Case: 23-2231 Document: 39 Page: 1 Filed: 03/10/2025

NOTE: This disposition is nonprecedential.

United States Court of Appeals for the Federal Circuit ______________________

WSOU INVESTMENTS LLC, DBA BRAZOS LICENSING AND DEVELOPMENT, Appellant

v.

ARISTA NETWORKS, INC., Appellee ______________________

2023-2231 ______________________

Appeal from the United States Patent and Trademark Office, Patent Trial and Appeal Board in No. IPR2022- 00231. ______________________

Decided: March 10, 2025 ______________________

BRETT AARON MANGRUM, Cherry Johnson Siegmund James, PLLC, Waco, TX, argued for appellant. Also repre- sented by SEAN D. BURDICK, Burdick Patents, PA, Boise, ID.

AMIT MAKKER, Latham & Watkins LLP, San Francisco, CA, argued for appellee. Also represented by GABRIEL K. BELL, Washington, DC; RICHARD GREGORY FRENKEL, Case: 23-2231 Document: 39 Page: 2 Filed: 03/10/2025

2 WSOU INVESTMENTS LLC v. ARISTA NETWORKS, INC.

DOUGLAS ETHAN LUMISH, Menlo Park, CA; JEFFREY G. HOMRIG, Austin, TX. ______________________

Before LOURIE, BRYSON, and STARK, Circuit Judges. LOURIE, Circuit Judge. WSOU Investments LLC (“WSOU”) appeals from the final written decision of the U.S. Patent Trial and Appeal Board (“the Board”) holding claims 1–6 and 12–17 of U.S. Patent 8,472,447 (“the ’447 patent”) unpatentable as obvi- ous over the combination of U.S. Patent 8,204,061 (“Sane”) and U.S. Patent 8,654,680 (“Subramanian”). Arista Net- works, Inc. v. WSOU Invs., LLC, No. IPR2022-00231, 2023 WL 5033118 (P.T.A.B. May 30, 2023) (“Decision”). We affirm. The ’447 patent is directed to aggregation switches that perform IP multicast snooping. Claim 1, which is repre- sentative for purposes of this appeal, recites: 1. An aggregation switch in a multi-chassis sys- tem for performing Internet Protocol (IP) mul- ticast snooping, comprising: a plurality of virtual fabric link (VFL) ports coupled to a VFL, wherein the VFL is con- nected to a remote aggregation switch, wherein the remote aggregation switch is active and in a separate physical chassis; a plurality of external ports coupled to at least one edge node and at least one net- work node; a database maintaining IP multicast snooping information; and a chassis management module for receiv- ing the snooping information via at least the external ports, storing the snooping Case: 23-2231 Document: 39 Page: 3 Filed: 03/10/2025

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information within the database and shar- ing the snooping information substantially in real-time with the remote aggregation switch via the VFL; wherein the chassis management module further builds respective forwarding vec- tors for multicast traffic flows received from the at least one network node via the external ports or the VLF [sic] ports based on the snooping information; wherein the chassis management module further determines a multicast index for a received multicast traffic flow to set-up hardware paths for forwarding the received multicast traffic flow to the external ports in a virtual local area network (VLAN) that requested the received multicast traffic flow via the at least one edge node, the mul- ticast index being used globally between the aggregation switch and the remote ag- gregation switch. ’447 patent, col. 27 ll. 2–31 (emphases added). WSOU argues that the Board’s findings that (1) Sane discloses the claimed “database maintaining IP multicast snooping information” and that (2) the combination of Sane and Subramanian discloses the claimed chassis manage- ment module that “determines a multicast index” were not supported by substantial evidence. Specifically, WSOU ar- gues that the Board misconstrued “maintaining,” which, in its view, “does not mean ‘storing’ or ‘sharing’” as later re- cited in the claims. See WSOU Br. 17–27. WSOU admits, however, that it has never proposed an affirmative con- struction of that term. Id. at 17. As for the “chassis man- agement module” that “determines a multicast index,” WSOU argues that the Board’s finding that the Case: 23-2231 Document: 39 Page: 4 Filed: 03/10/2025

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combination of Sane and Subramanian discloses that limi- tation lacked adequate support. See id. at 33–37. Arista Networks, Inc. (“Arista”) argues that the Board’s finding that Sane teaches the claimed database was sup- ported by substantial evidence and that WSOU’s attempt to recast the dispute into one of claim construction is un- timely and misguided. Arista Br. 26–38. Arista further ar- gues that the Board’s finding that the combination of Sane and Subramanian teaches a “chassis management module” that “determines a multicast index” was supported by sub- stantial evidence. Id. at 41–46. We agree with Arista. First, with respect to the “database maintaining IP multicast snooping information” limitation, the Board cited Sane’s disclosure that its switches each include an MCEC manager that “provides [a] repository of MCEC configura- tion and running status” and “exchanges configuration in- formation between MCEC switches.” Decision, at *10 (citing Sane, col 4 ll. 48–56). The Board also cited and found credible expert testimony that a person of ordinary skill in the art would have known that, at the time of the invention, switches such as Sane’s “stor[ed] snooped pack- ets and/or their information in a database,” as that was “common to virtually all IGMP snooping implementation” at the time. Id. (quoting J.A. 1550 ¶ 57). That is substan- tial evidence that supports the Board’s determination that the claimed “database maintaining IP multicast snooping information” reads on Sane’s MCEC manager. WSOU’s attempt to manufacture a claim construction dispute as to the term “maintaining” is both untimely and meritless. WSOU has never proposed an affirmative con- struction for this term, and instead only ever argued that the term is distinct from “storing” and “sharing.” WSOU Br. 17. Even if timely, that is an improper application of claim differentiation, which “is not an inflexible rule that supersedes all other principles of claim construction.” Sim- pleAir, Inc. v. Sony Ericsson Mobile Commc’ns AB, Case: 23-2231 Document: 39 Page: 5 Filed: 03/10/2025

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820 F.3d 419, 429 (Fed. Cir. 2016). We are unpersuaded by WSOU’s argument, which takes the individual words “maintaining,” “storing,” and “sharing” outside the context of the claims. The argument is particularly unpersuasive where WSOU has provided no indication of what “main- taining” affirmatively means, let alone how that meaning would have changed the Board’s analysis. The Board’s finding that the combination of Sane and Subramanian teaches the claimed “chassis management module” that “determines a multicast index” was, too, sup- ported by substantial evidence. Specifically, the Board ex- plained that the claimed “chassis management module” maps to Sane’s “control plane,” which performs IGMP snooping and forwards traffic to appropriate ports using an outgoing interface list, or “oif-list.” See Decision, at *14. Although Sane does not disclose how the oif-list is pro- grammed, the Board found that Subramanian does. In Subramanian’s switches, each multicast traffic flow is as- sociated with two unique identifiers, “MGID” and “EPI,” used to determine how to forward the information. Id. at *15. As unrebutted expert testimony established, MGID and EPI would have been known by a person of ordinary skill in the art to be “multicast indexes.” Id. Accordingly, the Board’s finding that it would have been obvious to mod- ify Sane’s control plane to include Subramanian’s multicast indexes to arrive at the claimed “chassis management mod- ule” that “determines a multicast index” was supported by substantial evidence. We have considered WSOU’s remaining arguments and find them unpersuasive. For the foregoing reasons, we affirm the final written decision of the Board. AFFIRMED