IP Law Daily, PATENT—Fed. Cir.: Obviousness affirmed in computer network threat detection system dispute, (Nov 1, 2024)

By Kevin M. Finson

A PTAB decision on obviousness was affirmed because the underlying claim construction was supported by the plain meaning of the terms used.

A network security company failed to show error in the claim construction of Patent Trial and Appeal Board decisions invalidating two of its patents, the U.S. Court of Appeals for the Federal Circuit has held. Although the Board’s claim construction was not a model of clarity, the court was able to find that the Board considered the meaning of the disputed term and construed it in accordance with plain meaning and the intrinsic evidence (Centripetal Networks, LLC v. Palo Alto Networks, Inc., Nos. 23-1654, 23-1655 (Fed. Cir. Oct. 31, 2024)).

Centripetal Networks, LLC (Centripetal) was the owner of U.S. Patents Nos. 10,542,028 (the ’028 patent) and 10,757,126 (the ’126 patent), which shared a specification and which were both titled “Rule-Based Network-Threat Detection.” The patents claimed an improved way of detecting “[n]etwork threats” such as viruses and malware. Palo Alto Networks, Inc. (Palo Alto), upon being sued for infringement of both patents, petitioned for inter partes review on the ground of obviousness. The Patent Trial and Appeal Board (PTAB) instituted review and found all of the challenged claims obvious in view of a reference called the Sourcefire 3D System User Guide (Sourcefire). Centripetal appealed.

Claim construction. Centripetal argued that the Board erred by declining to construe the claim term “responsive to” in the phrase “responsive to a determination by the packet filtering device that the first packet satisfies a first packet filtering rule.”

The court found that the Board had in fact construed the term, albeit with less clarity than might be ideal, by placing the construction and application of the construction in one section of the written decision rather than clearly separating them. Nevertheless, the court was able to determine that the Board had properly interpreted “responsive to” as requiring a cause-and-effect relationship, but not an exclusive relationship; e.g. the prior art reference’s use of both a packet filtering rule and some other triggering method met the plain meaning of the claim term, and there was no intrinsic evidence to support Centripetal’s preferred narrower construction.

Because Centripetal’s remaining arguments as to obviousness hinged on acceptance of Centripetal’s argument on claim construction, the Federal Circuit affirmed the Board’s obviousness determinations as to both patents.

The case is Nos. 23-1654 and 23-1655.

Judge: Taranto, R.

Attorneys: James R. Hannah (Kramer Levin Naftalis & Frankel LLP) for Centripetal Networks, LLC. Douglas Hallward-Driemeier (Ropes & Gray LLP) for Palo Alto Networks, Inc.

Companies: Centripetal Networks, LLC; Palo Alto Networks, Inc.

Cases: Patent FedCirNews USPTO