Hewlett Packard Enterprise Co. v. Parity Networks, LLC

1. Case Identification

• Case #: IPR2019-00433
• Patent #: 6,870,844
• Filed: December 13, 2018
• Petitioner(s): Hewlett Packard Enterprise Company
• Patent Owner(s): Parity Networks, LLC
• Challenged Claims: 1, 2, 6, 7, 10, 15, and 19-23

2. Patent Overview

• Title: Multicast-Capable Port for Replicating Multicast Data Packets
• Brief Description: The ’844 patent describes a system and method for handling multicast data packets in a network switching fabric. The invention is characterized by a multicast-capable port on a fabric card where incoming multicast packets are received on an egress path, diverted to a special multicast component for replication or re-addressing, and then output back to an ingress path to be sent through the switch fabric. Petitioner argued the patent’s earliest possible priority date is its filing date of May 10, 2001, not the March 6, 2001 date of its parent application (’891 patent), because key multicast features were new matter added to the ’844 patent application.

3. Grounds for Unpatentability

Ground 1: Claims 1, 2, 6, 7, 10, 15, and 19-23 are obvious over Rose in view of Lipp and Barnett.

• Prior Art Relied Upon: Rose (Patent 7,103,039), Lipp (Patent 6,751,219), and Barnett (Patent 5,436,893).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Rose taught a switching fabric with multiple ports capable of handling multicast data but failed to disclose the specific implementation for packet replication. Lipp was argued to supply this missing detail, teaching a "drop-and-continue" multicast technique where a single packet is sent in a chain to target egress ports. Crucially, Lipp described an egress port replicating a packet and releasing the new copy "back into the switch fabric." However, neither Rose nor Lipp detailed the specific hardware structure of a port capable of this replication. Barnett was alleged to provide this structure, teaching a port link controller with a dedicated processing engine and recirculate FIFOs that permit a multicast cell to be repeated, creating copies that can be sent on the same physical link.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA), starting with Rose's general switching fabric, would have been motivated to find an efficient multicast implementation. A POSITA would combine Lipp's method of replicating packets at an egress port and re-injecting them into the fabric to improve upon Rose's system. To build such a port, a POSITA would have looked for known port controller designs and would have found Barnett's detailed link controller architecture suitable for performing the replication taught by Lipp.
  • Expectation of Success: A POSITA would have a high expectation of success because all three references address analogous multicast switching networks and complement each other's teachings. Rose provides the foundation, Lipp provides the replication method, and Barnett provides the specific port-level hardware to implement that method, making their combination a predictable design choice.

Ground 2: Claims 1, 2, 6, 7, 10, 15, and 19-23 are obvious over the Admitted Prior Art (APA) in view of Lipp and Barnett.

• Prior Art Relied Upon: The ’844 patent’s Admitted Prior Art (“APA”), Lipp (Patent 6,751,219), and Barnett (Patent 5,436,893).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground mirrors the logic of Ground 1, but substitutes Rose with the APA described in the ’844 patent’s “Background of the Invention” section. Petitioner contended the APA acknowledged key prior art concepts, including routers with fabric cards, multiple interconnected ports, and the basic requirement of copying packets for multicasting. Like Rose, the APA described the general system but lacked a specific implementation for packet replication and the port structure to perform it.
  • Motivation to Combine: The motivation to combine was identical to Ground 1. A POSITA starting with the system described in the APA would integrate Lipp’s replication method and Barnett’s port controller architecture for the same reasons: to create a complete, functional multicast switching system by combining known, compatible techniques.

Ground 3: Claims 1, 2, 6, 7, 10, 15, and 19-23 are obvious over Tout in view of Lipp and Barnett.

• Prior Art Relied Upon: Tout (Patent 5,991,295), Lipp (Patent 6,751,219), and Barnett (Patent 5,436,893).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground again follows the same combination logic but substitutes Tout as the primary reference. Petitioner asserted that Tout disclosed an ATM switch with a switch fabric card and multiple full-duplex switch fabric ports. While Tout’s switch could handle multicast data, it did not provide specific implementation details for data replication.
  • Motivation to Combine: For the same reasons as in Ground 1, a POSITA seeking to implement multicasting in Tout’s switch would be motivated to incorporate Lipp’s efficient replication method and Barnett’s detailed port controller structure. This combination would fill the implementation gaps in Tout, resulting in the claimed invention.

4. Key Claim Construction Positions

• Petitioner argued that the claim terms “into the port,” “out of the port,” and “via one or more of the first ports” should be construed to mean “through the port.” This construction was based on prosecution history estoppel. During prosecution, the applicant distinguished the invention from a prior art reference (Takahashi) by explicitly stating that the claimed ingress and egress paths were paths through the port, not simply to or from the port. Petitioner contended this distinction was a clear and unambiguous disavowal that limits the scope of these terms.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that the Board should not exercise its discretion to deny institution under 35 U.S.C. §325(d). The core reason provided was that none of the primary prior art references relied upon in the petition (Rose, Lipp, Barnett, and Tout) were cited or considered during the original prosecution of the ’844 patent. Therefore, the Examiner never evaluated the specific combinations and arguments presented in the petition, which raised substantial new questions of patentability.

6. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1, 2, 6, 7, 10, 15, and 19-23 of the ’844 patent as unpatentable.