Context: Centripetal Networks and Cisco have been involved in long-running patent litigation over network-security technology since February 2018. In 2020, the United States District Court for the Eastern District of Virginia awarded Centripetal more than $1.9 billion after finding that Cisco infringed several patents, but the Federal Circuit later vacated that judgment. The patents associated with that dispute subsequently faced multiple United States Patent and Trademark Office (USPTO) Patent Trial and Appeal Board (PTAB) challenges. U.S. Patent No. 9,917,856 (“rule-based network-threat detection for encrypted communications”) was the last remaining patent at issue in the group of related reviews. In October 2025, the Federal Circuit remanded this particular inter partes review (IPR), directing the PTAB to reconsider evidence relating to alleged copying by Cisco.
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Court and counsel
Patent Trial and Appeal Board: Administrative Patent Judges Kevin F. Turner, Brian P. Murphy, and Mary C. Hoffman.
Petitioner Palo Alto Networks was represented by Ropes & Gray LLP’s Mark D. Rowland, James R. Batchelder, Scott McKeown, and Keyna Chow; as well as Munger, Tolles & Olson LLP’s Adam Kwon and Andrew Radsch.
Joined petitioner Cisco Systems was represented by Haynes and Boone LLP’s Theodore M. Foster, David L. McCombs, and Gregory P. Huh.
Joined petitioner Keysight Technologies was represented by Reed Smith LLP’s Gerard Donovan, Peter Chassman, Jonathan Detrixhe, and Sidharth Kapoor.
Patent owner Centripetal Networks was represented by Herbert Smith Freehills Kramer LLP’s James Hannah, Jeffrey Price, and Jenna Fuller; as well as Banner & Witcoff LTD’s Bradley Wright, Scott Kelly, and John Hutchins.