IN THE UNITED STATES DISTRICT COURT

FOR THE WESTERN DISTRICT OF TEXAS

WACO DIVISION

WSOU INVESTMENTS, LLC d/b/a 

BRAZOS LICENSING AND 

DEVELOPMENT,

Plaintiff,

v.

DELL TECHNOLOGIES INC., DELL 

INC., AND EMC CORPORATION, 

Defendants.

Case No. 6:20-cv-00474-ADA

Case No. 6:20-cv-00475-ADA

Case No. 6:20-cv-00476-ADA

Case No. 6:20-cv-00479-ADA

JURY TRIAL DEMANDED

DEFENDANTS’ RESPONSIVE CLAIM CONSTRUCTION BRIEF REGARDING 

PATENT NOS. 7,212,536, 7,453,888, 7,565,435 & 8,402,129

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 1 of 50
i

TABLE OF CONTENTS

Page

DISPUTED TERMS FROM THE ’536 PATENT............................................................ 1

A. “bridge” (claims 1, 12).............................................................................................2

B. “channel in a connection based network” (claims 1, 12).........................................4

C. “forwarding system configured to read a priority of a data frame to be 

forwarded onto the connection-based network by way of the first one of 

the ports, identify a service interface which the map indicates corresponds 

to the read user priority and forward the data frame over the channel in the 

connection-based network associated with the identified service interface” 

(claim 1)...................................................................................................................7

D. “means for reading priorities of data frames directed by the bridge to at 

least a first one of the bridge ports” (claim 12) .......................................................9

DISPUTED TERMS FROM THE ’888 PATENT.......................................................... 12

A. “stackable trunk port” (claims 1, 8, 9, 10, 11–13, 15, 19, 20)..............................13

B. “backbone VLAN trunk” (claims 1, 5, 6, 7, 12, 15–20)........................................15

C. “wherein the selection and association of at least one backbone VLAN ID 

with each one of the corresponding plurality of backbone VLAN trunks is 

undertaken irrespective of one of an in-use and a stand-by designation of 

each one of the plurality of backbone VLAN trunks and each one of the 

plurality of stackable trunk ports” (claim 1) / “wherein the association of 

the plurality of backbone VLAN IDs with the backbone VLAN trunk is 

undertaken irrespective of one of an in-use and a stand-by designation of 

the backbone VLAN trunk and the at least one stackable trunk port” 

(claim 15)...............................................................................................................18

DISPUTED TERMS FROM THE ’435 PATENT.......................................................... 20

A. “setting the IPPC of one of the ports of one of said bridges within the 

MSTI to a lower IPPC when said port is part of the VLAN member set” 

(claims 1, 8, 13) .....................................................................................................22

B. “ideally” (claims 7, 11, and 18) .............................................................................26

C. “processing unit for setting the Internal Port Path Cost (IPPC) of one of 

the ports of one of said bridges within the MSTI to a high IPPC when said 

port is not part of the VLAN member set” (claim 8) / “processing unit for 

setting the IPPC of one of the ports of one of said bridges within the MSTI 

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 2 of 50
ii

to a lower IPPC when said port is part of the VLAN member set” (claim 

8) ............................................................................................................................28

D. Entirety of claims 9–11 and 13–18 ........................................................................30

DISPUTED TERMS FROM THE ’129 PATENT.......................................................... 33

A. “rate of change” (claim 3)......................................................................................33

B. “initiating a poll of resources in the nodes of the network by the 

management station in response to reporting from the node or a time 

interval being exceeded” (claim 3) ........................................................................38

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 3 of 50
iii

TABLE OF AUTHORITIES

Page(s)

Cases

Abbott Labs. v. Sandoz, Inc.,

544 F.3d 1341 (Fed. Cir. 2008)..........................................................................................15, 38

Aristocrat Techs., Australia Pty. v. Int’l Game Tech.,

521 F.3d 1328 (Fed. Cir. 2008)................................................................................................11

Avago Techs. Gen. IP (Singapore) Pte Ltd. v. Asustek Computer, Inc.,

No. 15-CV-04525-EMC, 2016 WL 3029674 (N.D. Cal. May 27, 2016)................................24

Bicon, Inc. v. Straumann Co.,

441 F.3d 945 (Fed. Cir. 2006)..................................................................................................26

Blackboard, Inc. v. Desire2Learn, Inc.,

574 F.3d 1371, 91 USPQ2d 1481 (Fed. Cir. 2009) ...................................................................9

Bushnell Hawthorne, LLC v. Cisco Sys., Inc.,

No. 1:18-CV-760, 2019 WL 2745735 (E.D. Va. July 1, 2019), aff’d, 813 F. 

App’x 522 (Fed. Cir. 2020)......................................................................................................30

Cellular Commc’ns Equip. LLC v. HTC Corp.,

No. 6:13-CV-507, 2015 WL 1048890 (E.D. Tex. Mar. 9, 2015) ............................................28

Clear Imaging Rsch., LLC v. Samsung Elecs. Co.,

No. 2:19-CV-00326-JRG, 2020 WL 6384731 (E.D. Tex. Oct. 30, 2020)...............................27

Diebold Nixdorf, Inc. v. Int’l Trade Comm’n,

899 F.3d 1291 (Fed. Cir. 2018)................................................................................................27

Digital-Vending Servs. Int’l, LLC v. Univ. of Phoenix, Inc.,

672 F.3d 1270 (Fed. Cir. 2012)................................................................................................26

Digital Retail Apps, Inc. v. HEB, LP,

No. 6-19-00167-ADA, 2020 WL 376664 (W.D. Tex. Jan. 23, 2020)....................................34

Fisher-Rosemount Sys., Inc. v. Invensys Sys., Inc.,

No. A-13-CA-587-SS, 2015 WL 1275910 (W.D. Tex. Mar. 19, 2015)..................................16

Function Media, LLC v. Google, Inc.,

708 F.3d 1310 (Fed. Cir. 2013)................................................................................................10

Hewlett-Packard Co. v. Bausch & Lomb, Inc.,

909 F.2d 1464 (Fed. Cir. 1990)................................................................................................24

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 4 of 50
iv

Interval Licensing LLC v. AOL, Inc.,

766 F.3d 1364 (Fed. Cir. 2014)................................................................................................27

IPXL Holdings, L.L.C. v. Amazon.com, Inc.,

430 F.3d 1377 (Fed. Cir. 2005)................................................................................................30

Jack Guttman, Inc. v. Kopykake Enterprises, Inc.,

302 F.3d 1352 (Fed. Cir. 2002)..........................................................................................14, 17

Joao Control & Monitoring Sys., LLC v. Protect America, Inc.,

No. 1-14-cv-134-LY, 2015 WL 4937464 (W.D. Tex. Aug. 18, 2015)......................................8

K-2 Corp. v. Salomon S.A.,

191 F.3d 1356 (Fed. Cir. 1999)................................................................................................31

KLA-Tencor Corp. v. Xitronix Corp.,

No. A-08-CA-723-SS, 2011 WL 318123 (W.D. Tex. Jan. 31, 2011) .....................................26

Marine Polymer Techs., Inc. v. HemCon, Inc.,

672 F.3d 1350 (Fed. Cir. 2012)................................................................................................23

MasterMine Software, Inc. v. Microsoft Corporation,

874 F.3d 1307 (Fed. Cir. 2017)................................................................................................31

Maxim Integrated Prod., Inc. v. Silicon Mitus Tech., Inc.,

No. 17-CV-03507 NC, 2018 WL 4657384 (N.D. Cal. July 3, 2018)......................................24

Mendenhall v. Cedarapids, Inc.,

5 F.3d 1557 (Fed. Cir. 1993)....................................................................................................11

Mformation Techs., Inc. v. Rsch. in Motion Ltd.,

764 F.3d 1392 (Fed. Cir. 2014)................................................................................................23

Modine Mfg. Co., v. Int’l Trade Comm’n,

75 F.3d 1545 (Fed. Cir. 1996)..................................................................................................23

MTD Prod. Inc. v. Iancu,

933 F.3d 1336 (Fed. Cir. 2019)............................................................................................8, 28

Neodron, Ltd. v. Dell Technologies, Inc.,

No. 1-19-00819-ADA, 2019 WL 9633629 (W.D. Tex. Dec. 16, 2019)..................................34

Net MoneyIN, Inc. v. VeriSign, Inc.,

545 F.3d 1359 (Fed. Cir. 2008)................................................................................................11

O2 Micro Int’l Ltd. v. Beyond Innovation Tech. Co.,

521 F.3d 1351 (Fed. Cir. 2013)..................................................................4, 5, 7, 15, 17, 20, 32

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 5 of 50
v

Optis Wireless Tech., LLC v. Huawei Device Co.,

No. 2:17-CV-123-JRG-RSP, 2018 WL 476054 (E.D. Tex. Jan. 18, 2018).............................28

Pac. Coast Bldg. Prod., Inc. v. CertainTeed Gypsum, Inc.,

816 F. App’x 454 (Fed. Cir. 2020) ..........................................................................................26

Phillips v. AWH Corp.,

415 F.3d 1303 (Fed. Cir. 2005)..............................................................................................3, 4

Rembrandt Data Techs., LP v. AOL, LLC,

641 F.3d 1331 (Fed. Cir. 2011)................................................................................................30

Samsung Elecs. Am. v. Prisua Eng’g Corp.,

948 F.3d 1342 (Fed. Cir. 2020)................................................................................................28

SanDisk Corp. v. Kingston Tech. Co.,

695 F.3d 1348 (Fed. Cir. 2012)................................................................................................17

Sinorgchem Co., Shandong v. Int'l Trade Comm’n,

511 F.3d 1132 (Fed. Cir. 2007)................................................................................................16

Skky, Inc. v. MindGeek, s.a.r.l.,

859 F.3d 1014 (Fed. Cir. 2017)................................................................................................29

Southwall Technologies, Inc. v. Cardinal IG Co.,

54 F.3d 1570 (Fed. Cir. 1995)............................................................................................35, 36

Tech. Properties Ltd. LLC v. Huawei Techs. Co.,

849 F.3d 1349 (Fed. Cir. 2017)..............................................................................18, 19, 35, 36

TEK Glob., S.R.L. v. Sealant Sys. Int’l, Inc.,

920 F.3d 777 (Fed. Cir. 2019)..................................................................................................29

TMC Fuel Injection System, LLC v. Ford Motor Company,

682 F.App’x 895 (Fed. Cir. 2017) ...........................................................................................35

Twin Peaks Software Inc. v. IBM Corp.,

690 F. App’x 656 (Fed. Cir. 2017) ..........................................................................................12

UltimatePointer, L.L.C. v. Nintendo Co.,

816 F.3d 816 (Fed. Cir. 2016)..................................................................................................31

Ushijima v. Samsung Elecs. Co., Ltd,

No. 1:16-CV-585-LY, 2017 WL 3494229 (W.D. Tex. Aug. 14, 2017)............................14, 16

Uship Intellectual Properties, LLC v. U.S.,

714 F.3d 1311 (Fed. Cir. 2013)................................................................................................35

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 6 of 50
vi

V-Formation, Inc. v. Benetton Grp. SpA,

401 F.3d 1307 (Fed. Cir. 2005)................................................................................................15

Wi-LAN, Inc. v. Apple, Inc.,

811 F.3d 455 (Fed. Cir. 2016)..................................................................................................22

Williamson v. Citrix Online, LLC,

792 F.3d 1339 (Fed. Cir. 2015)................................................................................7, 11, 27, 29

Wilson Sporting Goods Co. v. Hillerich & Bradsby Co.,

442 F.3d 1322 (Fed. Cir. 2006)............................................................................................5, 33

WMS Gaming Inc. v. Int’l Game Tech.,

184 F.3d 1339 (Fed. Cir. 1999)................................................................................................29

Other Authorities

MPEP § 2181(I)(A)........................................................................................................................28

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 7 of 50
vii

TABLE OF EXHIBITS

Exhibit Description

1 Internetworking: A Guide to Network Communications, by Mark A. Miller 

(1997) (excerpts) (“Miller”)

2 Concise Telecom Networking Dictionary, McGraw-Hill (2000) (excerpts)

3 TCP/IP and Related Protocols, by Uyless Black (1992) (excerpts) (“Black”)

4 Plaintiff’s Infringement Contentions for U.S. Patent No. 7,212,536 (dated 

October 14, 2020) (excerpt)

5 Computer Networks, by Andrew S. Tanenbaum (1996) (excerpts) (“Tanenbaum”)

6 Plaintiff’s Preliminary Constructions (dated January 20, 2021)

7 ’888 patent File History, 10/19/07 Applicant Argument (“10/19/07 App. Arg.”)

8 ’888 patent File History, 6/9/08 Applicant Argument (“6/9/08 App. Arg.”)

9 RS Switch Router User Guide Release 7.0 (excerpt) (annotated) (“Riverstone”)

10 ’888 patent File History, 4/8/08 Applicant Argument (“4/8/08 App. Arg.”) 

11 ’888 patent File History, 1/8/08 Final Rejection (“1/8/08 Final Rej.”) 

12 U.S. Patent No. 6,678,241 (“Gai”) 

13 MPEP § 2181

14 Joint Chart and WSOU’s Claim Construction Summaries at Tab 2

15 Plaintiff’s Infringement Contentions for U.S. Patent No. 8,402,129 (dated 

October 14, 2020) (excerpt) (“’129 Infringement Contentions”)

16 ’129 patent File History, May 2, 2007 Applicant Response (“5/2/07 App. Arg.”) 

17 ’129 patent File History, Sept. 17, 2007 Applicant Response (“9/17/07 App. 

Arg.”)

18 Jan. 27, 2021 Sabanoglu to Loveless Email Subject “WSOU v. Dell et al., Case 

Nos. 6:20-CV-00473-486; Exchange of Constructions” (“1/27/21 Email”)

19 February 26, 2021 Rosenthal Email Subject: “WSOU v. Dell – 129 patent” 

(“2/26/21 Email”)

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 8 of 50
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TABLE OF ABBREVIATIONS

Abbreviation Term/Document(s)

’129 patent U.S. Patent No. 8,402,129

’435 patent U.S. Patent No. 7,565,435

’536 patent U.S. Patent No. 7,212,536

’888 patent U.S. Patent No. 7,453,888

Br. Opening Claim Construction Brief (No. 6:20-cv-474-ADA, Dkt. 82; 

Case No. 6:20-cv-00475-ADA, Dkt. 85; Case No. 6:20-cv-00476-

ADA, Dkt. 74; Case No. 6:20-cv-00479-ADA, Dkt. 81)

m-p-f Means-plus-function

MPEP Manual of Patent Examining Procedure

MSTI Multiple spanning tree instance

MSTP Multiple spanning tree protocol

POSA Person of skill in the art

VLAN Virtual Local Area Network

WSOU WSOU Investments, LLC D/B/A Brazos Licensing and Development

Emphasis added unless indicated otherwise.

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 9 of 50
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Of the 13 technical terms in dispute over the four asserted patents, WSOU offers no 

guidance for a jury for 12 of them, asserting “plain and ordinary meaning.” In some instances, 

WSOU apparently agrees with Defendants’ constructions but for others provides no guidance as 

to what the “plain and ordinary meaning” is, instead launching half-hearted attacks on Defendants’

construction, by simply calling them “confusing” and “unnecessary.” For the final term, WSOU 

agrees it must be construed under 35 U.S.C. § 112 ¶ 6 and admits that the structure needs to include 

an algorithm but then fails to identify what WSOU understands that algorithm to be—because 

none was disclosed. By contrast, Defendants’ constructions are drawn directly from the intrinsic 

record and should be adopted.1

 

DISPUTED TERMS FROM THE ’536 PATENT

The ’536 patent describes a particular type of network interface device, called a “bridge” 

that connects to another bridge through established “channels” in a “connection-based network.” 

Figure 3 (annotated below) depicts this arrangement:

1 The parties have agreed to divide the total claim term and page limits (as set forth in the Court’s 

Order Governing Proceedings) across the four agreed-upon groups of cases for claim construction 

(Group 4 (the above-captioned cases), Group 1 (Case Nos. -480, -481, -485, -486), Group 2 (Case 

Nos. -473, -478), and Group 3 (Case Nos. -477, -482)).

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 10 of 50
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As shown above, for the bridge port 26 within Bridge A, there are multiple different service 

interfaces 30. Each of these services interfaces is associated with a different channel 15 through 

the connection-based network 14. ’536 Patent, 4:54–57. Based on the user priority of an incoming 

data frame, the bridge assigns the frame to a particular channel in the connection-based network, 

and thus to its corresponding service interface. Id., 6:22–25. The patent provides examples of 

mappings that can be used between priorities and channels, depending on the number of 

established channels available:

Id., 7:1–17; see also Figs. 4, 5A–5I. As shown in the left column above (labeled “1”), if there is 

only one established channel in the network, all priorities are mapped to the same channel. If 

instead there are, for example, four established channels in the network, the fourth column (labeled 

“4”) provides the mappings from each of the eight priorities to one of the four available channels.

A. “bridge” (claims 1, 12)

Defendants’ Proposal WSOU’s Proposal

“a network interface device that operates no higher 

than the data link layer”

Plain and ordinary meaning

As the ’536 patent explains, the term “bridge” is a technical term that refers to a wellknown specific type of network interface device. For example, claim 1 recites a “[d]ata handling 

apparatus . . . comprising: a bridge.” As such, even in the context of the claims, “bridge” refers to 

a specific type of device, not just any data handling device. The specification confirms this 

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 11 of 50
3

understanding, referring to “bridges or similar data handling devices.” See ’536 patent, 1:7; see 

also id., 9:17–23 (distinguishing “bridges” from “ethernet LAN service units (‘ELSUs’)”). As an 

example, the specification refers specifically to “medium access control (MAC) bridges,” which 

are a well-known type of bridge. Id., 1:38–40. WSOU does not allege that applicants ascribed 

any special meaning to “bridge” in the patent. Br. 3. As such, there is no dispute that “bridge” 

should be given its well-understood meaning to a POSA at the time of the patent. See id. 3–4; 

Phillips v. AWH Corp., 415 F.3d 1303, 1313 (Fed. Cir. 2005) (claim term given “the meaning that 

the term would have to a person of ordinary skill in the art in question at the time of the invention”). 

WSOU does not dispute that the well-understood meaning of a “bridge” at the time of the 

invention was a network interface device that operates no higher than the data link layer—i.e., a 

layer-2 network device.2

 The claims and specification describe a bridge wholly consistent with 

that well-understood meaning. The asserted claims recite reading the priority of a “data frame,” 

which is the name of a packet at the data link layer. E.g., Ex. 1 (Miller), 15. The specification 

also uses “data frame.” E.g., ’536 patent, 6:15–16. Similarly, the patent describes the bridge as 

connecting different “network segments,” which is consistent with the traditional role of bridges 

at the data link layer. See id., 1:26–27; 2:34–36; 4:26–33; Ex. 1 (Miller), 15.

This well-understood meaning of “bridge” is confirmed by scores of contemporaneous 

extrinsic sources, including those cited by Defendants. For example, the Concise Networking 

Dictionary in 2000 defined bridge as “[a] device that connects two LANs. It performs its 

functions at the data link control (DLC) layer.” Ex. 2, 3; see Ex. 3 (Black), (stating that a bridge 

“operates at the data link layer”). This is often depicted as follows:

2 The data link layer is the second layer of the seven-layer OSI model of communications. Ex. 1 

(Miller), 15; see infra p. 4. 

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Ex. 1 (Miller), 16. That the bridge operates no higher than the data link layer is the defining 

characteristic of a bridge, as opposed to higher-layer devices such as a “router,” which operates at 

the network layer. Id. Because the bridge operates no higher than the data link layer, it is 

transparent to all of the higher layers. This means that the higher layers (such as the Network 

layer) do not need to know about—or account for—the presence of bridges when providing 

address information or making routing decisions. Id.

Rather than dispute what bridge means, WSOU instead states that Defendants’ construction 

is “unnecessary” and “confusing.” Br. 3. To the contrary, the meaning of “bridge” will be critical 

in this case, since WSOU will doubtless argue that a “bridge” includes devices that no one would 

consider a bridge in 2001. See ’536 patent, cover (“Filed: Dec. 27, 2001”). The lay jury should 

be instructed as to what the well-understood meaning of “bridge” was at the time of the patent, 

rather than being permitted to decide that issue for themselves. And WSOU should not be able to 

argue otherwise. See Phillips, 415 F.3d at 1313; O2 Micro Int’l Ltd. v. Beyond Innovation Tech. 

Co., 521 F.3d 1351, 1362 (Fed. Cir. 2013) (“When the parties present a fundamental dispute 

regarding the scope of a claim term, it is the court’s duty to resolve it.”). 

B. “channel in a connection based network” (claims 1, 12)

Defendants’ Proposal WSOU’s Proposal

“one of the paths that has been established in a network for 

communications”

Plain and ordinary meaning

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 13 of 50
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Construction of this phrase is necessary to give meaning to both components of the phrase: 

(1) the channel is “in” a network (the “connection-based network”), as opposed to contained within 

the bridge; and (2) the channel must be an active channel—i.e., it must be established—in a 

connection-based network. Both of these requirements are unambiguously required by the claims 

and the specification. Construction is necessary because WSOU apparently intends to argue to the 

jury that the claims are satisfied by internal queues within the bridge itself.3 Thus, the Court 

should rule as a matter of law as to this phrase. O2 Micro, 521 F.3d at 1362. 

First, the channel must be in the connection-based network, as stated in the disputed phrase 

itself. The claim states that the channel is “in” the connection-based network. ’536 patent, cls. 1, 

12. And the claims distinguish “a bridge having a plurality of bridge ports” from the channels “in 

a connection based network” that are “associated with” service interfaces in the ports. Id. In other 

words, the claims use different language for the ports and interfaces that are within the bridge and 

for the channels that are in the network. The claims further recite “forward[ing] the data frame 

over the channel in the connection-based network” (id.), which compels the conclusion that the 

“channel” is outside the claimed device. WSOU should thus not be permitted to argue that the 

“channels” phrase refers to something in the bridge itself, as it apparently intends to do. 

Second, the claim language and specification mandate that the “channels” are “established” 

in the network. Claim 1 makes this clear by reciting that service interfaces must be “associated 

with a channel in a connection-based network,” which requires an already-established channel. 

Claim 12 similarly requires that the data frames be sent over “service interfaces associated with 

3 WSOU relies upon service queues or subinterfaces within a port of the accused device in its 

infringement contentions. See Ex. 4 at 5; Wilson Sporting Goods Co. v. Hillerich & Bradsby Co., 

442 F.3d 1322, 1327 (Fed. Cir. 2006) (“Although the construction of the claim is independent of 

the device charged with infringement, it is convenient for the court to concentrate on those aspects 

of the claim whose relation to the accused device is in dispute.” (quotation omitted)).

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 14 of 50
6

active channels”—i.e., those that are established in the network. Indeed, this is the essence of a 

“connection-based network,” as distinct from a “connectionless” network. In a connection-based 

network (like the plain-old telephone system), channels are first established before 

communications occur. Ex. 5 at 23 (Tannenbaum); see also Ex. 3 at 6–7 (Black). By contrast, in 

connectionless networks (like the U.S. mail), each piece of information is separately routed and 

no channel is pre-established. Id.

The specification is entirely consistent with the well-understood meaning of connectionbased networks. The examples of networks in the specification are all conventional connectionbased networks, such as ATM and MPLS. Id., 1:24–37; 2:38–32 (“The connection based network 

may comprise an ATM network in which channels are each identified by a connection identifier 

comprising a VPI [Virtual Path Identifier] and a VCI [Virtual Channel Identifier].”). Moreover, 

the channels are established in the network—as they must be—prior to use by the bridge. See ’536 

patent, Fig. 3, 7:19–22 (“Where channels are made available in order, a higher-numbered channel 

cannot be established until all lower-numbered channels have been established.”). Indeed, the 

number of channels available to the bridge depends on how many channels are “active” at a given 

time—i.e., how many channels have been established. Id., 6:27–29 (“The mapping used by 

bridging system 27 for a bridge port 26 will depend upon the number of channels 15 available to 

the bridge port 26 (e.g. to a number of the service interfaces 30 which are connected to active 

channels in network 14).”). The patent also explains that when one channel fails, the bridge can 

remap data that was mapped to the failed channel to be assigned to another channel that “remains

available.” Id., 7:57–8:21.

WSOU has no meaningful opposition to Defendants’ construction, instead arguing that it 

is “confusing and unnecessary.” Br. 4. WSOU, however, acknowledged in opposing Defendants’ 

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 15 of 50
7

motion to dismiss that this is a claim construction dispute (No. 6:20-cv-474, Dkt. 53 at 5–6); it 

must be resolved now. See O2 Micro, 521 F.3d at 1362. WSOU quibbles with the language of 

Defendants’ construction by arguing (for the first time) that the term “paths” is more confusing 

than “channel” and that it suggests more than one channel must exist. While WSOU never raised 

this issue before briefing, it is a non-issue. Defendants would not object to modifying its 

construction to be “a channel that has been established in a network for communications.” But it 

is inescapable that the claim requires an established channel in a connection-based network.

C. “forwarding system configured to read a priority of a data frame to be forwarded 

onto the connection-based network by way of the first one of the ports, identify a 

service interface which the map indicates corresponds to the read user priority 

and forward the data frame over the channel in the connection-based network 

associated with the identified service interface” (claim 1)

Defendants’ Proposal WSOU’s Proposal

This term is subject to 35 U.S.C. § 112, ¶ 6.

Function: read a priority of a data frame to be forwarded onto the 

connection-based network by way of the first one of the ports, identify a 

service interface which the map indicates corresponds to the read user 

priority and forward the data frame over the channel in the connectionbased network associated with the identified service interface

Structure: Indefinite

Plain and ordinary 

meaning

The term “forwarding system” is a nonce word with the same effect as “forwarding means,” 

requiring that this term be construed under § 112, ¶ 6. The inquiry is “whether the words of the 

claims are understood by persons of ordinary skill in the art to have a sufficiently definite meaning 

as the name for structure.” Williamson v. Citrix Online, LLC, 792 F.3d 1339, 1349 (Fed. Cir. 

2015). “Generic terms such as ‘mechanism,’ ‘element,’ ‘device,’ and other nonce words that 

reflect nothing more than verbal constructs may be used in a claim in a manner that is tantamount 

to using the word ‘means’ because they ‘typically do not connote sufficiently definite structure’ 

and therefore may invoke § 112, [¶] 6.” Id. at 1350. The word “system” is another one of these 

nonce terms that has been found not to connote structure, including by this Court. See, e.g., Dyfan, 

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 16 of 50
8

LLC v. Target Corp., 19-cv-179-ADA, ECF No. 57 at 23–24 (Nov. 25, 2020); Joao Control & 

Monitoring Sys., LLC v. Protect America, Inc., No. 1-14-cv-134-LY, 2015 WL 4937464, at *5 

(W.D. Tex. Aug. 18, 2015) (“The court finds that system, as used in the claim, functions merely 

as a nonce word or a verbal construct that is not recognized as the name of structure and is simply 

a substitute for the term means for.”) (quotation and citation omitted). Indeed, this Court recently 

found an almost indistinguishable phrase “forwarding module” to be subject to § 112, ¶ 6. Huawei 

Techs. Co. v. Verizon Commn’s, Inc. et al., 20-cv-00090-ADA, ECF No. 73 at 4 (Nov. 30, 2020).

The term “system” had no readily understandable meaning or structure in the field of 

computer networking in 2001, nor does WSOU articulate any such structure. See Br. 5–7. Instead, 

WSOU block quotes three specification sections, that describe a “bridge” and a “bridging system,” 

and, with no support, argues that “the forwarding system may be a bridge with a bridge port and a 

bridging system, or a computer processor or a computer-readable medium comprising instructions 

for a processor (such as those found in Figure 6, see, e.g., Id., 6:15–25).” Because the specification 

does not link the claimed forwarding system to a bridge or bridging system, those passages are not 

relevant to the inquiry. The Federal Circuit has explained that courts must first determine whether 

“the claim limitation connotes sufficiently definite structure,” and only after concluding it does 

not, then identify corresponding structure in the specification. See MTD Prod. Inc. v. Iancu, 933 

F.3d 1336, 1344 (Fed. Cir. 2019) (applying section 112, ¶ 6 where only the specification—but not 

the claims—provided sufficient structure). Here, WSOU does not even attempt to show sufficient 

structure in the claim itself.

Indeed, the language of claim 1 is inconsistent with WSOU’s attempted correlation to a 

“bridge with a bridge port and bridging system.” Claim 1 requires a data handling apparatus in 

which the “bridge having a plurality of bridge ports” is a completely separate limitation from the 

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 17 of 50
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“forwarding system.” ’536 patent, 9:30–37. Thus, the one thing the forwarding system cannot be 

is the bridge. Indeed, WSOU’s block quotes reinforce that “system” has no readily understandable 

structure in the field because there can be many different types of systems and no common or usual 

structure. The term “forwarding system” itself is used only a single time in the specification, and 

simply mimics the language in the claim. ’536 patent, 2:17–25. And while the specification 

discloses forwarding in connection with Figure 6, there is no disclosure of structure in that 

description. Id., 6:15–25. At most, it is simply a black box which is insufficient to disclose any 

structure. Blackboard, Inc. v. Desire2Learn, Inc., 574 F.3d 1371, 1383–85, 91 USPQ2d 1481, 

1491–93 (Fed. Cir. 2009) (no structure because the specification disclosed no more than a black 

box). Because “forwarding system” is a nonce term and does not connote structure, this term is 

subject to a means-plus-function construction.

There does not appear to be any dispute as to the functions of this term in a § 112, ¶ 6 

analysis; Defendants’ identification of the functions comes right from the claim language. 

However, one of the required functions—“to read a priority of a data frame”—lacks any 

corresponding structure or algorithm for the same reasons discussed with the next term. See, infra 

§ I.D. For the same reasons that the “means for reading priorities . . .” term is indefinite, so too is 

the “forwarding system” term indefinite. 

D. “means for reading priorities of data frames directed by the bridge to at least a 

first one of the bridge ports” (claim 12)

Defendants’ Proposal WSOU’s Proposal

This term is subject to 35 U.S.C. 

§ 112, ¶ 6.

Function: reading priorities of 

data frames directed by the 

bridge to at least a first one of 

Subject to means-plus-function construction. 

Function: reading priorities of data frames directed by the 

bridge to at least a first one of the bridge ports

Structure: bridge, with bridging system and bridge port, and 

equivalents thereof4

4 WSOU changed its proposal in its brief from what it conveyed before briefing. Previously, 

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 18 of 50
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the bridge ports

Structure: Indefinite

Algorithm, (if required): see e.g.. ---, and equivalents thereof.

The parties agree that this term is subject to § 112, ¶ 6 and agree on the identified function. 

The only dispute is whether the specification provides corresponding structure for “reading 

priorities of data frames . . . .” It does not. The patent never discloses reading priorities from data 

frames, let alone describes any structure for doing so. Indeed, the four block quotes in WSOU’s 

brief do not even use the word “read” or any equivalent thereof. Br. 7–9.

The closest the patent ever comes to describing this function is in the flowchart of Figure 

6, which has a box that simply says “determine priority.” ’536 patent, Fig. 6. But nothing in the 

patent ever states or suggests that Figure 6 is performed by any particular structure. Indeed, the 

description of Figure 6 is “a flow chart which illustrates a method for forwarding data frames 

according to one embodiment of the invention.” Id., 3:24–26; see also id., 6:15–19 (“FIG. 6 

illustrates a method 100 according to the invention for forwarding a priority tagged data frame. A 

frame is received at block 102. In blocks 104 and 106 the priority of the frame is determined and 

the frame is forwarded to a bridge port for delivery to a destination.”). Such a flow chart, 

disconnected from any structure, is insufficient to connote any structure. See Function Media, 

LLC v. Google, Inc., 708 F.3d 1310, 1318 (Fed. Cir. 2013) (holding that flow charts in the 

specification failed to disclose sufficient structure). 

More importantly, even if the patent suggested that the method of Figure 6 is to be 

performed by a particular structure—which it does not—the method does not describe reading the 

priority of the data frames. Instead, it merely states that the priority of frames “is determined.” 

Id., 6:15–19. The patent never states how the priority is determined, or even if it is determined 

WSOU merely identified “bridge, and equivalents thereof.” Ex. 6 (Preliminary Constructions) at 

9. WSOU’s flip-flopping on this point illustrates that there is no corresponding structure in the 

patent that actually performs this function.

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from something within the frame itself or in another way. There cannot possibly be a 

corresponding structure given the complete absence of any description of the claimed function 

itself. See id.; Mendenhall v. Cedarapids, Inc., 5 F.3d 1557, 1565 (Fed. Cir. 1993) (a specification 

that does not disclose a function does not support a corresponding means-plus-function limitation). 

Because there is no disclosure of the recited function in the specification, WSOU instead 

relies on disclosure of other functions in the claim—e.g., mapping user priorities to service 

interfaces or assigning frames—presumably arguing that the same structure (bridge) should apply. 

Br. 7–8. This, of course, is completely beside the point. Whether corresponding structure exists 

for one claimed function does not affect the lack of corresponding structure for a separately 

claimed function. See Williamson, 792 F.3d at 1352.

WSOU’s proposed structure also fails based on the structure of claim 12. Claim 12 recites 

a “bridge comprising . . .” the “means for reading priorities of data frames . . . .” WSOU proposes 

that the “means for reading” is itself the bridge. Br. 7. That argument is circular and 

impermissible. The Federal Circuit has squarely rejected such an argument, where a patentee 

attempted to rely on a claimed apparatus that itself included the “means,” rather than identify the 

“component” of the apparatus that performed the recited function. Net MoneyIN, Inc. v. VeriSign,

Inc., 545 F.3d 1359, 1366 (Fed. Cir. 2008) (rejecting as “redundant and illogical” the argument 

that the requisite structure for “generating means” was a “bank computer” when the claim itself 

recited a “bank computer” that included the “generating means”).

Furthermore, for computer-implemented functions, like the “reading priorities” function 

here, the corresponding structure must further include “the algorithm disclosed in the 

specification.” Aristocrat Techs., Australia Pty. v. Int’l Game Tech., 521 F.3d 1328, 1334 (Fed. 

Cir. 2008). Even if the same physical structure for other functions were to apply to the function at 

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issue here, there is certainly no corresponding algorithm. WSOU string-cites a number of 

passages, but not a single one of them discloses reading a priority from a data frame, let alone an 

algorithm for doing so. Br. 9. As described above, the closest the patent comes is its generic 

statement that “the priority of the frame is determined,” with no explanation of how it is 

determined. ’536 patent, 6:17–18. This, of course, does not come close to a required algorithm. 

The case law is clear that the corresponding structure and algorithm must actually appear in the 

specification itself. See Twin Peaks Software Inc. v. IBM Corp., 690 F. App’x 656, 660 (Fed. Cir. 

2017) (describing prior cases as “holding that ‘a bare statement that known techniques or methods 

can be used does not disclose structure’” and “noting ‘[t]he requirement that a particular structure 

be clearly linked with the claimed function in order to qualify as corresponding structure’”). The 

lack of any corresponding structure and algorithm here renders this term indefinite.

DISPUTED TERMS FROM THE ’888 PATENT

The ’888 patent describes a method of provisioning (setting up) a particular type of VLAN 

called a backbone VLAN. See ’888 patent, 6:10–12. Applicants explained that “[b]ackbone 

VLANs travel over backbone VLAN trunks, which are defined between stackable trunk ports on 

core routers.” Ex. 7, (10/19/07 App. Arg.) at 11–13. The claimed backbone VLAN is depicted in 

Figure 3 (annotations added):

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The claimed provisioning methods involve the association of a special-purpose VLAN ID—which 

is known as a backbone VLAN ID—with stackable trunk ports (302) corresponding to backbone 

VLAN trunks (308) on core routers (306). See id., 8:61–9:3, 10:18–24. The patent asserts that the 

purpose of this special backbone VLAN ID (which is used in addition to the standard VLAN ID) 

is to prevent inadvertent sharing of packets in VLANs where multiple customers use the same 

standard VLAN IDs. See id., 7:27–33. The claims require that the association of backbone VLAN 

IDs with stackable trunk ports is done “irrespective of one of an in-use and a stand-by 

designation”5 of the backbone VLAN trunks and stackable trunk ports. Id., cl. 1; see also id. cl. 

15. 

A. “stackable trunk port” (claims 1, 8, 9, 10, 11–13, 15, 19, 20)

Defendants’ Proposal WSOU’s Proposal

“trunk port supporting the Riverstone solution (i.e. the Plain and ordinary meaning

5 “In-use” and “standby” designations are the result of running a spanning tree protocol. See, e.g., 

id., 10:9–12, Abstract. Spanning tree protocols provide redundancy in a VLAN by creating a tree 

of in-use ports/trunks and then assigning redundant ports/trunks as standby. See id., 2:51–55. If 

an in-use port/trunk becomes unreachable, the spanning tree algorithm reestablishes the connection 

by activating a standby port/trunk. See id., 2:55–62.

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additional extension 802.1Q packet header)”

Applicants expressly defined the term “stackable trunk port” in both the specification and 

the prosecution history. Defendants’ construction mirrors the exact language of these definitions, 

and should thus be adopted. See Jack Guttman, Inc. v. Kopykake Enterprises, Inc., 302 F.3d 1352, 

1360–61 (Fed. Cir. 2002) (“Where, as here, the patentee has clearly defined a claim term, that 

definition usually is dispositive; it is the single best guide to the meaning of a disputed term.”); 

Ushijima v. Samsung Elecs. Co., Ltd, No. 1:16-CV-585-LY, 2017 WL 3494229, at *2 (W.D. Tex. 

Aug. 14, 2017) (“[T]he patentee’s lexicography governs.”).

The specification states that: “trunk ports supporting the Riverstone solution are known 

as stackable trunk ports.” ’888 patent, 8:24–25. If this clear definition was not enough, applicants 

confirmed during prosecution that this disclosure shows “what is meant by” the term stackable 

trunk port:

[T]he description reads “the Riverstone solution brings about a backbone VLAN 

paradigm wherein: the extended VLAN identifiers are known as backbone VLAN 

identifiers defining corresponding backbone VLANs, trunk ports supporting the 

Riverstone solution are known as stackable trunk ports.” These passages clearly 

illustrate what is meant by a backbone VLAN ID and stackable trunk ports and 

the Examiner’s interpretation of “stackable trunk port” is incorrect. 

Ex. 8, (6/9/08 Appl. Arg.) at 11. These passages alone demonstrate that applicants acted as 

lexicographers and refute WSOU’s assertion that the “specification doesn’t require the specific 

elements of Defendants’ construction.” Br. 10. 

The ’888 patent further explains that the Riverstone solution is “the additional extension 

802.1Q packet header”: 

Developments in the field . . . include a proposed extension to the IEEE 802.1Q 

VLAN protocol by Riverstone Networks. The IEEE 802.1Q VLAN protocol 

extension proposes the use of an additional extension 802.1Q packet header . . . 

. FIG. 2 is a schematic diagram showing exemplary packet structures as specified 

in the IEEE 802.1Q VLAN protocol and the Riverstone solution, respectively; the 

Riverstone solution enables reuse of standard IEEE 802.1Q VLAN identifiers as 

long as the combined VLAN identification is unique.

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’888 patent, 5:49–62; see also id., 8:4–5 (“Riverstone stackable VLAN solution provides an 

extended VLAN identification[.]”). Even WSOU agrees that a stackable trunk port must “support 

the use of an additional VLAN header.” Br. 10. WSOU further cites Figure 2 (see id.) which 

shows that the Riverstone solution is an additional extended 802.1Q VLAN header:

’888 patent, Fig. 2 (annotations added); see also id., 5:57–62, 9:4–11. The Riverstone reference6 

also explains that an additional extended 802.1q header is added to packets traveling through the 

backbone ports. Ex. 9 (Riverstone) at 5-18, 5-19.

WSOU’s argument that “plain meaning” should apply does not serve the role of explaining 

highly technical terms to the jury.7 See Abbott Labs. v. Sandoz, Inc., 544 F.3d 1341, 1360 (Fed. 

Cir. 2008) (“‘Claim construction’ is for the purpose of explaining and defining terms in the claims 

. . . .”). Defendants thus respectfully request that “stackable trunk port” be construed, consistent 

with the applicants’ lexicography, to mean a “trunk port supporting the Riverstone solution (i.e. 

the additional extension 802.1Q packet header).” 

B. “backbone VLAN trunk” (claims 1, 5, 6, 7, 12, 15–20) 

Defendants’ Proposal WSOU’s Proposal

“data transport trunk links defined between stackable 

trunk ports on core routers”

Plain and ordinary meaning

6 Riverstone Network’s proposed extension to 802.1Q is cited on the face of the patent and is thus 

intrinsic evidence. V-Formation, Inc. v. Benetton Grp. SpA, 401 F.3d 1307, 1311 (Fed. Cir. 2005) 

(“[P]rior art cited in a patent or cited in the prosecution history of the patent constitutes intrinsic 

evidence. . . . [W]hen prior art that sheds light on the meaning of a term is cited by the patentee, it 

can have particular value as a guide to the proper construction of the term, because it may indicate 

not only the meaning of the term . . . but also that the patentee intended to adopt that meaning.”).

7 And, WSOU admitted that there is a claim construction dispute regarding this term (No. 6:20-

cv-00475, Dkt. 54 at 4–6), thus the Court must resolve this issue. See O2 Micro, 521 F.3d at 1362. 

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As with the prior term, applicants explicitly defined “backbone VLAN trunk” during 

prosecution:

Backbone VLANs travel over backbone VLAN trunks, which are defined between 

stackable trunk ports on core routers. . . . Claim 1 is directed to a method of 

provisioning a backbone VLAN. . . . A backbone VLAN is a path through the core 

of a network, defined by the switching rules for the stackable trunk ports, which 

is able to carry a number of VLANs. The backbone VLAN uses a field which is in 

addition to the usual VLAN ID field in order that the various core routers through 

which the backbone VLAN passes are able to switch packets to appropriate 

stackable trunk ports. Gai does not teach backbone VLANs in any way.

Ex. 7, (10/19/07 App. Arg.) at 11–13; see also Ex. 10, (4/8/08 App. Arg.) at 11 (“The present 

invention, as claimed, is directed to a provisioning method which enables a number of possible 

actual VLANs beyond the usual 4096 limit. Backbone VLANs travel over backbone VLAN 

trunks, which are defined between stackable trunk ports on core routers.”); id. at 12, 14 (same); 

Ex. 8 (6/9/08 App. Arg.) at 13–14, 16 (same). Applicants’ use of the words “is” and “are” make 

clear that they were defining backbone VLAN trunks to mean trunk links between stackable trunk 

ports on core routers. See Fisher-Rosemount Sys., Inc. v. Invensys Sys., Inc., No. A-13-CA-587-

SS, 2015 WL 1275910, at *11 (W.D. Tex. Mar. 19, 2015) (“Clear definitions are usually set off 

by quotation marks or are marked by the word ‘is.’”) (citing Sinorgchem Co., Shandong v. Int’l 

Trade Comm’n, 511 F.3d 1132, 1136 (Fed. Cir. 2007)). Thus, this term should be construed 

consistent with this lexicography. See Ushijima, 2017 WL 3494229, at *2.

Contrary to WSOU’s assertions (Br. 11), the specification, consistent with the explicit 

definition above, uniformly mandates that a “backbone VLAN trunk” sits between stackable trunk 

ports on core routers. See ’888 patent, 8:24–27 (“[T]runk ports supporting the Riverstone solution 

are known as stackable trunk ports and the data transport trunk links associated therewith are 

known as backbone trunks.”); see also id., 8:65–9:11, 10:4–29, 11:20–12:5, 9:12–50, Fig. 3. 

WSOU’s selective quotation of the specification is misleading and incorrect. Br. 11. WSOU cites 

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a portion of the specification that says “backbone VLAN trunks 308 bridg[e] two managed 

domains” to suggest that the specification is not limited to backbone VLANs connecting stackable 

trunk ports. See id. (quoting ’888 patent, 11:49–51). But the very next sentence states that even 

in that embodiment, the backbone VLAN trunk is still defined between stackable trunk ports:

Therefore backbone VLAN trunks 308 bridging two managed domains exist. For 

such backbone VLAN trunks, the backbone VLAN provisioning methods apply 

at least to the proximal managed corresponding stackable trunk ports 302.

’888 patent, 11:49–54; see id., Fig. 3 (reproduced supra p. 13) (showing backbone VLAN trunks 

(308) are defined between stackable trunk ports (302) on core routers (306) in the core network). 

In addition, while the patent notes that the definition of core routers is being blurred due to 

virtualization (see Br. 11 (quoting ’888 patent, 8:52–57)), the claims require associating “stackable 

trunk ports corresponding to the plurality of backbone VLAN trunks” and applicants defined the 

claimed stackable trunk to be “on core routers.” See ’888 patent, cls. 1, 15; Ex. 7, (10/19/07 App. 

Arg.) at 11–13; SanDisk Corp. v. Kingston Tech. Co., 695 F.3d 1348, 1363 (Fed. Cir. 2012) (“A 

patentee [] can disclaim [subject matter] by disclosing it in the specification. As we held . . . , 

‘[w]hen a patent drafter discloses but declines to claim subject matter, . . . this action dedicates 

that unclaimed subject matter to the public.’” (citation omitted)). If the term “core router” is 

ambiguous, as WSOU asserts (Br. 11), then “stackable trunk ports” should be held indefinite.

WSOU cannot be allowed to ignore applicants’ clear lexicography in favor of plain 

meaning. Plain meaning does not help the jury understand what a backbone VLAN trunk means, 

especially since the term was expressly defined. Indeed, WSOU has admitted that there is a claim 

construction dispute regarding this term (No. 6:20-cv-00475, Dkt. 54 at 4–6), thus the Court must 

resolve this issue. See O2 Micro, 521 F.3d at 1362. Defendants respectfully ask the Court to 

construe “backbone VLAN trunk” to mean “data transport trunk links defined between stackable 

trunk ports on core routers.” See Jack Guttman, 302 F.3d at 1360–61. 

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C. “wherein the selection and association of at least one backbone VLAN ID with 

each one of the corresponding plurality of backbone VLAN trunks is 

undertaken irrespective of one of an in-use and a stand-by designation of each 

one of the plurality of backbone VLAN trunks and each one of the plurality of 

stackable trunk ports” (claim 1) / “wherein the association of the plurality of 

backbone VLAN IDs with the backbone VLAN trunk is undertaken irrespective 

of one of an in-use and a stand-by designation of the backbone VLAN trunk and 

the at least one stackable trunk port” (claim 15)

Defendants’ Proposal WSOU’s Proposal

“wherein the provisioning method ignores the designation of a backbone 

VLAN trunk as in-use or stand-by when associating the backbone 

VLAN ID with the backbone VLAN trunks (as opposed to, during 

association of VLANs with trunks, explicitly designating physical 

VLANs associated with a logical VLAN as in-use and explicitly 

designating other physical VLANs associated with the logical VLAN as 

back-up)”

Plain and ordinary 

meaning

As with the other ’888 patent terms, Defendants’ construction for “irrespective” is taken 

verbatim from applicants’ own statements and should be adopted. See Tech. Properties Ltd. LLC 

v. Huawei Techs. Co., 849 F.3d 1349, 1357 (Fed. Cir. 2017) (“An applicant’s statements to the 

PTO characterizing its invention may give rise to prosecution disclaimer. Prosecution disclaimer 

can arise from both claim amendments and arguments made to the PTO.”).

During prosecution, the examiner rejected the claims as anticipated by U.S. Pat. No. 

6,678,241 (“Gai”). Ex. 11 (1/8/08 Final Rej.) at 4–5. The examiner explained that: 

As illustrated in [Gai] Fig. 5C, RED logical VLAN includes physical VLANs 10-

13 . . . . Further, each physical VLAN is designated as ACTIVE, STAND-BY, and 

UNUSABLE. This implies that the trunks in the physical VLANs associated with 

each logical VLAN are undertaken irrespective of a one in-use and/or stand-by 

designation[].

Id.; see Ex. 12 (Gai) Fig. 5C (excerpt reproduced below) (annotations added).

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In response, applicants distinguished Gai, arguing that the claimed methods must “ignore” 

spanning tree designations when associating backbone VLAN IDs with backbone VLAN trunks:

[T]he association of a backbone VLAN ID with a corresponding plurality of 

backbone VLAN trunks is carried out without any consideration of whether the 

backbone VLAN trunks are designated as in-use or standby. The backbone VLAN 

trunks may each already have a designation of in-use or standby, but the 

provisioning methods of the present claims8 ignore those designations when 

associating the backbone VLAN IDs with the backbone VLAN trunks.

Ex. 8, (6/9/08 App. Arg.) at 11. Applicants then explicitly disclaimed methods, like the one in 

Gai, that designate for a particular VLAN ID a single in-use trunk port and designate one or more 

other ports as backups. 

This is completely contrary to the backup method taught by Gai, which during 

association of VLANs with trunks explicitly designates one of the physical VLANs 

associated with a logical VLAN as in-use and explicitly designates one or more

other physical VLANs associated with the logical VLAN as back-up.

Id.; see also Ex. 7, (10/19/07 App. Arg.) at 11–12 (arguing Gai was “actually contrary to the 

limitation of claim 1” because Gai “deliberately has one active physical VLAN associated with it 

and a number of stand-by physical VLANs, the association cannot be said to be irrespective of 

whether the trunk is in-use or stand-by”); Ex. 10, (4/8/07 App. Arg.) at 11–12 (same). These 

repeated and unequivocal disclaimers made to distinguish painfully close prior art are particularly 

significant, as applicants admit in the “Background” of the ’888 patent that VLAN provisioning, 

spanning tree protocols, VLAN stacking, and backbone VLAN IDs were all known in the art. See

’888 patent, 3:45–6:7, Fig. 1–2. 

Thus, contrary to WSOU’s assertions, the claims require more than just associating all 

stackable trunk ports (whether in-use or standby) with a VLAN ID. Compare Br. 12, with Ex. 8, 

(6/9/08 App. Arg.) at 11. Just as in Tech. Properties, applicants here disclaimed this broader 

8 The claims at issue were the same claims that were allowed. See Ex. 8, (6/9/08 App. Arg.). 

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reading of this term when they distinguished prior art methods that only allow one in-use backbone 

VLAN trunk to be assigned to a particular backbone VLAN ID. See 849 F.3d at 1358 (affirming 

disclaimer where applicant argued during prosecution that prior art was “‘specifically 

distinguished from the instant case’” (citation omitted)). As such, the claims cannot read on a 

system that explicitly designates one port as active and others as backup, as applicants argued. 

WSOU’s only criticisms of Defendants’ construction are that: (1) the words “ignores the 

designation” are “vague and confusing” and (2) the word “designating” is not in the claims. Br. 

12. But these words come verbatim from applicants’ statements distinguishing the prior art.

9

 And, 

contrary to WSOU’s argument, the claims do recite “one of an in-use and a stand-by designation.” 

’888 patent, cls. 1, 15. Applicants expressly stated that these designations must be ignored. 

Thus, the “irrespective” limitation should be construed to mean what the applicants said it 

means, and cannot include methods that only allow one in-use backbone VLAN trunk to be 

assigned to a particular backbone VLAN ID. Moreover, because WSOU acknowledged this as a 

claim construction dispute (No. 6:20-cv-00475, Dkt. 53 at 5–6); it must be resolved now. See O2 

Micro, 521 F.3d at 1362. Defendants respectfully ask the Court to adopt Defendants’ construction. 

DISPUTED TERMS FROM THE ’435 PATENT

The ’435 patent generally describes configuring VLANs in a network managed by a 

MSTP.10 See ’435 patent, 1:8–13. The patent describes a network with a number of VLANs and 

a number of MSTIs used by those VLANs.11 See, e.g., id., 1:19–21, 25–27; 3:42–44, 61–63. 

9 If the applicants’ statements are “vague and confusing,” as WSOU asserts (Br. 12), then the 

“irrespective” term should be held indefinite. 

10 A spanning tree is a linking of nodes across the network with no loops. ’435 patent, 3:39–43. 

The word “multiple” in MSTP is used because there can be several tree structures within the 

network, each one used for a different group of VLANs. Id., 3:42–44. 

11 An MSTI is a particular spanning tree for a set of VLANs. Id., 3:45–49.

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sMore specifically, the patent describes first generating MSTIs and then assigning each 

VLAN to an appropriate MSTI. Id., Fig. 12. For example, Figures 2A/2B (left) depict MSTIs that 

are made up of the solid lines (which are active links) and dashed lines (which are inactive links). 

Id., 3:49–60. Figures 3A/B (right) depict VLANs, where the active links of the VLANs are 

represented by solid lines and potential alternative links by dashed lines. See id., 3:45–53; 3:63–

4:5. MSTI 1 in Figure 2A is appropriate for VLAN 1 in Figure 3A because MSTI 1’s active 

topology fully covers the topology of VLAN 1. MSTI 2 in Figure 2B is not appropriate for VLAN 

1 because MSTI 2’s active topology does not cover the topology of VLAN 1 entirely. Id., 4:16–20.

Figure 4A (below) shows MSTI 1 and VLAN 1 superimposed. In Figure 4A, the solid 

lines are active links, the dashed line is part of the MSTI and part of the VLAN but currently 

inactive, and the bold line is part of the MSTI but not part of the VLAN. According to the patent, 

when a link failure occurs in the MSTI, the MSTP will have to activate another link. See id., 1:28–

35. For example, if a link failure occurs between Bridges B and C in Figure 4A, the MSTI could 

activate either the bolded link between Bridges A and C (which is not preferred) or the dashed link 

between Bridges B and D (which is preferred). To ensure the newly activated link is both within 

the MSTI and within the VLAN (i.e., the dashed link between B and D), the patent discloses 

setting the path costs (IPPC) of ports that are within the MSTI but not within the VLAN to a higher 

cost, and setting the costs of ports that are within the MSTI and within the VLAN to a lower cost. 

See, e.g., id., 5:9–33. Thus, as shown in Figure 6 (below), when a link fails, the network will favor 

lower-cost ports, and thus attempt to activate a path within the MSTI and within the VLAN (the 

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 30 of 50
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path between B and D in Figure 6). See id.

A. “setting the IPPC of one of the ports of one of said bridges within the MSTI to a 

lower IPPC when said port is part of the VLAN member set” (claims 1, 8, 13)

Defendants’ Proposal WSOU’s Proposal

order of steps

The setting of the IPPC to a lower IPPC must occur after the 

creation and configuration of the Multiple Spanning Tree Instances 

step and after the creation of the VLAN member sets step

Plain and ordinary 

meaning

All of the asserted claims require creating the MSTIs and associating VLAN member sets 

with those MSTIs before setting port costs. For example, claim 112 of the ’435 patent recites:13

1[pre] A method ... comprising the steps of

1[a] creating and configuring a plurality of Multiple Spanning Tree Instances 

(MSTIs) whose active topology covers the topology of Virtual Local Area 

Networks (VLANs) being used within the computer network;

1[b] creating VLAN member sets and associating each of said VLANs with an 

appropriate one of the MSTIs, each of said VLAN member sets indicating 

the ports in each of the bridges within one of the MSTIs to which data traffic 

destined to members of the associated VLAN is being forwarded;

1[c] setting the Internal Port Path Cost (IPPC) of one of the ports of one of said 

bridges within the MSTI to a high IPPC when said port is not part of the 

VLAN member set; and

1[d] setting the IPPC of one of the ports of one of said bridges within the MSTI

to a lower IPPC when said port is part of the VLAN member set ... .

The plain language of this claim requires that the disputed limitation—1[d]—must occur 

12 Claim 8 is a “bridge” claim and claim 13 is a “computer network” claim. Both claims recite 

similar limitations as set forth in claim 1.

13 Bracketed notations (“[a],” “[b],” etc.) were added to facilitate identification of each limitation.

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 31 of 50
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after limitations 1[a] and 1[b].14 See, e.g., Wi-LAN, Inc. v. Apple, Inc., 811 F.3d 455, 460 (Fed. 

Cir. 2016) (claims have an “ordering requirement” when steps refer back to results of previous 

steps). Here “the MSTI” and “the VLAN member set” in limitation 1[d] refer back respectively 

to the “creating and configuring ... MSTIs” in step 1[a] and “creating VLAN member sets” in step 

1[b]. It is further axiomatic that “creating” needs to occur before it could be determined whether 

something is “within the MSTI” or “part of the VLAN member set” as required by step 1[d]. 

In addition to the unequivocal language of the claims, which is dispositive by itself, every 

embodiment discussed in the specification requires limitation 1[d] to be performed after

limitations 1[a] and 1[b], which further confirms the order required by the claim. See Mformation 

Techs., Inc. v. Rsch. in Motion Ltd., 764 F.3d 1392, 1400 (Fed. Cir. 2014) (noting order of steps 

“is consistent with the sole embodiment in the specification”). Limitation 1[d], which is described 

as the “first feature of the present invention,” is explicitly performed only after limitations 1[a] 

and 1[b] are completed. See, e.g., Marine Polymer Techs., Inc. v. HemCon, Inc., 672 F.3d 1350, 

1359 (Fed. Cir. 2012) (holding use of “the present invention” limits the claims); Modine Mfg. Co., 

v. Int’l Trade Comm’n, 75 F.3d 1545, 1551 (Fed. Cir. 1996) (“[W]hen the preferred embodiment 

is described in the specification as the invention itself, the claims are not necessarily entitled to a 

scope broader than that embodiment.”). The specification discusses creating MSTIs (see ’435 

patent at 3:29–60; 6:10–6:36), and creating VLAN member sets and associating each of said 

VLANs with one of the MSTIs. See id., 4:6–5:5; 6:37–7:9. The specification then states:

After the VLAN member sets are created and the VLANs are mapped onto and 

associated with an appropriate MSTI, then the first feature of the present invention

is performed [discussing limitations 1[c] and 1[d]].

14 The same reasoning mandates that limitation 1[c] must follow 1[a] and 1[b], but Defendants 

chose to focus only on 1[d] given claim construction term limits.

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 32 of 50
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See id., 5:6–50; 7:10–12 (same). Thus, the specification confirms the order required by the plain 

language of the claims.

WSOU does not dispute that limitation 1[d] must occur after limitations 1[a] and 1[b] 

begin.15 WSOU instead argues that 1[d] can be performed before steps 1[a] and 1[b] are finished. 

Br. at 14. WSOU’s argument selectively isolates words in the claim and ignores the remainder of 

the claim language. WSOU highlights “a plurality” in limitation 1[a] and “one of the [MSTIs]” in 

limitation 1[b] to conclude that “nothing in the claim language” prevents limitation 1[d] from being 

performed before limitations 1[a] and 1[b] are completed. Id. That argument ignores that 

limitation 1[b] requires “associating each of said VLANs with an appropriate one of the 

MSTIs”—that plain language requires limitation 1[a] to be completed before 1[b]. Moreover, as 

discussed above, WSOU further ignores that the specification specifically describes limitation 1[d] 

as being performed after limitations 1[a] and 1[b] are complete. 

WSOU is also incorrect in its position that applying an order to claims 8 and 13 “makes no 

sense.” Br. at 13–14. The law is clear: apparatus and system claims can have an order of steps 

when they are similar to the method claim. See Avago Techs. Gen. IP (Singapore) Pte Ltd. v. 

Asustek Computer, Inc., No. 15-CV-04525-EMC, 2016 WL 3029674, at *12 (N.D. Cal. May 27, 

2016) (noting case law supporting, and absence of any case law refuting, that “order can be 

required by a system/apparatus claim”); Maxim Integrated Prod., Inc. v. Silicon Mitus Tech., Inc., 

No. 17-CV-03507 NC, 2018 WL 4657384, at *9 (N.D. Cal. July 3, 2018) (collecting cases).16 

15 At a minimum the Court should thus require that steps 1[a] and 1[b] must begin before step 1[d].

16 WSOU fails to address this case law; its sole case cite is irrelevant as it does not address whether 

an apparatus claim can include an order of steps. See Hewlett-Packard Co. v. Bausch & Lomb, 

Inc., 909 F.2d 1464, 1468 (Fed. Cir. 1990) (discussing whether prior art covers apparatus claim).

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 33 of 50
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Here, claims 8 and 13 contain virtually identical limitations as limitations 1[a], 1[b], and 1[d], and 

most importantly contain exactly the same referential language back to prior steps:

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 34 of 50
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Claim 1 Claim 8 Claim 13

1[a] creating and 

configuring a plurality of 

Multiple Spanning Tree 

Instances (MSTIs) whose 

active topology covers the 

topology of Virtual Local 

Area Networks (VLANs) 

being used within the 

computer network;

a Multiple Spanning Tree 

Protocol (MSTP) engine used 

for creating and configuring a 

plurality of Multiple Spanning 

Tree Instances (MSTIs) whose 

active topology covers the 

topology of the plurality of 

VLANs within the computer 

network;

creating and configuring a 

plurality of Multiple Spanning 

Tree Instances (MSTIs) whose 

active topology covers the 

topology of Virtual Local Area 

Networks (VLANs) being used 

within the computer network;

1[b] creating VLAN member 

sets and associating each of 

said VLANs with an 

appropriate one of the 

MSTIs, each of said VLAN 

member sets indicating the 

ports in each of the bridges 

within one of the MSTIs to 

which data traffic destined to 

members of the associated 

VLAN is being forwarded;

a processing unit for creating 

VLAN member sets and 

associating each of said 

VLANs with an appropriate 

one of the MSTIs, each of said 

VLAN member sets indicating 

the ports in each of the bridges 

within one of the MSTIs to 

which data traffic destined to 

members of the associated 

VLAN is being forwarded;

creating VLAN member sets

and associating each of said 

VLANs with an appropriate 

one of the MSTIs, each of said 

VLAN member sets indicating 

the ports in each of the bridges 

within one of the MSTIs to 

which data traffic destined to 

members of the associated 

VLAN is being forwarded;

1[d] setting the IPPC of 

one of the ports of one of said 

bridges within the MSTI to a 

lower IPPC when said port is 

part of the VLAN member 

set;

said processing unit for setting 

the IPPC of one of the ports of 

one of said bridges within the 

MSTI to a lower IPPC when 

said port is part of the VLAN 

member set;

setting the IPPC of one of the 

ports of one of said bridges 

within the MSTI to a lower 

IPPC when said port is part of 

a [sic] the VLAN member set;

Since claims 8 and 13 recite a substantively identical limitation to 1[d], which requires the creation 

of MSTIs and association of VLAN member sets, both require the same order of steps as claim 1.

B. “ideally” (claims 7, 11, and 18)

Defendants’ Proposal WSOU’s Proposal

Indefinite Plain and ordinary meaning

The term “ideally,” as used in the claims, does not provide reasonable certainty as to when 

infringement occurs. Claims 7, 11 and 18 recite “said high IPPC is a value that is ideally between 

the highest value allowed by an encoding and the highest IEEE standard recommended value.” 

Based on the plain language of the claim, there is absolutely no way to determine the meaning of 

this limitation. By itself, “ideally” provides no objective indicia about whether the value must be 

near the range of possible values and if near, how close must a value be to meet the scope of 

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 35 of 50
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“ideally.” The claims and specification also do not provide any guidance about when a value is 

close enough to be “ideally.” KLA-Tencor Corp. v. Xitronix Corp., No. A-08-CA-723-SS, 2011 

WL 318123, at *5 (W.D. Tex. Jan. 31, 2011) (claims indefinite because “patent fail[ed] to identify” 

when line is “close enough to be substantially maximizing”).

On the other hand, “ideally” could arguably mean one of two totally opposite things: 

“required to be,” or “not required to be.” Both interpretations are contrary to well-established rules 

of claim construction. And in any event, there is no way to tell which of these two constructions 

applies. 

Interpreting “ideally” to mean either “required” or “not required” would make parts of the 

claim superfluous. For example, in Digital-Vending Servs. Int’l, LLC v. Univ. of Phoenix, Inc., 

672 F.3d 1270, 1275 (Fed. Cir. 2012), the Federal Circuit rejected a construction that rendered 

claim language superfluous because it was “contrary to the well-established rule that ‘claims are 

interpreted with an eye toward giving effect to all terms in the claim.’” (quoting Bicon, Inc. v. 

Straumann Co., 441 F.3d 945, 950 (Fed. Cir. 2006)). Here, if “ideally” meant “required,” that 

would render the word “ideally” superfluous. And if “ideally” meant “not required,” that would 

render the entire claim limitation in which it appears a nullity. Neither interpretation can be right.

Even if any of the preceding interpretations worked, there is no way to tell which applies. 

In Pac. Coast Bldg. Prod., Inc. v. CertainTeed Gypsum, Inc., 816 F. App’x 454, 457–59 (Fed. Cir. 

2020), the court found a term indefinite where “the plain language of the claim and specification 

did not” provide guidance as to its meaning among more than one potential meaning. Here, the 

plain language of the claims and the specification provides no guidance as to whether “ideally” 

means required or not required. See ’435 patent, 5:15–22 (using “ideally” as used in the claims); 

8:33–38 (using “ideally” to describe how a network administrator can set path cost values). 

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 36 of 50
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WSOU argues that “ideally” provides “an objective indication for what the high IPPC value 

should be set to.” Br. 15. But WSOU does not explain what that “objective indication” is and 

instead, simply reiterates the claim. Id. If WSOU means that “ideally” means the value must be 

set in the recited range, WSOU has rendered the term “ideally” superfluous. If instead, WSOU 

means that “ideally” does not have to be set in that range, the entire limitation is meaningless. 

Since there is no clear meaning, the term is indefinite. See Interval Licensing LLC v. AOL, Inc., 

766 F.3d 1364, 1371 (Fed. Cir. 2014) (“[A]term of degree fails to provide sufficient notice of its 

scope if it depends on the unpredictable vagaries of any one person’s opinion.”) (quotations 

omitted); Clear Imaging Rsch., LLC v. Samsung Elecs. Co., No. 2:19-CV-00326-JRG, 2020 WL 

6384731, at *20 (E.D. Tex. Oct. 30, 2020) (finding “substantially blur free” indefinite).

C. “processing unit for setting the Internal Port Path Cost (IPPC) of one of the 

ports of one of said bridges within the MSTI to a high IPPC when said port is 

not part of the VLAN member set” (claim 8) / “processing unit for setting the 

IPPC of one of the ports of one of said bridges within the MSTI to a lower IPPC 

when said port is part of the VLAN member set” (claim 8)

Defendants’ Proposal17 WSOU’s Proposal

This is subject to 35 U.S.C. § 112, ¶ 6.

Function: setting the Internal Port Path Cost (IPPC) of one of the ports 

of one of said bridges within the MSTI [to a high IPPC when said port 

is not part of the VLAN member set / to a lower IPPC when said port is 

part of the VLAN member set]

Structure: Indefinite

Plain and ordinary 

meaning

“Processing unit” does not connote sufficiently definite structure, thus, this term is subject 

to § 112, ¶ 6. Even if a claim does not use the word “means,” § 112, ¶ 6 applies if the term fails 

to “recite sufficiently definite structure” or recites “function without reciting sufficient structure 

for performing that function.” Williamson, 792 F.3d at 1349. Here, the claim language does not 

impart any structure for “processing unit.” Instead, the claim describes a “processing unit” by 

17 WSOU listed the wrong construction under Defendants’ proposal. Compare Br. 4, with id. 15. 

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 37 of 50
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solely describing its function: setting the path costs of ports. Diebold Nixdorf, Inc. v. Int’l Trade 

Comm’n, 899 F.3d 1291, 1298 (Fed. Cir. 2018) (“cheque standby unit” invoked § 112, ¶ 6 because 

the claims described the term “solely in relation to its function and location in the apparatus”). 

The term “processing unit” is a nonce word, equivalent to a generic black box. The MPEP 

§ 2181(I)(A), recognizes “unit” as a non-structural generic placeholder. Ex. 13 (MPEP) at 2. 

Adding a generic prefix such as “processing” to “unit” does not transform “unit” into having 

“sufficiently definite structure.” See Optis Wireless Tech., LLC v. Huawei Device Co., No. 2:17-

CV-123-JRG-RSP, 2018 WL 476054, at *32 (E.D. Tex. Jan. 18, 2018) (“processing unit” invoked 

§ 112(6)); Cellular Commc’ns Equip. LLC v. HTC Corp., No. 6:13-CV-507, 2015 WL 1048890, 

at *12 (E.D. Tex. Mar. 9, 2015) (“designating unit” invokes § 112(6)).

Contrary to WSOU’s argument, the claim does not provide sufficient structure for 

“processing unit.” Tellingly, WSOU does not point to any language in the claim for structure and 

only argues that the specification provides structure. See Br. 16 (alleging only that structure exists 

in the specification). WSOU’s argument, however, conflates the two-step m-p-f limitation inquiry. 

The first step considers “whether the claim limitation connotes ‘sufficiently definite structure’” 

and if so, then the second step “review[s] the specification to identify the structure that performs 

the claimed function(s).” MTD Prod. Inc. v. Iancu, 933 F.3d 1336, 1344 (Fed. Cir. 2019). The 

Federal Circuit criticized the PTAB for “conflat[ing] these distinct inquiries.” Id. Holding 

otherwise, would “leave § 112, ¶ 6 without any application: any [m-p-f] limitation that met the 

statutory requirements, i.e., which includes having corresponding structure in the specification, 

would end up not being a [m-p-f] limitation at all.” Id. Thus, WSOU’s reliance on the 

specification to impart structure on the claim at step one of the m-p-f inquiry is misplaced. 

WSOU’s inability to describe any structure in the claim is revealing—there is none.

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 38 of 50
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WSOU’s cited cases are inapposite. In Samsung Elecs. Am. v. Prisua Eng’g Corp., the 

party seeking to invoke § 112, ¶ 6 admitted that the claimed “digital processing unit” had structure. 

948 F.3d 1342, 1353 (Fed. Cir. 2020). In TEK Glob., S.R.L. v. Sealant Sys. Int’l, Inc., the claim 

language alone had sufficient structure by reciting “the container, the compressor assembly, and 

the inflatable article.” 920 F.3d 777, 785 (Fed. Cir. 2019). In Skky, Inc. v. MindGeek, s.a.r.l., the 

disputed term contained “means” and because the claim did not recite function but “instead 

denote[d] structure,” the presumption against § 112, ¶ 6 had been overcome. 859 F.3d 1014, 1020

(Fed. Cir. 2017). This is not the situation here.

Under § 112, ¶ 6, the claim is indefinite because there is no structure whatsoever in the 

specification that corresponds to the recited function. Indeed, WSOU does not even attempt to 

articulate what, if any, structure exists if the term is subject to § 112, ¶ 6. See Br. 15–16. To the 

extent WSOU argues that a “processor within a bridge device” is sufficient structure (Br. at 16), it 

is not. Under § 112, ¶ 6, “the structure disclosed in the specification must be more than simply a 

general purpose computer or microprocessor.” Williamson, 792 F.3d at 1352. For a general 

purpose processor, it must include an algorithm for performing the function. See WMS Gaming 

Inc. v. Int’l Game Tech., 184 F.3d 1339, 1349 (Fed. Cir. 1999); Dyfan, 2020 WL 8617821, at *7. 

Here, there is no algorithm disclosed in the specification for setting port costs; WSOU does not 

argue otherwise. Br. 16. Since the patent does not disclose any structure corresponding to the 

recited function, the term “processing unit” is indefinite. 

D. Entirety of claims 9–11 and 13–18

Defendants’ Proposal WSOU’s Proposal

Indefinite Plain and ordinary meaning

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 39 of 50
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Each of claims 9–11 and 13–18 recite a method step within non-method claims.18 Thus, 

these claims are indefinite under IPXL Holdings, L.L.C. v. Amazon.com, Inc., 430 F.3d 1377, 

1383–84 (Fed. Cir. 2005). For instance, in Rembrandt Data Techs., LP v. AOL, LLC, the Federal 

Circuit held that a claim to “a data transmitting device” that included a method step “transmitting 

the trellis encoded frames” was invalid under IPXL because the claim recited both apparatus and 

method steps. 641 F.3d 1331, 1339–40 (Fed. Cir. 2011). The same logic applies here.

Claims 9 and 16, 10 and 17, 11 and 18: Each of these claims depends on an apparatus 

claim (either independent claim 8 or 13) but requires the actual performance of a step. Dependent 

claims 9 and 16 require that the bridge of the independent claim “operates at layer 2 of the Open 

Systems Interconnection reference model.” ’435 patent, 11:18–19; 12:30–32. Similarly, 

dependent claims 10 and 17 require that the “said high IPPC is set to a value chosen” and “said 

lower IPPC is set to a value chosen.”19 Id., 11:20–30; 12:33–43.20 These method steps cannot be 

performed until the system of claims 8 and 13 respectively are actually used. See Bushnell 

Hawthorne, LLC v. Cisco Sys., Inc., No. 1:18-CV-760, 2019 WL 2745735, at *8 (E.D. Va. July 1, 

2019), aff’d, 813 F. App’x 522 (Fed. Cir. 2020) (finding claim indefinite under IPXL where claim 

element “constitute[d] a method of use element”). As such, these claims are indefinite under IPXL.

Claims 13 and 15: Dependent claim 15 requires the performance of actual steps—it recites 

that each creating and setting step “are repeated.” ’435 patent, 12:27–29 (“The computer network 

of claim 13, wherein said MSTI and VLAN member set creating steps and said setting steps are 

18 WSOU now disagrees that these claims can be grouped together as a single issue. Br. 18. 

WSOU never previously raised this dispute during the parties’ meet and confers, and WSOU itself

treated these terms as one term in its Feb. 1, 2021 spreadsheet submitted to the Court. See Ex. 14. 

Moreover, WSOU identifies no prejudice and should not be heard to complain now.

19 In contrast, independent claim 8 requires a processing unit “for setting” the IPPC. 

20 Claims 11/18 depend from indefinite claims 10/17 and are thus indefinite for the same reason. 

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repeated for each of the MSTIs.”). However, claim 15 depends on claim 13, but claim 13 is 

presented as a system claim. Yet, claim 15 treats certain limitations of system claim 13 as having 

method steps. It explicitly refers to claim 13’s “creating” and “configuring” limitations as “steps.” 

Id. If applicants’ word choice is given effect, then this confirms that claim 13 contains method 

steps in a system claim. K-2 Corp. v. Salomon S.A., 191 F.3d 1356, 1364 (Fed. Cir. 1999) (“Courts 

do not rewrite claims; instead, we give effect to the terms chosen by the patentee.”). Thus, claims 

13 and 15 are indefinite under IPXL.

Claim 14: Claim 14 depends on independent claim 13, and is additionally indefinite 

because it requires that “each MSTI is created and configured using a Multiple Spanning Tree 

Protocol (MSTP) engine.” Because the plain language of the claims requires the actual creation 

and configuration of the MSTIs (as opposed to mere capability), this claim is also indefinite.

* * *

WSOU states only that it “viewed each of the nine individual claims separately and 

disputes that there is any issue.” Br. 18. WSOU then cites two cases that stand for the 

unremarkable proposition that system claims reciting capability are not indefinite under IPXL. Id. 

However, WSOU does not explain how those cases are relevant (because they are not) to the 

specific claim language recited in the claims of the ’435 patent. For example, in MasterMine 

Software, the disputed claim language recited the “system’s capability to receive and respond” to 

selections. MasterMine Software, Inc. v. Microsoft Corporation, 874 F.3d 1307, 1316 (Fed. Cir. 

2017). In Ultimate Pointer, the disputed claim language “only indicate[d] that the associated 

structures have this capability (for example, the image sensor and processor in claim 1) and d[id] 

not require that any data be actually generated.” UltimatePointer, L.L.C. v. Nintendo Co., 816 

F.3d 816, 827 (Fed. Cir. 2016). Unlike either of those cases, the claims here cannot be properly 

described as system capabilities. Because it is unclear whether infringement occurs when one 

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33

creates the system or when the method steps are performed, these claims are indefinite under IPXL.

DISPUTED TERMS FROM THE ’129 PATENT

The ’129 patent relates to detecting adverse network conditions based on the “rate of 

change” of usage of resources on a network node. According to the patent, prior art systems could 

track usage of resources across multiple nodes in a network to perform “reactive monitoring.” See

’129 patent, 1:14–26; 1:6–10; 1:27–42; 1:65–2:3. “With reactive monitoring, the management 

station needs information about the network state in order to react (in real or semi-real time) to 

certain alarm conditions that may develop in the network.” Id., 1:25–38. One prior art method for 

tracking the network state was for nodes to send alerts to the management station when certain 

conditions are met, e.g., when the instantaneous value of an attribute hits a threshold. Id., 1:5–58. 

To improve upon such reactive monitors, the patent discloses that network nodes could 

instead generate alerts when the “rate of change” of the monitored attribute exceeds a threshold. 

See id., 6:37–44; see also id., Figs. 4–6. By measuring the rate of change of usage in a resource 

in a node, the monitor can track how much the usage has increased or decreased in a given period 

of time, which permits detection of denial of service type attacks. Id., 3:44–49. 

A. “rate of change” (claim 3)

Defendants’ Proposal WSOU’s Proposal

Plain and ordinary meaning; not an instantaneous 

value measured at a fixed point in time 

Plain and ordinary meaning

The plain and ordinary meaning of “rate of change” to a POSA does not include 

instantaneous values measured at a fixed point in time, as applicants made explicitly clear to get 

this patent allowed. WSOU seeks to interpret this term to include an instantaneous measurement 

of a usage parameter—i.e., current in a device at a particular time—necessitating resolution of the 

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 42 of 50
34

parties’ dispute as to claim construction.21 O2 Micro, 521 F.3d at 1362. And WSOU agrees that 

this claim construction dispute should be decided now. See No. 6:20-cv-00479, Dkt. 52 at 1, 3–5 

(stating whether “rate of change” could include an instantaneous value was “claim construction”). 

The intrinsic record is consistent in differentiating between a rate of change and an 

instantaneous value of a usage parameter. Claim 3 itself recites “monitoring usage of the resource

in a node to determine when a rate of change of the usage exceeds a first predetermined 

threshold.” This language differentiates between a monitored parameter itself (i.e., the usage of a 

resource) and the “rate of change” of that monitored parameter. In other words, the claim requires 

monitoring the usage of a particular resource, and determining the rate at which that usage is 

changing.

The specification makes this differentiation unequivocally clear in explaining the 

difference between Figure 2 and Figure 4, reproduced below. See id., 5:28–40, 6:11–20. 

21 WSOU alleges that this limitation is met by a device that compares an instantaneous parameter—

the current of a device—to a threshold at a particular point in time. See Ex. 15 ’129 Infringement 

Contentions at 5–6; Wilson Sporting Goods Co. v. Hillerich & Bradsby Co., 442 F.3d 1322, 1327 

(Fed. Cir. 2006) (“Although the construction of the claim is independent of the device charged 

with infringement, it is convenient for the court to concentrate on those aspects of the claim whose 

relation to the accused device is in dispute.” (quotation omitted)).

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“FIG. 2 is a flow diagram of the resource 

utilization monitoring process performed at the 

nodes in FIG. 1, in a first embodiment of the 

invention which monitors the value of the 

resources used.” See ’129 patent, 2:54–57; see 

also 5:28–30, 5:41–49.

“FIG. 4 is a flow diagram of the resource 

utilization monitoring process performed at the 

nodes in FIG. 1, in a second embodiment of the 

invention which monitors the rate of change

of the resources used;” See ’129 patent, 2:62–

65; see also 6:15–21, 6:37–44, 6:65–7:2. 

On one hand, Figure 2 compares the instantaneous value of the monitored resource at a particular 

time [Xi(t)] to a threshold in step 203. If the usage exceeds a threshold, the usage is sent to the 

network management station. Id., 5:35–39. Figure 4, on the other hand, calculates how much the 

usage of the monitored resource changes between two times [Xi(t)-Xi(t-1)] and comparing that 

difference to a threshold in step 403. That process requires knowing the value of the particular 

resource at two different times (t) and (t-1). If the difference between the usage at the first time 

and the usage at the second time is greater than amount λ, then the current usage is sent to the 

network management station. Id., 6:10–28. Thus, the specification, like the claims, makes clear 

that the rate of change of a usage parameter cannot be merely the value of the usage parameter at 

an instantaneous point in time. The Court has construed terms to have plain and ordinary meaning 

with limitation when the specification was clear the terms were distinct. See Digital Retail Apps, 

Inc. v. HEB, LP, No. 6-19-00167-ADA, 2020 WL 376664, at *19 (W.D. Tex. Jan. 23, 2020) 

(holding “‘wirelessly transmitting’ cannot include photographing or otherwise scanning a code 

because the specification makes clear the two are distinct”); see also Neodron, Ltd. v. Dell 

Technologies, Inc. No. 1-19-00819-ADA, 2019 WL 9633629 (W.D. Tex. Dec. 16, 2019).

Finally, the prosecution history conclusively compels Defendants’ construction because 

applicants expressly and unambiguously disavowed any claim scope that would include an 

instantaneous measurement of a usage parameter. During prosecution, applicants repeatedly 

distinguished between the claimed “rate of change” of a resource and the prior art’s disclosures 

(“instantaneous value[s] measured at a fixed point in time” or “generic parameters that may be 

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 44 of 50
36

measured or tested relative to predefined thresholds”). Ex. 16, (5/2/07 App. Arg.) at 7; Ex. 17, 

(9/17/07 App. Arg.) at 8. A most compelling passage is below:

In other words, as taught in Mandal, the value is an instantaneous value, measured 

at a fixed point in time, that is compared against the threshold value. An 

instantaneous value measured at a fixed point in time, as taught in Mandal, is 

simply not a rate of change, as claimed in Applicants’ claim 1. A rate is clearly 

measured using a time interval, or some other interval by which rate may be 

measured. There is no time interval in Mandal. Mandal is devoid of any teaching 

or suggestion of monitoring any rate. As such, since Mandal fails to teach or 

suggest a rate of change, Mandal must also fail to teach or suggest a rate of change 

of usage of a resource, as claimed in Applicants’ claim 1.

Ex. 16, (5/2/07 App. Arg.) at 11. WSOU chose to omit the second emphasized sentence in its 

brief, which undeniably states that a rate must be measured using an interval. Br. 20–21. If ever 

there were a clear and unmistakable disavowal in prosecution, this is it. This passage, which is 

completely consistent with the specification, compels the conclusion that the term “rate of change” 

cannot include an instantaneous value measured at a fixed point in time. See Tech. Properties Ltd. 

LLC v. Huawei Techs. Co., 849 F.3d 1349, 1358 (Fed. Cir. 2017); TMC Fuel Injection System, 

LLC v. Ford Motor Company, 682 F. App’x 895, 898 (Fed. Cir. 2017) (citing Uship Intellectual 

Properties, LLC v. U.S., 714 F.3d 1311, 1315 (Fed. Cir. 2013)). 

In an effort to overcome the overwhelming intrinsic support for Defendants’ construction, 

WSOU makes two arguments, both of which fail. First, WSOU argues (without support that) a 

POSA would understand that “rate of change” could include instantaneous values or continuous 

values for different time periods, analogizing to the speed of a car. Br. 19–20. That argument is 

the opposite of what Applicants said to get the claims allowed, which is not permitted. See 

Southwall Technologies, Inc. v. Cardinal IG Co., 54 F.3d 1570, 1576 (Fed. Cir. 1995). In addition, 

WSOU’s analogy simply has nothing to do with the claim language, which recites not just any 

“rate” but the “rate of change” of the monitored usage of a resource. The claim requires 

monitoring the usage parameter, and separately assessing the rate of change of that usage 

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 45 of 50
37

parameter. As discussed, the patent clearly distinguishes between Figure 4 and Figure 2 based on 

the requirement of Figure 4 (and the claims) to compare the usage at two different times. See 

supra. If “speed” were one of the monitored resource usage variables, Figure 2 (which is not 

claimed) would measure the instantaneous value of speed (i.e., the current speed), whereas Figure 

4 (and claim 3) would measure the “rate of change” of speed (i.e., how much the speed has changed 

since the last measurement).22

Second, WSOU argues that the ordinary meaning should apply because there is no 

lexicography or clear disavowal of claim scope. Br. 20–23.23 That is incorrect. At the outset, 

regardless of lexicography or clear disavowal, a POSA would have understood the ordinary 

meaning of “rate of change” of the usage of a resource to be distinct from a mere instantaneous 

value of usage at a fixed point in time. But even if lexicography or disavowal were required—

they are not—applicants’ express distinction between a “rate of change” and an instantaneous 

value rises to the level of a clear disavowal. See Tech. Properties, 849 F.3d at 1358 (affirming 

disclaimer where applicant argued during prosecution that prior art was “‘specifically 

distinguished from the instant case’” (citation omitted)). Here, applicants unambiguously stated 

that an instantaneous value at a fixed point in time “is simply not a rate of change” as recited in 

the claims, and that such a rate of change “is clearly measured using a time interval, or some other 

interval by which rate may be measured.” Ex. 16, (5/2/07 App. Arg.) at 11. That distinction is the 

textbook example of disavowal, and it cannot be ignored, as WSOU seeks to do. See Southwall, 

54 F.3d 1570 at 1576; Tech. Properties, 849 F.3d 1349 at 1358.

In view of the clear meaning of “rate of change” throughout the intrinsic record, consistent 

22 For example, if a car traveling at 50 mph at the first time and 60 mph at a second time, the 

difference in speed (10 mph) across those times reflects the “rate of change” of the parameter. 

23 WSOU’s “second” and “third” arguments are really a single argument regarding disavowal. Id.

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 46 of 50
38

with its plain meaning, the Court should hold that the meaning of “rate of change” does not include 

instantaneous values of measured at a fixed point in time.

B. “initiating a poll of resources in the nodes of the network by the management 

station in response to reporting from the node or a time interval being exceeded” 

(claim 3)

Defendants’ Proposal WSOU’s Proposal

Both of these events trigger a poll Plain and ordinary meaning

The parties now appear to agree that the ordinary meaning of this phrase is that both of the 

listed events—(1) reporting from the node, and (2) a time interval being exceeded—would cause 

a poll of resources to be initiated and that the management station must be capable of both.24 

WSOU states that “[t]he syntax of the claim requires that the management station must be capable 

of initiating a poll in response to both ‘reporting from the node’ and ‘a time interval being 

exceeded.’” Br. 22. Defendants agree and their construction makes that clear.25

The parties’ agreement that the management station must be capable of initiating a poll in 

response to both events is consistent with the specification. The patent states that both event 

reporting and periodic polling monitors were well known in the prior art. See ’129 patent, 1:43–

63. The patent purports to disclose “a technique for managing network elements significantly 

reduces the amount of monitoring related traffic by using a combination of aperiodic polling and

asynchronous event reporting.” Id., 2:16–19; see also id., 2:33–43, 4:4–14 1:43–67, 4:31–41, 6:1–

9, 6:37–44. In particular, the patent discloses that if polling has not occurred due to a rate of 

change exceeding a threshold, then a poll is initiated once “a time interval is exceeded.” See id., 

24 Before briefing, Defendants repeatedly asked WSOU to state whether or not its “plain and 

ordinary meaning” meant that the management station needed to be only capable of “initiating a 

poll” for one of the two triggers or capable of independently responding to both of the triggers, 

and WSOU refused to state its position until its brief. Ex. 18 (1/27/21 Email). 

25 WSOU takes umbrage with Defendants’ use of the word “trigger” rather than “initiate.” Br. 22. 

No distinction was meant between the words. Defendants are amenable to replacing “trigger” with 

“initiate.”

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 47 of 50
39

3:44–49, 6:37–44. A POSA would thus understand that the management station of the claim must 

be capable of initiating a poll in response to both a reporting from the node and when a time interval 

is exceeded, as WSOU agrees the claims require.

In view of this apparent agreement in WSOU’s brief, Defendants immediately reached out 

to propose an agreed construction of the “management station” portion of the disputed phrase to 

mean “a management station that is capable of initiating a poll in response to both reporting from 

the node and a time interval being exceeded.” Ex. 19 (2/26/21 Email). Despite this proposal being 

a direct quote from WSOU’s brief, WSOU inexplicably ignored this request. Rosenthal Decl., ¶ 

20. 

WSOU’s principal argument against Defendants’ construction is that while the 

management station must be capable of initiating a poll in either event, it needs to actually do so 

only in response to one of the events to practice the claimed method. Br. 22. Defendants agree, 

so this is a non-issue. Defendants’ construction is intended only to clarify the ambiguous claim 

language so that the jury understands that the management station must be capable of initiating a 

poll in both events—a position with which WSOU now agrees. Thus, contrary to WSOU’s 

assertions that Defendants’ construction “erases limitations in the term” or “will also confuse a 

jury” (Br. 23), Defendants’ construction (or its alternative compromise proposal) provides the jury 

clarity on the term. Abbott Labs., 544 F.3d at 1360. 

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 48 of 50
40

Dated: March 17, 2021 By: /s/ Barry K. Shelton

Barry K. Shelton

Texas State Bar No. 24055029

bshelton@sheltoncoburn.com

SHELTON COBURN LLP

311 RR 620, Suite 205

Austin, TX 78734-4775 

Telephone: 512.263.2165

Facsimile: 512.263.2166 

Benjamin Hershkowitz

bhershkowitz@gibsondunn.com

Brian A. Rosenthal

brosenthal@gibsondunn.com 

Allen Kathir

akathir@gibsondunn.com

Kyanna Sabanoglu

ksabanoglu@gibsondunn.com

GIBSON, DUNN & CRUTCHER LLP

200 Park Avenue

New York, NY 10166-0193 

Telephone: 212.351.4000

Facsimile: 212.351.4035 

Y. Ernest Hsin

ehsin@gibsondunn.com

Jaysen S. Chung

jschung@gibsondunn.com

GIBSON, DUNN & CRUTCHER LLP

555 Mission Street, Suite 3000

San Francisco, CA 94105-0921

Telephone: 415.393.8200

Facsimile: 415.393.8306

Ryan K. Iwahashi

riwahashi@gibsondunn.com

GIBSON, DUNN & CRUTCHER LLP

1881 Page Mill Road

Palo Alto, CA 94304-1211

Telephone: 650.849.5300

Facsimile: 650.849.5333

Attorneys for Defendants

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 49 of 50
CERTIFICATE OF SERVICE

The undersigned certifies that on March 17, 2021, all counsel of record who are deemed to 

have consented to electronic service are being served with a copy of this document through the 

Court’s CM/ECF system under Local Rule CV-5(b)(1). 

/s/ Barry K. Shelton

Barry K. Shelton

Case 6:20-cv-00475-ADA Document 88 Filed 03/17/21 Page 50 of 50