Net2Phone has sued eBay and its Skype unit, alleging that they infringed on a patent it obtained in 2000 and seeking a permanent injunction as well as unspecified monetary compensation.

Net2Phone charged eBay and Skype with violating US Patent 6,108,704, which describes a method for establishing a point-to-point communications link between two devices via internet protocol.

Net2Phone and Skype compete in the VOIP (voice over internet protocol) market.

An eBay spokeswoman said the company hasn't been served with the complaint and can't comment on the lawsuit. Net2Phone didn't immediately return a call seeking comment.

eBay bought Skype for around $2.6 billion last year. Founded in 2003, Skype already had 54 million registered users in 225 countries when eBay announced its intention to buy it in September 2005.

Skeptics say eBay paid too much for Skype, but eBay contends that VOIP is a key ingredient for its online marketplace, a service that will significantly improve the communication between buyers and sellers.

Skype's business and usage continue to grow quickly. It ended its 2006 first quarter on March 31 with almost 95 million registered users. Its revenue jumped 42 per cent to $35.2 million from 2005's fourth quarter. In 2004, it had revenue of around $7 million.

Meanwhile, Net2Phone ended its 2006 second quarter on January 31 with $25.8 million in revenue, up 19 per cent from 2005's fourth quarter and 45 per cent from 2005's second quarter.