Canada's second largest cable Internet provider has fessed up to throttling non-P2P traffic. Last month, Canadian gamer Teresa Murphy wrote to the country's telecom regulator (PDF) accusing Rogers of throttling games like World of Warcraft, rendering them unplayable.
Investigating the matter, the Canadian Radio-television and Telecommunications Commission (CRTC) contacted Rogers over the complaint and the ISP replied last week, admitting that its service has been throttling certain game-related traffic – albeit unintentionally.
"Our tests have determined that there is a problem with our traffic management equipment that can interfere with World of Warcraft," said Rogers. "We have been in contact with the game manufacturer and we have been working with our equipment supplier to overcome this problem."
The provider explained that it introduced a software modification to solve the issue, but a new problem has arisen following changes to the game. Rogers will have to issue another software tweak to address the new problem, but this won't be ready until sometime in June.
Although the service is mistakenly throttling WoW traffic, Rogers says this anomaly only occurs when users are running P2P applications at the same time. Murphy insists that she doesn't use any P2P software and "many" of her applications remain affected by the issue.
That said, it's worth noting that Blizzard's patch client may be the culprit as it uses P2P technology to distribute game updates among players. You can disable P2P connectivity in Blizzard's Downloader by going to View > Preferences > uncheck Enable Peer-to-Peer Transfer.