Cisco Systems Inc v. Portsmouth Network Corp

1. Case Identification

• Case #: IPR2024-00503
• Patent #: 7,035,279
• Filed: January 26, 2024
• Petitioner(s): Cisco Systems, Inc.
• Challenged Claims: 1-18

2. Patent Overview

• Title: Flow Allocation In A Ring Topology
• Brief Description: The ’279 patent relates to a method for controlling data flow allocation in a communication network arranged in a ring topology. The system employs a central "dispatcher" to allocate resources like bandwidth to various nodes and to select between clockwise and counterclockwise data paths, choosing the path with the lower level of current resource utilization.

3. Grounds for Unpatentability

Ground 1: Obviousness over Kovvali and Kalman - Claims 1-5 and 9-18 are obvious over Kovvali in view of Kalman.

• Prior Art Relied Upon: Kovvali (Patent 6,920,113) and Kalman (Patent 6,680,912).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Kovvali discloses the core architecture of the ’279 patent, including a bi-directional line switched ring (BLSR) network with an "arbiter" node that functions like the claimed "dispatcher." Kovvali’s arbiter allocates bandwidth resources in discrete "quanta" (disclosed as "columns" of a frame) to client nodes and manages requests for additional bandwidth. Kalman supplements this by teaching a method for selecting a preferred path (clockwise or counterclockwise) in such a ring network based on the "lowest cost," where cost is a function of factors including "the level of traffic congestion." The combination, therefore, discloses a network with a dispatcher that allocates resources and selects a path based on resource usage levels.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Kalman's efficient, lowest-cost path selection technique with Kovvali's dynamic resource allocation framework. This combination would be a predictable way to improve the efficiency of data transmission in Kovvali's multi-path ring network by intelligently selecting the less congested of the two available paths.
  • Expectation of Success: A POSITA would have a high expectation of success, as both references describe similar network architectures (bi-directional optical ring networks) and their respective technologies are directly compatible and complementary.

Ground 2: Obviousness over Kovvali, Kalman, and Masters - Claim 6 is obvious over Kovvali and Kalman in view of Masters.

• Prior Art Relied Upon: Kovvali (Patent 6,920,113), Kalman (Patent 6,680,912), and Masters (Patent 5,920,697).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground builds on the combination of Kovvali and Kalman to address claim 6, which recites that the allocated resources comprise "processing power associated with each of the links." Masters teaches a method for selecting a network route based on the lowest total cost, and it explicitly discloses that the cost calculation can incorporate various measures of resources, including the "processing power used to send a message by that connector."
  • Motivation to Combine: A POSITA, seeking to create a more robust cost calculation for the path selection method taught by Kalman, would be motivated to look to other known techniques like that in Masters. Incorporating the processing power of nodes or links into the cost metric is a known way to further optimize network routing decisions, especially in networks where node processing capability can be a bottleneck.
  • Expectation of Success: Masters explicitly states its techniques "find applicability in any network that transmits information between different nodes," making its application to the Kovvali/Kalman network straightforward and predictable.

Ground 3: Obviousness over Kovvali, Kalman, and RFC2892 - Claims 7-8 are obvious over Kovvali and Kalman in view of RFC2892.

• Prior Art Relied Upon: Kovvali (Patent 6,920,113), Kalman (Patent 6,680,912), and RFC2892 (an IETF standard dated August 2000).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground also builds on the Kovvali and Kalman combination to address claims 7 and 8, which recite comparing a resource request to a "resource budget" and permitting the flow only if the budget is not exceeded. Petitioner asserted that since Kovvali explicitly mentions using a Spatial Reuse Protocol (SRP), a POSITA would consult the defining IETF standard, RFC2892. RFC2892 describes an SRP Fairness Algorithm that uses a max_usage variable, a per-node parameter that functions as a configurable resource budget to limit the traffic a node can send.
  • Motivation to Combine: A POSITA implementing the SRP disclosed in Kovvali would naturally be motivated to consult the official RFC2892 standard for implementation details. This standard provides a known and standardized method for ensuring fair bandwidth allocation among nodes, a critical consideration in shared-media networks. The max_usage parameter directly provides the "resource budget" limitation recited in the challenged claims.

4. Arguments Regarding Discretionary Denial

• §325(d) Denial: Petitioner argued that discretionary denial under §325(d) is inappropriate because the asserted prior art combinations were never presented to the examiner. Specifically, the primary reference, Kovvali, was not considered during prosecution but teaches the key feature ("without requesting additional resources") that the Patent Owner relied upon to gain allowance.
• Fintiv Denial: Petitioner contended that discretionary denial under Fintiv is not warranted. The parallel district court litigation is in its earliest stages, with the IPR petition having been filed just over one month after the patent owner served its infringement contentions. The scheduled district court trial date (June 2025) is only one month before the statutory deadline for a Final Written Decision (July 2025). Petitioner also stated its intent to stipulate that it will not pursue in district court any ground on which the IPR is instituted.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-18 of Patent 7,035,279 as unpatentable under 35 U.S.C. §103.