As first reported by the Associated Press, two key sponsors of legislation that would effectively codify the meaning of "net neutrality" asked the chairman of the Senate Commerce Committee to hold public hearings into the motivations of Comcast and other broadband service providers in filtering certain categories of traffic.

"The phone and cable companies have previously stated that they would never use their market power to operate as content gatekeepers and have called efforts to put rules in place to protect consumers 'a solution in search of a problem,"' reads a citation from a letter to Chairman Daniel Inouye (D - Hawaii) co-authored by Sens. Byron Dorgan (D - N.D.) and Olympia Snowe (R - Maine).

A document that was circulated among congresspeople last week by FreePress.net (PDF available here) claims that Comcast was found to be using a kind of policy traffic switching (PTS) service manufactured for enterprise networks by Sandvine, whose intended purpose is to enable rerouting of certain classes of content for optimum availability. By pretending to be the user to which that content is being rerouted, says the FreePress.net report, Comcast can effectively force that traffic to be dropped.

"The method for doing this is by sending an exact replica of the requested packet back to both parties that includes a reset command (RST), which then drops the connection," the report reads. "In doing so, Comcast masquerades as one of the end users to send the false reset command. By cutting off uploads with other users, the session management tool also cuts off all potential connections with that user, including downloads. This service essentially tells a Comcast customer that they are not allowed to distribute any information and limits the speed at which they can gain access to information from others."

Despite that finding, last week's letter from Sens. Snowe and Dorgan may be more important not for what they complain about but for who they are, and the timing of their complaint. Net neutrality advocates recognize them as the principal sponsors of the Internet Freedom Preservation Act, a measure which went nowhere in the 109th Congress, and was reintroduced last January in the 110th. Progress on the bill has been stagnate since then.

"With respect to any broadband service offered to the public," reads one provision of the current version of S. 215, "each broadband service provider shall... enable any content, application, or service made available via the Internet to be offered, provided, or posted on a basis that...is reasonable and nondiscriminatory, including with respect to quality of service, access, speed, and bandwidth."

Notable co-sponsors of this round of legislation include presidential candidates Sen. Hillary Clinton (D - N.Y.) and Sen. Barack Obama (D - Ill.), former presidential candidate Sen. John Kerry (D - Mass.), and current Senate Judiciary Committee Chairman Patrick Leahy (D. - Vt.). While the Commerce Committee would be the entity responsible for recommending the bill to the Senate floor, Sen. Inouye has not scheduled a markup hearing, although time could conceivably have been set aside for it as soon as tomorrow.

It isn't that Inouye is opposed to the bill; in fact, it probably owes its continued existence to him. In the spring of 2006 when both houses of Congress were under Republican control, then-Chairman of the Commerce Committee Ted Stevens (R - Alaska) successfully drove through a broadband bill that intentionally omitted any mention of net neutrality. But a stroke of bad luck rendered debate on the bill dormant as the 109th Congress passed into history. Immediately after its leadership changed parties the following year, the alternative bill then-Vice Chairman Inouye had upheld as the alternative to the Stevens bill was re-reported as the current S. 215.

Inouye may have been putting progress on the measure on temporary hold to avoid the appearance of pressuring the Federal Communications Commission into taking a stand one way or the other on the issue. By omitting net neutrality from its legislative language last year, the Stevens bill effectively deferred the task of judging net neutrality cases to the FCC, which has since shown a similar reluctance to take up the mantle. Two weeks ago, in a decision championed by Chairman Kevin Martin, it took a stand against taking a stand on the matter, granting AT&T exclusions that would probably be illegal if S.215 had been made law earlier.

Martin's arguments against the need for federal regulation to enforce net neutrality may be picking up steam, and as Inouye knows all too well, steam makes the most noise when constrained.

As an opponent to the Dorgan/Snowe bill, Rep. Paul Gilmore (R - Ohio), wrote last February for The Hill, "Net neutrality has been a strong marketing tool, but it is weak in public policy. Not only is there no true definition of net neutrality; there is no attack on our Internet freedoms. Having a neutral Internet is paramount to everyone, but what Sen. Dorgan and other advocates for new regulations are advocating will do more harm than good."