Corrigent Corp v. Cisco Systems Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Corrigent Corporation (Delaware)
  • Defendant: Cisco Systems, Inc. (Delaware)
  • Plaintiff's Counsel: Parker, Bunt & Ainsworth, P.C.
• Case Identification: 6:22-cv-00396, W.D. Tex., 07/12/2024
• Venue Allegations: Plaintiff alleges venue is proper because Defendant has committed acts of infringement and maintains a regular and established place of business within the Western District of Texas.
• Core Dispute: Plaintiff alleges that Defendant's networking routers, switches, and collaboration platforms infringe five U.S. patents related to network failure detection, latency evaluation, bandwidth allocation, MAC address learning, and tunnel provisioning.
• Technical Context: The patents-in-suit relate to foundational technologies for improving the performance, reliability, and efficiency of large-scale telecommunications networks, a critical infrastructure for enterprise and service provider operations.
• Key Procedural History: The complaint alleges that a prior owner of the asserted patents, Orckit IP LLC, engaged in licensing discussions with Defendant beginning in March 2017. The complaint also notes that the Patent Trial and Appeal Board (PTAB) denied institution of inter partes review proceedings filed by Defendant (and a co-petitioner) against U.S. Patent No. 6,957,369. A separate court, in related litigation, reportedly found a claim of the '369 patent to be patent-eligible under 35 U.S.C. § 101. The complaint further notes a prior court ruling regarding the patent eligibility of U.S. Patent No. 7,113,485, with Plaintiff reserving its rights on that issue. This filing is a First Amended Complaint.

Case Timeline

Date	Event
2001-09-04	U.S. Patent No. 7,113,485 Priority Date
2002-05-30	U.S. Patent No. 6,957,369 Priority Date
2004-09-03	U.S. Patent No. 7,330,431 Priority Date
2005-05-06	U.S. Patent No. 9,118,602 Priority Date
2005-10-18	U.S. Patent No. 6,957,369 Issued
2006-05-19	U.S. Patent No. 7,593,400 Priority Date
2006-09-26	U.S. Patent No. 7,113,485 Issued
2008-02-12	U.S. Patent No. 7,330,431 Issued
2009-09-22	U.S. Patent No. 7,593,400 Issued
2015-08-25	U.S. Patent No. 9,118,602 Issued
2017-03-20	Prior patent owner Orckit IP sends letter to Defendant regarding patent portfolio
2018-07-11	Orckit IP sends second notice letter to Defendant
2018-11-20	Orckit IP identifies '485 patent in communications with Defendant
2024-07-12	First Amended Complaint Filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 6,957,369 - "HIDDEN FAILURE DETECTION"

The Invention Explained

• Problem Addressed: The patent addresses the problem of detecting "hidden failures" in networking components that are idle Compl. ¶16 Prior art methods for testing were often intrusive, requiring systems to be taken offline, involved complex manual steps, or necessitated dedicated testing hardware and additional system resources '369 Patent, col. 1:11-24 Compl. ¶¶16-17
• The Patented Solution: The invention provides a non-intrusive, self-testing method for modular electronic systems that uses existing components '369 Patent, col. 2:29-31 The system's main module selects an idle line to serve as an "aid line" and instructs the connected subsidiary module to loop back any traffic it receives on that line Compl. ¶18 The main module then selects a second idle line for testing, configures an internal switch to link the test line and the aid line, and instructs the second subsidiary module to transmit test traffic Compl. ¶18 If this traffic successfully travels through the switch to the first module, loops back, and returns to the second module, the path is deemed functional; otherwise, a failure is reported '369 Patent, abstract The system architecture is depicted in a figure reproduced in the complaint Compl. ¶17, p. 8
• Technical Importance: This approach enabled automated, background failure testing on idle network lines without disrupting live traffic on active lines or requiring additional hardware, thereby improving system reliability and uptime Compl. ¶17

Key Claims at a Glance

• The complaint asserts independent claims 1 (a method) and 15 (an apparatus), along with dependent claims 2, 18, and 22 Compl. ¶15
• Independent Claim 1 (Method) includes the elements of:
  • In an electronic system with a main module and at least first and second subsidiary modules connected by lines, selecting a first idle line to serve as an aid line.
  • Instructing the first subsidiary module to loop back traffic from the aid line.
  • Selecting a second idle line connected to the second subsidiary module for testing.
  • Configuring a switch on the main module to link the ports associated with the first and second idle lines.
  • Transmitting test traffic from the second subsidiary module over the second idle line, which is conveyed via the switch to the aid line.
  • Reporting a failure if the test traffic does not return to the second subsidiary module within a predetermined time Compl. ¶18
• Independent Claim 15 (Apparatus) includes the elements of:
  • A modular electronic apparatus comprising a backplane, a main module with a switch, and at least first and second subsidiary modules.
  • A system control processor operative to perform the steps analogous to method claim 1: select an idle trace as an aid trace, instruct the loopback, select a second idle trace for testing, configure the switch to link them, cause test traffic to be transmitted, and report a failure if the traffic does not return Compl. ¶24

U.S. Patent No. 7,113,485 - "LATENCY EVALUATION IN A RING NETWORK"

The Invention Explained

• Problem Addressed: The patent seeks to provide a simple and accurate method for measuring network latency, particularly round-trip latency between pairs of nodes in bidirectional ring networks Compl. ¶39 '485 Patent, col. 2:65-67 Prior art methods were often limited to unidirectional measurements, measured latency for an entire ring rather than specific node pairs, or required costly and complex clock synchronization between nodes to achieve accuracy '485 Patent, col. 2:38-55
• The Patented Solution: The invention proposes a method where an originating node sends a "latency measurement packet" (LMP) to a peer node on one ring (e.g., the inner ring) '485 Patent, col. 3:28-46 The peer node records its time of receipt and its time of transmission before sending the packet back to the originating node on the opposing ring (e.g., the outer ring) '485 Patent, col. 3:33-37 By comparing the timestamps recorded by the peer node (using its own clock) with the timestamps recorded by the originating node (using its own clock), the net round-trip latency can be calculated without requiring the clocks to be synchronized '485 Patent, col. 3:40-49 The packet can also be designated for a specific class of service to measure latency for different traffic priorities '485 Patent, abstract
• Technical Importance: This solution enabled accurate, class-of-service-specific latency measurements, which are critical for providers to monitor and enforce Service Level Agreements (SLAs) for real-time applications like voice and video Compl. ¶39 '485 Patent, col. 2:56-64

Key Claims at a Glance

• The complaint asserts at least independent claim 16 (an apparatus) Compl. ¶84
• Independent Claim 16 (Apparatus) includes the elements of:
  • An apparatus for measuring latency in a network with multiple classes of service, comprising a node.
  • The node generates a latency measurement packet containing an indication that it belongs to a selected class of service.
  • The node transmits the packet so it is passed through the network at the level of service for that class.
  • The node notes a time of receipt of the packet at a destination.
  • The node calculates latency by taking a difference between the time of transmission and the time of receipt Compl. ¶40

U.S. Patent No. 7,330,431 - "MULTIPOINT TO MULTIPOINT COMMUNICATION OVER RING TOPOLOGIES"

• Patent Identification: U.S. Patent No. 7,330,431, "MULTIPOINT TO MULTIPOINT COMMUNICATION OVER RING TOPOLOGIES," issued February 12, 2008 Compl. ¶43
• Technology Synopsis: The patent addresses the problem of efficiently allocating bandwidth in a network where the logical connections required by a service (e.g., a hub-and-spoke configuration) differ from the physical network topology (e.g., a ring) Compl. ¶¶45-46 The invention provides for a controller that receives a definition of the logical connections, determines their bandwidth requirements, maps the logical topology onto the physical topology, and allocates bandwidth on the underlying physical links accordingly '431 Patent, abstract Compl. ¶46
• Asserted Claims: The complaint asserts at least independent claim 25 Compl. ¶94
• Accused Features: The accused instrumentalities are Cisco's "Collaboration Platform" Compatible Products, such as the Cisco BE7000 Compl. ¶63 The complaint alleges these products comprise a controller that performs the claimed steps of defining logical connections, determining bandwidth needs, mapping them to the physical network, and allocating bandwidth Compl. ¶94 Compl. Ex. 10

U.S. Patent No. 7,593,400 - "MAC ADDRESS LEARNING IN A DISTRIBUTED BRIDGE"

• Patent Identification: U.S. Patent No. 7,593,400, "MAC ADDRESS LEARNING IN A DISTRIBUTED BRIDGE," issued September 22, 2009 Compl. ¶49
• Technology Synopsis: The patent presents a method for MAC address learning in a distributed bridge, such as those used in Virtual Private LAN Services (VPLS), particularly when Link Aggregation (LAG) groups are involved Compl. ¶51 The method uses separate forwarding databases (FDBs) on each line card within a network node and provides for sending messages between the line cards to ensure their FDBs remain synchronized regarding the association of MAC source addresses with ingress ports '400 Patent, abstract Compl. ¶52
• Asserted Claims: The complaint asserts at least independent claim 1 Compl. ¶104
• Accused Features: The accused instrumentality is the Cisco ASR 9000 series Compl. ¶63 The complaint alleges these products implement the claimed method of operating as a distributed MAC bridge with per-line-card FDBs and a mechanism for synchronizing MAC address associations Compl. ¶104

U.S. Patent No. 9,118,602 - "TUNNEL PROVISIONING WITH LINK AGGREGATION"

• Patent Identification: U.S. Patent No. 9,118,602, "TUNNEL PROVISIONING WITH LINK AGGREGATION," issued August 25, 2015 Compl. ¶55
• Technology Synopsis: The patent describes a method for provisioning tunnels (such as MPLS tunnels) over a LAG group Compl. ¶¶57-58 To ensure that all packets for a given tunnel traverse the same physical link within the LAG, the invention assigns a single physical port to the tunnel and encodes that port's serial number into a sub-set of bits in the data packet's label (e.g., the MPLS label) '602 Patent, abstract Compl. ¶59 A downstream switch can then read this encoded information to direct the packet to the correct physical port '602 Patent, abstract
• Asserted Claims: The complaint asserts at least independent claim 1 Compl. ¶114
• Accused Features: The accused instrumentality is the Cisco Nexus 9000 Series Switches Compl. ¶63 The complaint alleges these products utilize the claimed method of assigning a physical LAG port to a tunnel and encoding the port information within the packet label for routing Compl. ¶114

III. The Accused Instrumentality

Product Identification

The accused instrumentalities include the Cisco ASR 9000 Series routers, the Cisco Nexus 9000 Series Switches, and Cisco's "Collaboration Platform" Compatible Products (e.g., Cisco BE7000) Compl. ¶63

Functionality and Market Context

• The complaint identifies the accused products as enterprise and service-provider-grade networking hardware Compl. ¶62 The Cisco ASR 9000 is described as an "Aggregation Services Router" Compl. ¶65, Ex. 11 The Cisco Nexus 9000 is a series of data center switches Compl. ¶65, Ex. 13
• Cisco's "Collaboration Platform," exemplified by the BE7000, is described in an attached exhibit as a system for "On-Premises Deployments" that provides services such as voice communications, video, and conferencing Compl. Ex. 10, p. 3 A Cisco design guide for this platform shows a network architecture comprising various nodes and links across a headquarters and multiple branch sites Compl. Ex. 10, p. 5, Fig. 1-1 This platform is alleged to employ a "holistic approach to bandwidth management" including "end-to-end QoS architecture, call admission control, and video rate adaptation" Compl. Ex. 10, p. 4
• The complaint alleges that Defendant markets, advertises, and distributes these products with data sheets, manuals, and configuration guides that describe their infringing functionalities Compl. ¶65

IV. Analysis of Infringement Allegations

The complaint incorporates by reference expert reports and claim charts from attached exhibits to detail its infringement allegations Compl. ¶65 Exhibits detailing the infringement theories for the '369 and '485 patents were not provided with the complaint document.

'369 Patent Infringement Allegations

The complaint alleges that the Cisco Nexus 9000 Series Switches infringe one or more claims of the '369 patent, including claim 15 Compl. ¶¶63, 74 The specific technical basis for this allegation is contained in expert reports (Exhibits 6 and 8), which are incorporated by reference but not provided Compl. ¶74 Without these exhibits, a detailed comparison of the claim elements to the accused functionality is not possible. The complaint's narrative asserts that Defendant's acts of making, using, and selling the products, along with providing instructional materials to customers, constitute direct, induced, and contributory infringement Compl. ¶¶74-77

'485 Patent Infringement Allegations

The complaint alleges that the Cisco ASR 9000 products infringe one or more claims of the '485 patent, including claim 16 Compl. ¶¶63, 84 As with the '369 patent, the detailed infringement theory is located in expert reports (Exhibits 6 and 8) that are incorporated by reference but not provided Compl. ¶84 The complaint's narrative theory posits direct infringement through the product's operation and indirect infringement through Defendant's marketing, sales, and distribution of user guides Compl. ¶¶84-87 A detailed element-by-element analysis is not possible based on the provided documents. An exhibit included with the complaint illustrates a Cisco network architecture for its collaboration platform, showing a "Central Site" and multiple branches connected via an "MPLS VPN" Compl. Ex. 10, p. 7, Fig. 8-23 This visual evidence depicts the type of complex, multi-site network environment where technologies like those in the asserted patents would be deployed.

V. Key Claim Terms for Construction

Claim Term: "idle line" / "idle trace"

• Context and Importance: This term is fundamental to the patent's core concept of "non-intrusive" testing. The definition of "idle" will be critical for determining infringement, as it dictates the conditions under which the patented method can be practiced. Practitioners may focus on this term because its scope will determine whether the method applies only to completely inactive connections or also to lines with intermittent traffic.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The claim recites "at least some of which lines are sometimes idle," which may support an interpretation that "idle" refers to a temporary state, such as the time between data packet transmissions, rather than a line being permanently out of service '369 Patent, cl. 1:4-5
  • Evidence for a Narrower Interpretation: The background section describes hidden failures occurring "when [equipment] is idle between operational periods," which could suggest a more prolonged state of inactivity '369 Patent, col. 1:12-13 An argument could be made that the invention is directed at testing components that are configured but not actively provisioned for service, rather than testing for momentary gaps in live traffic.

Claim Term: "latency measurement packet"

• Context and Importance: The identity and characteristics of this specific packet are central to the infringement analysis. The dispute may turn on whether any packet used for timing measurements meets the claim limitation, or if a packet must have specific structural attributes or be part of a particular protocol to qualify.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: Claim 16 itself provides a functional definition, stating the packet is one "containing an indication that the packet belongs to a selected one of the classes of service" '485 Patent, cl. 16:3-5 This suggests any packet that can be identified and prioritized by class of service for the purpose of measurement could meet the definition.
  • Evidence for a Narrower Interpretation: The detailed description outlines a specific "latency measurement protocol" and a packet format (LMP) with distinct fields such as "Type," "Loopback (LE)," and "Serial number (SN)" '485 Patent, col. 7:20-44 A defendant may argue that these specific fields, described as part of the invention, implicitly define the "latency measurement packet" and narrow the claim's scope.

VI. Other Allegations

Indirect Infringement

For all five asserted patents, the complaint alleges both induced and contributory infringement. The basis for inducement is the allegation that Defendant encourages infringement by providing customers with products along with "data sheets, manuals, and guides" that instruct on their infringing use Compl. ¶¶76, 86, 96, 106, 116 The basis for contributory infringement is the allegation that the accused products are especially designed for an infringing use and are not staple articles of commerce with substantial non-infringing uses Compl. ¶¶77, 87, 97, 107, 117

Willful Infringement

The complaint alleges willful infringement for all five asserted patents. The primary basis is alleged pre-suit knowledge dating back to at least March 2017, when a prior owner of the patents, Orckit IP, allegedly initiated licensing discussions with Defendant regarding a portfolio that included the asserted patents Compl. ¶¶66-67 The complaint cites specific correspondence, including a November 2018 email in which Orckit IP allegedly identified the '485 patent and offered to provide "evidence of use charts" Compl. ¶71 Willfulness is also alleged based on knowledge acquired no later than the filing of the complaint Compl. ¶¶79, 89, 99, 109, 119

VII. Analyst's Conclusion: Key Questions for the Case

1. Architectural Mapping: A recurring question will be whether the specific network architectures described and claimed in the patents, which date from the early-to-mid 2000s, can be conceptually mapped onto the functionality of modern, complex Cisco products. For example, can the "main module" and "subsidiary module" architecture of the '369 patent be shown to exist, either literally or equivalently, within a Cisco Nexus 9000 switch?
2. Impact of Prior Proceedings: The pre-suit history, particularly the PTAB's decision to deny institution of an IPR against the '369 patent, will be a significant point of focus. A key question for the court will be what influence, if any, the PTAB's finding of "no reasonable likelihood" of invalidity on obviousness grounds has on the district court's own validity analysis.
3. Willfulness and Pre-Suit Knowledge: The extensive allegations of pre-suit notice and licensing discussions raise a central question regarding willfulness. The case will likely examine the substance of the communications between Defendant and the prior patent owner to determine if Defendant had the requisite knowledge and intent to support a finding of willful infringement from a date well before the lawsuit was filed.