F5 Networks Inc v. Radware Ltd

1. Case Identification

• Case #: IPR2017-00124
• Patent #: 9,231,853
• Filed: October 21, 2016
• Petitioner(s): F5 Networks, Inc.
• Patent Owner(s): Radware Ltd.
• Challenged Claims: 1-24

2. Patent Overview

• Title: Load Balancing
• Brief Description: The ’853 patent describes techniques for managing a "multi-homed" network where a client is connected to the Internet through multiple Internet Service Providers (ISPs). The invention uses a content router to select an optimal data route from the available ISP connections and performs network address translation (NAT) to manage traffic over the selected route.

3. Grounds for Unpatentability

Ground 1: Anticipation by Veerina - Claims 1-9 and 13-21 are anticipated by Veerina under 35 U.S.C. §102(a).

• Prior Art Relied Upon: Veerina (Patent 6,243,379).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Veerina discloses every element of the challenged claims. Veerina teaches a router circuit that connects a local area network (LAN) to the Internet through multiple single-user ISP accounts, creating a multi-homed network. The router receives client requests directed to remote servers, selects a data route (an ISP link) using a decision function (e.g., a "simple 'round robin' scheme" or a more "complex load-balancing" scheme), and performs IP address translation on both outbound requests and inbound responses to route them over the selected link. This directly maps to the method steps of independent claim 1 and the device limitations of independent claim 14.
  • Key Aspects: Petitioner asserted that Veerina's "IP translation table" and "link-selection algorithm" perform the same functions as the content router and decision function of the ’853 patent. Dependent claims were also argued to be anticipated, as Veerina discloses using metrics like link load, capacity, and cost (claim 6), availability (claim 7), and round-robin selection (claim 8).

Ground 2: Obviousness over Veerina in combination with Joshi - Claims 10-12 and 22-24 are obvious over Veerina in view of Joshi under 35 U.S.C. §103.

• Prior Art Relied Upon: Veerina (Patent 6,243,379) and Joshi (Patent 5,317,566).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner contended that Veerina teaches the foundational multi-homed network system as described in Ground 1. However, claims 10-12 and 22-24 add the specific limitation that the route selection decision function is based on a measured "proximity" between the client and server, defined to include metrics like latency and number of hops. Joshi was argued to explicitly teach a method for selecting a "least cost route" in a network based on metrics including "hop count" and "transit delay" (latency).
  • Motivation to Combine: A POSITA would combine Joshi's well-known proximity-based routing metrics with Veerina's multi-homed routing system to enhance its capabilities. Providing route selection options based on latency or hop count was a known method for optimizing network performance. A POSITA would have seen the benefit of incorporating these distinct and non-cumulative options into Veerina’s system to provide more sophisticated load-balancing capabilities.
  • Expectation of Success: Both hop count and latency were well-known network metrics, and evaluating them for different routes was straightforward. A POSITA would have had a high expectation of success in integrating Joshi's established cost-calculation methods into Veerina’s link-selection algorithm to achieve predictable performance improvements.

Ground 3: Obviousness over Guerin in combination with Veerina - Claims 8 and 20 are obvious over Guerin in view of Veerina under §103.

• Prior Art Relied Upon: Guerin (Patent 6,243,754) and Veerina (Patent 6,243,379).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that Guerin discloses a multi-homed system where a router selects from multiple ISPs based on criteria such as cost and quality of service. Claims 8 and 20 require the decision function to be based on a "round-robin selection parameter." While Guerin teaches various selection criteria, it does not explicitly name round-robin. Veerina was asserted to explicitly disclose using a "simple 'round robin' scheme" for link selection.
  • Motivation to Combine: A POSITA would have been motivated to incorporate Veerina’s simple round-robin selection method into Guerin's system. Both patents address the same problem of route selection in multi-homed networks. For applications where complex criteria like cost or QoS were unnecessary, a POSITA would have found it obvious and beneficial to implement a simple, low-computation alternative like round-robin, which was a well-known technique in the art.
  • Expectation of Success: The combination was argued to be a predictable use of prior art elements according to their established functions. Modifying Guerin's system to include the simple round-robin method from Veerina would have been trivial for a POSITA, yielding no more than the expected result of a simplified routing option.

• Additional Grounds: Petitioner asserted additional challenges, including that claims 1-7, 9, 13-19, and 21 are anticipated by Guerin, and that claims 10-12 and 22-24 are obvious over Guerin in combination with Joshi, relying on similar prior art mapping and combination rationales.

4. Key Claim Construction Positions

• "Multi-Homed Network" (Claims 1 and 14): Petitioner proposed the construction "a network that has multiple connections to the Internet." This construction was argued to be supported by the specification and the doctrine of claim differentiation, as dependent claims add the specific limitation of connections being "ISP links," implying the independent claim is broader.
• "Proximity" (Claims 10, 11, 22, and 23): Petitioner proposed that this term be construed as "a measurement or measurements based on hops, latency, TTL, or a combination thereof." This construction was based on a prior district court construction for related patents in the same family, which Petitioner argued the Board should adopt for consistency.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-24 of the ’853 patent as unpatentable.