Several of Canada’s biggest Internet service providers are defending their decision to “throttle” subscribers who use file-sharing protocols as a week-long regulatory hearing on the controversial issue nears completion.

Rogers Communications Inc. told a Canadian Radio-television Telecommunications Commission panel today that such traffic management practices are necessary to keep a small number of heavy-bandwidth users - particularly those using peer-to-peer protocols such as BitTorrent to swap large music and video files - from overwhelming their networks.

Failing to do so, it argued, would result in congestion and degraded service levels for all subscribers.

“This is not a network neutrality issue,” said Ken Engelhart, Rogers’ senior vice-president of regulatory affairs, referring to charges that the cable giant is improperly interfering with its subscribers’ ability to access content on the Web.

“The whole premise behind this (network neutrality) stuff is that we’re doing this to favour our video business,” he said. “But if that’s true, why … wouldn’t we be managing video streaming too?”

Bell Canada Inc. is expected to make a similar argument when the hearing resumes tomorrow for its final day.

Several ISPs have argued that the increasing popularity of online video, including user-generated content on YouTube, has resulted in an explosion of Internet traffic in recent years.

While they claim network investments are being made to accommodate the extra weight, they have also singled out peer-to-peer file sharing as an application that requires active management because of the way it uses available bandwidth.

“Traffic management is critical to providing Internet service that is fast, reliable and affordable,” said Ken Stein, the senior vice-president of corporate and regulatory affairs for Shaw Communications Inc.

But Web-based companies such as Google argue that targeting certain types of Internet applications and not others will limit the development of potentially beneficial products and services on the Web.

Consumer groups, meanwhile, have expressed concern that the technology used by ISPs to sniff out peer-to-peer traffic could be used to monitor subscribers’ individual surfing habits and develop pricing models that favour some types of Web surfing over others.

They have also argued that ISPs need to be more transparent about their use of traffic management tools, noting that the advertised speeds for many Internet packages don’t account for network congestion or traffic management techniques.

Engelhart told the CRTC that, if compelled, Rogers could disclose to subscribers the speeds that can be expected when uploaded traffic is throttled, although he said the company would prefer to keep such information confidential for competitive reasons.

The “throttling” issue landed on the CRTC’s plate last year after a group of wholesale Internet providers complained that Bell was applying its traffic management policies to their customers. While the CRTC ultimately ruled in Bell’s favour, it committed to holding a hearing on the larger issue of traffic management this year.

The various stakeholders in the debate have until July 24 to make their final submissions with the CRTC. Any decision could take up to 10 months, a CRTC spokesperson said.