Cisco Systems Inc v. WSOU Investments LLC

1. Case Identification

• Case #: IPR2021-00960
• Patent #: 8,665,733
• Filed: May 21, 2021
• Petitioner(s): Cisco Systems, Inc.
• Patent Owner(s): WSOU Investments LLC
• Challenged Claims: 1-20

2. Patent Overview

• Title: Method for Apportioning Delays on a Round Trip Path in a Network
• Brief Description: The ’733 patent discloses a method for obtaining key performance indicators in communication networks. The system measures round trip delay and apportions latency by transmitting a "loopback packet" with a probe session indicator from a user element to a core network element and back, with network elements recording and reporting timestamps.

3. Grounds for Unpatentability

Ground 1: Claims 1, 2, 4, 5, 7-10, 12, 14-17, and 19 are obvious over Mateski.

• Prior Art Relied Upon: Mateski (Patent 8,189,487).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Mateski taught all limitations of the challenged claims. Mateski disclosed a method to determine network latency using a "loop-back test" where a transmitter in a user device (e.g., a smartphone) sends a test packet to a network node, which then returns the packet to a receiver in the same user device, forming a round-trip path. This test packet contained a "test code" and a "unique tracking number," which collectively functioned as the claimed "probe session indicator." Mateski’s network nodes on the path would read the packet header to detect the test code, and in response, record arrival and departure timestamps. These timestamps were then transferred to a "test server," which functioned as the claimed "network management system," to determine latency for each node and the overall round-trip latency.
  • Key Aspects: Petitioner contended that Mateski’s disclosure of a "loop-back test" packet that traverses a round-trip path from a user device to a core network and back, while triggering timestamping at intermediate nodes, rendered the independent claims obvious. Dependent claims were allegedly met by Mateski’s teachings that the probe indicator could be a single bit in the message header and that indicator presence could be determined at the application layer.

Ground 2: Claims 6, 13, and 20 are obvious over Mateski in view of Abdo.

• Prior Art Relied Upon: Mateski (Patent 8,189,487) and Abdo (Application # 2006/0159025).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground addressed claims requiring the loopback message to be a "modified Internet Control Message Protocol (ICMP) PING message." Petitioner asserted that while Mateski taught the fundamental loopback testing method, Abdo supplied the specific implementation using a modified ICMP ping. Abdo disclosed a method for testing network performance and determining round-trip delay using an ICMP ping message modified with an "extension to the ping protocol" that allowed it to carry "additional" information beyond a standard ping.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these references because both addressed the same problem of measuring round-trip delay. A POSITA implementing Mateski’s loopback test would have recognized that ICMP pings were a well-known, standard mechanism for such tests. A POSITA would have been motivated to use Abdo’s modified ICMP ping to carry Mateski’s "test code" as the "additional" information. This would be an obvious design choice to leverage a standard, efficient protocol, thereby reducing network traffic and processing overhead compared to using a separate, non-standard test packet.
  • Expectation of Success: A POSITA would have had a high expectation of success because combining the references involved using a standard protocol (ICMP) for its intended purpose. Abdo’s modified ICMP was backward-compatible, ensuring no adverse impact on Mateski’s system, and computer networking was a predictable art.

Ground 3: Claims 3, 11, and 18 are obvious over Mateski in view of Buckley.

• Prior Art Relied Upon: Mateski (Patent 8,189,487) and Buckley (Application # 2009/0131022).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground challenged claims requiring the probe session indicator to be an "International Mobile Subscriber Identity (IMSI)." Petitioner argued that Mateski taught using a "unique tracking number" to identify a test session but was open-ended about its specific format. Buckley taught using a dynamically assigned IMSI as a "session identifier" for messaging in a wireless network. The combination involved implementing Mateski’s generic tracking number with the specific, well-known IMSI taught by Buckley.
  • Motivation to Combine: A POSITA looking to implement Mateski’s "unique tracking number" would have found it an obvious design choice to use a standard, unique identifier like an IMSI. Buckley demonstrated that IMSIs were known for this exact purpose—uniquely identifying a session. The combination was presented as a simple substitution of one known element (a generic identifier) for a more specific, known element (an IMSI) to obtain the predictable result of uniquely tracking a loopback test session.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success as both references operate in communication networks and using an IMSI as a session tracker was a well-known and trivial task.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under 35 U.S.C. §325(d) was inappropriate because the core prior art references, Mateski and Abdo, were not previously presented to or considered by the Examiner during the prosecution of the ’733 patent.
• Petitioner further argued that discretionary denial under the Fintiv factors was not appropriate. The parallel district court litigation was in its earliest stages, with the complaint having been filed only a few months prior to the petition. No trial date was set, no significant investment had been made by the court or parties, and Petitioner stipulated it would not pursue the same invalidity grounds in the district court if an inter partes review (IPR) was instituted, thus mitigating concerns of overlapping issues.

5. Relief Requested

• Petitioner requested the institution of an IPR and cancellation of claims 1-20 of Patent 8,665,733 as unpatentable.