PTAB

IPR2025-01523

Cisco Systems Inc v. Dynamic Mesh Networks Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Controlling Wireless Mesh Networks
  • Brief Description: The ’952 patent describes a method for managing an adaptive wireless mesh network composed of multiple relay nodes (access points). The method involves dynamically selecting a new parent relay node for a child node when a channel change is needed to meet a performance requirement, such as throughput or latency.

3. Grounds for Unpatentability

Ground 1: Obviousness over Ganz and Srikrishna - Claims 1-3, 5-10, 12-14, and 16-20 are obvious over Ganz in view of Srikrishna.

  • Prior Art Relied Upon: Ganz (Patent 6,584,080) and Srikrishna (Patent 7,031,293).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Ganz disclosed the core elements of a wireless mesh network with multiple repeaters (relay nodes) capable of reconfiguring their topology. Ganz’s system performed automatic link testing based on performance metrics like throughput and packet drop rates and could switch to "back-up links" if a primary link failed. This switching process inherently involved dynamically selecting a new relay node. Petitioner asserted that Ganz taught a scenario where two "sibling" repeaters (both connected to the same parent) could reconfigure upon a link failure such that one becomes the new parent to the other, thus forming a new parent-child relationship. Srikrishna was argued to supply the missing detail of making a channel selection change to meet a performance requirement. Srikrishna taught using separate channels for uplink and downlink traffic to minimize interference and improve link quality metrics like throughput, thereby providing a specific method for implementing the channel selection change recited in the claims.
    • Motivation to Combine: A POSITA would combine the references because they addressed the same problem of improving performance in multi-hop wireless networks. Petitioner contended that Ganz provided a general framework for link monitoring and failover but was light on implementation details for channel selection. Srikrishna provided a well-known technique (using distinct channels for uplink/downlink) to improve a similar system (Ganz's network) in a predictable way by reducing interference and increasing throughput.
    • Expectation of Success: A POSITA would have a high expectation of success because both references disclosed relay nodes with similar dual-transceiver architectures. Furthermore, both Ganz and Srikrishna contemplated using the IEEE 802.11 standard, which would ensure technological compatibility and interoperability, making the combination straightforward.

Ground 2: Obviousness over Ganz, Srikrishna, and Bishop - Claims 4 and 15 are obvious over Ganz and Srikrishna in view of Bishop.

  • Prior Art Relied Upon: Ganz (Patent 6,584,080), Srikrishna (Patent 7,031,293), and Bishop (Patent 6,377,782).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon the combination in Ground 1 to address the specific limitation of making a channel change to meet a "latency requirement" (claims 4 and 15). While Ganz and Srikrishna focused on metrics like throughput and packet loss, Bishop explicitly taught monitoring a wireless link's adequacy based on a predetermined threshold for the "latency of upstream data packet transmission." Bishop disclosed that if the link's performance fell below this latency threshold, the system would establish an alternate communications link.
    • Motivation to Combine: Petitioner argued that a POSITA seeking to optimize the Ganz/Srikrishna network for time-sensitive applications like voice (which Ganz mentioned) would be motivated to incorporate Bishop's teachings. Latency is a critical performance metric for real-time applications, and Bishop provided a known and direct method for using latency thresholds to trigger link switching. This was presented as a simple addition of a known technique (latency-based switching) to an existing system to improve its functionality for a known purpose.

Ground 3: Obviousness over Ganz, Srikrishna, and IEEE 802.11 - Claims 11 and 21 are obvious over Ganz and Srikrishna in view of the IEEE 802.11 Standard.

  • Prior Art Relied Upon: Ganz (Patent 6,584,080), Srikrishna (Patent 7,031,293), and IEEE 802.11 (ANSI/IEEE Std 802.11, 1999 ed.).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addressed the limitation of "receiving a monitoring signal that includes information about available nodes from which the second node is selected" (claims 11 and 21). Petitioner asserted that the IEEE 802.11 standard—which both Ganz and Srikrishna expressly incorporated—disclosed such a signal. Specifically, the standard specified that wireless nodes must transmit and scan for beacon frames. These beacon frames functioned as monitoring signals containing capability information about available nodes, and they were routinely used within a network to discover, assess, and maintain connections with neighboring nodes.
    • Motivation to Combine: The motivation was exceptionally strong, as Ganz and Srikrishna already directed a POSITA to the IEEE 802.11 standard. A POSITA implementing the failover system of Ganz would naturally turn to the protocols within the referenced IEEE 802.11 standard to accomplish network discovery and identify potential back-up links. Using the standard's mandatory beaconing feature for this purpose was argued to be a logical and obvious design choice.

4. Key Claim Construction Positions

  • Petitioner stated that no formal claim construction was necessary for the petition. However, Petitioner clarified its understanding that the term "a first one of the plurality of relay nodes" in step (b) of claim 1 provided the antecedent basis for "the first relay node" in step (c). Petitioner also noted that the prior art rendered the claims obvious regardless of whether the steps were causally connected.

7. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-21 of the ’952 patent as unpatentable under 35 U.S.C. §103.