Back on January 20, we noted here that the FCC had asked Comcast to explain its VoIP service. Comcast had earlier promised that its Internet service would not discriminate among types of content. Its later advertising said that network management efforts might slow other forms of VoIP – but not VoIP  provided by Comcast. The FCC demanded to know how Comcast could protect its own VoIP service without discriminating against other VoIP providers.

Comcast has now replied.

Comcast told the FCC that its VoIP “Comcast Digital Voice” (CDV) service does not run over its high-speed Internet service – or over the public Internet – and so is not subject to its promises concerning network management. Comcast notes that its CDV customers need not even subscribe to its high-speed Internet service. Because other providers’ VoIP does use the public Internet, Comcast says, those services can be affected by overall traffic slow-downs.

Comcasts’s letter, while saying how CDV does not work, discloses almost nothing about how it does work. That reticence may relate to the other issue raised in the FCC’s inquiry: whether CDV should be subject to telephone-style regulation. The more Comcast argues that CDV is not an Internet service, and instead runs over its own separate facilities, the more CDV looks like “telecommunications service,” a status that would trigger additional rules, and possibly payment obligations as well. Comcast insists that question is outside the scope of network management issues, and is properly under consideration in other FCC proceedings.

The Comcast letter is here.