Wsou Investments LLC, Dba Brazos Licensing and Development v. Arista Networks, Inc.

N OTE: This disposition is nonprecedential.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 S EAN D. BURDICK, Burdick Patents, PA, Boise,
ID.
AMIT M AKKER , Latham & Watkins LLP, San Francisco,
CA, argued for appellee. Also represented by GABRIEL K.
BELL, Washington, DC; RICHARD G REGORY FRENKEL ,
Case: 23-2231 Document: 39 Page: 1 Filed: 03/10/2025

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WSOU INVESTMENTS LLC v. ARISTA NETWORKS, INC . 2
D OUGLAS ETHAN LUMISH , Menlo Park, CA; JEFFREY G.
H OMRIG, Austin, TX.
______________________
Before LOURIE , BRYSON, and S TARK, 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
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WSOU INVESTMENTS LLC v. ARISTA NETWORKS, INC . 3
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
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WSOU INVESTMENTS LLC v. ARISTA NETWORKS, INC . 4
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,
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WSOU INVESTMENTS LLC v. ARISTA NETWORKS, INC . 5
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
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