In response to accusations by the Associated Press and EFF that it interrupts certain P2P traffic on its network, Comcast denied blocking BitTorrent traffic. Instead, the nations largest ISP said that it employs traffic shaping technologies to manage bandwidth during peak traffic times.
According to the Associated Press, however, a Comcast spokesperson acknowledged that it does exactly what the AP and EFF accused it of doing:
On Tuesday, Mitch Bowling, senior vice president of Comcast Online Services, added a nuance to that statement, saying that while Comcast may block initial connection attempts between two computers, it eventually lets the traffic through if the computers keep trying.
"During periods of heavy peer-to-peer congestion, which can degrade the experience for all customers, we use several network management technologies that, when necessary, enable us to delay — not block — some peer-to-peer traffic. However, the peer-to-peer transaction will eventually be completed as requested," Bowling said.
The explanation is not inconsistent with the AP's tests. In one case, a BitTorrent file transfer was squelched, apparently by messages generated by Comcast, only to start 10 minutes later. Other tests were called off after around 5 minutes, while the transfers were still stifled.
Frequently my file transfers using AIM to other Comcast customers are slowed to a crawl, apparently by Comcast's traffic shaping. Too bad there is no Verizon FIOS or RCN in my building.