PTAB

IPR2021-00984

Juniper Networks Inc v. Correct Transmission LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Multiplexing Data Streams with Different Priorities
  • Brief Description: The ’669 patent discloses a method and system for fragmenting, transmitting, and reassembling datagrams over multiple data links with multiple priority levels. The system allows a higher-priority datagram to interrupt the transmission of a lower-priority datagram, which is then resumed after the higher-priority transmission is complete.

3. Grounds for Unpatentability

Ground 1: Obviousness over Sourani, RFC1990, and Steer - Claims 1-27 are obvious over Sourani, RFC1990, and Steer.

  • Prior Art Relied Upon: Sourani (Patent 6,631,132), RFC1990 (“PPP Multilink Protocol,” Aug. 1996), and Steer (Patent 6,633,564).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Sourani taught the core concept of interrupting a lower-priority packet transmission to send a higher-priority "urgent" packet. The interruption divides the lower-priority packet into at least a first and last fragment. Petitioner contended that RFC1990, a well-known standard acknowledged by the ’669 patent, taught fragmenting packets for transmission over multiple physical links to increase bandwidth. Finally, Petitioner asserted Steer taught interrupting lower-priority packets with higher-priority ones and using a "continuation field" to indicate the number of interrupting packets, allowing for multiple, nested levels of interruption.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these references to improve network performance for time-sensitive applications. A POSITA would have been motivated to apply RFC1990’s established fragmentation and multi-link transmission techniques to Sourani’s priority interruption system to reduce latency. Further, a POSITA would have found it obvious to replace Sourani's simple "interruption bits" with Steer’s more robust "continuation field" or "interrupt level" concept. This would create a more flexible system capable of tracking multiple, nested interruptions and improving resistance to transmission errors, which was a known issue with Sourani's approach.
    • Expectation of Success: Petitioner contended a POSITA would have had a high expectation of success because all three references operate in the same field of network packet transmission and address the common problem of managing prioritized traffic. Combining known fragmentation techniques (RFC1990) with priority handling (Sourani) and then improving that handling with a more advanced field-based method (Steer) represented a predictable path of engineering improvement.

Ground 2: Obviousness over Olsson - Claims 1-4 and 8-12 are obvious over Olsson.

  • Prior Art Relied Upon: Olsson (Patent 6,577,596).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued Olsson taught a multi-layered network architecture with a "conventional priority queuing scheme" that allows higher-priority packets to be sent between fragments of lower-priority packets. This inherently discloses receiving datagrams of different priorities and interrupting the transmission of a lower-priority datagram to transmit a higher-priority one. Petitioner asserted that Olsson also taught adding a "tag" to packets for internal communication between layers, which could contain information redundant to the header.
    • Motivation to Combine (for claim 1.7): While Olsson taught adding a tag for internal use and suggested it "may be removed," Petitioner argued it would have been an obvious implementation choice for a POSITA to retain the tag and use it to store and communicate the number of interrupted datagrams to a receiver. The motivation was to improve the reliability of packet reassembly, a well-known challenge. Using an additional field for reassembly, as confirmed by the IP specification RFC791, provides redundancy and protects against transmission errors that could corrupt standard header fields.
    • Expectation of Success: A POSITA would have expected success in this modification because it involved retaining an existing, optional field rather than creating a new one. Since Olsson’s tag was non-standard, its retention would not disrupt interoperability with other network devices. The modification directly addressed the known goal of facilitating reliable packet reassembly.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge (Ground 3) for claims 5-7 and 13-27 over Olsson in view of RFC1990. This ground argued that to the extent Olsson did not explicitly detail a receiver capable of reassembling fragments from multiple links, a POSITA would have found it obvious to combine Olsson’s priority transmission scheme with the well-known receiver and reassembly teachings of the RFC1990 multilink protocol.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under either 35 U.S.C. §325(d) or §314(a) (based on Fintiv factors) would be inappropriate.
  • §325(d): The primary prior art references of Sourani, Steer, and Olsson were never considered by the Examiner during prosecution, making the petition's arguments neither cumulative nor previously addressed.
  • Fintiv Factors: Petitioner argued the factors weighed against denial because: (1) it intends to request a stay in the parallel district court litigation; (2) the court’s trial date is over a year away and speculative due to court backlogs and pending motions; (3) investment in the litigation has been minimal as the case is in its earliest stages, with fact discovery yet to begin; and (4) the inter partes review (IPR) challenges all 27 claims, whereas the district court case is limited to a small subset, and Petitioner stipulated not to pursue the same IPR grounds in court, thus promoting efficiency and avoiding duplicative efforts.

5. Relief Requested

  • Petitioner requests institution of an IPR and cancellation of claims 1-27 of the ’669 patent as unpatentable.