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@e-gerbil.net> ----- Date: Mon, 29 Jul 2002 19:43:32 -0400 From: Richard A Steenbergen <ras@e-gerbil.net> Subject: Re: routing table size To: Brian <bri@sonicboom.org> Cc: "nanog@merit.edu" <nanog@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@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 -----