routing table size
k claffy
kc at caida.org
Thu Aug 8 00:32:34 UTC 2002
richard; sorry for latency on this one
but might be worth reading andre's:
"Internet expansion, refinement and churn",
http://www.caida.org/outreach/papers/2002/EGR/
which shows that most prefixes in the table come from
large providers. among.andre.conclusions (there is
quite a bit in the paper):
"transit ASes originate prefixes than non-transit ASes
despite the fact that there are five times as many non-transit
as transit ASes.
[see table 16 of paper, p.11]
the number of non-transit multihomed ASes grew from 46% to 49%
from 2000 to 2001, but their share of global routes remained
stable at 30%."
etc etc
there's a lot of stuff in there
not at all a waste of time
k
----- Forwarded message from Richard A Steenbergen <ras at e-gerbil.net> -----
Date: Mon, 29 Jul 2002 19:43:32 -0400
From: Richard A Steenbergen <ras at e-gerbil.net>
Subject: Re: routing table size
To: Brian <bri at sonicboom.org>
Cc: "nanog at merit.edu" <nanog at merit.edu>
On Mon, Jul 29, 2002 at 03:35:19PM -0700, Brian wrote:
>
> the large quantity of /24 announcements is, I suspect, from comapnies just
> large enough to want the benefits of multihoming. You know, 2 t1s on a
> small router, and stuff like that..
Everyone and their mother says they "suspect" that, but noone ever proves
it. Ever wonder why?
Let's take it by the numbers:
Total ASes present in the Internet Routing Table: 13448
Origin-only ASes present in the Internet Routing Table: 11641
Origin ASes announcing only one prefix: 5154
Transit ASes present in the Internet Routing Table: 1807
Even if every origin-only AS was a smalltime company with just enough IPs
for a /24, it would take around 6-7 /24s each to account for the number of
/24s announced.
If someone has done an actual study of where these /24s (and probably /23s
too) come from, please point it out. Until then, my money is on clueless
redist connected/statics, large cable/dsl providers who announce a /24 per
pop/city/whatever to their single transit provider, and general ignorance.
Why attribute to functionality what can easily be explained by
incomptence. :)
--
Richard A Steenbergen <ras at e-gerbil.net> http://www.e-gerbil.net/ras
PGP Key ID: 0x138EA177 (67 29 D7 BC E8 18 3E DA B2 46 B3 D8 14 36 FE B6)
----- End forwarded message -----
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