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
Now the question is, of that 70% figure, how much of that is aggregateable? --Phil -----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of Paul Schultz Sent: Monday, July 29, 2002 10:28 PM To: nanog@merit.edu Subject: Re: routing table size On Mon, 29 Jul 2002, Richard A Steenbergen wrote: per
pop/city/whatever to their single transit provider, and general ignorance.
To ease my own curiousity I kludged together a script to look at how much of /24 land is taken up by smalltimers announcing few prefixes, and larger networks announcing many. My last snapshot of the routing table is from the end of june, so may be (very slightly) outdated. Data from June 29, 2002 Total /24's: 61931 ASN's announcing /24's: 8645 Number of /24's announced by AS breakdown /24's ASN Count ======= ========= 1 3474 2 1662 3 740 4 533 5 377 6 236 7 203 8 164 9 113 10-14 421 15-19 184 20-29 199 30-39 101 40-49 57 50-59 41 60-69 29 70-79 21 80-89 12 90-99 11 100-149 20 150-199 17 200+ 29 Those "basement multihomers" announcing 1-5 /24's only account for ~20% of the total number of /24's out there. Multihomers with slightly larger basements (6-10 /24's) account for 10% of the total. That leaves the remaining 70% of /24's in the DFZ announced by people pushing out over 10 /24's from their AS. Interpret however you will (I tend to lean towards Richard's take on the situation.) - Paul