“I think it has the appearance of the F.C.C. kicking the can down the road,” said Derek Turner, research director for Free Press. “The job of the F.C.C. is to protect the public interest. That includes making the really hard decisions that may anger some powerful industry incumbents.”

F.C.C. officials said the request for additional comments was tied in part to the Google-Verizon proposal. But the agency was also trying to guard against generating unintended negative consequences, and to ensure that any rules it did adopt would not be thrown out on a technical claim that the commission had not followed federal rule-making procedures.

“As we’ve seen, the issues are complex, and the details matter,” Julius Genachowski, the F.C.C. chairman, said in a statement. “Even a proposal for enforceable rules can be flawed in its specifics and risk undermining the fundamental goal of preserving an open Internet.”

The F.C.C.’s proposed rules on preserving an open Internet were also blocked by an appeals court decision in April that struck down the commission’s legal basis for enforcing net neutrality  the concept that no legal content or application should receive priority on the Internet or be blocked by an Internet service provider.

The commission has floated a separate proposal that would reclassify broadband Internet service under a portion of the Communications Act that regulates telephone and other telecommunications services.

Currently, Internet access is defined as an information service, a category that is lightly regulated under the act. The F.C.C.’s reclassification proposal is intended in part to allow the commission to enforce net neutrality.