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

[Patrick W Gilmore <patrick () ianai net>]

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