Verizon filed a legal challenge Thursday to net neutrality rules passed by the FCC less than a month ago, arguing the regulators overstepped their authority.

Verizon's suit, filed in a federal appeals court in Washington, D.C., wasn't unexpected, but it is extraordinary in that the rules have not yet gone into effect.

The still-proposed rules prohibit cable and DSL companies from blocking or slowing down legitimate internet traffic and require them to allow users to use their choice of devices, applications and online services. Mobile carriers face fewer restrictions but are not allowed to block VOIP applications such as Skype and may not block websites in their entirety.

Verizon is the country's largest mobile-phone carrier and is one of the country's largest broadband providers to homes. The company has long fought against the FCC's net-openness rules, including those attached to valuable 4G spectrum it bought in 2008. However, Verizon and Google together issued a controversial compromise policy statement this summer that proposed such rules for cable and DSL providers, while exempting wireless companies.

Public interest groups immediately denounced Verizon for challenging rules that aren't nearly as strong as the groups had pushed for.

"Verizon’s decision demonstrates that even the most weak and watered-down rules aren’t enough to appease giant phone companies," said Aparna Sridhar, policy counsel for Free Press. "It’s ironic that Verizon is unhappy with rules that were written to placate it, and it’s now clear that it will settle for nothing less than total deregulation and a toothless FCC in the relentless pursuit of profit.”

A challenge to the FCC's regulations was inevitable. An earlier version of these rules, which were put in place by the Bush Administration's FCC head Michael Powell, collapsed under a court challenge from Comcast. The FCC argues that the new rules are on a stronger foundation, but they seemed to please no quarter.

Public Knowledge, a D.C. group that pushed for very strong rules, laid into Verizon for not waiting for the rules to come into effect and for trying to get the same judges on this case as handled the Comcast one.

"Verizon is trying to be too cute in trying to pick not only the venue for the challenge to the rules, but also to pick the judges to hear it," said Harold Feld, an attorney for Public Knowledge. "The court should see through this ploy and reject Verizon’s attempt to pick the home field for its appeal."

House Republicans have accused the FCC of overreaching, while Sen. Al Franken has accused the agency of being a feckless toadie of business.

But the rules remain vulnerable since the FCC declined to put internet broadband providers in the same regulatory bucket as the phone company as it had been before the Bush administration deregulated them. The FCC floated that possibility last spring, but it drew howls of outrage from industry groups and Congress who foresaw heavy regulation, despite promises from the FCC to use a light touch.

See Also:- FCC Passes Compromise Net Neutrality Rules