Updated from 6:21 p.m. EST

Just a day after Apple ( AAPL) debuted its splashy new iPhone, Cisco Systems ( CSCO) said it is suing the company for infringing on Cisco's iPhone trademark.

The San Jose, Calif.-based networking giant filed a lawsuit in the U.S. District Court for the Northern District of California against Apple on Wednesday, seeking to stop it from using the iPhone name. Cisco is seeking injunctive relief.

Cisco obtained the name in 2000 after it acquired Infogear, which previously sold iPhone products. Infogear originally registered the trademark in March 1996.

Linksys, a division of Cisco, has been shipping an iPhone line of products since early 2006.

"Cisco entered into negotiations with Apple in good faith after Apple repeatedly asked permission to use Cisco's iPhone name," Mark Chandler, senior vice president and general counsel of Cisco said in a press release late Wednesday. "There is no doubt that Apple's new phone is very exciting, but they should not be using our trademark without our permission."

No agreement had been finalized between the two companies when Apple CEO Steve Jobs introduced the iPhone to thousands of Apple fans at the company's MacWorld on Tuesday in San Francisco.

"The potential for convergence of the home phone, cell phone, work phone and PC is limitless, which is why it is so important for us to protect our brand," Chandler said.

A spokesperson for Apple wasn't immediately available for comment.

"Steve Jobs was obviously busy rehearsing the keynote presentation, that's why he didn't get back to them," joked Mike McGuire, an analyst with Gartner who covers digital media.

McGuire said it would not be in the best interests of either company to "drag this out."

"Anything that involves such a large number of lawyers like that, anything could happen, but I do not believe Apple would want for this to stretch out very long at all," McGuire said in an interview.

"Clearly, it has to be dealt with before they can ship the thing," he said. "If the lawsuit did delay the launch, then I think that would say a lot about where we're at with trademark law and intellectual property law in general."

Shares of Apple, which set an all-time closing high in the regular session, slipped 44 cents to $96.56 in after-hours trading; Cisco shares gained 4 cents to $28.72.