EXHIBIT 1 

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Trials@uspto.gov Paper 13

571-272-7822 Entered: July 1, 2021

UNITED STATES PATENT AND TRADEMARK OFFICE

BEFORE THE PATENT TRIAL AND APPEAL BOARD

DELL TECHNOLOGIES INC., DELL INC., AND EMC CORPORATION,

Petitioners,

v.

WSOU INVESTMENTS, LLC d/b/a BRAZOS LICENSING AND 

DEVELOPMENT,

Patent Owner.

IPR2021-00272

Patent 8,913,489 B2

Before THU A. DANG, BRIAN J. McNAMARA, and

JOHN D. HAMANN, Administrative Patent Judges.

McNAMARA, Administrative Patent Judge. 

DECISION

Granting Institution of Inter Partes Review

35 U.S.C. § 314

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I. INTRODUCTION

Dell Technologies Inc., Dell Inc., and EMC Corporation (collectively, 

“Petitioner”) filed a petition, Paper 2 (“Petition” or “Pet.”), to institute an 

inter partes review of claims 1–20 (the “challenged claims”) of U.S. Patent 

No. 8,913,489 B2 (“the ’489 patent”). 35 U.S.C. § 311. WSOU 

Investments, LLC d/b/a Brazos Licensing and Development (“Patent 

Owner”) filed a Preliminary Response, Paper 11 (“Prelim. Resp.”), 

contending the Petition should be denied as to all challenged claims. We 

have jurisdiction under 35 U.S.C. § 314, which provides that an inter partes 

review may not be instituted unless the information presented in the Petition

and any response “shows that there is a reasonable likelihood that the 

petitioner would prevail with respect to at least 1 of the claims challenged in 

the petition.” 

“When instituting inter partes review, the Board will authorize the 

review to proceed on all of the challenged claims and on all grounds of 

unpatentability asserted for each claim.” 37 C.F.R § 42.108(a) (2021). 

Having considered the arguments and the associated evidence presented in 

the Petition and the Preliminary Response, for the reasons described below,

we institute inter partes review. 

II. REAL PARTIES IN INTEREST

The Petition identifies Dell Technologies Inc., Dell Inc., and EMC 

Corp. as real parties-in-interest. Pet. 1. Patent Owner identifies WSOU 

Investments, LLC d/b/a Brazos Licensing and Development as the sole real 

party-in-interest. Paper 4, 1.

III. RELATED MATTERS

Petitioner and Patent Owner state that the ’489 patent is asserted in the 

following litigation: WSOU Investments, LLC v. Dell Technologies Inc., et 

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al., No. 6:20-cv-477 (W.D. Tex.) (the “Texas Litigation” or the “parallel 

litigation” or the “District Court litigation”). Pet. 1; Paper 4, 2.

IV. DISCRETION UNDER SECTION 314(A)

A. Introduction

In view of the Texas Litigation, Patent Owner contends that we should 

exercise discretion under Section 314(a) to deny institution of inter partes 

review. See Prelim. Resp. 4–13. Under § 314(a), the Director has discretion 

to deny institution of an inter partes review. See 37 C.F.R. § 42.4(a) (“The 

Board institutes the trial on behalf of the Director.”); Cuozzo Speed Techs., 

LLC v. Lee, 136 S. Ct. 2131, 2140 (2016) (“[T]he agency’s decision to deny 

a petition is a matter committed to the Patent Office’s discretion.”); SAS Inst. 

Inv. v. Iancu, 138 S. Ct. 1348, 1356 (2018) (“[Section] 314(a) invests the 

Director with discretion on the question whether to institute review . . . .” 

(emphasis omitted)); Harmonic Inc. v. Avid Tech., Inc., 815 F.3d 1356, 1367 

(Fed. Cir. 2016) (“[T]he PTO is permitted, but never compelled, to institute 

an IPR proceeding.”).

In NHK Spring Co. v. Intri-Plex Techs., Inc., IPR2018-00752 (PTAB 

Sep. 12, 2018) (Paper 8 at 19–20) (precedential), the Board denied 

institution relying, in part, on § 314(a) because the parallel district court 

proceeding was scheduled to finish before the Board reached a final 

decision. “Thus, NHK applies to the situation where the district court has set 

a trial date to occur earlier than the Board’s deadline to issue a final written 

decision in an instituted proceeding.” Apple Inc. v. Fintiv, Inc., IPR2020-

00019 (PTAB Mar 20, 2020) (Paper 11, 3) (Precedential). When 

determining whether to exercise discretion to deny institution under NHK 

due to an earlier trial date, we consider the following factors articulated in 

Fintiv (“Fintiv factors”):

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1. whether the court granted a stay or evidence exists that one 

may be granted if a proceeding is instituted; 

2. proximity of the court’s trial date to the Board’s projected 

statutory deadline for a final written decision; 

3. investment in the parallel proceeding by the court and the 

parties; 

4. overlap between issues raised in the petition and in the 

parallel proceeding; 

5. whether the petitioner and the defendant in the parallel 

proceeding are the same party; and 

6. other circumstances that impact the Board’s exercise of 

discretion, including the merits. 

Id. at 5–6. “These factors relate to whether efficiency, fairness, and the 

merits support the exercise of authority to deny institution in view of an 

earlier trial date in the parallel proceeding.” Id. at 6. In evaluating these 

factors, we take “a holistic view of whether efficiency and integrity of the 

system are best served by denying or instituting review.” Id. (citing Patent 

Trial and Appeal Board Consolidated Trial Practice Guide November 2019 

(“CTPG”), 58.).

B. The Texas Litigation

On June 2, 2020, Patent Owner filed twelve (12) separate patent 

infringement actions against Petitioner, one of those actions alleging 

infringement of the ’489 patent; Petitioner waived service on July 2, 2020. 

Pet. 59. At the time of the Petition, the cases had not been formally 

consolidated. Id. As to consolidation of the cases, on November 2, 2020, 

the district court stated

the Court does not intend on trying the cases in ‘groups’ nor does 

the Court intend on trying all 12 patents in one trial. However, 

due to logistics and to provide flexibility, the Court is setting trial 

for all of these cases for 4/11/2022 which was the date provided 

to you by the Court in my 10/12/2020 email. 

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Dell Techs., Inc. v. WSOU Investments, IPR2021-00225 (the “-225 IPR”), 

Ex. 1105. On November 3, 2020 the court added 

For clarification, the Court does not intend on trying the cases in 

the Markman groups and currently has no intention of 

consolidating them for trial. However, as none of these cases 

have had their Markmans yet, the Court is unaware of exactly 

how related the patents may be and if the need does arise the 

Court may decide to consolidate certain patents for trial. But as 

of now, the Court is not intending on consolidating simply for 

the sake of consolidation. 

See the -0225 IPR, Ex. 1106 (emphasis by the Court). 

On October 14, 2020, Patent Owner served its preliminary 

infringement contentions in the district court and “for the first time, 

identified all 20 claims of the ’489 patent as the asserted claims.” Pet. 59. 

Petitioner states that on December 4, 2020, in the Texas Litigation Petitioner 

stipulated that, “if inter partes review is instituted on Grounds 1–4 in this 

proceeding, Petitioner will not pursue these grounds or any other possible 

prior art printed publication grounds based on the references in Grounds 1–4 

in the District Court litigation.” Id.at 59–60. On December 9, 2020, 

Petitioner filed its Petition for institution of the instant IPR. See Paper 6, 1.

According to the Petition, Markman hearings were set for April 29–

30, 2021, but in view of the multiple cases and unrelated cases scheduled for 

the same dates, the actual hearing date was uncertain. Pet. 60. Petitioner 

also states that “based off the Markman hearing,” “[t]he first of the 12 trials 

is currently assumed to start on May 2, 2022, but it is not yet determined 

which case will be tried first.” Id. 

The district court held Markman hearings on May 10, 2021, and May 

26, 2021, and issued a claim construction order on May 27, 2021. Paper 12. 

Petitioner has agreed to a case schedule proposed by Patent Owner with the 

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following additional dates: fact discovery to begin on April 19, 2021, parties 

can be added until May 28, 2021, final infringement and invalidity 

contentions are due on June 11, 2021, pleadings can be amended until 

August 6, 2021, fact discovery closes on November 12, 2021, expert 

discovery begins on November 19, 2021 and ends on January 14, 2022, and 

a final pre-trial conferences takes place on March 25, 2022. See, the -225

IPR, Ex. 1101, Exhibit A, Ex. 1004, 9, Ex. 1106, 2.

On April 22, 2021 the district court began a Markman hearing in a 

related one of the 12 cases, which it resumed and concluded on April 26, 

2021. See the -225 IPR, Transcript of Proceeding - Part 1 (Ex. 1107, 

“Markman Tr. Part 1”), Transcript of Proceedings, - Part 2 (Ex. 1108, 

“Markman Tr. Part 2”). Before adjourning the proceedings on April 22, the 

court requested the parties consider how the 12 patents involved could be 

grouped for purposes of trial, e.g. grouping the patents for three or four 

trials. See, -the 225 IPR, Ex. 1107, 46:17–48:3. Presiding Judge Albright 

stated “in terms of what trial would go first, maybe I’ll make that decision 

just because you all might have binary reasons to think one trial might 

benefit. You might not be able to agree with that.” Id. at 47:14–17. 

On April 26, 2021, the parties reported to the court that they believe 

three trials would be appropriate, although they have not yet determined how 

the patents should be grouped and could pick three dates after expert reports 

were shared. See the -225 IPR, Ex. 1108, 42:14–43:5, 44:17–30. Judge 

Albright determined that pre-trial activities, such as discovery, expert 

reports, and summary judgement should all be completed on the same 

schedule ahead of the first trial date. Id. at 43:6–44:23. Judge Albright then 

speculated that, for example, that he could set May 1, 2022 as the date to 

begin the first trial and a Monday every two months after that as the dates 

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for the three trials. Id. at 45:1–6. Judge Albright further noted that shortly 

after summary judgment, a decision could be made as to which patents are 

tried first. Id. at 45:4–6. Judge Albright further stated “only if you guys 

can’t decide which three or four patents to go first or how to do things, then 

you come to me and say, here's our suggestions, and I'll pick between them. 

But I am going to be as deferential to you all as I can, just assuming my 

schedule will permit it.” Id. at 45:19–24.

The parties have not identified any specific trial dates for any 

grouping of patents at this time. 

C. Analysis

We analyze each of the Fintiv factors as follows:

whether the court granted a stay or evidence exists that 

one may be granted if a proceeding is instituted

A district court stay of parallel litigation pending resolution of an inter

partes review allays concerns about inefficiency and duplication of efforts, a 

fact which weighs against exercising the authority to deny institution. 

Fintiv, Paper 11 at 6. Here, the district court in the parallel litigation has not 

granted a stay or been asked to do so yet. Pet. 60–61. Petitioner states that 

the district court would consider a motion to stay before an institution 

decision premature. Id. Patent Owner argues there is no evidence a stay 

would be granted in this case and, based on his rulings in other cases, it is 

unlikely Judge Albright would grant a stay. Prelim. Resp. 6. 

We decline to speculate based on the record in this proceeding as to 

whether the district court would grant a stay in the parallel litigation pending 

this inter partes review. Notably, neither party identifies any statements by 

Judge Albright or other evidence that specifically addresses a stay for this 

particular parallel litigation. “A judge determines whether to grant a stay 

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based on the facts of each specific case as presented in the briefs by the 

parties.” See Apple Inc. v. Fintiv, Inc., IPR2020-00019, Paper 15, 12 (PTAB 

May 13, 2020) (informative) (“Fintiv II”). “We decline to infer, based on 

actions taken in different cases with different facts, how the District Court 

would rule should a stay be requested by the parties in the parallel case 

here.” Id. Accordingly, we assess this factor as neutral. 

proximity of the court’s trial date to the Board’s 

projected statutory deadline for a final written decision

Patent Owner states “[t]he district court has set a trial date for May 2, 

2022 (admitted at page 60 of the Petition), a month before the expected Final 

Written Decision here.” Prelim. Resp. 6. During the April 26, 2021 

Markman hearing, Judge Albright clarified, and the parties agreed, that not 

all twelve of the 12 cases would proceed to trial on the same date. See

the -225 IPR, Ex. 1108, 41:12–41:22, 42:13–46:6. Rather, the cases would 

be divided into multiple groups for separate trials. Id.; see also id. at 46:3–5

(Judge Albright stating that “I’m thinking . . . four is probably the most 

patents I would do at a trial”).

Moreover, Judge Albright stated, and the parties agreed, that which 

patents are tried in which group (e.g., which of the twelve patents would go 

first) would be decided closer in time to the trials. See id. at 42:24–25

(Patent Owner stating that it “would suggest holding off on exactly which 

patents go into which trial dates”); id. at 44:12–14 (Petitioner stating that “it 

would be advantageous to [Petitioner] going forward if [it] could get [its] 

groupings prior to just before trial”); id. at 45:4–6 (Judge Albright stating 

that “we’ll figure out down the road, somewhere shortly after summary 

judgments, hopefully, which patents will go first”).

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In light of the above, we find that no trial date, in fact, has been set for 

the ’489 patent. More specifically, the district court and the parties agree 

(i) that there will be multiple trials, and (ii) which patents go with which trial 

has not been determined yet. Put differently, whether the ’489 patent will be 

part of the first trial remains to be decided. 

The projected statutory deadline for a final decision in this proceeding 

is July 5, 2022 (one year after the due date for an institution decision in this 

proceeding). This is about two months after the originally projected May 2, 

2022 trial date, assuming this date does not slip. A second trial likely would 

occur around, or shortly after, the entry of a final decision in this proceeding. 

See id. at 44:24–45:6 (Judge Albright suggested that there could be two 

months between trials). And a third trial likely would occur about two 

months after a final decision is entered in this proceeding. See id. at 44:24–

45:6, 46:3–5. However, the specific dates for any subsequent trials are 

speculative, as they have not been set yet by the district court. 

If the district court’s trial date is earlier than the projected statutory 

deadline, the Board generally has weighed this fact in favor of exercising 

discretion to deny institution. Fintiv, Paper 11 at 9. If the court’s trial date 

is at or around the same time as the projected statutory deadline, the decision 

whether to institute will likely implicate other Fintiv factors, such as the 

resources that have been invested in the parallel proceeding. Id. 

Accordingly, considering all of the circumstances present here, we assess 

this factor as neutral.

investment in the parallel proceeding by the court and 

the parties

Patent Owner argues that the parties have exchanged preliminary 

infringement contentions and preliminary invalidity contentions, and by the 

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institution date, the district court will have proceeded past claim construction 

stage and fact discovery will be well underway. Prelim. Resp. 7–8. 

Petitioner argues that it “worked diligently to file this petition while the 

related District Court litigation is still at an early phase.” Pet. 63 (noting that

on the Petition’s filing date, the parties had yet to file claim construction 

briefs, no claim construction orders had issued, and fact discovery had not 

formally opened). 

We recognize that the district court and the parties have invested 

effort with respect to claim construction in the parallel litigation. For 

example, the parties have exchanged proposed claim constructions, briefed 

the claim construction issues, participated in a Markman hearing and the 

district court entered its claim construction order. See Paper 12. However, 

much of this invested effort is unconnected to the patentability challenges 

presented here. See Sand Revolution II, LLC v. Continental Intermodal 

Group – Trucking LLC, IPR2019-01393, Paper 24, 11–12 (PTAB June 16, 

2020) (informative) (finding that Fintiv factor 3 “weighs only marginally, if 

at all” toward discretionary denial even though district court had held a 

Markman hearing and construed the claims, because “much of the district 

court’s investment relates to ancillary matters untethered to the validity issue 

itself” and “much work remains in the district court case as it relates to 

invalidity”). And although the parties have exchanged preliminary 

contentions, substantial work remains to be done as it relates to invalidity: 

fact discovery is in its early stages, expert reports are not yet due, and 

substantive motion practice is yet to come. See generally Exs. 1101 and 

2001; Ex. 1104, 9–10.

Secondly, we agree with Petitioner that it acted promptly by filing its 

Petition at the early stages of the litigation, i.e., on December 9, 2020, or 

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about seven weeks after receiving Patent Owner’s preliminary infringement 

contentions on October 14, 2021. See Pet. 59. “If the evidence shows that 

the petitioner filed the petition expeditiously, such as promptly after 

becoming aware of the claims being asserted, this fact has weighed against 

exercising the authority to deny institution under NHK.” Fintiv, Paper 11 at 

11.

Accordingly, on the whole, this factor weighs in favor of not 

exercising discretion to deny institution under 35 U.S.C. § 314(a). In 

particular, in considering this factor, we find that the substantial work that 

remains on invalidity issues in the parallel litigation and Petitioner’s 

expeditious filing of its Petition substantially outweighs the minimal 

investment in the work done so far.

overlap between issues raised in the petition and in the 

parallel proceeding

This factor evaluates “concerns of inefficiency and the possibility of 

conflicting decisions” when substantially identical prior art is submitted in 

both the district court and the inter partes review proceedings. Fintiv, Paper 

11 at 12. Petitioner cites its stipulation that it “will not assert that the 

challenged claims are invalid on the instituted grounds in the related

litigation, nor any other possible prior art printed publication grounds based 

on the references in Grounds 1–4.” Pet. 65. Patent Owner states Petitioner 

stipulated 

Defendants hereby stipulate that, if the Board institutes inter 

partes review on IPR2021-00272, then Defendants will not 

assert invalidity of claims 1–20 of the ’489 patent in this case

based on any of the four grounds listed above, or on any other 

grounds involving the Narayanan, Smith, Chin, Mullooly, and 

Moberg references alone or in combination with any other

patent or printed publication.

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This stipulation is not intended and should not be 

construed to limit Defendants’ ability to assert invalidity of the 

claims of the ’489 patent based on prior art not consisting of 

patents or printed publications, alone or in combination with 

any other reference whatsoever.

Prelim. Resp. 9 (quoting Ex. 2001). 

Patent Owner faults Petitioner’s stipulation as carving out “a large 

loophole for itself where Petitioner can assert the exact same grounds and 

prior art references in this Petition, but present it in ‘combination’ with any 

‘prior are not consisting of patents or printed publications’, such as any prior 

art system.” Id. at 10. According to Patent Owner, “Petitioner will be free 

to pursue invalidity in the district court litigation under any grounds, even 

the exact same grounds cited in the instant Petition, and Petitioner’s filed 

‘stipulation’ expressly provides for such a result.” Id. 

We disagree with Patent Owner. Inter partes review is limited to 

patents and printed publications, and Petitioner has stipulated that if we 

institute inter partes review, in the district court Petitioner will not pursue 

invalidity on the four grounds asserted in the Petition. Patent Owner’s 

argument that Petitioner has carved out a loophole because its stipulation 

does not forgo grounds outside the scope of inter partes review, i.e., grounds 

including “prior art not consisting of patents or printed publications,” is 

unavailing. Id. at 10. Simply put, the grounds asserted here will be 

addressed first by the Board in a final decision (assuming that this 

proceeding does not terminate beforehand (e.g., by settlement)) due to the 

stipulation. See Ex. 1102, 1. To the extent that we conclude that Petitioner 

has not demonstrated that the challenged claims are unpatentable, Petitioner 

likely is estopped from asserting these same grounds in the parallel 

litigation. See 35 U.S.C. § 315(e)(2) (“The petitioner in an inter partes 

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review of a claim in a patent . . . that results in a final written decision . . . 

may not assert . . . in a civil action . . . that the claim is invalid on any 

ground that the petitioner raised or reasonably could have raised during that 

inter partes review.”). Moreover, to the extent that the parallel litigation is 

not stayed, Petitioner’s stipulation likely precludes Petitioner from pursuing 

the grounds asserted here in the parallel litigation due to scheduling, such as 

provided for in the Order Governing Proceedings – Patent Case in the 

parallel litigation, which sets a deadline for Petitioner to serve final 

invalidity contentions of eight weeks after the Markman hearing. See, 

the -225 IPR, Ex. 2010, 9. 

Thus, Petitioner’s stipulation would function like the stipulation in 

Sand Revolution, where the Board found that “this factor weighs marginally 

in favor of not exercising discretion to deny institution” when the Petitioner 

stipulated not to pursue in district court the same grounds presented in its 

petition. See Sand Revolution, Paper 24 at 12. On the other hand, to the 

extent that we conclude that Petitioner has demonstrated that the challenged 

claims are unpatentable, the grounds asserted in the Petition likely would not 

be the subject of later district court litigation, subject to appeal of our final 

decision. 

Accordingly, we find that Petitioner’s stipulation mitigates to some 

degree the concerns of duplicative efforts between the district court and the 

Board, as well as concerns of potentially conflicting decisions. Thus, this 

factor weighs marginally in favor of not exercising discretion to deny 

institution under 35 U.S.C. § 314(a).

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whether the petitioner and the defendant in the parallel 

proceeding are the same party 

Patent Owner argues that this factor weighs against institution,

because Patent Owner is the plaintiff and Petitioner is the defendant in the 

parallel district court litigation. Prelim. Resp. 12. Petitioner argues that this 

factor depends on whether the final written decisions or the trial will occur 

first. Pet. 66 (citing Google LLC, et al. v. Parus Holdings, Inc., IPR2020-

00846, Paper 9 at 20–21 (PTAB Oct. 21, 2020)). This factor favors denial if 

trial precedes the Board’s Final Written Decision and favors institution if the 

opposite is true. 

We agree with Petitioner that, as discussed above, it is uncertain 

which proceeding will conclude first. Accordingly, this factor weighs 

neutral.

other circumstances that impact the Board’s exercise of 

discretion, including the merits

As explained below, on the preliminary record, the merits of 

Petitioner’s case are straightforward and strong. See infra Section X. We 

find that this factor weighs strongly in favor of not exercising discretion to 

deny institution under 35 U.S.C. § 314(a). See Fintiv, Paper 11 at 14–15S

(“[I]f the merits of a ground raised in the petition seem particularly strong on 

the preliminary record, this fact has favored institution.”); Sand Revolution, 

Paper 24 at 13 (“We determine, on this preliminary record, that Petitioner 

has set forth a reasonably strong case for the obviousness of most challenged 

claims. Thus, this factor weighs [strongly] in favor of not exercising 

discretion to deny institution under 35 U.S.C. § 314(a).”).

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D. Conclusion

Because the analysis is fact-driven, no single factor is determinative 

of whether we exercise our discretion and deny institution under 35 U.S.C. 

§ 314(a). On this record, based on a holistic review of the Fintiv factors, we 

conclude that the factors disfavoring denial outweigh those in favor. We 

therefore decline to exercise our discretion under 35 U.S.C. § 314(a) to deny 

institution of an inter partes review.

V. THE ’489 PATENT

The ’489 patent “relates generally to data networks and in particular 

to systems and methods for providing topological redundancy and resiliency 

between nodes of one or more data networks.” Ex. 1001, 1:47–50. 

According to the ’489 patent, a three tier data network includes an edge 

layer, an aggregation layer, and a core layer. Id. at 1:66–2:2. As the entry 

point of a network to which a customer network is nominally attached, the 

access/edge layer includes edge networks that provide connectivity between 

an Enterprise or home network, e.g., a local area network, and a metro or 

core network. Id. at 2:2–9. Switches residing at the edge layer, known as 

edge nodes, perform Open Systems Interconnection Data Link Layer (L2) 

switching for the attached devices and are generally connected to an 

aggregation layer that terminates access links from multiple edge nodes. Id.

at 2:9–15, see also id. at 4:22–23. Aggregation switches residing at the 

aggregation layer perform L2 switching or OSI Network Layer (L3) routing 

of traffic that is received via aggregate links from the edge nodes. Id. at 

2:16–18. The aggregation layer is connected to a metro or core network that 

performs L3 IP routing of traffic received from the aggregation switches (or 

from edge nodes in a two tier network). Id. at 2:19–22.

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Topological redundancy provides network resiliency. i.e., the ability 

to maintain high network availability during periodic failures of components 

or links. Ex. 1001, 2:25–30. Topical redundancy includes: redundant nodes, 

redundant components within nodes, redundant links, multiple physical 

paths between nodes, and L2/L3 protocols that exploit such redundancies to 

converge upon alternate paths for routing traffic through the network. Id. at 

2:29–35. Ethernet technology employs spanning tree protocol (STP) to 

detect failures and divert traffic. Id. at 2:51–57. 

STP relies on multiple physical paths between switches, but with 

only one path active at any one time for a particular packet flow, 

the other path being placed in a blocking mode (defining an 

“active/passive' paradigm). When failures occur, an alternative 

path is brought out of the blocking mode into an active state, 

thereby re-establishing the connection.

Id. at 2:57–63. According to the ’489 patent, STP can result in unacceptable 

convergence times. See id.at 2:64–3:12.

In the ’489 patent, a “Link Aggregation Control Protocol (LACP) 

provides a method to control the bundling of several physical links, called a 

link aggregation group (LAG), between two peer nodes to form a single 

logical channel there between.” Id. at 4:41–44. “To provide increased 

resiliency and remove a single point of failure, a LAG is split across two 

devices,” referred to as a multi-chassis link aggregation group (MC-LAG). 

Id. at 4:54–57. A schematic block diagram of a network architecture 

according to the invention is shown in Figure 1 of the ’489 patent 

reproduced below.

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Figure 1 of the ’489 patent

In Figure 1 Edge Node 104, e.g. a switch or a server, is connected over 

access network 122 to enterprise devices 110, 112 that may be operating a 

LAN or home network, respectively. Id. at 5:3–12. A MC-LAG 102a 

originating from edge node 104 is split into two subsets, with one or more 

physical links in each subset, across two devices, e.g., aggregation switches 

106a and 106b. Id. at 4:57–63. For each packet transmitted over MC-LAG 

102a, a physical link is selected based on load balancing techniques. Id. at 

4:62–65. Virtual fabric link (VFL) 124 provides connection for exchanging 

between aggregation switches 106 “traffic forwarding information, MAC

addressing, multicast flows, address resolution protocol (ARP) tables, Layer 

2 control protocols (e.g. spanning tree, Ethernet ring protection, logical link 

detection protocol), routing protocols (e.g. RIP OSPF, BGP) and the status 

of the MC-LAGs 102 connected thereto.” Id. at 5:13–22. When forwarding

traffic on MC-LAG 102a, node 104 treats aggregation switches 106 as a 

single logical device. Id. at 5:22–25. L2 packet flows over VFL 124 drive 

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synchronization of MAC address tables and other forwarding information 

between aggregation switches 106. Id. at 5:26–29. According to the ’489 

patent “[t]his feature enables dual homing of the edge node 104 to the pair of 

aggregation switches 106 and provides a Layer 2 multi-path intra-structure 

as well as basic Layer 3 access infra-structure,” without requiring L2 

redundancy protocols, e.g., STP between edge node 140 and aggregation 

switches 106. Id. at 5:30–40. Network nodes 116 of core network 120 can 

also be connected using MC-LAG functionality. See id. at 6:1–16.

Figure 9 of the ’489 patent is reproduced below.

Figure 9 of the ’489 patent

Figure 9 “illustrates an embodiment of the link status of the aggregation 

switches 106 when VFL 124 is operational.” Ex. 1001, 16:45–46. When 

VFL 124 is operational, a spanning tree protocol is automatically disabled 

on MC-LAG member ports S1/1, S1/2 in aggregation switch 106a and ports 

S2/1, S2/2 in aggregation switch 106b. Id. at 16:48–51. “From edge node 

104 the links of MC-LAG 102 coupled to aggregations switches 106a, 106b 

are part of a single link aggregate group (LAG) to a single logical node.” Id.

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at 16:51–54. The spanning tree protocol is enabled in the portion of the 

network between switches 106 and nodes in the metro/core network, e.g.,

network node 116; the spanning tree protocol also is enabled in the VFL 

member ports and configured to be in a forwarding state. Id. at 16:54–58. 

To prevent loops between aggregation switch 106 and node 116, the 

spanning tree protocol determines one or more ports for forwarding packets 

from aggregation switch 106 (link 442) and one or more ports that are 

blocked from forward packet flows (link 440). Id. at 16:59–63.

Aggregation switches 106 can detect a failure of the VFL Ex. 1001, 

17:7–8. “[W]hen the aggregation switches 106 determine that a connection 

failure has occurred such that the aggregation switches 106 are not able to 

communicate over the VFL 124, the aggregation switches 106 then 

reconfigure the MC-LAG 102 into one or more link aggregates connected to 

the edge node 104.” Id. at 18:2–7, 18:60–63, 19:11–15. 

Figure 11 of the ’489 patent is shown below.

Figure 11 of the ’489 patent

Figure 11 “illustrates an embodiment for recovery when a connection failure 

occurs over VFL 124.” Id. at 17:66–67. As shown in Figure 11, MC-LAG

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102 in Figure 9 now is configured into at least two link aggregates with at 

least one link aggregate, LAG1 (420), connected from edge node 104 to 

aggregation switch 106a and another link aggregate, LAG2 (422), connected 

from edge node 104 to switch 106b. Id. at 18:7–12, 19:11–20:24. The 

aggregation switches enable an STP on link aggregates LAG1 420 and 

LAG2 422 connected to edge node 104, as well as between aggregation 

switches 106 and core network 120. Id. at 18:12–16. The STP “determines 

an active path through the network and blocks one or more other paths to 

prevent loops.” Id. at 18:41–42, 19:15–18, 20:25–38.

MAC table entries previously learned for the member ports of 

MC-LAG 102 are flushed in both aggregations switches 106 and edge node 

104, and new MAC entries are learned for newly formed link aggregates 

LAG1 and LAG2. Id. at 18:24–30, 20:20–24. Aggregation switches 106 are 

assigned different MAC addresses and are viewed by edge node 104 as two 

independent local entities operating in a stand-alone mode, no longer 

needing to synchronize MAC table entries over VFL 124. Id. at 18:30–35. 

Link parameters for stand-alone mode and multi-chassis mode may be 

pre-configured by a system administrator or automatically determined by 

aggregation switch 106. Id. at 19:39–41. 

The ’489 patent further explains that a link aggregation module 416 in 

aggregation switch 106 reconfigures MC-LAG ports with a different second 

identifier and active administrative key for a link aggregate and regroups the 

member ports into a one or more new link aggregates to edge node 104. Id.

at 20:1–8. Aggregation switch 106 exchanges its system identifier and 

administrative keys across the member links and through the newly 

configured link aggregate to neighboring devices. Id. at 20:8–13. As a 

result, the edge node detects the change from MC-LAG 102 to a link 

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aggregate and reconfigures its member ports of the link aggregate with a 

new set of link parameters. Id. at 20:13–16. Referencing Figure 14, the 

’489 patent explains that “[w]hen the STP module 412 receives notification 

that the VFL 124 is ‘down’ or other event indicates a connection failure of 

the VFL 124, the STP application module enables STP operation of the 

newly configured link aggregate member ports [in step 520].” Id. at 20:29–

34.

VI. ILLUSTRATIVE CLAIM

Claim 1, reproduced below with paragraph designations uses in the 

Petition, is illustrative of the subject matter of the challenged claims.

1[Pre]. An aggregation switch in a multi-chassis system, 

comprising:

[A] 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 multichassis link aggregate, wherein the multi-chassis link 

aggregate couples the aggregation switch and the remote 

aggregation switch to an edge node;

[B] a second set of port interfaces configured to form a virtual

fiber link for coupling the aggregation switch to the remote 

aggregation switch;

[C] a processing module operable to:

[D] determine a connection failure of the virtual fiber link to

the remote aggregation switch;

[E] reconfigure one or more of the first set of port interfaces

of the multi-chassis link aggregate to form a link aggregate 

for coupling to the edge node; and

[F] initiate a spanning tree protocol in the one or more of the 

first set of port interfaces.

VII. ASSERTED GROUNDS

Petitioner asserts that claims 1–20 would have been unpatentable on 

the following grounds (Pet. 7): 

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Claim(s) Challenged 35 U.S.C. § Reference(s)

1–3, 5–9, 11–17, 

19–20 102 Narayanan1

1–20 103 Narayanan, Smith2, Chin3

4, 10, 18 103 Narayanan, Mullooly4

15–20 103 Narayanan, Moberg5, Mullooly

Petitioner notes that Smith and Chin are incorporated by reference into 

Narayanan and asserts the combination of Smith and Chin with Narayana to 

the extent they are not considered to be part of Narayanan. Pet. 43 (citing 

Ex. 10046, 4:12–15, 5:33–37).

VIII. LEVEL OF ORDINARY SKILL IN THE ART

According to Petitioner, a person of ordinary skill in the art in August, 

2010 “would have a Bachelor’s degree in Computer Science, Computer 

Engineering, Electrical Engineering, or an equivalent discipline, and at least 

one year’s worth of experience developing computer networking or network 

architecture”, or “two or more years of work experience in computer 

networking and in the development of client-server systems in lieu of the

education requirements.” Pet. 9 (citing Ex. 1004, Declaration of Dr. 

Nicholas Bambos (“Bambos Decl.”) ¶ 18. Patent Owner does not offer a 

competing definition. Prelim. Resp. 17

The level of ordinary skill in the art usually is evidenced by the 

references themselves. See Okajima v. Bourdeau, 261 F.3d 1350, 1355 

(Fed. Cir. 2001); In re GPAC Inc., 57 F.3d 1573, 1579 (Fed. Cir. 1995); In 

 

1 US Patent No. 7.639,605 B2 (Ex. 1005)

2 US Patent Pub. No. 2005/0063395 A1 (Ex. 1006)

3 US Patent No. 5,959,968 (Ex. 1007)

4 US Patent No. 8,503,329 B2 (Ex. 1008)

5 Patent No. 7,610,405 B1 (Ex. 1009)

6 Petitioner misidentified Exhibit 1005 as Exhibit 1004.

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re Oelrich, 579 F.2d 86, 91 (CCPA 1978). Petitioner’s unchallenged 

definition of a person of ordinary skill appears consistent with the scope of 

the subject matter of the ’489 patent and the art cited by Petitioner. We 

apply Petitioner’s definition for purposes of this Decision. 

IX. CLAIM CONSTRUCTION

A. Introduction

For petitions filed after November 13, 2018, we interpret claim terms 

using “the same claim construction standard that would be used to construe 

the claim in a civil action under 35 U.S.C. 282(b).” 37 C.F.R. § 42.100(b) 

(2019). In this context, claim terms “are generally given their ordinary and 

customary meaning” as understood by a person of ordinary skill in the art in 

question at the time of the invention. Phillips v. AWH Corp., 415 F.3d 1303, 

1312–13 (Fed. Cir. 2005) (citations omitted) (en banc). “In determining the 

meaning of the disputed claim limitation, we look principally to the intrinsic 

evidence of record, examining the claim language itself, the written 

description, and the prosecution history, if in evidence.” DePuy Spine, Inc. 

v. Medtronic Sofamor Danek, Inc., 469 F.3d 1005, 1014 (Fed. Cir. 2006) 

(citing Phillips, 415 F.3d at 1312–17). Extrinsic evidence is “less significant 

than the intrinsic record in determining ‘the legally operative meaning of 

claim language.’” Phillips, 415 F.3d at 1317 (citations omitted).

Any special definition for a claim term must be set forth in the 

specification with reasonable clarity, deliberateness, and precision. In re 

Paulsen, 30 F.3d 1475, 1480 (Fed. Cir. 1994). We construe only those claim 

terms that require analysis to determine whether to institute inter partes 

review. See Vivid Techs., Inc. v. Am. Sci. & Eng’g, Inc., 200 F.3d 795, 803 

(Fed. Cir. 1999) (holding that “only those terms need be construed that are in 

controversy, and only to the extent necessary to resolve the controversy”).

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B. Claim Limitation [1.F]

Petitioner posits “no formal claim constructions are necessary.” Pet. 

17. Although Patent Owner proposes no claim constructions, Patent Owner 

contends we should deny institution because in the Texas Litigation 

Petitioner argued the term “the first set of port interfaces of the multi-chassis 

link aggregate” (claim limitation [1.F]) is indefinite. Prelim. Resp. 13–16. 

See also Ex. 2002, 11–14. Patent Owner notes that in the Texas Litigation, 

Petitioner argued that claim 1 is indefinite because claim limitation [1A] 

recites “a first set of member port interfaces of the aggregation switch” 

grouped with “one or more member port interfaces of a remote aggregation 

switch”, but claim limitation [1F] recites “the first set of port interfaces of 

the multi-chassis link aggregate” without antecedent. Ex. 2002, 12. 

Patent Owner argues that Petitioner cannot maintain that a claim is 

indefinite and anticipated/rendered obvious. Prelim. Resp. 14 (citing Enzo 

Biochem, Inc. v. Applera Corp., 599 F.3d 1325, 1332 (Fed. Cir. 2010). In 

Enzo, the Federal Circuit reversed the district court’s decision that the claims 

were indefinite and affirmed the district court’s determination that some of 

the claim were anticipated, some of the claim were not infringed, and 

remanded for further proceedings concerning other claims. Enzo, 599 F. 3d 

at 1343. 

In this proceeding, Petitioner does not assert any claim is indefinite. 

Petitioner explains its silence in its Petition before the Board regarding its 

indefiniteness position in district court by stating the similarities between the 

prior art and the ’489 patent disclosure are such that no formal claim 

construction position is required. Ex. 2002, 13 n. 11. Before the Board a 

petitioner may request to cancel as unpatentable patent claims “only on a 

ground that could have been raised under section 102 or 103 and only on the 

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basis of prior art consisting of patent or printed publication.” 35 U.S.C. 

§ 311(b). That is the only issue before us. The statute explicitly precludes 

Petitioner from asserting indefiniteness as a ground to seek cancellation of 

claims in an inter partes review. The potential existence of issues outside 

our purview that the statute anticipates a district court will address does not 

justify denying inter partes review

At the time Patent Owner filed its Preliminary Response, there had 

been no ruling by the court in the Texas Litigation that claim 1 is indefinite. 

On May 27, 2021, the district court ruled that this term is not indefinite and 

should be given its plain and ordinary meaning. Paper 12, 12. We address 

the plain and ordinary meaning of this term in more detail below.

For purposes of this Decision, we note that in its preamble, claim 1 is 

drawn to “an aggregation switch in a multi-chassis system.” Claim 1 recites 

both an “aggregation switch” and a “remote aggregation switch.” Claim 

limitation [1A] recites that the aggregation switch (recited in the preamble as 

being in a multi-chassis system) includes a first set of member port 

interfaces that is grouped with one or more member port interfaces of a 

remote aggregation switch configured to form a multi-chassis link aggregate 

that couples the aggregation switch and the remote aggregation switch to an 

edge node. As claim limitation 1[A] recites that the aggregation switch 

includes a first set of aggregation switch port interfaces grouped with port 

interfaces of a different switch, i.e., the remote aggregation switch, in claim 

limitation 1[F], the first set of port interfaces is part of the multi-chassis link

of the aggregation switch. Thus, we understand “the first set of port 

interfaces” in claim limitation 1[F] to refer to the “first set of member port 

interfaces of the aggregation switch” in claim limitation 1[A]. 

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X. ANALYSIS

A. Introduction

“In an [inter partes review], the petitioner has the burden from the 

onset to show with particularity why the patent it challenges is 

unpatentable.” Harmonic Inc. v. Avid Tech., Inc., 815 F.3d 1356, 1363 (Fed. 

Cir. 2016) (citing 35 U.S.C. § 312(a)(3) (requiring inter partes review 

petitions to identify “with particularity . . . the evidence that supports the 

grounds for the challenge to each claim”)). This burden of persuasion never 

shifts to Patent Owner. See Dynamic Drinkware, LLC v. Nat’l Graphics,

Inc., 800 F.3d 1375, 1378 (Fed. Cir. 2015) (discussing the burden of proof in 

inter partes review).

Anticipation is a question of fact, as is the question of what a prior art 

reference teaches. In re NTP, Inc., 654 F.3d 1279, 1297 (Fed. Cir. 2011). “A 

claim is anticipated only if each and every element as set forth in the claim is 

found, either expressly or inherently described, in a single prior art 

reference.” Verdegaal Bros. Inc., v. Union Oil Co., 814 F.2d 628, 631 (Fed. 

Cir. 1987); see also Finisar Corp. v. DirecTV Group, Inc., 523 F.3d 1323, 

1334 (Fed. Cir. 2008) (to anticipate a patent claim under 35 U.S.C. § 102, “a 

single prior art reference must expressly or inherently disclose each claim 

limitation”). Moreover, “[b]ecause the hallmark of anticipation is prior 

invention, the prior art reference—in order to anticipate under 35 U.S.C. 

§ 102—must not only disclose all elements of the claim within the four 

corners of the document, but must also disclose those elements ‘arranged as 

in the claim.’ ” Net MoneyIN, Inc. v. VeriSign, Inc., 545 F.3d 1359, 1369 

(Fed. Cir. 2008) (quoting Connell v. Sears, Roebuck & Co., 722 F.2d 1542, 

1548 (Fed. Cir. 1983)). 

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Whether a reference anticipates is assessed from the perspective of an 

ordinarily skilled artisan. See Dayco Prods., Inc. v. Total Containment, Inc., 

329 F.3d 1358, 1368 (Fed. Cir. 2003) (“[T]he dispositive question regarding 

anticipation [i]s whether one skilled in the art would reasonably understand 

or infer from the [prior art reference’s] teaching that every claim element 

was disclosed in that single reference.” (Emphasis omitted) (quoting In re 

Baxter Travenol Labs., 952 F.2d 388, 390 (Fed. Cir. 1991))). 

Additionally, under the principles of inherency, if the prior art 

necessarily functions in accordance with, or includes, the claimed 

limitations, it anticipates. MEHL/Biophile Int’l Corp. v. Milgraum, 192 F.3d 

1362, 1365 (Fed. Cir. 1999) (citation omitted); In re Cruciferous Sprout 

Litig., 301 F.3d 1343, 1349–50 (Fed. Cir. 2002).

The question of obviousness is resolved on the basis of underlying 

factual determinations including: (1) the scope and content of the prior art; 

(2) any differences between the claimed subject matter and the prior art; 

(3) the level of ordinary skill in the art; and (4) objective evidence of 

nonobviousness. Graham v. John Deere Co., 383 U.S. 1, 17–18 (1966). 

Additionally, the obviousness inquiry typically requires an analysis of 

“whether there was an apparent reason to combine the known elements in 

the fashion claimed by the patent at issue.” KSR Int’l Co. v. Teleflex Inc., 

550 U.S. 398, 418 (2007) (citing In re Kahn, 441 F.3d 977, 988 (Fed. Cir. 

2006) (requiring “articulated reasoning with some rational underpinning to 

support the legal conclusion of obviousness”)); see In re Warsaw 

Orthopedic, Inc., 832 F.3d 1327, 1333 (Fed. Cir. 2016) (citing DyStar 

Textilfarben GmbH & Co. Deutschland KG v. C. H. Patrick Co., 464 F.3d 

1356, 1360 (Fed. Cir. 2006)).

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An obviousness analysis “need not seek out precise teachings 

directed to the specific subject matter of the challenged claim, for a court 

can take account of the inferences and creative steps that a person of 

ordinary skill in the art would employ.” KSR, 550 U.S. at 418; accord In re 

Translogic Tech., Inc., 504 F.3d 1249, 1259 (Fed. Cir. 2007). Petitioner 

cannot satisfy its burden of proving obviousness by employing “mere 

conclusory statements.” In re Magnum Oil Tools Int’l, Ltd., 829 F.3d 1364, 

1380 (Fed. Cir. 2016). Instead, Petitioner must articulate a reason why a 

person of ordinary skill in the art would have combined the prior art 

references. In re NuVasive, 842 F.3d 1376, 1382 (Fed. Cir. 2016).

A reason to combine or modify the prior art may be found explicitly 

or implicitly in market forces; design incentives; the “‘interrelated teachings 

of multiple patents’”; “‘any need or problem known in the field of endeavor 

at the time of invention and addressed by the patent’”; and the background 

knowledge, creativity, and common sense of the person of ordinary skill. 

Perfect Web Techs., Inc. v. InfoUSA, Inc., 587 F.3d 1324, 1328–29 (Fed. Cir. 

2009) (quoting KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 418–21 (2007)).

Before determining whether a claim is obvious in light of the prior art, 

we consider any relevant evidence of secondary considerations of nonobviousness. See Graham, 383 U.S. at 17. Notwithstanding what the 

teachings of the prior art would have suggested to one of ordinary skill in the 

art at the time of the invention, the totality of the evidence submitted, 

including objective evidence of non-obviousness, may lead to a conclusion 

that the challenged claims would not have been obvious to one of ordinary 

skill. In re Piasecki, 745 F.2d 1468, 1471–72 (Fed. Cir. 1984). The current 

record include no evidence of secondary considerations.

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We analyze the asserted grounds of unpatentability in accordance with 

these principles to determine whether Petitioner has met its burden to 

establish a reasonable likelihood of success at trial.

B. Anticipation of Claims 1–3, 5–9, 11–15, 19, 20 by Narayanan

Narayanan Ex. 1005

Narayanan relates to a system and method for detecting and 

responding to failures in a virtual switch. Ex. 1005, 1:58–60. In Narayanan, 

“[a]virtual switch is a logical representation of a plurality of physical 

switches as a single switch.” Id. at 1:60–61. A virtual switch within a 

computer network interconnects a plurality of access switches with one or 

more core switches. Id. at 2:2–5. 

Narayanan discloses that a virtual switch is formed by interconnecting 

physical switches via one or more virtual switch links (VSLs). Id. at 61–63. 

The physical switches communicate with each other over the VSLs, electing 

one switch as the active part of the switch, i.e., a Master Chassis that 

executes bridging and routing protocols for the entire virtual switch, while 

the remaining parts of the switch, i.e., the Slave Chassis, remain in standby. 

Id. at 2:61–3:2. Each switch has a supervisor module that includes a 

protocol engine and virtual switch engine. Id. at 5–8. In cooperation with 

access switches, by exchanging control packets (Protocol Data Units or 

“PDUs”) the protocol engine executes a link aggregation protocol that 

allows the virtual switch to determine whether it is coupled to any given 

access switch by more than one link. Id. at 2:8–13. “If so, the multiple links 

connecting the virtual switch to the given access switch are aggregated 

together.” Id. at 2:13–15. 

Figure 1 of Narayanan, which is a partial block diagram of a computer 

network (Ex. 1005, 2:60–61), is reproduced below.

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Figure 1 of Narayanan

In Figure 1, distribution switches 108, 109 linked by VSL 134 are logically 

organized to form virtual switch 130 and distribution switches 110, 111 

linked by VSL 136 are logically organized to form virtual switch 132. Id. at 

3:32–40, Figs. 1–2. VSLs 134, 136 carry control and data traffic between 

peer physical switches or chassis of the respective physical switch. Id. at 

3:40–42. By forming virtual switch 130, distribution switches 108, 109 

appear as a single large distribution switch to “access switches” 102–104. 

Id. at 3:42–45. Similarly, distribution switches 110, 111 appear as a single, 

large distribution switch to “access switches” 105, 106.

Figure 2 of Narayanan, showing a functional block diagram of a 

virtual switch, is reproduced below:

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In Figure 2, distribution switches 110 and 111 are logically organized 

to form virtual switch 132 linked by VSL 136. Distribution switch 110 

includes active supervisor module 202, standby supervisor module 204 and a 

plurality of line cards 206, 208, each having a plurality of ports 210. Id. at 

3:50–56. Active supervisor 202 includes virtual switch engine 220 and a 

protocol engine, e.g., link aggregation engine 222 and, in the embodiment 

shown, its own ports 210. Id. at 3:56–61. Link aggregation engine 222 has 

sub-components, including one or more state machines, control packet 

generator 226, and data store 228. Id. at 3:61–64. VSL 136, which leads to 

similarly constructed second distribution switch 111 of virtual switch 132, is 

coupled to port P1 210 of active supervisor module 202. Id. at 3:64–67.

In operation, each distribution switch with one or more supervisor 

modules elects one of them to be the active supervisor module for that 

switch and its other supervisor modules become standby supervisor 

modules. Id. at 4:56–64. Switches 110, 111 communicate with each other 

across VSL 136 electing one of them, e.g., 110, to be the active part of the 

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virtual switch 132 (Master Chassis); the other distribution switch, e.g., 111, 

becomes the standby part (Slave Chassis). Id. at 4:64–5:7. Forwarding 

decisions for virtual switch 132 are made by the Master Chassis Active 

Supervisor, which also executes bridging and routing protocols, such as the 

Spanning Tree Protocol. Id. at 5:8–15. Control packets, such as Bridge 

Control Data Units (BPDUs) received by the line card of the Slave Chassis,

are sent to the Master Chassis for processing; similarly, control packets to be 

sent from the Slave Chassis are generated by the active supervisor module of 

the Master Chassis and sent to the Slave Chassis for transmission. Id. at

5:15–23. 

Cessation of communication to the standby part from the active part 

across the VSLs indicates a failure of either the active part or the VSL, 

causing the standby part to presume it should become the active part of the 

virtual switch. Ex. 1005, 2:26–30, 7:45–55. In that case “the Slave Active 

Supervisor 230 initializes, and begins running the bridging and routing 

protocols of the virtual switch, including the forwarding of data messages.” 

Id. at 7:55–59. The standby part loads its own ID into the active part ID of 

the PDUs and transmits these PDUs from its ports, signaling to the access 

switches that the former standby part is now the active part of the virtual 

switch. Id. at 2:30–36. The access switches respond by including this new 

information in the PDUs they send back to the virtual switch. Id. at 2:38–40. 

If the failure is a failure of the VSLs and the originally active part of the 

virtual switch continues to function, the original part will receive the PDUs 

from the access switches that carry the information indicating the former 

standby part is now the active part. Id. at 2:41–45. “The originally active 

part of the virtual switch will thus conclude that the VSLs have failed. In 

response the originally active part will take corrective action,” e.g., by 

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relinquishing its role as the active part and entering a recovery mode in 

which ports of the active part, other than the ports of the VSLs are shut 

down. Id. at 2:45–47, see also id. at 7:45–8:58 (describing the process in the 

context of the Port Aggregation Protocol (“PAgP”) from Cisco Systems, 

Inc., described in U.S. Patent No 5,959,968 and incorporated by reference 

(id. at 5:33–36)). According to Narayanan, although the process is described 

as an extension to PAgP, those of ordinary skill would understand it can be 

used with other protocols, such as the Link Aggregation Control Protocol 

(IEEE 802.3ad-2000 standard, incorporated by reference), the Cisco 

Discovery Protocol, and the Spanning Tree Protocol. Id. at 10:38–50.

Claims 1, 8

Petitioner argues apparatus claim 1 and parallel method claim 8 

together. Pet. 22–32. Below, we address claim 1 as illustrative of the 

limitations of claims 1 and 8 and reach the same conclusions as to claims 1 

and 8. As discussed below, Patent Owner disputes that Narayanan’s 

microprocessor carries out the steps recited in claim limitations [1D], [1E], 

and [1F]. Patent Owner does not respond to Petitioner’s other challenge 

grounds or Petitioner’s contentions concerning any of the references other 

than Narayanan. See generally Prelim. Resp.

a) Claim 1 Preamble

The preamble of claim 1 recites “[a]n aggregation switch in a 

multi-chassis system.” Pet. 29. Petitioner cites Narayanan’s distribution 

switches 110, 111 logically organized to form virtual switch 132 as 

disclosing such an aggregation switch. Id. at 22, 29 (citing Ex. 1005, 3:34–

36, Figs. 1, 2). Patent Owner does not respond explicitly to Petitioner’s 

contentions concerning the preamble of clam 1. On the current record, we 

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are persuaded that Petitioner demonstrates that Narayanan discloses the 

preamble of claim 1.

b) Claim Limitation [1.A]

Petitioner designates as claim limitation [1.A] the recitation “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, wherein the multi-chassis link aggregate 

couples the aggregation switch and the remote aggregation switch to an edge 

node.” Pet. 29. Petitioner cites Narayanan as disclosing distribution

switches 110 (designated by Petitioner as the claimed remote aggregation 

switch), and 111 (designated by Petitioner as the claimed aggregation 

switch) logically organized to form virtual switch 132. Id. at 23–24. 

Petitioner notes that each aggregation switch has two line cards 234, 236 

with a first set of ports 210 grouped in line cards 206, 208 of remote 

aggregation switch 110. Id. at 24, 29 (citing Ex. 1005, 3:34–36, 4:3–5, Figs. 

1–2). Petitioner further notes that by the exchange of PDUs, virtual switch 

132 and access switch 105 discover that they are interconnected by four 

links, 112 f–i aggregated together to from a single logical link or channel. 

Id. at 29 (citing Ex. 1005, 7:31–38)

Patent Owner does not respond explicitly to Petitioner’s contentions 

concerning the clam limitation [1A]. On the current record, we are 

persuaded that Petitioner has demonstrated that Narayanan discloses claim 

limitation [1A].

c) Claim Limitation [1.B]

Petitioner designates as claim limitation [1.B] the recitation “a second 

set of port interfaces configured to a form a virtual fiber link for coupling the 

aggregation switch to the remote aggregation switch.” Pet. 29. Petitioner 

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cites Narayanan as disclosing a second set of port interfaces 210 in active 

supervisor module 230 that form a virtual fiber link (VSL 136) with remote 

aggregation switch 110. Pet. 25. Specifically, Petitioner argues that

distribution switch 111 has a plurality of ports 210, one of which (P1) is 

coupled to VSL 136 and to distribution switch 110. Id. at 29 (citing Ex. 

1005, 3:39–40, 4:6–11, Figs. 1–2).

Patent Owner does not respond explicitly to Petitioner’s contentions 

concerning the clam limitation [1B]. On the current record, we are 

persuaded that Petitioner has demonstrated that Narayanan discloses claim 

limitation [1B]. 

d) Claim Limitation [1C]

Petitioner designates as claim limitations [1.C] the recitation “a 

processing module operable to.” Petitioner cites Narayanan’s Active 

Supervisor Module 230 as having processing module 216 configured to 

carry out the claimed steps. Pet. 26, 29–30. Patent Owner does not dispute 

that Narayanan discloses a structure having a microprocessor, but disputes 

that Narayanan’s microprocessor 216 carries out the steps recited in claim 

limitations [1D], [1E], and [1F].

e) Claim Limitation [1.D]

Petitioner designates as claim limitation [1.D] the recitation 

“determine a connection failure of the virtual fiber link to the remote 

aggregation switch.” Pet. 30. According to Petitioner, Narayanan discloses 

processing module 216 is configurable to determine VSL 136 fails when it 

stops receiving communications from switch 110. Id. at 27, 30 (citing Ex. 

1006, 7:48–59); Ex. 1004, Bambos Decl. ¶ 99). 

Patent Owner argues that Narayanan cannot anticipate “determining a 

failure of the virtual fiber link to the remotes aggregation switch” because 

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the subject matter of Narayanan cited by Petitioner states explicitly that 

Slave Chassis 111 cannot tell whether this communication failure is due to 

some failure of the Active Chassis, or to a failure of the VSL 136. Prelim. 

Resp. 18–20 (citing Ex. 1005, 7:48–59). 

The text of Narayanan reads “[s]uppose that the VSL of virtual switch 

132 fails, thereby cutting off communication between two distribution 

switches 110 and 111 that make up virtual switch as indicated at block 428 

[of Fig. 4C]”. Ex. 1005 7:45–48. Block 428 in Figure 4C reads “VSL 

Fails.” Id. at Fig. 4C. Thus, Narayanan is configured to “determine a failure 

of the virtual fiber link to the remote aggregation switch.” Narayanan makes 

this determination based on the absence of communications from the switch. 

At this stage Narayanan’s system has not distinguished between a failure of 

the VSL or the Active Chassis; in either case Slave Chassis 111 responds by 

taking the active role for virtual switch 132. Id. at 7:53–55. Narayanan 

further discloses that, if running, Active Chassis 110 determines a failure of 

VSL 136 if its link aggregation engine 222 discovers the Master Chassis ID 

field does not carry the ID assigned to switch 110, as shown in block 446, 

but instead carries the ID assigned to switch 111. Ex. 1005, 8:37–46, see 

also, id. at 2:26–49. Thus, we are persuaded for purposes of this Decisioin

that Petitioner has demonstrated Narayanan discloses the features recited in 

claim limitation [1D].

f) Claim Limitation [1.E]

Petitioner contends Narayanan teaches a processor operable to 

“reconfigure the first set of port interfaces of the multi-chassis link aggregate 

to form a link aggregate for coupling to the edge node” (claim limitation 

[1.E]) because Narayanan discloses that, in taking over the role of the virtual 

switch, Slave Active Supervisor in Slave Chassis 111 initializes and begins 

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running the bridging and routing protocols of the virtual switch, including 

forwarding of data messages. Pet. at 30 (citing Ex. 1005, 7:54–59). 

Patent Owner argues that although Narayanan discloses Slave Chassis 

111 is configured to respond by taking over the active role of the virtual 

switch, including forwarding data messages, Narayanan does not disclose 

reconfiguring any port interfaces. Prelim. Resp. 20–21. Petitioner, 

however, cites Narayanan as disclosing processing module 216 

“reconfigures the multi-chassis link aggregate into at least one link 

aggregate formed of ports 210 in line cards 234 and/or 236 for coupling with 

the edge nodes 105 and 106.” Pet. 27 (citing Ex. 1005, 7:48–59, Ex. 1004, 

Bombas Decl. ¶ 100). According to Petitioner, “at least links 112h and 113i 

form a link aggregate from switch 111 to node 105.” Id. (citing Ex. 1004, 

Bombas Decl. ¶ 100). Referencing Figure 1, Petitioner’s expert testifies that 

in Narayanan, although links 112 f–i that connect to edge nodes 105 come 

from two different physical switches 110, 111, “links 112 f–i ‘are preferably 

aggregated together to form a single logical link or channel,’” i.e., a single 

logical link aggregate. Ex. 1004, Bombas Decl. ¶ 76 (quoting Ex. 1005, 

7:33–38). Dr. Bombas further explains that, in Narayanan,

[s]witch 110 concludes that the VSL 136 between it and switch 

111 has failed. In response, switch 110 preferably takes 

corrective action, as indicated at block 448. In this illustrative 

embodiment, this corrective action includes placing all of its 

ports and interfaces other than the ports and interfaces associated 

with VSL 136 in a down state, such that no data traffic is sent or 

received by switch 110.

Id. ¶ 100 (quoting Ex. 1005, 8:44–51), see Ex. 1005, Fig. 4. Accordingly 

“while links 112f–i formed a link aggregate pre-failure, post failure links 

112 f–g are severed and links 112 h–i have to be reconfigured into a new 

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link aggregate to allow communication between virtual switch 132 (i.e., its 

only active physical switch 111) and switch 105.” Id.

On the current record, we credit Dr. Bombas’s testimony and find that 

for purposes of institution, Petitioner has demonstrated that Narayanan 

discloses claim limitation [1.E].

g) Claim Limitation [1.F]

Petitioner identifies as claim limitation [1.F], the recitation to “initiate 

a spanning tree protocol in the one or more of the first set of port interfaces.” 

Pet. 30. Petitioner contends that Narayanan discloses claim limitation [1F] 

because in Narayanan processing module 216 in Slave Active Supervisor 

230 runs the necessary bridging and routing protocols, which includes

initiating a Spanning Tree Protocol, such as that executed by the Master 

Active Supervisor 202. Pet. 28, 30 (citing Ex. 1005, 7:54–59, 5:12–15; Ex. 

1004, Bombas Decl. ¶ 101). 

Patent Owner argues that Narayanan “only discloses executing the 

Spanning Tree Protocol,” but does not disclose “the required initiating a 

spanning tree protocol in the one or more of the first set of port

interfaces.” Prelim. Resp. 23. Patent Owner also argues that Petitioner does 

not advance an argument that this limitation is inherent in Narayanan. Id. at 

23–24.

As discussed above, Petitioner argues, and Patent Owner does not 

dispute, that Narayanan discloses a first set of member port interfaces 210 at 

the line cards of the aggregation switch in the form of ports 210, as 

distinguished from a second set of ports 210 coupled to VSL 136. 

Petitioner’s expert explains that as a result of Narayana’s active switch 110 

disabling all its ports and severing its communication links, a major network 

change occurs. Ex. 1004, Bombas Decl. ¶ 101. This network change “will 

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require identifying loop-free paths afresh, which the Spanning Tree Protocol 

now run by module 230 of switch 111 will do.” Id. 

As discussed above, the ’489 patent discloses a Spanning Tree 

Protocol is disabled on the MC-LAG member ports coupled to edge node 

104 in aggregation switches 106a and 106b and enabled in the portion of the 

network between the aggregation switches and nodes in the metro/core 

network. Ex. 1001, 16:45–63, Fig. 9. However, during failure recovery, 

aggregation switches 106 enable a Spanning Tree Protocol on link 

aggregates LAG-1 420 and LAG-2 422 connected to edge nodes as well as 

between aggregation switch 106 and core network 120. Ex. 1001, 18:13–16, 

Fig. 11. 

Petitioner does not identify a disclosure in Narayanan explicitly 

stating that the aggregation switch enables a Spanning Tree Protocol on links 

between ports on edge or access switches to ports of the aggregation switch. 

However, Petitioner points out that in Narayanan, when there is a failure, the 

Slave Active Supervisor takes over the active role of virtual switch 132 by 

running the bridging and routing protocols, including Spanning Tree 

Protocols. Pet. 30 (citing Ex. 1005, 5:1–2–15, 7:54–59). Narayanan

illustrates the process in the context of the PAgP protocol, in which the 

standby part (the Slave) loads its own ID into the active part ID of the PDUs 

and transmits these PDUs from its ports (the first set of port interfaces), 

signaling to the access switches that the former standby part is now the 

active part of the virtual switch. Id. at 2:30–36. The access switches 

respond by including this new information in the PDUs they send back to the 

virtual switch. Id. at 2:38–40. Narayanan also expressly states the process 

could be implemented using a Spanning Tree Protocol. Id. at 10:38–50. In 

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view of this disclosure, we are persuaded that for purposes of institution that 

Petitioner has demonstrated Narayanan discloses claim limitation 1[F].

h) Conclusion as to Claims 1 and 8 

Based on our review of evidence in the current record, for the reason 

discussed above, we find that Petitioner has demonstrated a reasonable 

likelihood it will prevail in its challenge to claims 1 and 8 as anticipated by 

Narayanan.

Claims 2–3, 5–7, 9, and 11–14

As to claim 2, which depends from claim 1 and recites “the remote 

aggregation switch is in a separate physical chassis,” Petitioner cites 

Narayanan as disclosing distribution switch 111 and remote switch 110 are 

separate physical chassis. Pet. 32 (citing Ex. 1005, Abstract, 3:32–47, Figs.

1–2). Claim 14 depends from claim 8 and recites an additional limitation 

that is substantially the same as that of claim 2. Based on the current record, 

we are persuaded that for purposes of this Decision, Petitioner has 

demonstrated Narayanan discloses all the features of claims 2 and 14. 

Claims 3 and 9 depend from claims 1 and 8, respectively, and recite 

“re-assigning link parameters designating the first set of ports as a multichassis link aggregate to link parameters designating the first set of ports as 

a link aggregate.” As to this limitation, Petitioner cites Narayanan’s 

explanation that “switch 111 changes the Master Chassis ID link parameter 

to the unique ID associated with switch 111 upon failure of the VFL.” Pet. 

33 (citing Ex. 1005, 8:4–15; Ex. 1004, Bambos Dec. ¶ 105). Based on the 

current record, we are persuaded that for purposes of this Decision, 

Petitioner has demonstrated Narayanan discloses all the features of claims 3

and 9.

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Claim 5 depends from claim 1 and recites “enabling a spanning tree 

protocol on the first set of port interfaces.” As to this limitation, Petitioner 

references its discussion of clam limitation 1[F]. Pet. 33. Claim 5 also 

recites “identifying a loop through the aggregation switch of packets 

belonging to a virtual local area network” and “blocking forwarding of

packets belonging to the virtual local area network on one or more port 

interfaces of the aggregation switch to prevent the identified loop.” 

Petitioner argues a person of ordinary skill would have known that “the 

purpose of running an STP is to identify loops and block packets over 

certain ports as necessary.” Id. Petitioner also notes that explicit disclosure 

in Chin (incorporated by reference in Narayanan) states the purposes of STP 

is to avoid the formation of loops using an algorithm that severs certain 

paths or ports by placing them in blocking mode that prevents forwarding 

packets over the blocked port. Id. (citing Ex. 1005, 5:32–42; Ex. 1007, 

3:11–36). Based on the current record, we are persuaded that for purposes 

of in this Decision, Petitioner has demonstrated Narayanan discloses all the 

features of claims 5.

Claim 6 depends from claim 1 and further recites (i) receiving an 

incoming packet that includes a destination address, (ii) determining 

destination hardware device information corresponding to a hardware device 

in the remote aggregation switch based on the destination address of the 

incoming packet, and (iii) from the incoming packet generating a packet 

with a pre-pended packet that includes the destination hardware device 

information. See, Ex. 1001, 23:8–18. Claim 12 depends from claim 8 and 

recites limitations similar to those in claim 6. Petitioner cites details from 

Smith, incorporated by reference in Narayanan, as disclosing receiving 

incoming packet with a destination address, determining the packet is 

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destined for an address that should be sent via peer chassis 110 and 

generating a packet with a header that includes the destination port. Pet. 36 

(citing Ex. 1006 ¶¶ 78, 80). Petitioner further argues a person of ordinary 

skill would understand that the header is added to the beginning of the 

packet (i.e., pre-pended). Id. at 36–37 (citing Ex. 1006 ¶111). Recognizing 

that Narayanan incorporates Smith by reference, based on the current record, 

for purposes of this Decision, we are persuaded Petitioner has demonstrated 

Narayanan discloses all the limitations of claims 6 and 12. 

Claim 7 depends from claim 1 and recites that the second set of port 

interfaces is operable to determine a failure of the virtual fiber link and block 

forwarding of packets over the virtual fiber link. Ex. 1001, 23:22–25. 

Claim 13 depends from claim 8 and recites limitations similar to those of 

claim 7. Petitioner cites Narayanan as disclosing that failure of the VSL cuts 

off communication between switches 110 and 111, effectively blocking the 

forwarding of packets over the link. Pet. 39 (citing Ex. 1004, Bombas Decl.

¶ 114) . Based on the current record, we are persuaded that for purposes of 

this Decision, that Petitioner has demonstrated Narayanan discloses all the 

features of claims 7 and 13.

Claims 15 and 19–20

Petitioner notes that independent method claim 15 is similar to 

independent apparatus claim 1 and independent method claim 8, but claim 

15 further recites “receiving a command to operate in a stand-alone mode.” 

Pet. 40. Petitioner states that a person of ordinary skill would know that 

when a VSL goes down, the processor in the supervisor module for switch 

111 receives a command to operate in a stand-alone mode independent of 

switch 110 after the disconnection. Pet. 40–42 (citing Ex. 1005, 7:48–59, 

(“the Slave Chassis 111 is preferably configured to respond by taking over 

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the active role for the virtual switch . . . Slave Supervisor 230 initializes and 

begins running the bridging and routing protocols of the virtual switch, 

including the forwarding of data messages.”)(emphasis omitted); Ex. 1004, 

Bambos Decl. ¶ 121. Although Petitioner does not cite an explicit disclosure 

of “receiving a command to operate in a stand-alone mode,” we are 

persuaded for purposes of this Decision that Petitioner has demonstrated a 

person of ordinary skill would reasonably understand or infer this feature 

from the subject matter disclosed in Narayanan. Dayco Prods., 329 F.3d at 

1368.

Claims 19 and 20 depend from claim 15. Petitioner contends that 

Narayanan anticipates claim 19 for the same reasons Narayanan anticipates 

the similar limitations recited in claims 5 and 11 discussed above. Pet. 42.

Petitioner contends that Narayanan anticipates claim 20 for the same reason 

Narayanan anticipates the similar limitations recited in claims 7 and 13

discussed above. Id. For the same reasons as those discussed above with 

respect to claims 5, 7, 11 and 13, on the current record we are persuaded 

Petitioner has demonstrated Narayanan discloses the limitations recited in 

claims 19 and 20.

C. Claims 1–20 As Obvious Over Narayanan (Incorporating Smith 

and Chin by Reference)

Claims 1–3, 5–9, and 11–14

Petitioner notes that Narayanan incorporates Smith and Chin by

reference. Pet. 43 (citing Ex. 1004, 4:12–15, 5:33–37). Petitioner argues 

that, to the extent we do not consider Smith and Chin to be part of 

Narayanan’s disclosure, in view of Narayanan’s explicit reference to Smith 

and Chin, a person of ordinary skill would have had reason to combine their 

teachings with those of Narayanan. Id. Petitioner notes that Narayana cites 

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Smith as providing details for a suitable design of switch 132, including 

components such as forwarding engines, filtering databases, and spanning 

tree engines. Id. (citing Ex. 1004 (sic), 4:17–18). Petitioner also notes 

Narayanan’s explanation that Chin discloses details of an illustrative 

embodiment of PAgP as run by link aggregations engines 222 and 310 

disposed in virtual switch 132 and access switches 105, 106. Id. (citing Ex. 

1004 (sic), 5:32–39). On the current record, we are persuaded for purposes 

of the Decision that Petitioner has demonstrated a person of ordinary skill 

would have had reason to combine the teachings of Smith and Chin with 

those of Narayanan.

To the extent Narayanan is considered not to teach explicitly

“reconfiguring[ing] one or more of the first set of port interfaces of the 

multi-chassis link to form a link aggregate” (clams 1, 8, and 15), Petitioner 

contends person of ordinary skill would have recognized that while the VFL

was down, port interfaces could not operate as a multi-chassis link aggregate 

and the ports in switch 111 would have to operate as a link aggregate at least 

until the VFL comes back online, and two switches are synchronized. Pet. at 

44.

To the extent Narayanan is considered not to teach explicitly

“initiat[ing] a spanning tree protocol in the one or more of the first set of 

port interfaces,” (claim 1, 8, and15), Petitioner argues the a person of 

ordinary skill would have known an Spanning Tree Protocol must be run 

because upon failure of the VSL, switch 111 initializes and begins running 

bridging and routing protocols that Narayanan teaches include Spanning 

Tree Protocols. Pet. 45 (citing Ex. 1005, 5:13–14, 7:57–58, 8:11–15).

To the extent Narayanan is considered not to teach explicitly

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chassis link aggregate to link parameters designating the first set of ports as 

a link aggregate” (claims 3 and 9), Petitioner contends a person of ordinary 

skill would have understood that certain parameters within active supervisor 

230 must be reassigned when switch 111 takes over the active role, e.g., 

Active Supervisor 230 must use the unique ID for switch 111 in the Master 

Chassis ID field in messages it sends. Pet. 46 (citing Ex. 1005, 7:57–58; Ex. 

1004, Bambos Decl. ¶ 132).

To the extent Narayanan is considered not to teach explicitly 

“blocking forwarding of packets over the virtual fiber link” (claims 7, 13, 

and 20) Petitioner argues a person of ordinary skill would understand that 

upon detection of a VFL link failure by Active Supervisor 230, it would be 

wasteful to attempt to send resources over a failed link and communication

over that link would be blocked until the connection is re-established. Pet. 

46–47 (citing Ex. 1004, Bambos Decl. ¶ 134).

To the extent Narayanan is considered not to teach explicitly 

“generat[ing] a packet with pre-pended header from the incoming packet, 

wherein the pre-pended header includes the destination hardware device 

information” (clams 6 and 12) Petitioner argues that a person of ordinary

skill would have understood that headers are typically pre-pended, i.e., 

added to the head of a packet for networking protocols. Id. at 47 (citing Ex. 

1004, Bambos Decl. ¶ 133).

Claims 15–17, and 19–20

Petitioner contends that to the extent Narayanan is considered to not 

teach explicitly “receiving a command to operate in stand-alone mode” 

(claim 15), a person of ordinary skill would have understood that a network 

administrator powering down switch 110 for maintenance could send a 

command to switch 111 to operate in stand-alone mode, causing switch 111 

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to operate in the same way it would operate if a VSL failed. Pet. 47–48 

(citing Ex. 1004, Bambos Decl. ¶136).

Claim 16 depends from claim 15, and recites “determining link 

parameters for operating in the stand-alone mode from a pre-determined 

table, wherein the link parameters for operating in the stand-alone mode 

include link parameters for the link aggregate and a system identifier that is 

different from the system identifier of the remote aggregation switch.” 

Petitioner contends a person of ordinary skill would have understood that 

stand-alone mode Active Supervisor 230 could store in a predetermined 

table link parameters useful to improve efficiency by reducing calculation 

processing required by switch 111. Pet. 48. Petitioner further notes that 

Slave Active Supervisor 230 places the unique ID assigned to Slave Chassis 

111 into Master Chassis ID field 542, as opposed to the ID assigned to 

Active Chassis 110 used in the PAgP PDUs 500 prior to the failure. Id. 

(citing Ex. 1005, 8:4–15).

Claim 17 depends from claim 16 and further recites “re-configuring 

the plurality of the first set of ports with the link parameters for the link 

aggregate.” Noting its prior discussion of claims 3 and 9, which recite reassigning” the link parameters for the first set of ports, Petitioner contends it 

would have been obvious to “re-configure” the link parameters as recited in 

claim 17 for the same reasons as those discussed with respect to claims 3 

and 9. Pet. 49.

Claim 4, 10, and 18

Claim 4 depends from claim 3. Petitioner characterizes claim 4 as 

detecting a change of link parameters, flushing MAC table entries, and 

repopulating MAC table entries. Pet. 49. Petitioner contends that Narayana 

(via Smith incorporated by reference) discloses that each switch 110 and 111 

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has its own Layer 2 forwarding table with MAC addresses (a MAC table) 

and that the VSL maintains consistency between the two tables. Id. (citing 

Ex. 1006 ¶¶ 17, 48). Petitioner notes that, in, Narayanan when the VSL goes 

down and switch 111 becomes the active switch, MAC table entries that 

came from switch 110 would no longer work and would need to be flushed 

from the table. Id. at 50 (citing Ex. 1004 Bambos Decl. ¶ 141). According 

to Petitioner, Narayanan discloses repopulating the MAC table entries by 

flooding the network to determine the proper route. Id. (citing Ex. 1006 

¶ 48).

Petitioner notes that claim 10 depends from claim 9 (see claims 3 and 

9 discussed above) and recites the additional limitations similar to those of 

claim 4. Claim 18 depends from claim 17, discussed above, and recites 

limitations similar to those of claim 4. Petitioner contends that claims 10 

and 18 would have been obvious to one of ordinary skill over Narayanan for 

the same reasons as discussed relative to claim 4.

Conclusion

On the current record, we are persuaded that Petitioner has 

demonstrated for purposes of this Decision that Narayanan, which 

incorporates the Smith and Chin by reference, would have taught or 

suggested the limitations of claims 1–20 to a person of ordinary skill in the 

art.

D. Claims 4, 10, and 18 As Obvious Over Narayanan and 

Mullooly

Figure 1 of Mullooly is reproduced below.

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Figure 1 of Mullooly

Figure 1 of Mullooly shows network system 100 utilizing a multi-chassis 

link aggregation including dual-homed routing device 102 linked with 

routing devices 104, 106 via communication links 150, 151, each of which is 

aggregated to form a single logical communication link. See, Ex. 1008, 

2:57–3:16. Routing devices 104, 106 are in communication with each other 

by way of inter-chassis control plane channel 108. See, id. at 3:60–4:20. 

In view of the similarity of their subject matter, Petitioner contends a 

person of ordinary skill would have had reason to combine the teachings of 

Narayana and Mullooly. Pet. 54. Petitioner cites Mullooly as disclosing 

switches configured to form multi-chassis link aggregations and details 

about the control channel session between two switches over inter-chassis 

control plane 108, including synchronizing information. Id. at 52–53 (citing 

Ex. 1008, 3:61–62, 6:51–65). 

As to the limitations of claim 4 (and similar limitations of claim 10 

and 18), Petitioner notes that Mullooly discloses that if a routing device 

fails, other routing devices may be required to flush and repopulate their 

MAC tables. Id. at 53–54 (citing Ex. 1008, 8:40–43). According to 

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Petitioner, Smith, incorporated by reference in Narayanan, teaches one way 

to repopulate a table is by flooding all ports and hardware learning. Id. at 54 

(citing Ex. 1006 ¶ 48).

On the current record, we are persuaded that Petitioner has 

demonstrated for purposes of this Decision that a person of ordinary skill 

would have had s reason to combine the teachings of Narayanan and 

Mullooly and the combined teachings disclose the limitations of claims 4, 

10, and 18.

E. Claims 15–20 As Obvious Over Narayanan, Moberg, and 

Mullooly

Moberg relates to computer networks and systems and methods for 

replacing software controlling active routers, while minimizing the impact 

on network operation. See Ex. 1009, 1:16–54. Petitioner cites Moberg as 

disclosing a method for upgrading active switching device A that requires 

reboot: active switching device A sends a command to switch B, indicating 

switch B should start acting as the primary switch, until primary switch A 

comes back online. Pet. 55 (citing Ex. 1009, Fig. 2, 3, 4:53–56).

Noting that switches 110, 111 of Narayanan are software controlled 

deices that may benefit from occasional upgrades, Petitioner argues a person 

of ordinary skill would have had reason to upgrade switches 100, 111 with 

minimal data interruption using Moberg’s redundant switch to handle traffic 

while an upgrade is being performed. Pet. 56–57 (citing Ex. 1004, Bambos 

Decl. ¶¶ 149–151). Thus, according to Petitioner, claim 15, which recites 

“receiv[ing] a command to operate in stand-alone mode,” would have been 

obvious to a person of ordinary skill over Narayanan and Moberg. Id. at 58. 

According to Petitioner, claims 16, 17, 19, and 20 would have been obvious 

over Narayanan and Moberg for the reasons discussed above; similarly 

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claim 18 would have been obvious over Narayanan, Moberg, and Mullooly. 

Id.

On the current record, we are persuaded that Petitioner has 

demonstrated for purposes of this Decision that a person of ordinary skill 

would have has reason to combine the teachings of Narayanan, Moberg and 

Mullooly and the combined teachings disclose the limitations of claims 15–

20.

XI. CONCLUSION

For the reasons discussed above, we are persuaded that Petitioner has 

demonstrated a reasonable likelihood that it will succeed on the following 

challenges to patentability: 

Claims 1–3, 5–9, 11–17, and 19–20 as anticipated by Narayanan;

Claim 1–20 as obvious over Narayanan;

Claims 4, 10, and 18 as obvious over Narayanan and Mullooly; and

Claims 15–20 as obvious over Narayanan, Moberg, and Mullooly.

XII. ORDER

In consideration of the foregoing, it is hereby:

ORDERED that, pursuant to 35 U.S.C. § 314(a) an inter partes

review of the ’489 patent is hereby instituted, commencing on the entry date 

of this Order, and pursuant to 35 U.S.C. § 314(c) and 37 C.F.R. § 42.4, 

notice is hereby given of the institution of a trial;

FURTHER ORDERED that the trial is authorized on all grounds set 

forth in the Petition; and

FURTHER ORDERED that the trial will be conducted in accordance 

with a separately entered corresponding Scheduling Order

Case 6:20-cv-00477-ADA Document 110-2 Filed 08/18/21 Page 51 of 52
IPR2021-00272

Patent 8,913,489 B2

51

FOR PETITIONER:

Y Ernest Hsin

Ryan Iwahashi

GIBSON, DUNN & CRUTCHER LLP

ehsin@gibsondunn.com

riwahashi@gibsondunn.com

FOR PATENT OWNER:

Ryan Loveless

Jeffry Stephens

Brett Mangrum

James Etheridge

Brian Koide

Jeffrey Huang

ETHERIDGE LAW GROUP

ryan@etheridgelaw.com

jstephens@etheridgelaw.com

brett@etheridgelaw.com

jim@etheridgelaw.com

brian@etheridgelaw.com

jeff@etheridgelaw.com

Case 6:20-cv-00477-ADA Document 110-2 Filed 08/18/21 Page 52 of 52