Honest Cogent opinions without rhetoric.

Todd Underwood todd-nanog at renesys.com
Wed Mar 8 16:29:56 UTC 2006

dan, all,

On Wed, Mar 08, 2006 at 09:35:15AM -0500, Daniel Golding wrote:

> If your choice is between Cogent and some other provider, you are making a
> mistake. Cogent (and other low cost transit providers) can be part of a
> balanced stable of transit providers. Folks who single-home to Cogent
> deserve whatever Darwin delivers to them.

we referred to this in the presentation about the depeering (
http://nanog.org/mtg-0510/underwood.html ), but just to update it: i
see that that 258 ASes are relying on cogent for all or substantially
all (>95%) of their connectivity to the Internet.  many of these may
be multi-homed and just never using their backup connection, but
still, that's a lot of people trusting cogent for their day-in day-out
connectivity.  i'm not a cogent cheerleader or basher (or customer).
just here to provide concrete, objective info.

also, in response to a couple of questions that i've taken in private
about the rankings: the good part about these network rankings that
we've been doing is that they are objective, repeatable and difficult
to falsify. this is in contrast to traffic stats, that are notoriously
unreliable (read: false, lies) and difficult to confirm.  there are
certainly a couple of potential optimizations available in the future,

we think that the current customer-base rankings may under-represent
consumer broadband networks (such as comcast) , in part because these
networks tend to generate substantially more traffic for each amount
of prefix-space than do many other kinds of networks.  we're thinking
about ways to model that difference.  the other reason we think that
they may under-represent these networks is because many of them still
use lots of different ASes--BellSouth is a good example here.
although we could (and probably will) fix that with some AS clustering
algorithms, the ASes in question could (and probably will) fix that by
consolidating ASes, too. :-)

the current rankings are accurate with respect to routing and are a
reasonable approximation of some of the other metrics that people wish
could be directly measured (traffic, market power, etc.).  [people
should also be aware that we're producing 5 different rankings that
measure different kinds of things, so just focusing on the
customer-base ranking may be a mistake].


todd underwood                                 +1 603 643 9300 x101
renesys corporation                            chief of operations & security 
todd at renesys.com                               http://www.renesys.com/blog

More information about the NANOG mailing list