For the second time in three years, U.S. regulators face a test of their ability to enforce equal treatment of traffic on the Internet, a dispute that pits long-standing practices for running the Web against the carriers' desire to find new revenue sources and better recover costs.

The U.S. Court of Appeals for the District of Columbia Circuit will hear oral arguments Monday in a suit brought by Verizon Communications Inc. challenging "net neutrality" rules imposed by the Federal Communications Commission in 2011.

At the heart of the case is whether the FCC has the authority to tell broadband Internet providers such as Comcast Corp. and Verizon that they can't give priority to some Internet services or adjust fees and speeds to handle data-heavy traffic like video.

The FCC argues that, except for reasonable network management, such prioritization would undermine the openness that has allowed the Internet to flourish.

Verizon says the FCC is overstepping its bounds.