PTAB

IPR2017-01714

Cavium Inc v. Alacritech Inc

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Petition
petition Intelligence

1. Case Identification

2. Patent Overview

  • Title: Freeing Transmit Memory on a Network Interface Device Prior to Receiving an Acknowledgement that Transmit Data Has Been Received by a Remote Device
  • Brief Description: The ’104 patent describes a method and system for offloading host protocol processing, specifically TCP/IP functions, to an intelligent network interface device (NIC). The purported invention is a NIC that sends an indication to the host computer that data has been transmitted to the network before the NIC receives a final delivery acknowledgement (ACK) from the remote destination, thereby freeing up host resources more quickly.

3. Grounds for Unpatentability

Ground 1: Claims 1, 6, 9, 12, 15, and 22 are obvious over Connery in view of the knowledge of a POSA.

  • Prior Art Relied Upon: Connery (Patent 5,937,169).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Connery teaches all limitations of the challenged claims. Connery discloses a smart NIC that offloads TCP segmentation from a host computer to reduce host CPU utilization. The central dispute involves the ’104 patent’s core limitation: sending a transmit completion signal to the host before receiving a final ACK from the remote device. Petitioner contended that Connery’s teaching of reducing host interrupts to "one per ‘large packet’" would be understood by a Person of Ordinary Skill in the Art (POSA) as a "transmit completion interrupt." This interrupt, sent from the NIC to the host upon successful transmission of a large data block, necessarily occurs before the final ACK arrives from the remote destination due to network latency. Therefore, Petitioner asserted that Connery’s disclosure of a "transmit completion" interrupt inherently teaches the key limitation of the ’104 patent.
    • Motivation to Combine (for §103 grounds): This ground is based on a single reference plus the knowledge of a POSA. The motivation to implement the system as described was inherent in Connery’s stated goal of reducing host CPU load. A POSA implementing Connery’s system would have naturally used a transmit completion interrupt—a well-known technique—to signal that the NIC was ready for the next data block, which achieves Connery’s objective.
    • Expectation of Success (for §103 grounds): A POSA would have had a high expectation of success because implementing a transmit completion interrupt was a common, well-understood, and simple technique at the time for managing data flow between a host and a peripheral device like a NIC.

Ground 2: Claims 1, 6, 9, 12, and 15 are obvious over Connery in view of Boucher.

  • Prior Art Relied Upon: Connery (Patent 5,937,169) and Boucher (WO 00/13091).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground was presented as an alternative, primarily to address the limitation of "maintaining...a Transport Control Protocol (TCP) connection" on the NIC (limitation [1.6]). Petitioner argued that to the extent Connery does not explicitly disclose this feature for bidirectional data flows, Boucher does. Boucher teaches an intelligent NIC that maintains TCP connection state, including ACK and window values, in a Connection Control Block (CCB) cache to handle fast-path processing. This directly supplies the teaching for maintaining the TCP connection on the NIC.
    • Motivation to Combine (for §103 grounds): A POSA implementing Connery’s system would combine it with Boucher’s teachings to improve performance, particularly for bidirectional traffic. Both references address the same technical problem of offloading TCP processing to a NIC. A POSA would look to solutions like Boucher’s CCB cache as a known and efficient method to manage the connection state required for the advanced offloading described in Connery.
    • Expectation of Success (for §103 grounds): There would be a high expectation of success, as this combination involves applying a known technique (Boucher's connection state management) to a similar system (Connery's offload architecture) to achieve a predictable improvement in performance.

4. Key Claim Construction Positions

  • "network interface device": Petitioner argued that this term should be given its plain and ordinary meaning. Critically, Petitioner noted that its primary prior art, Connery, discloses a NIC that functions as a peripheral card connected to the host computer's bus. This aligns with the Board's construction of the term during the ’104 patent’s prosecution, where it was distinguished from a standalone "gateway" device.
  • "prepending": Petitioner proposed this term means "adding to the front," consistent with its use in the patent's provisional application, and noted Patent Owner had not disputed this construction in related litigation.
  • Means-Plus-Function Terms (Claim 22): Petitioner contended that several terms in claim 22 (e.g., "means for receiving...a command," "means for sending...an indication") are means-plus-function terms under 35 U.S.C. §112, ¶6. Petitioner argued these terms are indefinite because the specification fails to disclose sufficient corresponding structure or algorithms for performing the claimed functions, apart from the NIC itself. In the alternative, Petitioner argued that if the terms are not indefinite, the structure disclosed in Connery meets these limitations.

5. Key Technical Contentions (Beyond Claim Construction)

  • The petition’s central technical contention was that a POSA would interpret Connery’s disclosure of reducing interrupts to "one per 'large packet'" as an explicit teaching of a "transmit completion interrupt." Petitioner asserted this single interrupt is fundamentally different from an ACK-based interrupt. It must be generated by the NIC and sent to the host immediately upon placing the data on the network, a process that is far faster than the round-trip time required to receive an ACK from a remote device. This timing difference, Petitioner argued, is the key to proving obviousness of the ’104 patent’s purported point of novelty.

6. Relief Requested

  • Petitioner requested the institution of an inter partes review and cancellation of claims 1, 6, 9, 12, 15, and 22 of the ’104 patent as unpatentable.