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Each Patent Claim Need Not Address Every Problem with Prior Art Stated in Specification

August 05, 2003

Decision icon Decision

Last Month at the Federal Circuit - September 2003

Judges: Plager (author), Bryson, and Prost

In Resonate Inc. v. Alteon Websystems, Inc., No. 02-1201 (Fed. Cir. Aug. 5, 2003), the Federal Circuit vacated the district court’s claim construction and remanded for further proceedings after construing the claims.

Resonate, Inc. (“Resonate”) owns U.S. Patent No. 5,774,660 (“the ‘660 patent”) directed to an Internet server. Resonate sued Alteon Websystems, Inc. (“Alteon”) for infringement of the ‘660 patent. After the district court construed the claims, Resonate stipulated that it could not prevail on infringement, and the district court entered final judgment of noninfringement in favor of Alteon. The ‘660 patent concerns a load-balancing approach for web-server access. In particular, a router determines what type of information the client is requesting and then selects a server to handle the request based on the content requested. The claimconstruction dispute centered on whether the claim language was “transmitting the requested resource to the client,” specifically, whether the claim at issue required a dated transmission path from a selected server back to a client to bypass a load-balancer router. The district court construed this phrase to mean “transmitting outbound data packets from the server directly to the client using the connection with the client which was transferred to the server, causing the outbound data to bypass the load balancer.”

In the accused devices, all data is transmitted from the selected server to the client through the load-balancer router. Thus, under the district court’s construction, the accused devices do not infringe.

The Federal Circuit concluded that the claim language itself fails to specify whether the data must pass through or bypass the load balancer. Thus, by the plain language of the claim, any transmission path from the selected server to the client appears to be within the scope of the claim. Alteon argued that the claimed connection would be understood by those of ordinary skill in the art to occur in the TCP/IP Internet context, which would bypass the load balancer.

The Federal Circuit rejected this argument, however, because nothing in the claim defined the limitations in terms of the TCP/IP protocol. The Federal Circuit also rejected Alteon’s argument that the specification required the bypass feature. The Federal Circuit reviewed the specification and noted that it set out two different problems in the prior art that the claimed invention overcame. The Court characterized the issue as follows: when the written description sets out two different problems present in the prior art, is it necessary that the invention claimed, and thus each and every claim in the patent, address both problems? According to the Federal Circuit, the answer is no. Likewise, the Federal Circuit rejected any attempts by Alteon to read the preferred embodiment, which did indeed bypass the load balancer, into the claims.

Accordingly, the Federal Circuit vacated the judgment of noninfringement and remanded for further proceedings.