a routing chip.  Doing the same for longest-match requires a lot
more effort.  With perfect-match having 2 million routes is not much of
a problem too.

--
Andre


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