PTAB

IPR2019-01292

Nokia of America Corporation v. Packet Intelligence LLC

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1. Case Identification

2. Patent Overview

  • Title: System and method for monitoring packet-based communications
  • Brief Description: The ’646 patent discloses a system for examining network data packets to determine if a packet belongs to a previously encountered "conversational flow." The system is designed to identify and link multiple, distinct data connections that are all part of a single, higher-level user activity, such as a single application session.

3. Grounds for Unpatentability

Ground 1: Obviousness over Riddle, Wakeman, Bruins, and Cheriton - Claims 1-3, 7, 16, and 18 are obvious over Riddle in view of Wakeman and Bruins (with Cheriton added for Claim 7).

  • Prior Art Relied Upon: Riddle (Patent 6,412,000), Wakeman (Patent 5,740,175), Bruins (Patent 6,308,148), and Cheriton (Patent 6,091,725).
  • Core Argument for this Ground: Petitioner asserted that the primary limitation of a "conversational flow," which was a key issue in a previously denied IPR on the ’646 patent, is explicitly taught by Riddle. Riddle’s disclosure of “service aggregates” describes linking disjointed network connections (e.g., separate control and data channels for an FTP application) into a single traffic class, which directly corresponds to the patent’s definition of a conversational flow. The additional references provide well-known components to complete the claimed invention.
    • Prior Art Mapping:
      • Petitioner argued that Riddle teaches the core system of a packet monitor that classifies packet flows based on multi-layer protocol information. Riddle’s “service aggregates” for applications like FTP and its methods for classifying PointCast traffic (which the ’646 patent’s own provisional application identifies as a conversational flow) meet the key "conversational flow" limitation of independent claims 1, 7, and 16.
      • Wakeman was cited to add a cache subsystem using content-addressable memory (CAMs). Petitioner contended this directly teaches the “cache subsystem” of claim 1 and the “associative cache subsystem including...CAMs” of claim 3.
      • Bruins was introduced as teaching a more formal database structure for storing flow information, arguing this renders Riddle's "saved list" concept obvious as the claimed "flow-entry database" in claims 1, 7, and 16.
      • For claim 7 specifically, Cheriton was cited for its disclosure of using an "input buffer memory" to temporarily store incoming packets in a network device, meeting that claim’s limitation.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these references to achieve predictable improvements. A POSITA would combine Riddle with Wakeman's CAM-cache to increase the speed of flow lookups. Similarly, a POSITA would incorporate Cheriton’s input buffer into Riddle’s system to improve performance by reducing packet loss. Modifying Riddle’s saved list to use a more structured database as taught by Bruins was presented as a routine design choice for improved data management.
    • Expectation of Success: Petitioner argued a POSITA would have a high expectation of success, as combining these elements involves applying known solutions (caching, buffering, databases) to their conventional problems (performance, packet loss, data management) to achieve their expected results.

Ground 2: Obviousness over Riddle, Wakeman, Bruins, Cheriton, and RFC 1945 - Claims 1-3, 7, 16, and 18 are obvious over the combination of Ground 1 art further in view of RFC 1945.

  • Prior Art Relied Upon: Riddle (Patent 6,412,000), Wakeman (Patent 5,740,175), Bruins (Patent 6,308,148), Cheriton (Patent 6,091,725), and RFC 1945.
  • Core Argument for this Ground: This ground presented an alternative basis for finding the "conversational flow" limitation obvious. Petitioner argued that even if Riddle's "service aggregates" were insufficient, combining Riddle with the well-known RFC 1945 standard teaches another method for creating conversational flows. Specifically, RFC 1945 discloses the HTTP "Referer" header field, which links a current web request to a previous one. Petitioner supported this by citing testimony from the Patent Owner's own expert in related litigation, who allegedly confirmed that using the Referer field to correlate separate flows constitutes a "conversational flow."
    • Prior Art Mapping: The mapping for Riddle, Wakeman, Bruins, and Cheriton remained the same as in Ground 1. The incremental teaching from RFC 1945 was the disclosure of various HTTP header fields, including "Content-Type," "User-Agent," and, critically, "Referer." Petitioner argued that using the "Referer" field to link otherwise disjointed HTTP requests meets the "conversational flow" limitation.
    • Motivation to Combine: A POSITA, seeking to implement Riddle's teaching of classifying web traffic, would have been motivated to use all available tools for that purpose. Riddle already disclosed classifying traffic based on HTTP header types like "Content-Type" and "User-Agent." It would have been a simple, obvious step to also use other header fields defined in the contemporaneous and fundamental RFC 1945 standard, such as the "Referer" field, to improve classification by associating related web traffic.
    • Expectation of Success: Since RFC 1945 explicitly defined the "Referer" field for the purpose of linking related web pages, a POSITA would have a clear expectation that using this field in Riddle's classification system would successfully create "conversational flows" for web traffic.

4. Key Claim Construction Positions

  • "Conversational Flow[s]": This term, present in all independent claims, was central to the petition. Petitioner noted the Patent Owner had previously agreed to a construction meaning "the sequence of packets that are exchanged...as a result of an activity...where some conversational flows involve more than one connection." Petitioner argued that the prior art, particularly Riddle's "service aggregates" and the use of the HTTP "Referer" field, meets this construction by explicitly teaching the linking of multiple, separate connections that result from a single user activity.
  • Means-Plus-Function Terms: Petitioner noted a dispute over whether terms like "lookup engine," "state processor," and "parser subsystem" should be treated as means-plus-function terms. However, Petitioner asserted its invalidity arguments prevail even under the Patent Owner's proposed plain and ordinary meaning construction, which treats them as standard structural components.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that the Board should not exercise its discretion to deny institution under §314 or §325. The core reasons provided were:
    • This was the Petitioners' first IPR challenging the ’646 patent.
    • The petition presented new prior art (Riddle, Wakeman, Cheriton, Bruins, RFC 1945) and new arguments that were not considered during original prosecution or in a previous IPR filed by a different party (Sandvine), which was denied for failing to show the "conversational flow" limitation in its chosen prior art.
    • A final written decision from the Board would likely issue before a final, appealable judgment in the parallel district court litigation, promoting efficiency and avoiding conflicting results.

6. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-3, 7, 16, and 18 of the ’646 patent as unpatentable.