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Re: T1 vs. T2 [WAS: Apology: [Tier-2 reachability and multihoming]]

  • From: Patrick W Gilmore
  • Date: Tue Mar 29 10:50:18 2005 
On Mar 29, 2005, at 1:24 AM, Richard A Steenbergen wrote:


On Tue, Mar 29, 2005 at 02:23:06AM +0100, Stephen J. Wilcox wrote:

701 is not the most connected, it has only customers and a restrictive
set of peers?
Ok, I'm just bored enough to bite. If we're talking about a contest to see
who has the most number of directly connected ASNs, I think UU might still
win, even with a restrictive set of peers.

Taking a look at a count of customer ASNs behind some specific networks of
note, I come up with the following (some data a couple weeks out of date,
but the gist is the same):

Network ASN Count
------- ---------
701 2298
7018 1889
1239 1700
3356 1184
209 1086
174 736
3549 584
3561 566
2914 532
2828 427
6461 301
1299 243

Which begs the question, what is the largest number of ASNs that someone
peers with? Patrick? :) Somehow I suspect that 701's customer base (702
and 703 aren't included in the above count BTW) overpower even the most
aggressively open of peering policies, in this particular random pointless
and arbitrary contest at any rate.
Of course. There is a difference between "most peers" and "most adjacent ASes".

But it is non-trivial to see which of those adjacencies are transit and which are peering. (Nearly impossible if you define such things on Layer 8, but not impossible if you only include which ASes are propagated to which other ASes.)

At the end of the day, an AS with a LOT of downstream ASes can always beat a well peered AS - there just aren't that many ASes which peer.

--
TTFN,
patrick