PTAB

IPR2016-00303

Arista Networks Inc v. Cisco Systems Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Access Control List Processing in Hardware
  • Brief Description: The ’577 patent describes techniques for enforcing access control rules in a computer network using a content-addressable memory (CAM). The system matches information from an incoming data packet against access control information stored in the CAM to generate a routing decision.

3. Grounds for Unpatentability

Ground 1: Claims 1, 2, 7-10, 12-16, 18-22, 25, and 28-31 are obvious over Huey in view of the ATM UNI Specification.

  • Prior Art Relied Upon: Huey (Patent 5,467,349) and ATM UNI Specification (ATM User-Network Interface Specification, Version 3.0).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the combination of Huey and the ATM UNI Specification taught every limitation of the challenged claims. Huey taught an address handling circuit for an Asynchronous Transfer Mode (ATM) switch that used CAMs to filter data cells based on header information, specifically the Virtual Path Identifier (VPI) and Virtual Channel Identifier (VCI). Huey’s CAMs stored VPI/VCI addresses (the "access control patterns") and compared them in parallel against the headers of incoming cells (the "packet label"). Huey further disclosed a priority circuit to select the highest-priority match when multiple matches occurred. The ATM UNI Specification, a standard for ATM networks, taught a Usage Parameter Control (UPC) function for enforcing a negotiated "Traffic Contract," which defines Quality of Service (QoS) and bandwidth parameters. The UPC function monitored traffic and made routing decisions—specifically, passing, tagging, or discarding cells—to enforce this contract. Petitioner asserted that combining these teachings rendered the method of independent claim 1 obvious: maintaining access control patterns (VPI/VCI addresses in Huey's CAMs), receiving a packet label (cell header in Huey), matching it in parallel against the patterns (Huey's parallel CAM search), selecting a match based on priority (Huey’s priority circuit), generating an access result (pass/discard decision from the ATM UNI Spec), and making a routing decision (implementing the pass/discard decision). Arguments for dependent claims were based on additional disclosures, such as Huey’s teaching of mask registers enabling "don't care" bits, which Petitioner equated to the "ternary content-associative memory" of claim 7, and its disclosure of pipelined processing for the "pipeline technique" of claim 2.
    • Motivation to Combine (for §103 grounds): A person of ordinary skill in the art (POSITA) would combine the references because Huey described an ATM switch that utilized standard User-to-Network Interfaces (UNIs). The ATM UNI Specification was the formal industry standard that defined the specific functionality of those UNIs. Therefore, a POSITA would have looked to the ATM UNI Specification to understand how the cell traffic policer and other access control features described in Huey would be implemented in a standard-compliant manner.
    • Expectation of Success (for §103 grounds): A POSITA would have had a high expectation of success because combining the references involved nothing more than applying the teachings of a standard ATM interface specification to an ATM switch explicitly designed to use such interfaces.

4. Key Claim Construction Positions

  • "access control": Petitioner argued for a broad construction encompassing "restrictions or modifications of the transmission of a packet." This construction was deemed necessary because the patent specification described access control as including not just permit/deny decisions but also implementing QoS and other administrative policies that modify routing decisions.
  • "associative memory": Petitioner proposed this term be construed to include a "content-addressable memory (CAM)." This was based on the ’577 patent’s specification, which consistently described the "associative memory" as being implemented with CAM hardware that searches all entries at once.
  • "packet label": Petitioner contended this term should be construed as "information related to the packet, such as the packet header." This construction was supported by patent examples describing the packet label as a set of selected elements from the packet header or any collection of information derived from it for access control purposes.
  • "access control specifier": For this proceeding, Petitioner adopted a construction from co-pending litigation, meaning "a specifier that includes information for matching with a packet and that may indicate, or aid in indicating, an access result."

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1, 2, 7-10, 12-16, 18-22, 25, and 28-31 of the ’577 patent as unpatentable.