Vonage spoke informally to the FCC in February, alleging that an unnamed ISP was blocking some of its VoIP customers' calls.
Voice over Internet Protocol, also known as VoIP or IP telephony, is basically the transport of telephone calls over an internet connection. Until recently, it was a niche phenomenon, but VoIP now has hit the mainstream consumer and business markets, offering cheaper calls and disrupting the dominance of the traditional communications companies.
While VoIP software allows a broadband internet connection to double as a telephone service, ISPs can, if they wish, control the use of that connection by blocking certain network ports. This technique is often used to try to combat unsolicited commercial e-mail, but it can also be used to block the digital data that makes up an on-line telephone conversation.
According to reports, Vonage began an investigation after consumers complained that they could no longer make VoIP calls. The company found that certain ports had been blocked, but managed to reroute its customers' calls temporarily.
Vonage raised the issue with the FCC, which launched its own investigation in February.
According to the communications watchdog, it has now resolved the matter. Publishing a Consent Decree between it and Madison River, a rural telephone operator, based in North Carolina, outgoing FCC Chairman Michael K Powell said:
"We saw a problem, and we acted swiftly to ensure that internet voice service remains a viable option for consumers."
According to the settlement, thought to be the first of its kind, Madison River has agreed to make a voluntary payment to the US Treasury of $15,000. It has also agreed not to "block ports used for VoIP applications or otherwise prevent customers from using VoIP applications."
Madison River has made no comment on the settlement, but Vonage Chief Executive Officer Jeffrey Citron told CNET News.com, "We're very pleased that the commission took very swift action to address the concerns that we had regarding an internet service provider's ability to block our customers' communications with each other".
"This sends a clear message that port blocking will not be tolerated," he added.