Net2Phone has sued eBay and its Skype unit, alleging that they infringed on a patent it obtained in 2000.
The company is seeking a permanent injunction as well as unspecified monetary compensation.
Net2Phone charged eBay and Skype with violating U.S. Patent 6,108,704, which describes a method for establishing a point-to-point communications link between two devices via the Internet.
Net2Phone and Skype compete in the VOIP market. They provide services that let users talk to each other via the Internet using either PCs or telephones.
An eBay spokeswoman said the company hadn't been served with the complaint and couldnt comment on the lawsuit. Net2Phone didn't immediately return a call seeking comment. Net2Phone filed the lawsuit last Thursday in the U.S. District Court for the District of New Jersey.
Last year, eBay bought Skype for around US$2.6 billion, snapping up a fast-growing company that had quickly become immensely popular worldwide because of the high quality of its voice communications and user friendly interface.
Founded in 2003, Skype already had around 54 million registered users in 225 countries when eBay announced its intention to acquire it in September 2005.
Net2Phone ended its 2006 second quarter on Jan. 31 with $25.8 million in revenue, up 19 percent from 2005's fourth quarter and 45 percent from 2005's second quarter. The company recorded a net loss of $4.1 million in 2006's second quarter, narrower than the net loss of $10.6 million in 2005's second quarter.