Cisco Systems Inc v. Sable IP LLC

1. Case Identification

• Case #: IPR2020-01721
• Patent #: 7,012,919
• Filed: October 5, 2020
• Petitioner(s): Cisco Systems, Inc., Hewlett Packard Enterprise Company and Aruba Networks, Inc.
• Patent Owner(s): Sable Networks, Inc.
• Challenged Claims: 1-24

2. Patent Overview

• Title: Method and Apparatus for Intelligent Load Balancing of Micro-Flows
• Brief Description: The ’919 patent discloses methods for transmitting a "micro-flow" of information across a Multi-Protocol Label Switching (MPLS) network using intelligent load balancing. The system defines a set of label switched paths (LSPs), defines a micro-flow with an associated Quality of Service (QoS) type, and selects a particular LSP based on that QoS type to transmit the micro-flow.

3. Grounds for Unpatentability

Ground 1: Obviousness over Rabbat, Rouhana, and Gibson - Claims 1-15 are obvious over Rabbat in view of Rouhana and Gibson.

• Prior Art Relied Upon: Rabbat (an IEEE conference paper on traffic engineering using MPLS), Rouhana (an IEEE symposium paper on using MPLS for differentiated services), and Gibson (Patent 6,678,264).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Rabbat taught the core method of the ’919 patent, including using a centralized resource manager to define LSPs and select a path that meets a micro-flow’s quantitative QoS requirements. However, to fully meet the claims, Petitioner asserted that Rouhana supplied the key limitation of associating the micro-flow with a Forwarding Equivalence Class (FEC) that defines additional transmission constraints, such as available bandwidth. This FEC limitation was added during prosecution to overcome a rejection. Gibson was introduced for its teachings on load balancing by selecting paths with fewer data packets (i.e., lower utilization) from a set of suitable paths, which maps to the limitations of dependent claims 4, 8, and 15.
  • Motivation to Combine: A POSITA would combine Rabbat and Rouhana because both sought to improve QoS in MPLS networks. A POSITA would recognize that Rouhana’s use of FECs to classify packets and define constraints would directly further Rabbat’s goal of providing quantitative QoS guarantees. Combining Gibson was motivated by the desire to implement well-known load-balancing techniques to maximize bandwidth utilization across multiple paths in the Rabbat/Rouhana system, especially for micro-flows exceeding their allotted bandwidth.
  • Expectation of Success: A POSITA would have a reasonable expectation of success, as combining known MPLS tools like FECs (from Rouhana) and load balancing (from Gibson) with a QoS-aware MPLS routing system (Rabbat) were standard network engineering practices to improve performance and efficiency.

Ground 2: Obviousness over Gibson and Rouhana - Claims 1-15 are obvious over Gibson in view of Rouhana.

• Prior Art Relied Upon: Gibson (Patent 6,678,264) and Rouhana (an IEEE symposium paper).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground presented an alternative to Ground 1, starting with Gibson as the primary reference. Petitioner argued that Gibson, which the Examiner relied on during prosecution, taught most limitations of the independent claims, including establishing a connection with a specified QoS level by determining a plurality of possible paths (LSPs) and selecting a preferred path. The key element missing from Gibson, which led to the patent’s allowance, was the FEC limitation. Petitioner contended that Rouhana explicitly taught using an FEC to classify traffic streams and define transmission constraints for selecting an LSP.
  • Motivation to Combine: A POSITA would combine Rouhana’s FEC teachings into Gibson’s system to improve it. Adding FEC information would allow Gibson’s system to make more sophisticated path selections based on additional constraints like bandwidth availability, thereby improving its ability to provide guaranteed QoS, which was the primary goal of both references.
  • Expectation of Success: A POSITA would expect success in implementing Rouhana’s FEC and service class concepts into Gibson’s software-based system to enhance its ability to guarantee QoS, as these were complementary and well-understood techniques in the field.

Ground 3: Obviousness over Sterne, Rabbat, Rouhana, and Gibson - Claims 16-24 are obvious over Sterne in view of Rabbat, Rouhana, and Gibson.

• Prior Art Relied Upon: Sterne (Patent 7,184,440), Rabbat, Rouhana, and Gibson.
• Core Argument for this Ground:
  • Prior Art Mapping: This ground addressed the apparatus claims (16-24), which recite a network switch. Petitioner asserted that Sterne taught the foundational multi-protocol switch architecture, including ingress/egress line cards, a switching fabric, and a lookup table for making forwarding decisions for MPLS traffic. The teachings of Rabbat, Rouhana, and Gibson were then mapped onto Sterne’s hardware. Specifically, Rabbat’s logic for selecting an LSP based on QoS requirements would be implemented in Sterne's switch. Rouhana’s use of FECs would be incorporated to classify packets and improve path selection logic, and Gibson’s load-balancing principles would be used to select less congested paths.
  • Motivation to Combine: A POSITA would be motivated to combine these references because they all operate in the same field of MPLS network traffic management. A POSITA would naturally implement the advanced QoS, FEC, and load-balancing methods from Rabbat, Rouhana, and Gibson into the physical switch taught by Sterne to create a more capable and efficient networking device.
  • Expectation of Success: A POSITA would have a reasonable expectation of success in implementing the software-based methods of the secondary references onto the switch hardware of Sterne, as this involved predictable software changes to improve the performance of a known switch architecture.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under §325(d) was unwarranted because the petition presented new prior art combinations (specifically involving Rabbat, Rouhana, and Sterne) that were not considered during the original prosecution.
• Petitioner also contended that denial under Fintiv was inappropriate. They argued the parallel district court litigation was in its very early stages, with minimal investment from the parties or the court, and that a motion to stay had not yet been filed but would be appropriate upon institution. The scheduled trial date was after the projected FWD, and Petitioner argued the strong merits of the petition weighed heavily against discretionary denial.

5. Relief Requested

• Petitioner requests the institution of an inter partes review of claims 1-24 of the ’919 patent and the cancellation of those claims as unpatentable.