PTAB

IPR2018-01644

Juniper Networks, Inc. v. Parity Networks, LLC

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1. Case Identification

2. Patent Overview

  • Title: System for Fabric Packet Control
  • Brief Description: The ’963 patent discloses systems and methods for managing data packet traffic in a network routing fabric to avoid congestion, a process referred to as "flow control." The invention describes a switching element with a managed queuing system that monitors queue fullness and implements a multi-stage packet discard process, increasing the rate of discarding as the queue fills and dropping all incoming packets when the queue is full, thereby avoiding problematic upstream notifications common in conventional systems.

3. Grounds for Unpatentability

Ground 1: Claims 1-3 are obvious over Schwartz in view of Muller.

  • Prior Art Relied Upon: Schwartz (International Publication No. WO 00/02347 A2) and Muller (International Publication No. WO 00/52882 A2).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Schwartz taught a switching node within a fabric network that addresses packet congestion. Schwartz's system included internally coupled input and output ports, a managed queuing system, and a "packet meta-data processor" that functions as the claimed "queue manager." This processor monitors buffer capacity against a "predetermined threshold" and makes pass/drop decisions, including discarding packets when a queue is full. However, Petitioner contended Schwartz only suggested, but did not explicitly disclose, the claimed multi-stage packet discard rate. Muller was asserted to supply this missing element. Muller taught an "Early Random Discard of Packets" method using a "fullness gauge" and programmable "probability indicators" to discard packets at increasing rates as queue fullness crosses various thresholds, directly mapping to the limitations of initiating discards at one rate and increasing that rate as congestion worsens.
    • Motivation to Combine: Petitioner asserted a person of ordinary skill in the art (POSITA) would combine Schwartz and Muller because both references addressed the same fundamental problem of managing packet congestion in network nodes. A POSITA implementing the switching architecture of Schwartz would have been motivated to incorporate the well-known and more sophisticated random early discard techniques from Muller to improve upon Schwartz's simpler pass/drop mechanism, thereby creating a more robust and efficient system.
    • Expectation of Success: The combination was presented as a predictable application of known technologies. A POSITA would have reasonably expected that integrating Muller's established packet-dropping scheme into Schwartz's switching architecture would successfully manage network traffic with predictable results.

Ground 2: Claims 1-3 are obvious over Firoiu in view of Muller.

  • Prior Art Relied Upon: Firoiu (Canadian Patent Application No. CA 2 310 531 A1) and Muller (International Publication No. WO 00/52882 A2).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner presented Firoiu as an alternative primary reference that also taught a system for queue management to prevent buffer overflow in a network node. Firoiu disclosed a "node congestion control module" (the queue manager) that regulates queue size by adjusting a packet drop probability based on queue fullness. Firoiu's control function included defined operational ranges and thresholds, including a point at which the packet drop rate reaches one hundred percent ("qclip"), thereby teaching the monitoring and full-queue discard limitations. As in the first ground, Petitioner argued that Muller supplied the explicit teaching of a staged, increasing discard rate. Muller's programmable probability indicators, which trigger different discard rates for different queue fullness regions, provided the specific implementation for the adjustable drop probability described more generally in Firoiu.
    • Motivation to Combine: The motivation was similar to Ground 1. Firoiu and Muller both aimed to solve network congestion through intelligent packet discarding. A POSITA developing a system based on Firoiu's queue management principles would naturally look to practical and known implementations like Muller's random discard method to realize Firoiu's adjustable drop-rate concept. The shared goal of preventing network stultification would have driven the combination.
    • Expectation of Success: Petitioner argued a POSITA would have had a high expectation of success. Combining Muller's specific, programmable discard mechanism with Firoiu's conceptual framework for queue management was a straightforward integration of complementary technologies that would predictably result in an improved traffic control system.

4. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-3 of the ’963 patent as unpatentable.