The recent spat between Level 3 Communications, Inc. and Cogent Communications, Inc illustrates how the Internet is more fragile than most people would suspect. In this case the problem is not technical but turns on the often obscure business arrangements that keep the bits flowing around the world. In a story that got little coverage in the press except for a brief article in The Boston Globe and Slashdot, Level(3) decided it no longer wanted Cogent among the exclusive club of Internet service providers who share traffic without demanding payment from each other.
On October 7, Level(3) decided to disconnect their peering connections with Cogent. While they may have been privately negotiating for months, Level(3) did not give any advance notice at all to its customers. As a result, many people woke up to find that parts of the Internet were no longer connected to each other. For example, customers of Time Warner Roadrunner (which was serverd by Level(3)) suddenly got errors when they tried to connect to Web sites that were on Cogent's network.
Why did this happen? If you are a user of the Internet, the money you pay for your service goes for two things: the transport provided by your local cable or phone company, and the cost for that company to connect to the Internet at large. The latter cost gets passed up to increasingly larger companies until it reaches an exclusive club of Tier 1 Service Providers who are so big that they don't need to pay anyone above them. Rather, they trade traffic amongst themselves with no exchange of money. Although these "peering" arrangements are really a bunch of seperately negotiated bilateral agreements, it all works out fairly well as long as each party thinks it is getting a fair exchange. In the Level(3)/Cogent case, Level(3) apparently thought it was getting the short end of the stick.
While none of the players are talking publicly about the details, the conjecture on The North American Network Operators' Group was that Cogent has signed up lots of content providers while Level(3) had lots of content consumers. Because of the hot potato routing used in the Internet, most of the cost is born by the ISP receiving the traffic, in this case Level(3). This imbalance was doubtless more aggravating becuase Cogent was underpricing Level(3) in the marketplace. What resulted was a poker game in which both sides gambled the the other side's customers would complain more loudly. In the first round Level(3) blinked first and turned the connection back on, but they promised to disconnect Cogent again on November 9, so stay tuned for more details.
Full disclosure: Convoq uses Cogent as one of its providers. We have our own AS and use Border Gateway Protocol (BGP) so most of our customers were not affected, but we do appreciate the way declining bandwidth prices allow us to support voice and video in a way that would not have been possible a few years ago.
