When federal regulators approved Comcast Corp.’s takeover of a 51 percent stake in NBCUniversal last year, they imposed various conditions on the nation’s largest cable TV provider, including those that would protect the burgeoning Internet video marketplace and promote the spread of broadband Internet access.

One of the conditions called on Comcast to offer stand-alone broadband Internet access services at reasonable prices and with sufficient bandwidth to customers who don’t pay to get Comcast’s cable TV service. The Federal Communications Commission launched an investigation after it received information suggesting that Comcast wasn’t adequately marketing the service.