United States wireless telco Sprint Nextel has filed a suit in Kansas federal court against Vonage , Voiceglo Holdings, and theglobe.com (Voiceglo’s parent), claiming infringement of seven Sprint patents relating to voice over data packet technology, including VoIP. Injuctions against Vonage and Voiceglo, as well as unspecified damages, are being sought.

Vonage and Voiceglo are big business. Vonage is the largest United States independent VoIP service, with over 1 million subscribers, and is thought to be preparing for an IPO. Its service is designed to replace traditional telephones. Voiceglo offers a computer-based system that allows voice calls between computers or from computers to traditional phones, adopting a similar business model to Skype.

What does Sprint Nextel hope to gain from this lawsuit? Sprint has admitted that it has not created VoIP technology — just technology for facilitating it. With all the emerging VoIP companies out there, Sprint stands to gain a great deal if it compels VoIP providers to licence fundamental technology from it, however.

Another motivation for the lawsuit is suggested by the the Business Week tech blog:

…I wouldn’t be surprised if Sprint is bickering with Vonage simply to get a better feel for the worth of Vonage’s intellectual property portfolio — and then to make up.

In other words, Sprint sees Vonage as a potential takeover target. Which is probably why the lawsuit has been launched at what is probably an extremely sensitive time at Vonage, should it be true that an IPO is in the wings.

An interesting map of the companies and issues involved in this dispute and in the VoIP space generally is presented by CNET here.