PTAB

IPR2019-00795

Metaswitch Networks Ltd v. Ribbon Communications Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: User and Session Identification Based on Connections, Protocols and Protocol Fields
  • Brief Description: The ’536 patent describes systems and methods for applying specific service levels to data packets from multiple users transferred over a single connection. The appropriate service level for a given set of packets is determined based on the packet's connection identifier and its communication protocol.

3. Grounds for Unpatentability

Ground 1: Claims 1-10 and 13-24 are obvious over Maher in view of Heller and Kloth.

  • Prior Art Relied Upon: Maher (2003/0118029), Heller (6,888,807), and Kloth (6,643,260).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Maher taught the foundational system: a network device that enforces service level agreements (SLAs) by scanning packet headers to associate data with a specific subscriber. Maher’s system creates a "session ID" for each traffic flow based on header information like source/destination ports (Layer 4) and protocol. Heller was alleged to teach the critical improvement of associating a specific Quality of Service (QoS) level with an entire session or flow ID. This allows a QoS policy to be applied to all subsequent packets in that flow without repetitive analysis. Kloth was presented as teaching the use of various connection identifiers to distinguish flows, including more efficient Layer 2 identifiers (e.g., VLANs, Layer 2 addresses), as a known alternative to the Layer 4 identifiers disclosed in Maher.
    • Motivation to Combine: A POSITA would combine Maher with Heller for improved efficiency. Applying a pre-determined QoS to an entire session (as taught by Heller) is more efficient and less computationally intensive than analyzing each packet individually (as suggested by Maher). A POSITA would be further motivated to incorporate Kloth's teachings because using Layer 2 identifiers to define connections was a known, predictable method for simplifying packet header processing. This would directly address the recognized performance limitations associated with processing more complex Layer 3 or Layer 4 information, thereby improving router performance.
    • Expectation of Success: Petitioner asserted that a POSITA would have had a reasonable expectation of success in making this combination. The proposed modifications involved applying known networking techniques (per-session QoS, use of Layer 2 identifiers) to a standard type of system (packet-switched networks) to achieve the predictable benefits of increased efficiency and performance.

4. Key Claim Construction Positions

  • "storing the service level associated with the user device" (claims 3, 10): Petitioner argued this requires storing the association between the service level and the user device, not merely the existence of a service level. This construction was central to showing how the prior art stores subscriber policies (the association) to enforce service levels on all subsequent packets belonging to a session.
  • "Determining a session identifier... using the connection identifier and communication protocol" (various claims): Petitioner asserted this means the system translates the identified connection and protocol information into a session identifier. This interpretation supported mapping how the combined prior art uses connection details (from Maher and Kloth) to create a session ID that is then linked to a specific service level (from Heller).

5. Arguments Regarding Discretionary Denial

  • Petitioner argued against discretionary denial under 35 U.S.C. §325(d), asserting that the primary references (Maher, Heller, and Kloth) were not cumulative of art of record and had never been considered by the USPTO during the original prosecution of the ’536 patent.
  • Petitioner also contended that denial based on a co-pending district court case would be inappropriate. The arguments centered on the district court trial date being over a year away at the time of filing, the IPR addressing a broader set of claims than those asserted in the litigation, and the petition representing Petitioner's sole opportunity to address the validity of these claims before the statutory time bar expired.

6. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-10 and 13-24 of the ’536 patent as unpatentable.