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Re: routing table size

  • From: k claffy
  • Date: Wed Aug 07 20:35:59 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 <[email protected]> -----
  
    Date: Mon, 29 Jul 2002 19:43:32 -0400
    From: Richard A Steenbergen <[email protected]>
    Subject: Re: routing table size
    To: Brian <[email protected]>
    Cc: "[email protected]" <[email protected]>
    
    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 <[email protected]>       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 -----