Bell Canada is at the centre of the net neutrality debate, although other big ISPs —including Rogers Communications — are also shaping internet traffic. (Paul Chiasson/Canadian Press)

The CRTC has launched a public inquiry into the controversial internet traffic shaping practices of Canadian service providers, a move that will prompt a raft of submissions and may result in greater regulation of internet access in Canada by the fall.

The regulator on Thursday released a letter addressed to Bell Canada Inc. and the Canadian Association of Internet Providers, which represents 55 smaller ISPs around the nation, requesting comments on a dispute over traffic shaping between the two parties. CAIP in April complained that Bell had extended its traffic shaping — which slows speeds of internet applications such as BitTorrent — to its members, who rent portions of the company's network to provider their own internet services.

On Wednesday, the Canadian Radio-television and Telecommunications Commission turned down a request from CAIP for a temporary cease-and-desist order but told CBCNews.ca it would launch a public inquiry into the traffic shaping that many large ISPs, including Bell and Rogers Communications Inc., are engaged in.

In its letter on Thursday, the CRTC followed through. Bell and CAIP have until May 29 to submit their comments while other interested parties have until June 12. Bell will then be able to reply to those submissions by June 19 while CAIP will have until June 26 to respond. The CRTC said it will issue its decision within 90 days, or by late September.

Industry observers say the battle over traffic shaping, or "throttling" as it is also known, is really based on net neutrality — or keeping the internet free from interference by ISPs. The service providers say they have no choice but to throttle certain internet applications, particularly those that use peer-to-peer technology, because a small portion of users are slowing down speeds for the majority.

The CAIP-Bell battle has served as a lightning rod for ISP critics, with the NDP, the National Union of Public and General Employees, the Canadian Internet Policy and Public Interest Clinic and the government's Standing Committee on Canadian Heritage all calling for legislation that will enshrine net neutrality. CAIP's application also drew letters of support to the CRTC from Primus Telecommunications Canada Inc., the Toronto-based co-operative ISP Wireless Nomad and more than 1,100 individuals.

Facebook groups have sprung up, and more than 11,000 people have signed a petition in favour of net neutrality legislation. A protest rally on Parliament Hill has also been called for May 27.