Skype Technologies and its parent company, eBay are being sued by Internet phone company and rival Net2Phone for patent infringement.
Net2Phone, which filed its lawsuit last week in US District Court in New Jersey, alleges Skype infringed on its VoIP patent, which was issued to Net2Phone in August 2000.
Net2Phone's lawsuit comes as the voice over IP industry has seen a flood of new entrants from small start-ups to large, established ISPs.
Net2Phone alleges Skype, a wholly owned subsidiary of eBay, violated its "point-to-point IP" patent. The patent calls for the exchange of IP addresses between processing units in order to establish a direct communications link between the devices via the internet.
Skype uses a peer-to-peer technology to operate its VoIP service, whereas companies such as AT&T and Vonage largely use a system that is centrally managed to transfer calls to a traditional phone network.