PTAB

IPR2015-01510

Cisco Systems Inc v. Network Congestion Solutions LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Network Congestion Control System and Method
  • Brief Description: The ’620 patent discloses a system and method for alleviating congestion in a communication network. The technology involves monitoring data flows for indications of congestion and controlling the data rate of one or more end-user devices in response to those indications.

3. Grounds for Unpatentability

Ground 1: Claims 1, 6, 9, 13, and 16 are obvious over Vaid in view of Packer ’216.

  • Prior Art Relied Upon: Vaid (Patent 6,078,953) and Packer ’216 (Patent 6,038,216).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Vaid taught a gateway positioned between end-points and a network that implements a "source TCP rate control" method. Vaid’s gateway monitored network conditions like round-trip times and available bandwidth to detect congestion. In response, it controlled the data rate of source end-points by modifying TCP window sizes and delaying acknowledgment signals, which Petitioner asserted mapped directly to the core limitations of independent claims 1 and 13.
    • Motivation to Combine: Petitioner contended that while Vaid disclosed a rate-control gateway, its network diagrams did not explicitly show other ubiquitous components like routers. Packer ’216, however, taught the conventional architecture of connecting end systems to a network via multiple communication devices, including routers. A person of ordinary skill in the art (POSITA) would combine Packer ’216’s conventional network architecture with Vaid’s rate-control functionality to create a complete, operational network, yielding predictable results.
    • Expectation of Success: A POSITA would have a high expectation of success because the combination involved integrating a known rate-control system (Vaid) into a standard network topology using conventional components (Packer ’216) to achieve its expected function.

Ground 2: Claims 2, 3, 7, 8, 10, 14, 15, and 17 are obvious over Vaid, Packer ’216, and Packer ’630.

  • Prior Art Relied Upon: Vaid (Patent 6,078,953), Packer ’216 (Patent 6,038,216), and Packer ’630 (Patent 6,456,630).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addressed dependent claims reciting specific network types. Petitioner argued that Packer ’630 disclosed rate control for TCP data that is encapsulated and mapped to underlying Frame Relay or Asynchronous Transfer Mode (ATM) networks. Packer ’630 also taught that its rate control device could be implemented in a frame relay access device (FRAD), which corresponds to the claimed frame relay access unit (FRAU).
    • Motivation to Combine: Petitioner highlighted that Packer ’630 expressly incorporated Packer ’216 by reference, making the combination explicit. A POSITA would be motivated to apply the general TCP rate control methods of the Vaid/Packer ’216 combination to the specific, widely used network environments (Frame Relay, ATM) described in Packer ’630 to improve quality of service in those networks.
    • Expectation of Success: Applying known TCP-level rate control techniques to different, but common, underlying network transport technologies like Frame Relay and ATM was a predictable implementation with a high expectation of success.

Ground 3: Claims 4, 5, 11, 12, 18, and 19 are obvious over Vaid, Packer ’216, and Floyd.

  • Prior Art Relied Upon: Vaid (Patent 6,078,953), Packer ’216 (Patent 6,038,216), and Floyd (an August 1995 article in IEEE/ACM TRANS. ON NET.).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addressed claims requiring the classification of data flows into "mission critical" and "non-mission critical" categories and controlling data rates based on that classification. Petitioner asserted that Vaid taught a basic classification of data flows into priority levels like "business critical" and "casual." Floyd was cited for teaching a detailed and robust framework for link-sharing and priority-based scheduling to manage bandwidth allocation among different traffic classes.
    • Motivation to Combine: Petitioner argued that while Vaid introduced the concept of prioritization, Floyd provided a more sophisticated and effective method for its implementation. A POSITA would be motivated by Floyd's promise of "more efficient and productive implementations" to incorporate its advanced priority scheduling and link-sharing methods into the rate-control system of Vaid/Packer ’216. This would provide more granular and effective quality of service differentiation for critical versus non-critical traffic.
    • Expectation of Success: The combination of known rate-control techniques with known priority-based scheduling mechanisms was a well-understood approach to network management, and a POSITA would expect predictable improvements in network efficiency and performance.

4. Key Claim Construction Positions

  • "end user device": Petitioner argued for a broad construction based on a dictionary definition: "a device or computer system that utilizes a computer network for the purpose of data processing and information exchange." This construction was central to arguing that servers and clients described in the prior art meet this limitation.
  • "means for monitoring data flows... for indications of congestion" (claim 6): Petitioner proposed that the corresponding structure is a computer-implemented algorithm from the specification comprising two steps: (i) monitoring each TCP connection and maintaining a TCP state machine, and (ii) maintaining a real-time estimate of the current rate of each TCP connection.
  • "means for controlling the data rate..." (claim 6): Petitioner proposed that the corresponding structure is a computer-implemented algorithm from the specification comprising two steps: (i) controlling both the rate of TCP acknowledgement packets and the TCP window size within those packets, and (ii) using a combination of pacing the packets and/or calculating the TCP window size needed to maintain the desired data rate.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-19 of the ’620 patent as unpatentable.