PTAB

IPR2020-00338

Juniper Networks Inc v. Packet Intelligence LLC

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Key Events
Petition
petition Intelligence

1. Case Identification

2. Patent Overview

  • Title: Method and Apparatus for Identifying Flows in a Computer Network
  • Brief Description: The ’751 patent relates to systems and methods for monitoring network traffic. The purported invention addresses the problem of "disjointed flows" by providing a technique to recognize that multiple, separate connection flows belong to the same higher-level "conversational flow" based on a specific software application's activity.

3. Grounds for Unpatentability

Ground 1: Claims 1-2, 5, 10, 14-15, and 17 are obvious over Riddle in view of Ferdinand.

  • Prior Art Relied Upon: Riddle (Patent 6,412,000) and Ferdinand (WO 92/19054).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Riddle teaches a packet monitor that classifies network traffic based on application-level attributes. Specifically, Riddle discloses grouping multiple, distinct connection flows (e.g., the command and data channels of an FTP session) into a single "service aggregate." Petitioner contended this teaching directly maps to the ’751 patent’s central concept of a "conversational flow." Riddle also teaches looking up flow information in lists to determine if a packet belongs to a new or existing flow. Ferdinand, a reference describing network monitoring, was argued to teach the use of a robust database structure for storing examined packet and flow-entry information, including protocol identifiers, addresses, and hashes.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Riddle’s classification system with Ferdinand’s database structure. This combination was presented as a predictable design choice to gain the enhanced functionality of a database—such as improved searching, analysis, and modification of flow-entries—and to allow multiple network operators to access the classification information simultaneously.
    • Expectation of Success: A POSITA would have had a high expectation of success, as combining a traffic classification engine with a database for storing the resulting data was a well-known and conventional approach in network monitoring.

Ground 2: Claims 1-2, 5, 10, 14-15, and 17 are obvious over Riddle in view of Ferdinand and further in view of Yu.

  • Prior Art Relied Upon: Riddle (Patent 6,412,000), Ferdinand (WO 92/19054), and Yu (Patent 6,625,150).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground incorporated the arguments from Ground 1 and added Yu to further strengthen the teachings on conversational flows and state tracking. Petitioner asserted that Yu discloses a policy engine that classifies traffic into "flows" which can comprise multiple "streams" (analogous to connection flows), thus teaching the "conversational flow" concept. Critically, Yu was argued to teach sophisticated, stateful packet inspection where the "application’s flow classification logic keeps track of the flow’s state until a matching criteria is met."
    • Motivation to Combine: A POSITA, seeking to improve the Riddle and Ferdinand system, would have been motivated to incorporate Yu’s teachings for more flexible and efficient state-tracking logic. Petitioner argued that implementing Yu's stateful inspection techniques would be a straightforward modification to enhance Riddle’s classification process without changing its fundamental principles of operation.
    • Expectation of Success: The combination was presented as predictable, as Yu provides an evolved but compatible method for stateful flow classification that a POSITA would readily apply to the system disclosed by Riddle and Ferdinand.

Ground 3: Claims 1-2, 5, 10, 14-15, and 17 are obvious over Riddle in view of Ferdinand and further in view of RFC1945.

  • Prior Art Relied Upon: Riddle (Patent 6,412,000), Ferdinand (WO 92/19054), and RFC1945 (Hypertext Transfer Protocol -- HTTP/1.0).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground also built upon Ground 1, adding RFC1945 to demonstrate that linking separate connections to form a "conversational flow" was a known technique, particularly in the context of web traffic. Petitioner highlighted that RFC1945, the standard for HTTP/1.0, discloses the "Referer" header field. This field explicitly provides the source URI of a request, thereby linking a new HTTP request to a previous one. Petitioner noted that Patent Owner’s own expert in related litigation had identified the use of Referer fields as a way to create a "conversational flow."
    • Motivation to Combine: A POSITA implementing Riddle’s packet classifier, which explicitly contemplates classifying "Web aware" traffic, would have been motivated to consult and use the well-known HTTP/1.0 standard defined in RFC1945. Using the Referer field as taught by RFC1945 provides a direct, known, and obvious way to link otherwise disjointed flows, thereby identifying "conversational flows."
    • Expectation of Success: Success would be expected because implementing a standard protocol feature (the Referer header) within a protocol-aware classifier is a routine task in network engineering.

4. Key Claim Construction Positions

  • “Conversational Flow(s)”: Petitioner argued this term should be construed as "the sequence of packets that are exchanged in any direction as a result of specific software program activity, where such packets form multiple connection flows that are linked based on that activity." This proposed construction was based heavily on Patent Owner's own arguments and expert testimony in prior district court litigation, where Patent Owner allegedly defined the term narrowly to overcome prior art.
  • “New Flow” / “Existing Flow”: Petitioner argued that based on the claim language and logic, these terms should be construed to mean "new conversational flow" and "existing conversational flow," respectively. This construction was asserted to be consistent with prior Board findings on a related patent.
  • “Flow-Entry Database”: Petitioner contended this term should be construed as a "database having a separate entry for each encountered conversational flow." This was based on statements made during the prosecution of a related patent to distinguish the invention from prior art that did not maintain such distinct entries.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under §325(d) or §314(a) would be inappropriate.
  • The primary argument was that the Examiner did not consider any of the four prior art references asserted in the petition (Riddle, Ferdinand, Yu, RFC1945) during the original prosecution.
  • Petitioner also distinguished this petition from a prior, denied IPR (IPR2017-00451) by noting the prior petition relied on a different primary reference (Engel) and that the current arguments based on the Riddle-Ferdinand combination are substantially different. A second prior IPR was terminated by joint motion before any decision on the merits.

6. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-2, 5, 10, 14-15, and 17 of Patent 6,839,751 as unpatentable.