's announcement that it has a collaborative agreement with Vonage to help ensure it can deliver its services smoothly has drawn criticism.

Comcast has been for slowing or blocking network traffic, but the company it has done so only to alleviate network congestion, without regard to the source of the content.

The two companies said their network operators will be able to communicate directly to address any problems that come up. They will also work together as Comcast tests new methods, which Comcast has said will be "content-agnostic."

Critics have jumped on this week's announcement, saying it calls into question Comcast's network management practices.

Marvin Ammori, general counsel of Free Press, lodged an official complaint with the Federal Commission after media reported that Comcast blocked legal file-sharing. As regulators prepare to investigate the charges, Ammori launched fresh attacks.

"We are baffled as to why it was necessary for Vonage to strike a network management agreement with Comcast to guarantee that their services are not degraded or blocked," he said. "Such anti-competitive, anti-consumer practices are already against the law. And beyond that, Comcast has been on the record as saying that they do nothing to deter their customers' use of VoIP. This announcement calls into question the company's honesty about its treatment of competing services."

He wants to know if Comcast degraded Vonage's VoIP service and if they continue to degrade other services from competitors.

"That these questions remain unanswered by today's announcement is cause for great concern. This collaboration should do nothing to deter the FCC from investigating and stopping Comcast's blocking other Internet services," he said.

A Comcast representative said that the agreement was to ensure that the protocol-agnostic technique doesn't affect services and stressed that Vonage service was not affected in the past because only applications were affected.