F5 Networks has been awarded a patent for its Cookie Persistence technology and has filed an infringement lawsuit against three companies for violating the patent.

The Seattle company has been awarded U.S. patent number 6,473,802, entitled "Method and System for Storing Load Balancing Information with an HTTP cookie." This technology stores a cookie on a customer's computer to allow that customer to reconnect to the same server he or she previously visited on a Web site. A shopper, for instance, can go back and access information stored in a "shopping cart," F5 said in a statement Friday. Without its technology, the customer would go back to the Web site but may be directed to another server which does not have the necessary information.

Having been awarded the patent, F5 has filed a patent infringement suit against Array Networks, NetScaler and Radware in the U.S. District Court in Seattle, looking for "permanent injunctive relief and damages," it said.

The IDG News Service is a Network World affiliate.