North American Network Operators Group

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Re: Cogent/Level 3 depeering

  • From: Daniel Golding
  • Date: Wed Oct 05 17:12:53 2005

On 10/5/05 1:43 PM, "Jeff Shultz" <[email protected]> wrote:
> Undereducated rant to follow...

Don't ever rant when uneducated. Its like driving angry. (/groundhog day)

> While I realize that the "nuke survivable" thing is probably an old
> wives tale, it seems ridiculous that "the Internet" can't adjust by
> routing any packets that used to go directly from Cogent to Level 3
> though some 3rd (and) 4th (and) 5th set of providers that are connected
> in some fashion to both...

They can. Cogent has transit and is preventing traffic from traversing its
transit connection to reach Level(3). Level(3) does not have transit - they
are in a condition of settlement free interconnection (SFI). The ball is in
Cogent's court. This is not the first time or the second that they have
chosen to partition.

I'm not judging them on this, its a strategic call. However, considering the
have backed down the last couple times, Level(3) would be smart to call
their bluff.

> Level 3 and Cogent can't be operating in a vacuums - if we can get to
> Kevin Bacon in 6 degrees, Level 3 and Cogent should be able to get to
> each other in under 30 hops through other providers.
> And why isn't this apparently happening automatically? Pardon the
> density of my brain matter here, but I thought that was what BGP was all
> about?
> I welcome any education the group wishes to drop on me in this matter.

This is about more than routing protocols. Its about how the Internet (large
I) works. Peers, transit, etc. Not usually found in your favorite BGP book.

Think of the SFI networks in the center. They may not be the largest
networks in terms of traffic, but they have complete mesh SFI relationships
with each other. Then, there are numerous other networks with some degree of
SFI - think of them as a donut surrounding the SFI core. They are
interconnected with a subset of the SFI networks and to each other in order
to "short circuit" those networks who won't perform settlement free
interconnection with them.

Cogent has been attempting to establish SFI relationships with many of
Level(3)'s customers since Level(3) threatened them with depeering. This is
so that a) the partition is less painful and/or b) they'll have to buy less

We will now return this thread to the normal stream of "why is Cogent
broken", "Level(3) is a bunch of meanies", and "my traceroutes feel FUNNY".

- Daniel Golding