Arista Networks, Inc. v. Cisco Systems, Inc.

1. Case Identification

• Case #: TBD
• Patent #: 6,377,577
• Filed: December 8, 2015
• Petitioner(s): Arista Networks, Inc.
• Patent Owner(s): Bechtolsheim & Cheriton
• Challenged Claims: 1-2, 7-10, 12-16, 18-22, 25, and 28-31

2. Patent Overview

• Title: Access Control List Processing in Hardware
• Brief Description: The ’577 patent describes techniques for enforcing access control for a computer network using a content-addressable memory (CAM). The system is designed to match information from an incoming packet against access control information stored in the CAM, analyze any matches according to priority, generate an access control result, and make a subsequent 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 teaches every element of the challenged claims. Huey discloses an address handling circuit for an asynchronous transfer mode (ATM) switch that uses CAMs (an "associative memory") to store and process access control patterns, specifically Virtual Path/Virtual Channel (VP/VC) addresses. Huey’s circuit receives packet headers (a "packet label"), compares VP/VC information from the header against the stored patterns in parallel, and uses a priority circuit to select the highest-priority match from a potential set of matches. However, Petitioner contended Huey’s "cell traffic policer" is described functionally without implementation details. The ATM UNI Specification supplies these details, describing the standard industry implementation for such a policer. It teaches a Usage Parameter Control (UPC) function that enforces administrative policies, such as a negotiated "Traffic Contract" or Quality of Service (QoS), by monitoring traffic and making a decision to pass, tag, or discard cells. This UPC functionality provides the claimed "access result" (e.g., a discard instruction) which informs the final "routing decision" for the packet.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine the references because Huey explicitly describes an ATM switch that includes a "cell traffic policer" and operates using a user-to-network interface (UNI). The ATM UNI Specification is the governing industry standard that defines the precise operation of UNIs and their associated policing functions (the UPC) for the exact type of ATM system disclosed in Huey. Therefore, a POSITA implementing Huey's system would have naturally looked to the ATM UNI Specification to understand and implement the standard functionality of its components.
  • Expectation of Success: A POSITA would have a high expectation of success in combining the teachings. The combination does not require modification of either reference but rather involves applying a standard network policing protocol (ATM UNI Specification) to a network switch (Huey) that was expressly designed to operate within that standard's framework, representing a straightforward integration of known technologies.

4. Key Claim Construction Positions

• "access control": Petitioner argued for a broad construction to mean "restrictions or modifications of the transmission of a packet." This interpretation was asserted to be critical because it encompasses not only simple permit/deny filtering but also the broader Quality of Service (QoS) and administrative policy enforcement (e.g., cell rate limiting) taught by the ATM UNI Specification.
• "associative memory": The petition asserted that this term should be construed to include a Content-Addressable Memory (CAM). This construction aligns with the specific hardware implementation disclosed in the ’577 patent's specification and is central to mapping the functionality of the CAM-based address handling circuits described in the Huey prior art onto the claims.
• "packet label": Petitioner argued this term should be construed broadly to include "information related to the packet, such as the packet header." This construction is based on disclosures in the ’577 patent and is necessary to map the cell header information used for matching in Huey to this claim element.

5. Key Technical Contentions (Beyond Claim Construction)

• Ternary CAM Functionality: Petitioner contended that the masking capability disclosed in Huey's CAMs, which allows specific bits of an address to be set as "don't care" bits during a comparison, would be immediately recognized by a POSITA as a "ternary feature." Based on this, Petitioner argued that Huey's address handling circuit inherently discloses the use of ternary CAMs, thereby directly teaching the "ternary content-associative memory" limitation of dependent claim 7.

6. 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 Patent 6,377,577 as unpatentable.