LAS VEGAS, NV – The Federal Communications Commission will investigate complaints that Comcast discriminates against users by throttling their bandwidth when it suspects files are being shared online, Chairman Kevin Martin announced Tuesday during an appearance at the Consumer Electronics Show.In November, a coalition of consumer groups asked the FCC to investigate Comcast’s data-discrimination practices. Two of the groups also asked the commission to fine Comcast $195,000 for every affected subscriber, according to an Associated Press report.

Comcast is the second largest Internet service provider in the U.S.

In its own investigation last year, the Associated Press discovered Comcast hindered file sharing among subscribers who used BitTorrent, a popular peer-to-peer technology. Subscribers also complained Comcast throttled the bandwidth of users of other popular file-sharing programs.

Comcast has denied it blocks traffic, but after the AP confronted it the company acknowledged it “delays” some traffic between computers it suspects of trading files. Comcast said the practice is necessary to improve network availability for all users.

Internet watchdog groups have called the practice outrageous and said Comcast, as a so-called public utility, should not be able to decide what is “good” and “bad” traffic. Not all P2P traffic is used to share illicit materials, the groups argued: Some content producers use file-sharing networks for the legitimate distribution of their games, video, and music.

By investigating Comcast, the FCC has a chance to convince the public it is dedicated to “network neutrality,” or the idea that all traffic is created equal. A broadly stated commission policy supports the idea — with an exception for “reasonable traffic management” — but the policy hasn’t been tested.

One significant test of whether Comcast’s policies embody “reasonable traffic management” is whether the company discloses them publicly, Martin said.

Based on Comcast’s answer to subscribers who complained about their bandwidth shrinking, it doesn’t seem the company is particularly transparent in that area.