Cogent Communications (CCOI) has discontinued a traffic-swapping agreement with Telia, a major European broadband network. The dispute makes it harder for customers using one network to connect to web sites hosted on the other. These arrangements, known as peering, rarely attract wide attention. When they do, it usually involves Cogent, which is known primarily for its cheap bandwidth and has previously been involved in peering disputes with Limelight Networks (LLNW) in 2007, Level 3 (LVLT) and France Telecom in 2005 and AOL in 2002.
Peering allows providers to exchange traffic with one another at no cost (or low cost) by establishing direct connections between their networks, instead of routing traffic across the public Internet. Peering is often free as long as the amount of traffic exchanged is not out of balance, providing substantial cost savings for bandwidth for high-traffic sites and networks.
Sune Christesen and GigaOm have posted a copy of a letter Telia has sent to its customers. An excerpt:
Cogent has decided not to exchange traffic directly with TeliaSonera's AS 1299 or indirectly with AS 1299 through a third-party provider. As a result, Cogent has partitioned the Internet and disrupted the flow of traffic between Cogent and TeliaSonera customers. While this has a negative impact on some users of the Internet, this effect is the result of Cogent's decision and is unfortunately beyond TeliaSonera's control.
When a peering relationship goes sour, it's usually because of an imbalance in the volume of traffic exchanged. If the two sides can't work things out, one party may pull the plug. This is often a negotiating tactic, with the resulting screams from end users providing an incentive to compromise. An example is the 2005 dispute in which Level 3 de-peered Cogent, after which the two parties struck a modified agreement which spelled out financial compensation if the traffic exchange got out of whack.