Unified Patents, LLC v. Centripetal Networks, LLC

Case Overview and Background

This dispute involves a challenge to the validity of a cybersecurity patent held by an aggressive licensor, Centripetal Networks, LLC, a Virginia-based cybersecurity company. Centripetal develops and sells threat intelligence gateway products and services, such as its CleanINTERNET and RuleGATE platforms, which use threat intelligence to filter network traffic and block malicious data packets. The petitioner, Unified Patents, LLC, is a membership-based organization that works to deter non-practicing entity (NPE) patent assertions by challenging the validity of patents it deems weak or overly broad, often through inter partes review (IPR) proceedings. Unified Patents files these challenges on behalf of its members, which include a wide range of technology companies, to protect them from what it considers to be frivolous litigation threats.

The case centers on U.S. Patent No. 10,193,917, which discloses a system and method for a packet-filtering device that uses rules based on network-threat indicators to either block or allow data packets to pass through a network. This IPR was filed at the USPTO's Patent Trial and Appeal Board (PTAB), an administrative venue that allows parties to challenge the validity of issued patents in a faster and often more successful manner than in federal district court. The proceeding is notable as it represents a defensive measure against Centripetal's widespread and high-stakes patent assertion campaign. Centripetal has engaged in major patent litigation against several large technology companies, including a suit against Cisco that initially resulted in a since-vacated $1.9 billion damages award and a successful $151.5 million jury verdict against Palo Alto Networks.

The filing of this IPR by Unified Patents is consistent with its business model of proactively challenging patents being asserted by entities like Centripetal against the technology industry. The '917 patent was also part of a multi-patent infringement suit Centripetal brought against Keysight Technologies at the U.S. International Trade Commission (ITC). In that action, Centripetal accused Keysight's network monitoring and security products of infringement. This broader context of aggressive litigation underscores the significance of the PTAB challenge. By seeking to invalidate the '917 patent, Unified Patents aimed to remove a legal threat not just to a single company, but to the broader technology ecosystem targeted by Centripetal. The PTAB's final decision, which invalidated a majority of the challenged claims, represented a significant setback for Centripetal's enforcement efforts regarding this patent.

Key Legal Developments and Outcome for IPR2022-01097

This inter partes review (IPR) represents a key challenge to Centripetal Networks' U.S. Patent No. 10,193,917, a patent instrumental in its broader litigation campaign. The proceeding resulted in the invalidation of the majority of the patent's claims, a decision largely affirmed and expanded upon by the Federal Circuit.

It is important to note a discrepancy in the case metadata provided. While the case caption lists Unified Patents, LLC as the petitioner, the available legal documents, including the Final Written Decision and the subsequent appeal, identify Keysight Technologies, Inc. as the petitioner in IPR2022-01097. This summary will proceed with Keysight as the petitioner, consistent with the official record.

Chronological Developments:

• 2022-06-02: IPR Petition Filed
  Keysight Technologies, Inc. filed a petition for inter partes review against U.S. Patent No. 10,193,917, challenging all 20 claims as obvious. The petition was primarily based on two grounds:

  1. Claims 1-5, 11-15, and 20 were alleged to be obvious over the "Sourcefire 3D System User Guide Version 4.10" (Sourcefire).
  2. Claims 6-10 and 16-19 were alleged to be obvious over Sourcefire in view of U.S. Patent Application Publication No. 2015/0207809 (Macaulay).

  Keysight significantly relied on collateral estoppel, arguing that claims of a related Centripetal patent ('722) with very similar limitations had already been found unpatentable over the same Sourcefire reference in a prior IPR.

• 2023-06-05: Final Written Decision
  The Patent Trial and Appeal Board (PTAB) issued its Final Written Decision (FWD). The Board found that Keysight had successfully demonstrated by a preponderance of the evidence that claims 1–3, 5–13, and 15–20 were unpatentable for obviousness. However, the PTAB concluded that Keysight had not met its burden to prove that claims 4 and 14 were unpatentable. The Board's decision on these two claims hinged on its interpretation of the prior art, specifically finding that Sourcefire did not disclose updating an "existing flow log entry" as required by the claims.

• Post-Decision Appeals to the Federal Circuit
  Both parties appealed the PTAB's decision to the U.S. Court of Appeals for the Federal Circuit. Centripetal appealed the invalidation of the majority of the claims, while Keysight cross-appealed the PTAB's finding that claims 4 and 14 were not unpatentable.

• 2026-04-23: Federal Circuit Decision
  The Federal Circuit issued a non-precedential decision that largely sided with Keysight, affirming in part and reversing in part the PTAB's FWD.

  • Affirmed: The court upheld the PTAB's determination that claims 1–3, 5–13, and 15–20 were unpatentable as obvious. It rejected Centripetal's arguments regarding claim construction of "packet flow entry," finding that Centripetal had sufficient notice and opportunity to be heard on the issue during the IPR proceedings.
  • Reversed: The court reversed the PTAB's decision on claims 4 and 14, finding them unpatentable as well. The Federal Circuit concluded that the PTAB's finding that Sourcefire failed to disclose updating an "existing flow log entry" was not supported by substantial evidence. The court reasoned that since Sourcefire's logs were updated "on the fly," it necessarily had to have an existing entry to update.

  The ultimate outcome of this IPR and its subsequent appeal was the invalidation of all challenged claims (1-20) of the '917 patent.

Parallel Proceedings and Their Impact

The '917 patent was also a subject of litigation in other venues, and the IPR decision had a direct effect on those cases:

• ITC Investigation (Inv. No. 337-TA-1314): Centripetal asserted the '917 patent, among others, against Keysight at the International Trade Commission. In a parallel Federal Circuit appeal decided on the same day as the IPR appeal, the court affirmed the ITC's finding of no violation by Keysight. The court explicitly noted that its decision to affirm the unpatentability of claims in the IPR rendered the issues related to the '917 patent in the ITC appeal moot.

This IPR proceeding, initiated by Keysight, proved to be a highly effective defensive strategy. It not only resulted in the invalidation of a significant patent from Centripetal's portfolio but also neutralized the threat posed by that patent in a parallel, high-stakes ITC investigation.

Counsel for Plaintiff/Petitioner (Keysight Technologies, Inc.)

Note on Parties: While the initial case metadata lists Unified Patents, LLC as the plaintiff, the official dockets for IPR2022-01097 confirm that the petitioner was Keysight Technologies, Inc. The counsel listed below represented Keysight in this matter.

The legal team from Alston & Bird LLP represented petitioner Keysight Technologies throughout the IPR proceeding at the PTAB and the subsequent appeal at the Federal Circuit.

• Name: Ryan Z. Koppelman
  Role: Lead Counsel
  Firm: Alston & Bird LLP (Atlanta, GA)
  Note: Koppelman is a partner specializing in patent litigation and post-grant proceedings, frequently representing technology companies in complex PTAB trials.

• Name: Kirk T. Bradley
  Role: Counsel
  Firm: Alston & Bird LLP (Atlanta, GA)
  Note: Bradley is a partner with extensive experience in patent infringement litigation and IPRs before the PTAB, representing both petitioners and patent owners.

• Name: Chris McArdle
  Role: Counsel
  Firm: Alston & Bird LLP (Atlanta, GA)
  Note: A partner in the Intellectual Property Litigation Group, McArdle focuses on patent cases in federal courts and at the PTAB.

• Name: Adam D. Swain
  Role: Counsel
  Firm: Alston & Bird LLP (Washington, D.C.)
  Note: Swain co-chairs the firm's Patent Group and has significant experience in high-stakes patent litigation and appeals at the Federal Circuit.

• Name: B. Clayton Dean, Jr.
  Role: Counsel
  Firm: Alston & Bird LLP (Atlanta, GA)
  Note: Dean is a senior associate whose practice includes patent litigation in district courts and post-grant reviews before the PTAB.

Counsel for Defendant (Patent Owner)

Centripetal Networks, LLC, the patent owner in this IPR, was represented by the law firm of Kramer Levin Naftalis & Frankel LLP. This firm has a long-standing relationship with Centripetal, having represented them in multiple high-stakes patent litigations. The legal team for this specific PTAB matter included several partners and associates known for their work in complex patent disputes.

• Paul J. Andre | Lead Counsel

  • Firm: Kramer Levin Naftalis & Frankel LLP, Silicon Valley (Menlo Park/Redwood Shores), CA.
  • Note: Co-chair of the firm's Intellectual Property practice, Andre has led Centripetal's litigation efforts in landmark cases, including those against Cisco and Palo Alto Networks.

• James R. Hannah | Lead Counsel

  • Firm: Kramer Levin Naftalis & Frankel LLP, Silicon Valley (Menlo Park/Redwood Shores), CA.
  • Note: An internationally recognized patent litigator who is a leading practitioner in inter partes review (IPR) proceedings and was instrumental in securing major verdicts for Centripetal.

• Hannah J. Lee | Back-up Counsel

  • Firm: Kramer Levin Naftalis & Frankel LLP, Silicon Valley (Menlo Park/Redwood Shores), CA.
  • Note: A partner at the firm, she has significant experience in high-stakes IP disputes for technology clients, including her work on Centripetal's major victory against Cisco.

• Jeffrey H. Price | Back-up Counsel

  • Firm: Kramer Levin Naftalis & Frankel LLP, Washington, D.C.
  • Note: While specific involvement in this IPR is based on PTAB filings, Price's role aligns with the firm's broader representation of Centripetal in its extensive patent campaigns. His experience is primarily in patent litigation, although detailed public records on his specific contributions to this case are limited.