Data center gear makers battle over patents

Data center gear makers Radware and F5 Networks are at each other again.

Radware, which makes networking products that balance traffic between servers, announced Tuesday that it has filed a lawsuit against competitor F5 Networks for infringing on a patent that was awarded to Radware in April 2004.

The suit alleges that F5 Networks' three-DNS load-balancing product infringes on U.S. Patent No. 6,718,359. The patent awarded to Radware only a few months ago is for technology that determines the proximity of devices within a network when making load-balancing decisions. The technology is used in Radware's flagship product, the Web Server Director.

The suit was filed in the U.S. District Court of New Jersey, where Radware's U.S. headquarters are located. Radware is seeking an undisclosed amount of monetary damages as well as permanent injunctive relief.

"Since inception, Radware has been focused on investment in (research and development) and has continued to demonstrate its leadership and innovation in the application-switching space," Roy Zisapel, CEO of Radware, said in a statement. "Unfortunately, we learned that in order to protect our intellectual property and our investment in R&D, we must, in certain cases, resort to legal action."

F5 Networks said it has not yet received the complaint and declined to comment further.

This isn't the first legal wrangling between the two companies. In March, F5 filed suit against Radware and two other companies--NetScaler and Array Networks--for infringing on one of its patents.

F5's patent covers a technology called "cookie persistence." Cookies are files stored on desktop computers from Web sites that have been visited. F5's technology allows traffic management devices to reunite a computer with a particular server, if the user returns to that site. This feature is often used on e-commerce sites. It allows customers to leave the site and return to the same shopping cart.

Radware had said when the suit was filed that it believed that the claims against it were without merit. The company continues to take that stance, as it fights to disprove the validity of F5's suit, said Jon Rabinowitz, a spokesman for Radware. Neither company would provide an update on the suit.