PTAB

IPR2025-00188

Cisco Systems Inc v. WSOU Investments LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Multiprotocol Label Switching (MPLS) Network Path Protection
  • Brief Description: The ’691 patent discloses methods for protecting against dual failures in Multiprotocol Label Switching (MPLS) networks. The technology involves establishing a secondary "Backup" Label Switched Path (LSP) to protect an already-established primary "Bypass" LSP, which in turn protects the main "Primary" LSP.

3. Grounds for Unpatentability

Ground 1: Obviousness over EDC_525, EDC_892, and Hanif - Claims 1-10 are obvious over EDC_525 in view of EDC_892 and Hanif.

  • Prior Art Relied Upon: EDC_525 (Application # 2004/0218525), EDC_892 (Application # 2004/0246892), and Hanif (Application # 2009/0292943).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that EDC_525, the primary reference, teaches the core concept of protecting a network against multiple failures by using multiple backup paths in a Generalized MPLS (GMPLS) network. EDC_525 discloses establishing a working path and a first backup path, and then dynamically computing a second backup path in response to network degradation or to avoid a Shared Risk Link Group (SRLG). This combination of a primary path, first backup, and second backup allegedly maps to the claimed Primary LSP, Bypass LSP, and Backup LSP. Petitioner asserted that EDC_892, which is expressly incorporated by reference into EDC_525, provides further detail on setup messages used to establish these protection paths. To meet the limitations requiring a "Point of Local Repair" (PLR) node and a "Merge Point" (MP) node, Petitioner relied on Hanif, which teaches implementing local repair in MPLS networks using precisely these PLR and MP ingress/egress nodes.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine EDC_892 with EDC_525 because EDC_525 explicitly suggests the combination by incorporating EDC_892 by reference. Petitioner argued a POSITA would have been motivated to apply Hanif’s local repair techniques to the network protection system of EDC_525 to gain the known benefits of local protection, such as faster and more efficient failure recovery, which were recognized as important in the art.
    • Expectation of Success: Petitioner contended a POSITA would have had a reasonable expectation of success. The combination involves applying known local repair techniques (Hanif) to a known multiple-failure protection scheme (EDC_525) using conventional network components and signaling (EDC_892), all within the analogous art of MPLS/GMPLS networking, to achieve the predictable result of improved network resilience.

Ground 2: Obviousness over EDC_525, EDC_892, Hanif, and Li - Claims 1-10 are obvious over the combination of Ground 1 in view of Li.

  • Prior Art Relied Upon: EDC_525 (Application # 2004/0218525), EDC_892 (Application # 2004/0246892), Hanif (Application # 2009/0292943), and Li (Chinese Publication # CN101645848A).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground builds upon the combination asserted in Ground 1, with the addition of Li to address the sequence of failover between multiple backup paths. Petitioner argued that while EDC_525 teaches establishing multiple backup paths, it does not specify the order in which they should be used upon failure. Li allegedly remedies this by teaching a method for prioritizing backup LSPs in an MPLS network, wherein a higher-priority backup path is used first upon a primary path failure, and a lower-priority backup path is only used if the higher-priority backup also fails. This directly teaches an ordered failover sequence for the multiple backup paths disclosed by the primary combination.
    • Motivation to Combine: A POSITA implementing the multiple backup path system of EDC_525 would have been motivated to consult teachings like Li to determine an optimal failover sequence. Petitioner asserted that Li’s priority scheme offers predictable benefits, including greater control over path selection, maintaining Quality of Service (QoS) by using a high-QoS backup path first, and reducing the probability that a critical backup path is preempted by other network traffic. These were all well-known goals in network management.
    • Expectation of Success: A POSITA would have had a high expectation of success in applying Li's well-known path prioritization techniques to the multiple-path system of EDC_525. Implementing priority fields in network signaling messages was a standard and predictable method for controlling path selection in MPLS networks.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under Fintiv is inappropriate because the parallel district court proceeding is in its early stages, with significant events like claim construction and discovery scheduled to occur after the Board’s institution decision.
  • The scheduled trial date in the Eastern District of Texas is late March 2026, which is proximate to the statutory deadline for a Final Written Decision (FWD), making the timing factor neutral.
  • Petitioner argued there is not a complete overlap of issues, as claims 1-5 challenged in the inter partes review (IPR) are not asserted in the parallel litigation. Petitioner also stipulated that it will not pursue the same invalidity grounds in district court if the IPR is instituted.
  • It was argued that denial under §325(d) is unwarranted because the prior art references presented in the petition were not before the Examiner during prosecution. The art is therefore not cumulative and presents a compelling challenge to the patent’s validity, particularly as it addresses the very limitations added to overcome prior art during prosecution.

5. Relief Requested

  • Petitioner requests institution of an IPR and cancellation of claims 1-10 of the ’691 patent as unpatentable under 35 U.S.C. §103.