DCT

6:20-cv-00480

WSOU Investments LLC v. Dell Tech Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 6:20-cv-00480, W.D. Tex., 10/19/2020
  • Venue Allegations: Venue is alleged to be proper based on each Defendant having established places of business, being registered to do business, and having committed alleged acts of infringement within the Western District of Texas.
  • Core Dispute: Plaintiff alleges that Defendants' Software-Defined Wide-Area-Network (SD-WAN) products infringe a patent related to preventing network congestion by adjusting packet queuing priority based on the congestion status of a packet's destination egress node.
  • Technical Context: The technology addresses traffic management within load-balancing networks, a foundational element for the performance and reliability of modern cloud computing and SD-WAN services.
  • Key Procedural History: The complaint notes that Plaintiff filed a prior suit in May 2020 asserting infringement of the same patent by the same products, which was dismissed before the current action was filed. Subsequent to the filing of this complaint, the U.S. Patent and Trademark Office issued an Ex Parte Reexamination Certificate on November 16, 2022, which cancelled asserted independent claim 1 of the patent-in-suit. This event fundamentally impacts the basis of the original complaint.

Case Timeline

Date Event
2006-03-23 ’133 Patent Priority Date
2009-05-26 ’133 Patent Issue Date
2020-05 Prior lawsuit filed (approximate)
2020-10-19 Complaint Filing Date
2022-11-16 ’133 Patent Reexamination Certificate Issued (Cancelling Claim 1)

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

U.S. Patent No. 7,539,133 - Method and Apparatus for Preventing Congestion in Load-Balancing Networks, issued May 26, 2009

The Invention Explained

  • Problem Addressed: In complex, load-balancing networks, it is difficult to prevent traffic congestion at network exit points ("egress nodes"). The patent’s background explains this is because network entry points ("ingress nodes") are typically unaware of the traffic load and conditions at distant egress nodes, making it difficult to enforce system-wide traffic constraints, known as the "hose constraint." (’133 Patent, col. 1:31-44, 1:56-59).
  • The Patented Solution: The invention proposes a method where an ingress node, upon receiving a data packet, first determines the packet's ultimate egress node. It then checks whether a "congestion condition exists" on that specific egress node. If congestion is present, the ingress node processes the packet to modify its "queuing priority," effectively marking it as less critical. This allows the network to proactively identify and manage traffic destined for a congested point at the moment it enters the network, rather than reacting after the packet has already contributed to the bottleneck. (’133 Patent, col. 2:50-59; Abstract).
  • Technical Importance: This method of providing ingress nodes with egress congestion awareness enables more intelligent, proactive traffic management, which can prevent service degradation and improve overall network performance. (’133 Patent, col. 3:17-21).

Key Claims at a Glance

  • The complaint asserts infringement of at least independent claim 1. As noted, this claim was cancelled in a 2022 reexamination proceeding.
  • The essential elements of the now-cancelled independent claim 1 include:
    • Determining an egress node for a packet at an ingress node, where the ingress node is adapted for splitting traffic flow "independent of the egress node."
    • Determining if a "congestion condition exists" on that egress node.
    • Processing packets so that those destined for non-congested egress nodes have a "different queuing priority" than packets destined for congested egress nodes.
  • The complaint’s prayer for relief seeks judgment on "one or more claims," which could potentially include surviving dependent or apparatus claims.

III. The Accused Instrumentality

Product Identification

  • The complaint identifies the "Accused Products" as cloud-related solutions, including "devices incorporating VMware's VeloCloud solutions and SD-WAN software, such as Dell EMC SD-WAN Edge 600 series products." (Compl. ¶15).

Functionality and Market Context

  • The Accused Products are alleged to provide cloud-delivered SD-WAN services that aid enterprise and cloud application performance over various network types. (Compl. ¶16). A core alleged feature is "Dynamic Multipath Optimization (DMPO) technology," which performs "packet level redirection," "path selection and remediation techniques," and "per-packet load balancing." (Compl. ¶¶17, 19). The complaint alleges these products deploy "VMware SD-WAN Gateways" in a "hub-spoke design" and use "Multi-Source Inbound QoS" to manage traffic. (Compl. ¶¶17, 20). The complaint provides a marketing image of the "Dell EMC SD-WAN Solution powered by VMware," showing a network dashboard and an associated hardware device. (Compl. p. 4).

IV. Analysis of Infringement Allegations

’133 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
determining an egress node associated with each of a plurality of packets of a traffic flow received at an ingress node adapted for splitting the traffic flow... independent of the egress node... The Accused Products operate in a "hub-spoke design" where a hub receives traffic and transmits it to spokes. This system performs "per-packet load balancing" and "Dynamic Multi-Path Optimization" to route traffic. ¶¶17, 19, 20 col. 16:26-34
determining, for each packet, whether a congestion condition exists on the egress node; and The Accused Products' "Business Policy" feature is alleged to "examine the traffic being used (whether congestion condition exists or not)." When "congestion conditions are detected at an edge," the system reacts. ¶¶20, 22 col. 16:35-37
processing the packets such that packets associated with egress nodes for which the congestion condition does not exist have a different queuing priority... than packets associated with egress nodes for which the congestion condition exists. When congestion is detected at an edge, "the edge will proactively inform the hub to slow down the low priority traffic." The complaint alleges this constitutes processing packets to have a different queuing priority based on the congestion status of the egress node. ¶¶20, 21 col. 16:38-44
  • Identified Points of Contention:
    • Procedural Question: The primary point of contention is procedural: with Claim 1 cancelled, the infringement analysis presented in the complaint is moot. The case's viability would depend on whether Plaintiff amended its allegations to assert infringement of one of the surviving claims (e.g., dependent claim 3 or apparatus claim 13).
    • Technical Question: A key technical question is whether the accused functionality of an "edge" node "inform[ing] the hub to slow down the low priority traffic" is equivalent to the claimed step of "processing the packets" at an ingress node to give them a "different queuing priority." The former describes an inter-node signaling mechanism, while the claim language may suggest a modification to the packet data itself at the ingress point.
    • Scope Question: A potential dispute over scope is whether the accused SD-WAN architecture, which relies on "Dynamic Multi-Path Optimization," meets the claim limitation of an ingress node "splitting the traffic flow... independent of the egress node." The defense could argue that such optimization is inherently dependent on the egress node or destination path, creating a mismatch with the claim language.

V. Key Claim Terms for Construction

  • The Term: "queuing priority"

    • Context and Importance: This term is central to the claimed invention, as modifying it is the core action taken in response to congestion. The outcome of the case could depend on whether the accused system's traffic management method (signaling a hub to slow traffic) is construed as changing a packet's "queuing priority."
    • Intrinsic Evidence for a Broader Interpretation: The specification describes the process in general terms, such as "process[ing] the packet for modifying the queuing priority" or "marking the packet" (’133 Patent, col. 5:32-37), which could support an interpretation that covers various methods of designating a packet for different handling, not just altering a specific data field.
    • Intrinsic Evidence for a Narrower Interpretation: Dependent claim 5, which specifies "assigning the packets... a lower queuing priority," may be used to argue that the "different" priority in claim 1 implies a direct assignment of a specific priority level to the packet itself. (’133 Patent, col. 16:56-64).

  • The Term: "ingress node adapted for splitting the traffic flow... independent of the egress node"

    • Context and Importance: This limitation defines the specific type of load-balancing network in which the invention operates. Infringement requires showing the accused system's entry point functions in this manner.
    • Intrinsic Evidence for a Broader Interpretation: The patent describes this functionality as distributing packets "evenly" or "substantially equally" over the network nodes, which could be argued to encompass a range of general load-balancing techniques. (’133 Patent, col. 3:14-16, 7:3-5).
    • Intrinsic Evidence for a Narrower Interpretation: The explicit requirement that the splitting be "independent of the egress node" is a significant qualifier. A defendant might argue that its "Dynamic Multipath Optimization" is, by definition, not independent of the destination, as it selects optimal paths to a destination, and therefore does not meet this limitation. (’133 Patent, col. 16:29-32).

VI. Other Allegations

  • Indirect Infringement: The complaint alleges inducement by asserting that Defendants provide "product descriptions, operating manuals, and other instructions" that direct end users to configure and use the Accused Products in an infringing manner. (Compl. ¶27). It also alleges contributory infringement, claiming the products are "especially made or adapted for infringing" and lack substantial non-infringing use. (Compl. ¶28).
  • Willful Infringement: Willfulness is alleged based on Defendants having "notice and actual or constructive knowledge" of the patent and their alleged infringement since at least May 2020, as a result of a prior, dismissed lawsuit filed by the Plaintiff. (Compl. ¶26).

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

  • A dispositive issue for the lawsuit is procedural and legal: given the post-filing cancellation of asserted independent claim 1 during reexamination, does the Plaintiff have a viable infringement theory under any of the surviving patent claims? The resolution of this question precedes all other technical or factual disputes.
  • Should the case proceed on a surviving claim, a central question will be one of functional mapping: does the accused SD-WAN system's method of signaling between an "edge" and a "hub" to "slow down low priority traffic" constitute the claimed invention of modifying a packet's "queuing priority" at the ingress node itself?
  • A further key issue will be one of definitional scope: does the architecture of the accused products, which utilizes "Dynamic Multipath Optimization," fall within the patent's described environment of a load-balancing network where the ingress node splits traffic "independent of the egress node," or is there a fundamental mismatch in the operational premise?