Cisco Systems Inc v. Corrigent Corp

1. Case Identification

• Case #: IPR2023-00447
• Patent #: 9,118,602
• Filed: January 10, 2023
• Petitioner(s): Cisco Systems, Inc.
• Patent Owner(s): Corrigent Corporation
• Challenged Claims: 1-26

2. Patent Overview

• Title: Assigning and Utilizing an Ethernet Physical Data Port in a Link Aggregation Group
• Brief Description: The ’602 patent discloses methods and apparatuses for managing network traffic in a Multi-Protocol Label Switching (MPLS) environment. The technology involves using a Link Aggregation Group (LAG) between two switches, selecting a single physical port from the LAG that meets a specific bandwidth requirement for a network tunnel, encoding an identifier for that port into a data packet label, and using this label to route packets through the designated port.

3. Grounds for Unpatentability

Ground 1: Claims 1-13, 15-24, and 26 are obvious over Raz

• Prior Art Relied Upon: Raz (Patent 7,466,697).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Raz, which was not considered during prosecution, discloses all key elements of the challenged claims in the context of a single Label Switching Router (LSR). Raz teaches a "subport forwarding and provisioning mechanism" where multiple lower-speed "subports" are aggregated to handle a high-speed packet stream. Raz's system assigns a specific subport to a connection based on bandwidth requirements, generates an MPLS label that includes a serial number identifying the chosen subport, and sends that label to an upstream node to direct traffic accordingly. Petitioner contended that Raz’s subports are analogous to the claimed physical ports, and its Label Switched Path (LSP) is analogous to the claimed network tunnel.
  • Motivation to Adapt: A person of ordinary skill in the art (POSITA) would have recognized that the principles Raz applied to managing subports within a single device are directly applicable to managing physical ports forming a LAG between two separate switches. The motivation would be to achieve the same benefits of efficient bandwidth allocation and predictable routing for inter-switch connections, a simple and predictable design choice.
  • Expectation of Success: A POSITA would have had a high expectation of success in applying Raz's intra-device logic to an inter-device LAG, as the underlying networking concepts of packet switching, label-based routing, and bandwidth management are identical in both scenarios.

Ground 2: Claims 1-26 are obvious over Raz in view of Ferguson

• Prior Art Relied Upon: Raz (Patent 7,466,697) and Ferguson (Patent 7,277,386).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground asserted that Ferguson explicitly bridges any gap between Raz’s intra-device disclosure and the ’602 patent’s claimed inter-device system. While Raz provides the core methodology of selecting a specific path based on bandwidth and encoding its identity in a label, Ferguson teaches techniques for distributing MPLS packets across an aggregated link composed of multiple "physical interconnects" that can couple different devices, including "two switches." Ferguson addresses the same problems of load balancing and bandwidth utilization in MPLS LAGs.
  • Motivation to Combine: A POSITA would combine Raz and Ferguson because they are analogous arts addressing the identical problem of ensuring sufficient bandwidth for high-speed packet streams in an MPLS network. Ferguson expressly teaches that its techniques for managing aggregated links apply between switches. A POSITA would therefore have been motivated to implement Raz's more specific and detailed subport assignment and labeling method within the inter-switch framework described by Ferguson to achieve predictable, high-bandwidth connections. This combination results in the system claimed in the ’602 patent.
  • Expectation of Success: The combination would have yielded predictable results. Applying Raz’s specific allocation scheme to Ferguson’s inter-device LAG system is a straightforward combination of a known technique (Raz) with a known system (Ferguson) to achieve the expected benefit of improved bandwidth management.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial would be inappropriate under both 35 U.S.C. §325(d) and §314(a) (Fintiv factors).
• §325(d): Denial was argued to be unwarranted because the primary references, Raz and Ferguson, present new arguments and art combinations that were never considered by the PTO during the original prosecution of the ’602 patent.
• §314(a) (Fintiv): Denial was argued to be inappropriate because the parallel district court litigation is in its infancy. Key factors weighing against denial included that fact discovery had not yet begun, no trial date was set, and investment by the court and parties was minimal. Further, Petitioner offered to stipulate that it would not pursue in the district court any invalidity ground on which an inter partes review (IPR) is instituted, thereby avoiding duplicative efforts and conserving judicial resources.

5. Relief Requested

• Petitioner requests the institution of an IPR trial and the cancellation of claims 1-26 of Patent 9,118,602 as unpatentable.