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-00477-ADA

Case No. 6:20-cv-00482-ADA

JURY TRIAL DEMANDED

DEFENDANTS’ RESPONSIVE CLAIM CONSTRUCTION BRIEF 

REGARDING PATENT NOS. 7,424,020 & 8,913,489 

Case 6:20-cv-00477-ADA Document 83 Filed 03/17/21 Page 1 of 22
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TABLE OF CONTENTS

Page

I. DISPUTED TERMS FROM THE ’020 PATENT............................................................. 1

A. “removing, at the network node, the protocol data of a portion of protocol 

layers from the received data stream” (claim 1) / “removes protocol data 

from a portion of protocol layers from a data stream” (claim 6)............................ 2

B. “a control unit which removes protocol data from a portion of protocol 

layers from a data stream received from the communication network via 

the second interface, the data stream comprising useful data and the 

protocol data, and switches a remaining data stream to be transmitted to 

one of the terminals via the first interface” (claim 6)............................................. 5

1. The term is indefinite under IPXL .............................................................. 6

2. Alternatively, the term is subject to 35 U.S.C. § 112, ¶ 6 .......................... 7

C. “bus system” (claims 1 and 6) ................................................................................ 9

II. DISPUTED TERM FROM THE ’489 PATENT ............................................................. 11

A. “the first set of port interfaces of the multi-chassis link aggregate” 

(claims 1, 8, 15) .................................................................................................... 12

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TABLE OF AUTHORITIES

Page(s)

Cases

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

813 F. App’x 522 (Fed. Cir. May 14, 2020)......................................................................13, 14

Canon, Inc. v. TCL Elecs. Holdings, Ltd.,

2:18-CV-546-JRG, 2020 WL 2098197 (E.D. Tex. May 1, 2020).............................................9

Digital Retail Apps, Inc. v. H-E-B, LP,

No. 6-19-CV-00167-ADA, 2020 WL 376664 (W.D. Tex. Jan. 23, 2020)..........................8, 10

Dow Chem. Co. v. Nova Chems. Corp. (Canada),

803 F.3d 620 (Fed. Cir. 2015)....................................................................................................2

Dyfan, LLC v. Target Corp.,

No. W-19-CV-00179-ADA, 2020 WL 8617821 (W.D. Tex. Nov. 24, 2020)...........................9

Enzo Biochem, Inc. v. Applera Corp.,

599 F.3d 1325 (Fed. Cir. 2010)................................................................................................14

Insituform Techs., Inc. v. Cat Contracting, Inc.,

99 F.3d 1098 (Fed. Cir. 1996)....................................................................................................7

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

430 F.3d 1377 (Fed. Cir. 2005)..............................................................................................6, 7

Kimberly-Clark Corp. v. Tyco Int’l, Inc.,

No. 98-C-0756-C, 1999 WL 33944112 (W.D. Wis. Nov. 1, 1999) ..........................................2

Kinik Co. v. Int’l Trade Comm’n,

362 F.3d 1359 (Fed. Cir. 2004)................................................................................................10

Light Transformation Techs. LLC v. Lighting Sci. Grp. Corp.,

No. 2:12-CV-826, 2014 WL 3402125 (E.D. Tex. July 11, 2014).............................................5

Maxwell v. J. Baker, Inc.,

86 F.3d 1098 (Fed. Cir. 1996)..................................................................................................11

MTD Prod. Inc. v. Iancu,

933 F.3d 1336 (Fed. Cir. 2019)..................................................................................................9

Nautilus, Inc. v. Biosig Instruments, Inc.,

572 U.S. 898 (2014)...................................................................................................................2

Case 6:20-cv-00477-ADA Document 83 Filed 03/17/21 Page 3 of 22
TABLE OF AUTHORITIES

(continued)

Page(s)

iii

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

No. 2:17-CV-123, 2018 WL 476054 (E.D. Tex. Jan. 18, 2018) ...............................................8

Poly-Am., L.P. v. API Indus., Inc.,

839 F.3d 1131 (Fed. Cir. 2016)..................................................................................................5

Power Integrations, Inc. v. ON Semiconductor Corp.,

No. 16-CV-06371-BLF, 2018 WL 5603631 (N.D. Cal. Oct. 26, 2018)....................................8

Rain Computing, Inc. v. Samsung Elecs. Am., Inc.,

2021 WL 786361 (Fed. Cir. Mar. 2, 2021)................................................................................8

SandBox Logistics LLC v. Proppant Express Invs. LLC,

813 F. App’x 548 (Fed. Cir. 2020) ..........................................................................................11

SkinMedica, Inc. v. Histogen Inc.,

727 F.3d 1187 (Fed. Cir. 2013)..................................................................................................4

Teva Pharms. USA, Inc. v. Sandoz, Inc.,

789 F.3d 1335 (Fed. Cir. 2015)..............................................................................................3, 5

Toshiba Corp. v. Imation Corp.,

681 F.3d 1358 (Fed. Cir. 2012)..................................................................................................4

Transcend Med., Inc. v. Glaukos Corp.,

No. CV 13-830, 2015 WL 5546988 (D. Del. Sept. 18, 2015)...................................................5

In re Walter,

698 F. App’x 1022 (Fed. Cir. 2017) ..........................................................................................5

Well-man, Inc. v. Eastman Chem. Co.,

642 F.3d 1355 (Fed. Cir. 2011)................................................................................................14

Williamson v. Citrix Online, LLC,

792 F.3d 1339 (Fed. Cir. 2015)..................................................................................................8

Statutes

35 U.S.C. § 311(b).........................................................................................................................14

Other Authorities

MPEP § 2181 ...................................................................................................................................8

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TABLE OF EXHIBITS1

Exhibit Description

1 ’020 patent File History, 10/3/06 Non-Final Rejection

2 ’020 patent File History, 4/3/07 Final Rejection

3 ’020 patent File History, 6/25/07 Applicant Argument

4 ’020 patent File History, 10/3/02 Claims

5 ’020 patent File History, 1/03/07 Applicant Argument

6 MPEP § 2181

7 Disclosures of Extrinsic Evidence

8 ’020 patent File History, 10/5/07 Non-Final Rejection

9 ’020 patent File History, 2/4/08 Applicant Argument

10 Concise Telecom Networking Dictionary

11 Federal Standard 1037C: Telecommunications: Glossary of Telecommunications 

Terms (1996)

12 ATIS Glossary

1

 Exhibits are attached to the Declaration of Brian A. Rosenthal in Support of Defendants’

Responsive Claim Construction Brief Regarding Patent Nos. 7,424,020 & 8,913,489.

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TABLE OF ABBREVIATIONS

Abbreviation Term/Document(s)

’020 patent U.S. Patent No. 7,424,020

’489 patent U.S. Patent No. 8,913,489

Br. Opening Claim Construction Brief (Case No. 6:20-cv-00477-ADA, 

Dkt. 80; Case No. 6:20-cv-00482-ADA, Dkt. 76)

Defendants Dell Technologies Inc., Dell Inc., and EMC Corporation

IPR Inter partes review petition

LAG Link aggregation group

m-p-f Means-plus-function

MC-LAG Multi-chassis link aggregation group 

MPEP Manual of Patent Examining Procedure

Plaintiff WSOU Investments, LLC d/b/a Brazos Licensing and Development

POSA Person of ordinary skill in the art

PTAB Patent Trial and Appeal Board

Emphasis added unless indicated otherwise.

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Both the ’020 and ’489 patents are indefinite due to hopelessly ambiguous claim language. 

The ’020 patent recites removing protocol layer information, but then has wildly inconsistent

statements about how much—and what portions—must be removed. WSOU’s attempt to

resuscitate the claims only highlights the indefiniteness, as its reading is directly contradicted by

the plain language and the prosecution history. The patent also improperly—and intentionally—

recites apparatus claims that actually perform functions, which violates long-standing precedent. 

The one disputed term that is definite—bus system—is explicitly limited in the specification.

The ’489 patent fares no better, as each claim recites a term that has multiple possible

meanings, yet there is no way to determine which applies. The claims are thus indefinite.

I. DISPUTED TERMS FROM THE ’020 PATENT

The ’020 patent has a terse disclosure of a network node that sits between a communication

network and multiple terminals. ’020 patent, 1:33–43. Figure 1 depicts a communication system

with communication network KN, network nodes FSW 1/2, and terminals TE1–6. Id., 2:14–19. 

Communication network KN is preferably “a bus system” (id., 2:28–29), but alternatively could 

instead have “active components such as switching nodes, gateways, routers, bridges.” Id., 2:30–

33. The patent states there must be at least two terminals connected to each network node but each 

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network node has only one IP address. ’020 patent, 5:1–3.

The data received by the node and destined for a terminal can consist of “useful data and 

protocol data.” Id., 2:57–59. The network node removes protocol data and sends useful data to 

the terminals. Id., Abstract; 1:33–43. The patent explains that removing protocol information at 

layers2 one and three has “[s]pecial advantages,” and that there is little benefit to removing any 

protocol information above layer four. Id., 3:35–42.

A. “removing, at the network node, the protocol data of a portion of protocol layers from

the received data stream” (claim 1) / “removes protocol data from a portion of

protocol layers from a data stream” (claim 6)

Defendants’ Proposal WSOU’s Proposal

Indefinite Plain and ordinary meaning

The intrinsic record is wildly inconsistent in its description of what “portion of protocol

data” must be removed to meet the claims. While the broadest plain meaning would suggest that

removal of any protocol information from multiple layers will do, the specification and file history

state otherwise, and leave the term completely undefinable. Because the intrinsic record “fail[s]

to inform, with reasonable certainty, those skilled in the art about the scope of” these terms, they

are indefinite. Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. 898, 901 (2014). 

The claim language itself does not fully inform a POSA about the meaning of “a portion.” 

Instead, the plain meaning would suggest only that “a portion” is anything than less than the whole.

Kimberly-Clark Corp. v. Tyco Int’l, Inc., No. 98-C-0756-C, 1999 WL 33944112, at *13 (W.D.

Wis. Nov. 1, 1999) (“The ordinary and accustomed meaning of ‘portion’ is some part less tha[n]

the whole.”). However, among the many potential remaining possibilities, it is still not clear what

protocol data must be removed. Dow Chem. Co. v. Nova Chems. Corp. (Canada), 803 F.3d 620,

630 (Fed. Cir. 2015) (“[T]he patent and prosecution history must disclose a single known approach

2 The layers refer to the seven-layer Open System Interconnection (OSI) model. Id., 3:64–67.

Case 6:20-cv-00477-ADA Document 83 Filed 03/17/21 Page 8 of 22
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or establish that, where multiple known approaches exist, a person having ordinary skill in the art

would know which approach to select.”). For example, the claim language does not specify

whether it is sufficient to remove some protocol data from at least one protocol layer or whether

all protocol data must be removed from at least one protocol layer. Teva Pharms. USA, Inc. v.

Sandoz, Inc., 789 F.3d 1335, 1344–45 (Fed. Cir. 2015) (claim indefinite where weight could be

measured three different ways and intrinsic record did not provide guidance as to which measure

to use). The rest of the intrinsic record serves only to heighten the ambiguity.

The short specification does not use the word “portion,” which only appears in the claims,

and instead uses the word “majority” to discuss removing protocol data. ’020 patent, 2:60–64

(“The network nodes FS1 and FS2 now remove the majority of the protocol data.”); Abstract;

1:39–43; 1:46–49; 3:24–28. The specification does not explain how “majority” maps onto

“portion,” and there is no guidance as to what “majority” means.3 The specification also discloses

removing protocol data from “one or more communication layers,” id., 3:29–34, and suggests

“removal of the protocol data of the first (simple point-to-point protocol) and/or the third layer

(e.g., saving IP addresses)” and processing layers 1 to 4, but not layers 5 or higher. Id., 3:35–42;

3:60–64 (discussing “layers 1, 2, 3, and 4” but also suggesting to “process protocols of more or

fewer layers”). In short, the specification provides no further clarity.

Finally, the prosecution history provides grossly inconsistent guidance as to what “portion”

means. After the examiner rejected the claims because “majority” was indefinite, applicant

amended the claims to recite a “portion”: “removing, at the network node, a majority of the

3

 The examiner noted that “majority” is indefinite because it is not clear if it refers to removing

more than half of the total bytes of data, more than half of the bytes of data in each layer, a certain

percentage of bytes from each layer, or something else. Exs. 1 (10/3/06 Non-Final Rejection) at

2–3; 2 (4/3/07 Final Rejection) at 2–3. 

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protocol data of a portion of protocol layers from the received data stream.” Ex. 3 (6/25/07

Response) at 2.

4

 But then applicant made inconsistent arguments about the meaning of “portion.” 

First, applicant defined “portion” to mean the data from protocol layers 1-4. 

Thus, regarding the removal of “a portion” of the protocol data, refers to the

removal of the data from protocol layers 1-4 of the OSI model, and further the

“portion” removed refers to the portion of the protocol layers, i.e., layers 1-4, out

of the seven layers of the OSI model.

Id., 6; SkinMedica, Inc. v. Histogen Inc., 727 F.3d 1187, 1202 (Fed. Cir. 2013) (“i.e.” is “an intent

to define the word to which it refers”). In the same response, applicant backtracked from its

definitional “i.e.” statement and referred to removing layers 1–4 as only an “example”:

On the contrary, as pointed out above, protocol data related to layers 1-4 of the OSI

model, for example, are simply removed from the data stream.

id., 7; Toshiba Corp. v. Imation Corp., 681 F.3d 1358, 1371 (Fed. Cir. 2012) (“i.e.” not definitional

when applicant was “explaining [an] example”). Further inconsistency and confusion ensued. 

After the first amendment/argument, the examiner again rejected the claims, this time based on a

prior art reference (Huitema) that removed one layer of protocol data. Ex. 2 (4/3/07 Final

Rejection) at 4. In response, applicant argued:

Huitema does not disclose the protocol data of a portion of protocol layers. On the

contrary, Huitema simply removes data from a single protocol layer, i.e., IPv4. 

Thus, since Huitema contemplates removing data from only one protocol layer,

Applicant submits Huitema fails to teach or suggest removing protocol data of a

portion of protocol layers.

Ex. 3 (6/25/07 Applicant Argument) at 8 (underlining in original; bold/italics added). Thus, based

on this disavowal, the term “portion” cannot mean only a single layer. 

Applicant’s vacillating description of “portion” removes any possible meaning from these

4 Earlier in prosecution, applicant asserted “majority” meant “one or more.” Ex. 5 (1/3/07

Applicant Arguments) at 5 (“[R]emoving a majority of the protocol data is fully described . . . the

specification explains . . . that the protocol data of one or more layers is processed and removed.”). 

Case 6:20-cv-00477-ADA Document 83 Filed 03/17/21 Page 10 of 22
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terms. The intrinsic record, as discussed, at various times suggests that “portion” could mean: one

or more layers; more than one layer; i.e., not just one; layers 1–4; any number of layers, but not

all; and some part of some layers, without removing any single layer. These inconsistencies leave

the term hopelessly vague, and the claims are thus indefinite. In re Walter, 698 F. App’x 1022,

1026 (Fed. Cir. 2017) (indefinite because “term’s ill-defined boundaries coupled with the

patentee’s erratic use of the term [in prosecution] fails to inform [POSAs] about the scope”).

WSOU’s argument that “a POSITA would understand that the data need only be removed

in at least one protocol layer” cannot be correct. Br. 3. As explained, applicant expressly

distinguished the claims from the prior art because the prior art only removed one layer. This was

a clear disavowal of claim scope. Poly-Am., L.P. v. API Indus., Inc., 839 F.3d 1131, 1137 (Fed.

Cir. 2016) (disavowal in file history notwithstanding claim language that implied broader scope). 

Moreover, given that the intrinsic record contradicts WSOU’s alleged plain meaning of removing

only one layer, and provides numerous other inconsistent interpretations, a POSA could not be

reasonably certain as to what these terms mean. Teva, 789 F.3d at 1345 (indefinite when patentee

ascribed different meanings to term at different times); Transcend Med., Inc. v. Glaukos Corp.,

No. CV 13-830, 2015 WL 5546988, at *7 (D. Del. Sept. 18, 2015) (indefinite due to inconsistent

descriptions in specification and file history); Light Transformation Techs. LLC v. Lighting Sci.

Grp. Corp., No. 2:12-CV-826, 2014 WL 3402125, at *9 (E.D. Tex. July 11, 2014) (indefinite when

intrinsic record didn’t indicate which of multiple possible axes was referred to).

B. “a control unit which removes protocol data from a portion of protocol layers from a

data stream received from the communication network via the second interface, the

data stream comprising useful data and the protocol data, and switches a remaining

data stream to be transmitted to one of the terminals via the first interface” (claim 6)

Defendants’ Proposal WSOU’s Proposal

Indefinite. In the alternative: this term is subject to 35 U.S.C. 

§ 112, ¶ 6.

Plain and ordinary 

meaning

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Function: [1] removes protocol data from a portion of protocol 

layers from a data stream5 received from the communication 

network via the second interface, the data stream comprising useful 

data and the protocol data, and [2] switches a remaining data stream 

to be transmitted to one of the terminals via the first interface

Structure: control unit CONTR executing function PHN, containing 

processes P1 to P3 and function SW; and equivalent structures 

1. The term is indefinite under IPXL

Because claim 6 recites a method step within an apparatus claim, it is indefinite under IPXL

Holdings, L.L.C. v. Amazon.com, Inc., 430 F.3d 1377, 1383–84 (Fed. Cir. 2005).

6 Claim 6 recites

an apparatus that must perform actual steps. Specifically, the claim recites a “control unit which

removes . . . and switches.” This is not sloppy drafting; these claims were intentionally written

this way, as shown in the prosecution history:

Original Claim (10/3/02) Claim Amendment (01/3/07) Claim Amendment (6/25/07)

wherein the network node 

has a control unit which is 

designed so that it removes

the majority of the protocol 

data from a data stream 

received on the network 

side via the second 

interface, which data stream 

consists of useful data and 

protocol data and is 

directed towards one of the 

terminals connected with 

the first interface, and 

switches the remaining data 

stream in the direction of 

this terminal

wherein-the-network-node-has a 

control unit which is configured 

to remove designed-se that it 

removes the a majority of the

protocol data from a data stream 

received on the-network side from 

the communication network via the 

second interface, which the data 

stream consists of comprising

useful data and protocol data, and 

is directed towards one of the 

terminals connected with the first 

interface, and switches to switch

the remaining data stream in the 

direction of this terminal to be 

transmitted to a terminal of the 

terminals via the first interface.

a control unit which is 

configured to remove

removes a majority of

protocol data from a portion 

of protocol layers from a 

data stream received from 

the communication network 

via the second interface, the 

data stream comprising 

useful data and the protocol 

data, and to switches the

switches a remaining data 

stream to be transmitted to a 

terminal one of the terminals 

via the first interface,

5

 This term includes “removes protocol data from a portion of protocol layers from a data stream,”

which is itself indefinite, as stated above. This section addresses the “control unit” phrase

separately, even if “removes protocol data from a portion” phrase is not held indefinite.

6 WSOU argues that Defendants have not preserved indefiniteness because Defendants “listed this

term as indefinite in its Invalidity Contentions and did not provide any notice of its indefiniteness

theory.” Br. 4–5. The Court’s order governing proceedings, however, requires only “an

identification of any limitations the Defendant contends are indefinite.” OGP v. 3.2 at 2.

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Exs. 4 at 1–2 (issued claim 6 was originally claim 5), 5 at 3–4, 3 at 3 (amendments in underline). 

The first two versions of the claims appropriately recited a control unit with the capability to

perform steps by using the phrases “which is designed” and “which is configured.” However,

applicant’s June 2007 claim amendment is contrary to IPXL. Applicant’s amendment from “which

is configured to remove” to “which removes,” changed the claim from mere capability to reciting

actual performance, and makes it unclear when infringement occurs. IPXL, 430 F.3d at 1384. 

WSOU’s arguments against IPXL ignore both the prosecution history and plain language

of the claim. First, WSOU’s brief is silent as to the prosecution history and applicant’s claim

amendment reciting actual performance. Br. 4–5. Second, WSOU attempts to avoid the plain

language of the claim by improperly rewriting it. According to WSOU, the claim recites a structure

“which is capable of performing recited functions.” Id., 5. However, “which is capable” or

analogous phrasing does not appear in the claim—indeed, applicant explicitly amended the claim

to remove such language and replace it with the active verb “removes.” Insituform Techs., Inc. v.

Cat Contracting, Inc., 99 F.3d 1098, 1106 (Fed. Cir. 1996) (“attorney argument cannot control in

light of the language of the claim”). Nor does WSOU explain how “which removes” indicates

mere capability. Finally, WSOU erroneously argues that the lack of “user” in the claims means

IPXL does not apply. Br. 5. But “the law is clear that user-action is not the only cause of

indefiniteness under IPXL.” Power Integrations, Inc. v. ON Semiconductor Corp., No. 16-CV06371-BLF, 2018 WL 5603631, at *17 (N.D. Cal. Oct. 26, 2018).

2. Alternatively, the term is subject to 35 U.S.C. § 112, ¶ 6

If the Court determines that this term is not indefinite, then it is subject to § 112, ¶ 6. A

term lacking the word “means” invokes § 112, ¶ 6 if “the claim term fails to recite sufficiently

definite structure or else recites function without reciting sufficient structure.” Rain Computing,

Inc. v. Samsung Elecs. Am., Inc., 2021 WL 786361, at *2 (Fed. Cir. Mar. 2, 2021). Here, the claim

Case 6:20-cv-00477-ADA Document 83 Filed 03/17/21 Page 13 of 22
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language relies on the nonce word “control unit” without providing structure in the claim. MPEP

section 2181(I)(A), recognizes “unit” as a non-structural generic placeholder. Ex. 6 (MPEP) at 2. 

Adding a generic prefix such as “control” to “unit” does not change the language of the claim into

having “sufficiently definite structure.” Optis Wireless Tech., LLC v. Huawei Device Co., No.

2:17-CV-123, 2018 WL 476054, at *32 (E.D. Tex. Jan. 18, 2018) (“unit” a nonce word even with

prefix “processing”); cf. Rain Computing, 2021 WL 786361, at *2 (prefix “user identification”

didn’t impart structure to “module”); Digital Retail Apps, Inc. v. H-E-B, LP, No. 6-19-CV-00167-

ADA, 2020 WL 376664, at *4–5 (W.D. Tex. Jan. 23, 2020) (prefix “first communication” didn’t

impart structure to “module”); Williamson v. Citrix Online, LLC, 792 F.3d 1339, 1351 (Fed. Cir.

2015) (prefix “distributed learning control” didn’t impart structure to module).

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

unit.” First, WSOU states that “claim language at issue is not purely functional but rather recites

specific structure (‘control unit’) that can perform respective tasks set forth in the body [of] the

claims.” Br. 5–6. WSOU’s argument confirms Defendants’ position—the claim describes

“control unit” solely based on its functionality. 

Second, WSOU argues the specification imparts sufficient structure onto “control unit.” 

Step one of the m-p-f inquiry looks at “whether the claim limitation connotes ‘sufficiently definite

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

performsthe 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

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specification to impart structure on the claim at step one of the inquiry is misplaced. Dyfan, LLC

v. Target Corp., No. W-19-CV-00179-ADA, 2020 WL 8617821, at *6 (W.D. Tex. Nov. 24, 2020).

Finally, WSOU cites one inapposite case to argue “control unit” recites specific structure. 

Br. 6. In Canon, Inc. v. TCL Elecs. Holdings, Ltd., 2:18-CV-546-JRG, 2020 WL 2098197, at *16

(E.D. Tex. May 1, 2020), the court determined “control unit” imparted sufficient structure because

the prosecution history indicated applicant “made, clear affirmative choices to avoid using meansplus-function language” through amendments to the claim language. Here, there are no similar

amendments avoiding § 112, ¶ 6. Moreover, as this Court explained, that reasoning is flawed

because relying on applicant’s intentions during prosecution would allow an applicant to draft

claims with functional language while “completely bypass[ing] all of the restrictions placed” on

[m-p-f] claims. Dyfan, 2020 WL 8617821, at *4 n.3.

7

Defendants’ identified function is taken from the claim language. WSOU does not state

what, if any, function and structure exists if the term is subject to § 112, ¶ 6. Br. 5–6. The only

structure that performs the recited function is the control unit CONTR (a general purpose

computer) executing function PHN, containing processes P1 to P3 and function SW. ’020 patent,

3:15–4:25; Fig. 2. Thus, if it is not indefinite, it should be construed under § 112, ¶ 6.

C. “bus system” (claims 1 and 6) 

Defendants’ Proposal WSOU’s Proposal

“a network that does not include any active components such as 

switching nodes, gateways, routers, or bridges, wherein all 

nodes are connected to a single wire”

Plain and ordinary meaning

The parties dispute whether “bus system” should be subject to the express distinctions

7

 The Canon court also relied on undisputed extrinsic evidence. Canon, 2020 WL 2098197, at

*15. Here, neither party disclosed extrinsic evidence for the term. Ex. 7 (Extrinsic Evidence

Disclosures) at 2, 10. WSOU’s reliance on a dictionary, which it did not disclose, produce, or

attach as an exhibit, is improper and should be stricken. No. 6:20-cv-00482, Dkt. 34 (OGP) at 7.

Case 6:20-cv-00477-ADA Document 83 Filed 03/17/21 Page 15 of 22
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provided in the specification and confirmed by the file history. It should. Kinik Co. v. Int’l Trade

Comm’n, 362 F.3d 1359, 1365 (Fed. Cir. 2004) (“[C]laims have the meaning and scope with which

they are used in the specification and the prosecution history.”). The specification states:

The communication network KN is a communication network by means of which

data can be exchanged between the components connected to the communication

network. Preferably the communication network KN is a bus system. It is

however also possible that the communication network KN comprises active

components such as switching nodes, gateways, routers, bridges. It is also

possible here that the communication network KN consists of several different part

networks which use different communication protocols for data exchange or are

allocated to different network operators.

’020 patent, 2:26–35. Thus, in describing different networks, the specification distinguishes a “bus

system” from a network that has “active components such as switching nodes, gateways, routers

[and] bridges.” Id. When the specification makes such a distinction, it is appropriate to construe

the claims accordingly.8

 Digital Retail Apps, 2020 WL 376664, at *9 (“wirelessly transmitting”

“does not include photographing or scanning” because they are distinct in specification).

The examiner confirmed this definition during prosecution, stating that “by reciting a bus

system, the invention is defined within the context of a simple bus network not involving any

switching or routing.” Ex. 8 (10/5/07 Non-Final Rejection) at 3. By not challenging that

statement, Ex. 9 (2/4/08 Applicant Argument), applicant’s conduct during prosecution also

confirmed the specification’s definition of “bus system.” SandBox Logistics LLC v. Proppant

Express Invs. LLC, 813 F. App’x 548, 554 (Fed. Cir. 2020) (acquiescence or failure to challenge

examiner’s understanding amounted to disclaimer). Defendants’ construction uses the

specification’s definition of a “bus system” and explains that a bus system requires that all nodes

8

 Even WSOU admits “bus system” is but one type of “communication network.” Br. 7. 

Case 6:20-cv-00477-ADA Document 83 Filed 03/17/21 Page 16 of 22
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connect to a single wire.9 Exs. 10–12. 

WSOU avoids the definition of bus system in the intrinsic record by advocating “plain and

ordinary meaning.” Br. 7. But a bus system is distinct from networks with active components. 

See supra. While other “communication networks” are described in the specification, these other

communication networks (those with “active components”) are not claimed; claims 1 and 6

explicitly state “the communication network is a bus system.” By not claiming other disclosed

networks, applicant dedicated them to the public. Maxwell v. J. Baker, Inc., 86 F.3d 1098, 1106

(Fed. Cir. 1996). Thus, WSOU’s argument about what a communication network can include is

inapposite to the construction of “bus system.”

II. DISPUTED TERM FROM THE ’489 PATENT

The ’489 patent relates to a LAG, which is a group of physical links between network 

devices that provides redundancy. ’489 patent, Abstract, 4:45. According to the patent, when a 

LAG is split across two switches it is called a “multi-chassis link aggregation group (MC-LAG).” 

Id., 4:54–57. Figure 1 (annotated below) depicts both a LAG 118 from a single device and MCLAGs 102a, 102b and 102c from multiple devices.

9

 WSOU takes issue with “single wire,” even though the evidence confirms a bus uses a single

wire. Exs. 10–12. Regardless, Defendants do not object to replacing “wire” with “interface.”

Case 6:20-cv-00477-ADA Document 83 Filed 03/17/21 Page 17 of 22
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In an MC-LAG, the traffic can be load-balanced across the two devices, and redundancy is 

provided if one device fails. Id., 4:54–63. The claims are directed to what happens when one 

device in the MC-LAG (or the link between them) fails.

A. “the first set of port interfaces of the multi-chassis link aggregate” (claims 1, 8, 15)

Defendants’ Proposal WSOU’s Proposal

Indefinite Plain and ordinary meaning

The term “the first set of port interfaces of the multi-chassis link aggregate” is incurably

indefinite because it is unclear which, if any, of the previously mentioned sets of port interfaces in

the claim the disputed phrase refers to. Claim 1, for example, recites: 

An aggregation switch in a multi-chassis system, comprising:

a first set of member port interfaces of the aggregation switch grouped with one 

or more member port interfaces of a remote aggregation switch configured to 

form a multi-chassis link aggregate . . . 

a processing module operable to: . . .

reconfigure one or more of the first set of port interfaces of the multi-chassis link 

aggregate to form a link aggregate10

In other words, the claim recites one set of port interfaces “of the aggregation switch” (green) and 

another set of port interfaces “of a remote aggregation switch” (blue). The term at issue, however, 

refers to a set of port interfaces “of the multi-chassis link aggregate” (red). Because there is no 

prior element referring to a “first set of port interfaces of the multi-chassis link aggregate,” it is 

unclear to what set of port interfaces refers. It could, for example, refer to a) the set of port 

interfaces of the aggregation switch, b) the set of port interfaces of the remote aggregation switch, 

or c) the combination of both sets—which would seem to be the most natural reading since the 

claims recite that those sets are “grouped . . . to form a multi-chassis link aggregate.” WSOU 

insists that the term refers to the set in the claimed switch (green), even though that set is not 

10 Independent claims 8 and 15 recite similar language, and the analysis herein applies equally.

Case 6:20-cv-00477-ADA Document 83 Filed 03/17/21 Page 18 of 22
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recited to be “of the multi-chassis link aggregate,” and instead is recited to be “of the aggregation 

switch.” Br. 8–9. This lack of clarity renders the term indefinite. 

The Federal Circuit recently affirmed indefiniteness of a similar term in Bushnell 

Hawthorne, LLC v. Cisco Systems, Inc., 813 F. App’x 522, 526 (Fed. Cir. May 14, 2020). There, 

the claim recited three sets of IP addresses. Later in the claim, the patent used the term “said 

different IP address,” which lacked an antecedent basis. The Federal Circuit explained that, 

“[w]ith three different IP addresses to choose from, a POSA faced with the ‘said different IP 

Address’ limitation is left to wonder which of the different IP addresses is ‘said’ different one.” 

See id. The exact same thing is true here. There are at least three different possible sets of “port 

interfaces” to which the term “the first set of port interfaces of the multi-chassis link aggregate” 

could refer. “A [POSA], faced with the claims and the specification, could not, with reasonable 

certainty, discern the meaning of the claim term.” Id.

Looking at the whole claim only compounds the ambiguity. The claims all focus on the

operation of a single switch. E.g., claim 1 is directed to “[a]n aggregation switch in a multi-chassis

system,” while claims 8 and 15 are each directed to a “method in a switch.” The term at issue,

however, refers to a “set of port interfaces of the multi-chassis link aggregate,” which, by

definition, requires multiple physical switches (i.e., more than one chassis). This mismatch

between the claims focusing on a single switch and the term requiring multiple switches, renders

this term further indefinite because it is unclear when, if ever, an accused switch could possibly

meet this limitation—e.g., when sold as a single switch or when combined with another switch.11

11 Contrary to WSOU’s argument (Br. 8 n.2), there is nothing inconsistent with Defendants’ IPR

because indefiniteness challenges cannot be raised in IPRs. 35 U.S.C. § 311(b). Given the

similarities between the IPR prior art and the ’489 patent disclosure, no formal claim construction

was necessary to resolve the IPR. Well-man, Inc. v. Eastman Chem. Co., 642 F.3d 1355, 1361

Case 6:20-cv-00477-ADA Document 83 Filed 03/17/21 Page 19 of 22
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(Fed. Cir. 2011) (“[C]laim terms need only be construed to the extent necessary to resolve the

controversy.”). Enzo Biochem, Inc. v. Applera Corp. is consistent with this approach. 599 F.3d

1325, 1332 (Fed. Cir. 2010). There, the accused infringer argued that the claims were indefinite,

or, alternatively, anticipated. The same holds true here.

Case 6:20-cv-00477-ADA Document 83 Filed 03/17/21 Page 20 of 22
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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-00477-ADA Document 83 Filed 03/17/21 Page 21 of 22
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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-00477-ADA Document 83 Filed 03/17/21 Page 22 of 22