Cloudflare Inc v. Sable IP LLC

1. Case Identification

• Case #: IPR2021-01067
• Patent #: 6,954,431
• Filed: June 14, 2021
• Petitioner(s): Cloudflare, Inc.
• Patent Owner(s): Sable Networks, Inc.
• Challenged Claims: 1-9

2. Patent Overview

• Title: Micro-Flow Management
• Brief Description: The ’431 patent discloses methods for managing quality of service (QoS) for data traffic in a computer network. The technology relies on per "micro-flow" state information to control data transmission rates and delay variations, with a stated goal of damping jitter associated with a microflow.

3. Grounds for Unpatentability

Ground 1: Obviousness over Beshai and Simpson - Claims 1-8 are obvious over Beshai in view of Simpson.

• Prior Art Relied Upon: Beshai (Patent 6,034,960) and Simpson (International Publication No. WO 98/09470).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Beshai taught an Asynchronous Transfer Mode (ATM) switch that uses a scheduler to allocate bandwidth among multiple data streams ("microflows") and a cell buffer to implement a scheduling technique that reduces delay-jitter. Simpson, in turn, taught techniques for managing congestion in an ATM switch's cell buffer by partitioning the buffer based on traffic characteristics (e.g., constant bit rate, or CBR) and monitoring the partitions against specific thresholds. Petitioner contended that combining these references renders claim 1 obvious. Simpson’s method of partitioning a buffer based on traffic type taught "determining a capacity of a buffer containing a microflow based on a characteristic." Simpson’s use of congestion thresholds to monitor buffer content taught "assigning an acceptable threshold value." Beshai’s scheduler taught "delegating a portion of available bandwidth...to the microflow," and its core jitter-reduction technique taught "using the buffer for damping jitter." The dependent claims were allegedly met by further disclosures in the combination, such as assigning data rates (claim 2) and handling various traffic types (claims 3-5).
  • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine Beshai and Simpson because both address traffic management in ATM switches and their teachings are complementary. Beshai focused on scheduling outgoing traffic to reduce jitter, while Simpson focused on managing incoming traffic to prevent buffer congestion. A POSITA would have recognized that Simpson’s buffer partitioning and congestion control techniques would improve the operation of Beshai’s switch by preventing the buffer from being overloaded by bursts of incoming traffic, a known issue in such networks.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success because the combination involved applying a known technique (Simpson's memory partitioning) to a similar system (Beshai's ATM switch) to achieve the predictable result of improved congestion management.

Ground 2: Obviousness over Beshai, Simpson, and Beshai-049 - Claim 9 is obvious over Beshai and Simpson in light of Beshai-049.

• Prior Art Relied Upon: Beshai (Patent 6,034,960), Simpson (WO 98/09470), and Beshai-049 (Patent 5,881,049).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that claim 9, which depends on claim 1, adds the limitation that the "characteristic" used for determining buffer capacity "includes a microflow burst." The primary combination of Beshai and Simpson taught determining buffer capacity based on a characteristic, such as the traffic’s equivalent bit-rate (EBR). While Beshai mentioned calculating an EBR, it did not specify the method. Beshai-049, from the same inventor and assignee as Beshai, disclosed a precise technique for calculating the EBR for variable bit rate (VBR) traffic. Critically, this calculation explicitly incorporated the "burst size" of the traffic. Therefore, by supplementing the Beshai/Simpson combination with the specific EBR calculation method from Beshai-049, the resulting system would determine buffer capacity based on a characteristic (EBR) that includes a microflow burst, as required by claim 9.
  • Motivation to Combine: A POSITA seeking to implement the switch in Beshai, which required an EBR calculation, would have been motivated to consult the prior art for a suitable method. A POSITA would naturally look to Beshai-049, as it shares an inventor and assignee with Beshai and explicitly teaches a "precise technique" for this exact purpose. The stated benefits in Beshai-049, such as being fast enough for real-time call admission, would have provided further motivation for its adoption.
  • Expectation of Success: A POSITA would have had a high expectation of success because the technique in Beshai-049 was an extension of a well-known algorithm. Applying this established calculation method to the Beshai/Simpson switch would have been a straightforward implementation with predictable results.

4. Key Claim Construction Positions

• Petitioner argued for the plain and ordinary meaning of most terms but proposed constructions for two terms based on the specification and the Patent Owner's positions in related litigation.
• "guaranteed rate traffic" (claim 3): Petitioner proposed this term means "network traffic that has a guaranteed transmission rate."
• "packet discard time" (claim 8): Petitioner proposed this term means "a time value that ensures buffer availability within the switch."

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under 35 U.S.C. §314(a), considering the Fintiv factors, would be inappropriate.
• The parallel district court litigation was in a very early stage, with no scheduling order issued, no contentions exchanged, and no discovery commenced.
• Petitioner asserted it acted diligently by filing the inter partes review (IPR) petition less than three months after being served with the complaint.
• Petitioner stated it would stipulate not to pursue the same invalidity grounds in the district court case if the IPR was instituted, thereby avoiding duplicative efforts and mitigating concerns of conflicting decisions.
• Finally, Petitioner argued that the strong merits of the petition, showing a clear case of obviousness, weighed heavily in favor of institution.

6. Relief Requested

• Petitioner requested institution of IPR and cancellation of claims 1-9 of the ’431 patent as unpatentable.