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): Casimir M. Kaczmarczyk, et al. (Sonus Networks Inc. identified as related party)
• Challenged Claims: 1-10, 12-26, and 28-32

2. Patent Overview

• Title: Method and System to Internetwork Telecommunication Networks of Different Protocols
• Brief Description: The ’441 patent describes a telecommunications "softswitch" designed to interconnect disparate networks, such as circuit-switched and packet-switched networks. The system architecture is built around functional components including a "signaling agent" to handle protocol termination and a "call agent" to manage call session control.

3. Grounds for Unpatentability

Ground 1: 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 taught the core architecture of the ’441 patent. Shankar’s telecommunications system included "signaling units" responsible for processing signaling messages (a "virtual switch") and "coding units" to convert voice traffic between legacy and packet formats. Petitioner mapped the ’441 patent's "signaling agent" to Shankar's Originating/Terminating Call Control (OCC/TCC) components and the "call agent" to Shankar's Universal Call Model (UCM), which manages the call logic. To meet the "network directory server" limitation of claim 1, Petitioner asserted that Huang disclosed a gateway computer with "routing resolution modules" containing address resolution logic and a network routing database.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Huang's routing resolution module with Shankar's system to provide a well-defined mechanism for call routing. Shankar’s UCM required routing information to function, and Huang provided an effective and known module for this purpose. The combination represented a predictable integration of known elements to achieve the common goal of routing calls efficiently across different networks.
  • Expectation of Success: A POSITA would have a high expectation of success because the combination involved applying a known routing solution (Huang) to a known telecommunications switching system (Shankar) to achieve the predictable result of improved routing capability.

Ground 2: 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 built upon Ground 1 to address claim 2, which added a "resource manager" operable to provide resource availability. Petitioner argued that Capers taught this limitation. Capers disclosed a signaling gateway that performed resource and call state management, including a "call/circuit state data store" that tracked the availability of network circuits to handle calls. This data store functioned as the claimed resource manager.
  • Motivation to Combine: While Shankar mentioned selecting bearer channels based on "channel availability," it did not provide specific implementation details. Capers explicitly taught how to monitor and manage resource availability. A POSITA would combine Capers’s detailed resource management system with the Shankar/Huang combination to enhance system reliability and efficiency, ensuring that call setup only used resources confirmed to be available.
  • Expectation of Success: Success would be expected, as this combination involved augmenting the base system with a well-understood feature (resource management) to solve a known problem (selecting available channels for calls), leading to a more robust and reliable system.

Ground 3: 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 Architecture For Residential Internet Telephony Service, IEEE Internet Computing, June 1999).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground addressed claims 4 and 10, which required a "network gateway" and specified the use of Media Gateway Control Protocol (MGCP). Petitioner asserted that Huitema taught a telephony system where call agents use MGCP to control gateways. Huitema also described coordination between different call agents to set up calls across networks, which Petitioner mapped to the "network gateway" function of interfacing between signaling units to exchange routing information.
  • Motivation to Combine: A POSITA would be motivated to combine Huitema with the Shankar/Huang system for two primary reasons. First, Shankar taught the use of SGCP, a direct predecessor to MGCP. A POSITA would naturally upgrade to the newer, more functional MGCP taught by Huitema to keep the system current. Second, Huitema’s teachings on inter-agent communication provided a clear blueprint for implementing the claimed network gateway to handle calls to external networks.
  • Expectation of Success: The combination was a straightforward technological progression. A POSITA would expect success in upgrading a known protocol (SGCP) to its successor (MGCP) and implementing a well-documented method for inter-gateway communication to improve scalability.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including combining Janning (Patent 6,052,448) for its teachings on generating Call Detail Records (CDRs) upon call disconnection to address claims 18-25 and 28-32. A final ground combined all references (Shankar, Huang, Capers, Janning, and Huitema) to argue the obviousness of claim 26.

4. Key Claim Construction Positions

• "logic control": Petitioner proposed this term, consistent with the ’441 patent's specification, refers to the "data configurable generic state machine processor that execute logic control programs." This construction was central to mapping Shankar’s state machines to the claimed invention.
• "[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." This supported the argument that Shankar’s state machines, which transition between states to model a call, execute such programs.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under 35 U.S.C. §325(d) was inappropriate. Although the Examiner considered Capers during prosecution, it was in combination with a different primary reference (Elliott). Petitioner contended that the current primary reference, Shankar, was not the same as or substantially the same as Elliott, as Shankar properly disclosed elements that were based on a flawed reading of Elliott during prosecution. Therefore, the new combination of Shankar, Huang, and Capers presented new arguments and art not previously before the Office.

6. Relief Requested

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