Mandatory DSL line-sharing is a common practice in other developed countries, and was in the US as well until an FCC decision ruled that DSL was an "information service" and not subject to the rules. Line-sharing is what enables much of the competition in other countries and allows small ISPs like Wireless Nomad to thrive in Canada and offer innovative services. But line-sharing has its drawbacks; chief among them, of course, is that without control of the line, an ISP is not ultimately in control of the service it is selling. Canadian DSL resellers learned that lesson the hard way this week as ISPs learned that Bell Canada now runs traffic-shaping hardware even on the lines it resells.

Readers at Broadband Reports noted the issue earlier this week as owners of small ISPs suddenly found that their customers were having traffic throttled, even though the ISPs were vehemently anti-throttling. The problem was compounded by the fact Bell Canada did not apparently tell the ISPs that it was about to make the change. The company has subsequently confirmed the throttling and says it should be fully in place by April 7.

The throttling itself is not uncommon in Canada, where network neutrality has not been the heated issue it has become in the US. Cable operator Roger has been shaping P2P traffic for years, and when encryption became common, simply throttled all encrypted network traffic in 2007. Shaw is also reported to be a fan of throttling, but Bell Canada's move is potentially more incendiary because it now affects wholesellers and retailers of Bell service.

Details of Bell Canada's implementation remain scarce or contradictory, but the timing of the news is interesting, coming as it does just days after the CBC announced its own plans to use BitTorrent to distribute Canada's Next Great Prime Minister. Given P2P's obvious (and growing) legal uses, transparency is going to be an important part of any throttling scheme. If a network operator makes clear that BitTorrent speed is reduced after 30GB a month, for instance, that's one thing; if the throttling remains mysterious and arbitrary, that's another.

Hitting back at throttling

Users are fighting back, though. Canadian law professor Michael Geist points to a Google map that Canadian users have been collaboratively using to comment on filtering. Here in the US, where Comcast is under FCC scrutiny for its own traffic-shaping practices, much has been made of the need for transparency. But until transparency truly arrives, the P2P video company Vuze is developing an open- source plug-in for Azureus that makes it easy to sniff out ISPs using Comcast's "TCP reset packets" P2P blocking scheme. Vuze tells Ars that the plug-in "monitors network connections, and every 10 minutes, it measures the number of reset TCP connections, displaying the results to the user. If they then click the "share results" checkbox, their results go to Vuze's central server that aggregates the results and compares them across ISPs." Wikis have also been set up to track ISP traffic-shaping practices around the world.

Taken together, such measures show that consumers (and, increasingly, legitimate businesses like Vuze and even NBC Universal) at least have the tools to shine a light into some traffic-shaping's darker corners. But what good is this sort of transparency without a truly competitive market? Bell Canada's move, should it turn out to affect all wholesalers and resellers of Bell's DSL service, could mean that many of the options consumers once had in the DSL market are suddenly subject to throttling, and on Bell's terms.

That leaves lobbying action and government regulatory bodies, both of which are slow to achieve results, and are certainly places where telcos and cable operators deploy huge resources to prevent "bad" decisions from being made.

Damien Fox, one of the cofounders of Wireless Nomad mentioned above, tells Ars today that the situation is "unacceptable, and a symptom of Bell's arrogance. It is blatant censorship of our users' Internet connections, and Bell is not going to escape a fight on this one. Either they back down, or independent providers should go to the CRTC, or the Federal Court if need be, to get our Internet connections unblocked."

We'll keep an eye on this one as it develops.