Centripetal Networks, LLC v. Keysight Technologies, Inc.

This patent infringement case involves a dispute between two operating companies in the cybersecurity sector. The plaintiff, Centripetal Networks, LLC, is a Virginia-based cybersecurity company founded in 2009 that provides "intelligence-driven security" products, including a Threat Intelligence Gateway designed to filter network traffic against vast and dynamic threat intelligence data. The defendant, Keysight Technologies, Inc., is a large global technology company that produces a wide array of electronic test and measurement equipment, as well as hardware and software for network monitoring, visibility, and security. Centripetal accused Keysight's network security and monitoring products of infringing its patent. The litigation was filed in the U.S. District Court for the Eastern District of Virginia, a venue well-known for its fast-paced patent litigation docket, often called the "Rocket Docket."

The core of the dispute is U.S. Patent No. 10,193,917, titled "Rule-Based Network-Threat Detection." The patent describes a packet-filtering device that inspects network traffic, determines whether data packets correspond to criteria specified in a filtering rule (such as a known security threat), and then either allows or blocks the packets from reaching their destination while logging the action. This case is notable due to Centripetal's history of high-stakes litigation against major technology companies, including a now-famous multi-billion dollar judgment against Cisco involving related network security patents, which was later vacated on appeal for reasons of judicial recusal and ultimately resulted in a finding of non-infringement. This created significant industry interest in Centripetal's subsequent enforcement actions.

The district court case was stayed pending the outcome of a parallel challenge to the patent's validity at the U.S. Patent and Trademark Office. Keysight filed an inter partes review (IPR) petition challenging all claims of the '917 patent. The Patent Trial and Appeal Board (PTAB) found most, but not all, of the patent's claims to be unpatentable. Both parties appealed to the U.S. Court of Appeals for the Federal Circuit. In a decisive ruling on April 23, 2026, the Federal Circuit affirmed the PTAB's invalidity findings and reversed the small part of the decision in Centripetal's favor, concluding that all challenged claims of the '917 patent were unpatentable for obviousness. As a result of this appellate decision invalidating the sole patent-in-suit, the district court case is now stayed and subject to dismissal.

Key Legal Developments and Outcome

This litigation was short-lived in the district court, with its trajectory almost entirely dictated by a parallel validity challenge at the U.S. Patent and Trademark Office. The case was stayed early on pending an inter partes review (IPR) initiated by Keysight. The ultimate invalidation of the sole asserted patent by the U.S. Court of Appeals for the Federal Circuit has effectively terminated the dispute in Keysight's favor.

Chronological Timeline

• 2022-01-03: Complaint Filed
  Centripetal Networks, LLC filed a patent infringement complaint against Keysight Technologies, Inc. in the Eastern District of Virginia. Centripetal alleged that Keysight's "Threat Simulator," "ThreatARMOR," and "BreakingPoint" product lines infringed U.S. Patent No. 10,193,917. The complaint sought damages and a permanent injunction. (Case No. 1:22-cv-00001, Dkt. 1).

• 2022-03-04: Answer and Counterclaims
  Keysight filed its answer, denying infringement and asserting invalidity of the '917 patent. Keysight also filed counterclaims seeking a declaratory judgment of non-infringement and invalidity of the patent-in-suit. (Case No. 1:22-cv-00001, Dkt. 15).

• 2022-04-12: IPR Petition Filed by Keysight
  Keysight Technologies filed a petition for inter partes review with the Patent Trial and Appeal Board (PTAB), challenging all 20 claims of the '917 patent as unpatentable on grounds of anticipation and obviousness over prior art. This action initiated the parallel administrative proceeding that would ultimately decide the fate of the district court case. (IPR2022-00812, Paper 1).

• 2022-07-29: Motion to Stay Filed
  Citing the pending IPR petition, Keysight filed a motion to stay the district court litigation. Keysight argued that a stay would conserve judicial and party resources, as the PTAB's review of the '917 patent's validity would simplify or potentially dispose of all issues in the case. (Case No. 1:22-cv-00001, Dkt. 25).

• 2022-10-25: PTAB Institutes IPR
  The PTAB issued a decision instituting inter partes review on all 20 claims of the '917 patent, finding that Keysight had established a reasonable likelihood that it would prevail in showing the unpatentability of the challenged claims. (IPR2022-00812, Paper 9).

• 2022-11-15: District Court Case Stayed
  Following the PTAB's institution decision, the district court granted Keysight's motion to stay the case pending the outcome of the IPR proceeding. The court reasoned that the IPR's outcome would be determinative and that a stay served the interests of judicial economy. (Case No. 1:22-cv-00001, Dkt. 35). This order effectively paused all district court activity, including discovery and claim construction.

• 2023-10-24: PTAB Final Written Decision
  The PTAB issued its Final Written Decision in the IPR. The Board found that claims 1–13, 15, and 17–20 of the '917 patent were unpatentable as obvious. However, it concluded that Keysight had not demonstrated that claims 14 and 16 were unpatentable. This mixed result prompted both parties to appeal. (IPR2022-00812, Paper 45).

• 2024-12-20: Appeals Filed at the Federal Circuit
  Both Centripetal and Keysight appealed the PTAB's decision to the U.S. Court of Appeals for the Federal Circuit (CAFC). Centripetal challenged the PTAB's finding that most claims were unpatentable, while Keysight cross-appealed the finding that claims 14 and 16 were patentable.

• 2026-04-23: Federal Circuit Decision
  In a precedential opinion, the Federal Circuit affirmed the PTAB's decision on the unpatentability of claims 1-13, 15, and 17-20. Crucially, the court reversed the PTAB's finding on claims 14 and 16, concluding that those claims were also obvious in view of the prior art. The CAFC held that the PTAB had erred in its analysis of these two claims. The result of the appellate decision was the invalidation of all challenged claims of the '917 patent. (Keysight Techs., Inc. v. Centripetal Networks, LLC, No. 2024-1487 (Fed. Cir. Apr. 23, 2026)).

Outcome and Current Posture

The Federal Circuit's decision to invalidate all claims of the sole patent-in-suit is dispositive of the litigation. With no remaining valid patent claims to assert, Centripetal's infringement case is moot.

As of today, 2026-05-05, the district court case remains administratively stayed. The parties are expected to file a joint stipulation of dismissal with prejudice in light of the Federal Circuit's final judgment. Should they fail to do so, Keysight will likely file a motion for judgment on the pleadings or summary judgment, which the court would be compelled to grant based on the collateral estoppel effect of the invalidity ruling. The case is, for all practical purposes, concluded in Keysight's favor.

Counsel for Plaintiff Centripetal Networks, LLC

Centripetal Networks has consistently been represented by the intellectual property group at Kramer Levin Naftalis & Frankel LLP, a firm known for handling high-stakes patent litigation. The same core team has represented Centripetal across multiple actions, including its litigation against Cisco, Palo Alto Networks, and Keysight.

The attorneys of record for Centripetal in this matter are:

• Paul J. Andre (Lead Counsel)

  • Firm: Kramer Levin Naftalis & Frankel LLP (Silicon Valley, CA)
  • Note: Co-chair of Kramer Levin's Intellectual Property practice, he led the team that secured a multi-billion dollar judgment for Centripetal against Cisco, which was later vacated on appeal.

• Lisa S. Kobialka (Lead Counsel)

  • Firm: Kramer Levin Naftalis & Frankel LLP (Silicon Valley, CA)
  • Note: A key partner on the Centripetal litigation team, she worked alongside Paul Andre in securing the initial landmark judgment against Cisco Systems.

• James R. Hannah (Of Counsel)

  • Firm: Kramer Levin Naftalis & Frankel LLP (Silicon Valley, CA)
  • Note: A partner in the IP group, he has been an integral part of the Kramer Levin team representing Centripetal in its major patent enforcement campaigns.

Counsel for Defendant Keysight Technologies, Inc.

Keysight Technologies was represented by a multi-firm team, with the international law firm Fish & Richardson P.C. taking the lead in both the district court litigation and the parallel inter partes review (IPR) proceedings before the PTAB. They were supported by local counsel in Virginia. Another firm, Reed Smith, represented Keysight in the successful appeal at the Federal Circuit.

The attorneys of record for Keysight in this matter include:

• Michael R. Headley (Lead Counsel)

  • Firm: Fish & Richardson P.C. (Silicon Valley, CA)
  • Note: A seasoned intellectual property litigator, Headley has a strong track record in complex patent disputes and secured a $139 million verdict for Power Integrations against Fairchild Semiconductor.

• David M. Hoffman (Lead Counsel)

  • Firm: Fish & Richardson P.C. (Austin, TX)
  • Note: Hoffman's practice is focused on patent litigation and PTAB proceedings, having appeared in over 60 IPRs, making him key to the successful invalidation strategy.

• Gerard M. Donovan (Appellate Counsel)

  • Firm: Reed Smith LLP
  • Note: Donovan was counsel for Keysight in the successful Federal Circuit appeal that resulted in the invalidation of all asserted claims of the '917 patent.

• Stephen A. Cortiaus (Of Counsel)

  • Firm: Slater & Matsil, LLP (Dallas, TX)
  • Note: Cortiaus is a patent attorney with a background in computer hardware and software who provides support in patent litigation and post-grant challenges.

• Robert W. Zelnick (Local Counsel)

  • Firm: McDermott Will & Emery LLP (Washington, D.C.)
  • Note: While a registered patent attorney, Zelnick's practice primarily focuses on trademark and unfair competition litigation; he likely served as local counsel in the Eastern District of Virginia.