Metaswitch Networks Ltd v. Sonus Networks Inc

1. Case Identification

• Case #: IPR2019-00395
• Patent #: 6,950,441
• Filed: December 5, 2018
• Petitioner(s): Metaswitch Networks Ltd. and Metaswitch Networks Corporation
• Patent Owner(s): Sonus Networks, Inc.
• Challenged Claims: 1-10, 12-26, 28-32

2. Patent Overview

• Title: Method and System to Internetwork Telecommunication Networks of Different Protocols
• Brief Description: The ’441 patent describes a telecommunications device, referred to as a "softswitch," for interconnecting networks that use different protocols. The softswitch architecture comprises key functional components including a "signaling agent" to handle protocol translation and a "call agent" to manage call control.

3. Grounds for Unpatentability

Ground 1A: Obviousness over Shankar and Huang - Claims 1, 3, 5-9, and 12-17 are obvious over Shankar in view of Huang.

• Prior Art Relied Upon: Shankar (Patent 6,570,869) and Huang (Patent 7,336,649).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Shankar discloses a telecommunications system that functions as a softswitch, using "signaling units" that correspond to the claimed "signaling agent" and a "Universal Call Model" (UCM) that performs the functions of the claimed "call agent." Shankar’s system interconnects legacy and packet-switched networks. However, Shankar’s disclosure on call routing is not exhaustive. Huang was argued to supply this missing detail by teaching a gateway computer with a "routing resolution module" that includes address resolution logic and a network routing database, which corresponds to the claimed "network directory server."
  • Motivation to Combine: A POSITA would combine Huang’s routing resolution module with Shankar’s system to provide a more robust and efficient method for routing calls between different network types. Petitioner contended this combination involves applying a known technique (using a routing module for address resolution) to a known system (Shankar's softswitch) to achieve predictable results and enhance its functionality.
  • Expectation of Success: A POSITA would have a reasonable expectation of success because integrating a routing database to manage call routing was a well-understood and common practice in telecommunications system design.

Ground 1B: Obviousness over Shankar, Huang, and Capers - Claim 2 is obvious over Shankar in view of Huang and Capers.

• Prior Art Relied Upon: Shankar (Patent 6,570,869), Huang (Patent 7,336,649), and Capers (Patent 6,418,205).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground specifically targets claim 2, which adds a "resource manager" operable to handle resource requests and provide availability responses. Petitioner asserted that the base combination of Shankar and Huang discloses the other elements of the claim. Capers was argued to teach the claimed "resource manager" through its disclosure of a signaling gateway that performs resource state management using a "call/circuit state data store" to track the availability of network resources like circuits.
  • Motivation to Combine: A POSITA would be motivated to incorporate the resource management teachings of Capers into the Shankar/Huang system to improve system reliability and efficiency. While Shankar mentions selecting bearer channels based on "channel availability," it lacks implementation details. Capers provides a clear method for tracking resource availability, which would prevent the assignment of unavailable resources and reduce call failures.
  • Expectation of Success: Petitioner argued success would be expected, as incorporating resource management was a known feature of conventional call processing systems designed to enhance performance and reliability.

Ground 1D: Obviousness over Shankar, Huang, and Huitema - Claims 4 and 10 are obvious over Shankar in view of Huang and Huitema.

• Prior Art Relied Upon: Shankar (Patent 6,570,869), Huang (Patent 7,336,649), and Huitema (an IEEE article, "An Architecture For Residential Internet Telephony Service," June 1999).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground addresses claims 4 and 10, which add limitations for a "network gateway" and the use of Media Gateway Control Protocol (MGCP), respectively. Petitioner argued that Shankar’s system uses an older protocol (SGCP) and describes communication between originating and terminating signaling units. Huitema teaches a more advanced telephony system using MGCP to control gateways and describes how different call agents coordinate to set up calls, especially to external networks. This inter-agent coordination maps to the functionality of the claimed "network gateway."
  • Motivation to Combine: A POSITA would combine Huitema's teachings to upgrade the Shankar/Huang system from the predecessor SGCP to the more current and functional MGCP. This would be a natural and predictable technological progression. Further, a POSITA would use Huitema’s teachings on inter-agent communication via a network gateway to improve the system’s ability to handle calls to external parties, thereby increasing scalability and reliability.
  • Expectation of Success: A POSITA would expect success in upgrading a known protocol to its successor and in implementing a known method for inter-gateway communication to improve a system's reach and robustness.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including combining Shankar, Huang, and Capers with Janning (Patent 6,052,448) for its teachings on generating call detail records upon call disconnection (Ground 1C), and an omnibus ground combining all five references against claim 26 (Ground 1E).

4. Key Claim Construction Positions

• "logic control": Petitioner proposed this term, consistent with the ’441 patent’s specification, refers to a "data configurable generic state machine processor that execute[s] logic control programs."
• "[logic control] program": Petitioner proposed this term refers to "actions, transitions, and data as a series of data items or independent building blocks that define what a logic engine application is to perform."

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under 35 U.S.C. § 325(d) would be inappropriate. It contended that its proposed combination of Shankar, Huang, and Capers is not the "same or substantially the same prior art or arguments" presented during the original prosecution, as the Examiner’s previous rejection relied on a different primary reference (Elliott) which Petitioner alleged has key deficiencies not present in Shankar.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-10, 12-26, and 28-32 of the ’441 patent as unpatentable.