United States Court of Appeals 

for the Federal Circuit ______________________ 

ALTERWAN, INC.,

Plaintiff-Appellant

v.

AMAZON.COM, INC., AMAZON WEB SERVICES, 

INC.,

Defendants-Appellees

______________________ 

2022-1349

______________________ 

Appeal from the United States District Court for the 

District of Delaware in No. 1:19-cv-01544-MN, Judge 

Maryellen Noreika.

______________________ 

Decided: March 13, 2023

______________________ 

C. GRAHAM GERST, Global IP Law Group, LLC, Chicago, IL, argued for plaintiff-appellant. Also represented 

by STEVEN J. FALETTO, ALISON AUBREY RICHARDS, HANNAH L. SADLER. 

 J. DAVID HADDEN, Fenwick & West LLP, Mountain 

View, CA, argued for defendants-appellees. Also represented by JOHNSON KUNCHERIA, RAVI RAGAVENDRA RANGANATH, SAINA S. SHAMILOV; TODD RICHARD GREGORIAN, San 

Francisco, CA. 

 ______________________ 

Case: 22-1349 Document: 37 Page: 1 Filed: 03/13/2023
2 ALTERWAN, INC. v. AMAZON.COM, INC. 

Before LOURIE, DYK, and STOLL, Circuit Judges.

DYK, Circuit Judge. 

In this patent infringement action, the parties entered 

into a stipulation of non-infringement based on two of the 

district court’s claim construction rulings. Because the 

stipulation is ambiguous and therefore defective, we vacate 

and remand for further proceedings.

BACKGROUND

Appellant AlterWAN sued appellee Amazon for infringement of claims of two patents: U.S. Patent Nos. 

8,595,478 (“the ʼ478 patent”) and 9,015,471 (“the ʼ471 patent”).1 AlterWAN’s patents concern improvements to implementing wide area networks (“WANs”) over the 

Internet. Both patents share a common specification. The 

specification describes two core problems with using the Internet for WANs. The first is the problem of latency (or 

delay) due to uncontrolled “hops” from one node to another 

while the data packet is en route to its destination. ’478 

patent, col. 3 ll. 32–49. The second is the lack of security 

for data transmitted over the Internet. ’478 patent, col. 3 

ll. 50–53. The patents purport to address those problems 

with a “private tunnel” that provides “preplanned high 

bandwidth, low hop-count routing paths between pairs of 

customer sites.” ’478 patent, col. 4 ll. 17–18, 34.

At the claim construction phase, the parties disputed 

two terms relevant to this appeal: “non-blocking bandwidth” and “cooperating service provider.” 

1 There were originally six patents involved in the 

proceedings below, but only two are relevant to this appeal. 

AlterWAN voluntarily stipulated to dismissal of claims 

based on the other four patents with prejudice. 

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ALTERWAN, INC. v. AMAZON.COM, INC. 3

I. Non-Blocking Bandwidth

The term “non-blocking bandwidth” appears in claims 

1, 13, and 14 of the ʼ471 patent but not in the asserted 

claims of the ʼ478 patent. Claim 1 of the ʼ471 patent, which 

appears to be representative of the ʼ471 claims, uses the 

term “non-blocking bandwidth:” 

1. An apparatus, comprising:

an interface to receive packets;

circuitry to identify those packets of the received packets corresponding to a set of one 

or more predetermined addresses, to identify a set of one or more transmission paths 

associated with the set of one or more predetermined addresses, and to select a specific transmission path from the set of one 

or more transmission paths; and

an interface to transmit the packets corresponding to the set of one or more predetermined addresses using the specific 

transmission path;

wherein 

each transmission path of the set of 

one or more transmission paths is 

associated with a reserved, nonblocking bandwidth, and

the circuitry is to select the specific 

transmission path to be a transmission path from the from the [sic] set 

of one or more transmission paths 

that corresponds to a minimum 

link cost relative to each other 

transmission path in the set of one 

or more transmission paths.

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4 ALTERWAN, INC. v. AMAZON.COM, INC. 

ʼ471 patent, col. 15 ll. 44–63 (emphasis added). The specification explains that “the quality of service problem that 

has plagued prior attempts is solved by providing nonblocking bandwidth (bandwidth that will always be available and will always be sufficient).” ʼ471 patent, col. 4 l. 66–

col. 5 l. 2.

Amazon sought the construction “bandwidth that will 

always be available and will always be sufficient,” J.A. 430,

mirroring the language of the specification. AlterWAN argued that no construction was necessary for “non-blocking 

bandwidth.” Alternately, AlterWAN proposed the construction “bandwidth that will always be available and will 

always be sufficient while the network is operational.” Id. 

AlterWAN urged that the language “while the network is 

operational” was necessary because “[t]here is no such 

thing as a network that can never fail.” Id. at 431. The 

district court agreed with Amazon, reasoning that the patentee acted as its own lexicographer and that the claim 

language required that the bandwidth be available even if 

the Internet is down. 

II. Cooperating Service Provider

The term “cooperating service provider” appears in 

claims 1, 6, 10, 18, 42, 51, and 63 of the ʼ478 patent and in 

claim 19 of the ʼ471 patent. Claim 1 of the ʼ478 patent appears to be representative: 

1. A method of operation in a router that is part of 

a wide area network, the method comprising:

filtering inbound data packets received on 

an input port of the router to identify data 

packets that correspond to a selected group 

of addresses relative to data packets that 

are not within the selected group of addresses; and

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ALTERWAN, INC. v. AMAZON.COM, INC. 5

providing priority routing for the data 

packets in the selected group of addresses, 

including

performing a look-up into a routing table 

applicable to the selected group of addresses to identify one or more transmission paths that meet a minimum 

transmission requirement relative to other 

available transmission paths, and

routing the data packets to at least one cooperating service provider using one of the 

identified one or more transmission paths.

ʼ478 patent, col. 15 ll. 43–58 (emphasis added). 

AlterWAN argued that no construction was necessary 

for “cooperating service provider,” or, if construction is necessary, that the term ought to be construed as a “service 

provider whose transmission equipment is coupled to the 

path” or “third party service provider whose transmission 

equipment is coupled to the path.” J.A. 436. Amazon urged 

that the term should be construed to mean “service provider that agrees to provide nonblocking bandwidth.” Id. 

After a Markman hearing, the district court initially

construed “cooperating service provider” as “service provider that agrees to provide blocked bandwidth.”2 J.A. 40. 

The district court reasoned that the prosecution history, in 

which the patentee stated that “cooperating services providers . . . have prearranged for blocked bandwidth[,]” supported this construction. Id. The district court refused to 

2 Claim 2 of the ʼ471 patent includes the related 

term “cooperating third party service provider.” In its 

claim construction order, the district court assigned the 

same construction to both “cooperating service provider” 

and “cooperating third party service provider.” 

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6 ALTERWAN, INC. v. AMAZON.COM, INC. 

substitute “non-blocking bandwidth” for “blocked bandwidth,” as Amazon requested, because “the parties disagree[d] whether ‘blocked bandwidth’ has the same meaning 

as ‘non-blocking bandwidth,’” but the parties did not ask 

the court to construe “blocked bandwidth.” Id. The court 

noted that “[s]hould a dispute based on the meaning of 

‘blocked bandwidth’ later arise, the parties may raise it to 

the extent necessary.” Id. 

At the summary judgment stage, AlterWAN argued 

that “blocked bandwidth” should be construed as “bandwidth reserved for a particular purpose,” while Amazon 

sought to substitute the term “non-blocking bandwidth” for 

“blocked bandwidth.” J.A. 771. At a hearing, the district 

court agreed with Amazon and changed its construction of 

“cooperating service provider” to be a “service provider that 

agrees to provide non-blocking bandwidth.” Id. at 3. 

III. Further Proceedings

The stipulated judgment that is appealed here was entered into after the filing of motions for summary judgment, including Amazon’s motion for summary judgment 

of non-infringement.3 After changing the construction of 

3 The stipulation provided, in relevant part: 

[T]he parties stipulate and agree as follows:

1. Under the Court’s constructions of “cooperating service provider” and “nonblocking 

bandwidth,” Amazon has not infringed, 

and does not infringe, the ’478 and ’471 patents.

2. The parties stipulate to the entry of judgment of non-infringement of the ’478 and 

’471 patents, subject to AlterWAN’s 

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ALTERWAN, INC. v. AMAZON.COM, INC. 7

“cooperating service provider” at the summary judgment 

hearing, the district court gave AlterWAN the opportunity 

to submit a supplemental expert report to make additional 

infringement contentions based on the new construction, 

or, if the new construction meant there was no reasonable

infringement argument that AlterWAN could make, to 

stipulate to non-infringement. 

After the summary judgment hearing, the parties filed 

a stipulation and order of non-infringement of the patentsin-suit. The parties stipulated to “the entry of judgment of 

non-infringement of the ʼ478 and ʼ471 patents.” J.A. 4. 

The stipulation explained, “[u]nder the Court’s constructions of ‘cooperating service provider’ and ‘non-blocking 

bandwidth,’ Amazon has not infringed, and does not infringe, the ’478 and ’471 patents.” Id. Based on the stipulation, the district court entered a final judgment. 

AlterWAN appealed. 

In its appeal, AlterWAN challenges the district court’s 

construction of “cooperating service provider” and “nonblocking bandwidth” as well as a third term, “routing.” AlterWAN concedes that “routing,” a term that the district 

court offered guidance on at the summary judgment hearing, is not included in the stipulation, but AlterWAN argues we should address the term to conserve judicial 

resources. We have jurisdiction under 28 U.S.C. 

§ 1295(a)(1). 

forthcoming appeal of the Court’s Claim 

Construction and Summary Judgment Orders. 

J.A. 4.

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8 ALTERWAN, INC. v. AMAZON.COM, INC. 

DISCUSSION

I 

In past cases, we have held that stipulated judgments 

are defective if they are ambiguous in material respects. 

See Jang v. Bos. Sci. Corp., 532 F.3d 1330, 1335–36 (Fed. 

Cir. 2008). The stipulated judgment here provides that

Amazon does not infringe under the district court’s constructions of “cooperating service provider” and “non-blocking bandwidth.” Under the circumstances of this case, the 

stipulation does not provide sufficient detail to allow us to 

resolve the claim construction issues presented on appeal.

First, the stipulation does not identify which claims of 

the ’471 patent remain at issue in this appeal. We have 

vacated judgments that fail to identify which claims are 

implicated by the judgment. See Allen Eng’g Corp. v. Bartell Indus., Inc., 299 F.3d 1336, 1342 (Fed. Cir. 2002) (vacating a judgment in part “[b]ecause the district court did 

not . . . identify the specific claims it held to be infringed 

under the doctrine of equivalents.”). 

More importantly, it is unclear whether the judgment 

requires the affirmance of both “cooperating service provider” and “non-blocking bandwidth,” where the interpretation of cooperating service provider includes the term 

“non-blocking bandwidth.”4 It is also unclear whether affirmance requires the approval of all aspects of the construction of “cooperating service provider.”

Stated differently, the parties dispute two aspects of 

the construction of the term “cooperating service provider” 

– (1) the construction of the incorporated term “non-blocking bandwidth,” and (2) the meaning of the term 

4 It would appear that approval of both terms would 

be needed since some claims use one term and some use the 

other. 

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“cooperating service provider” apart from the incorporated 

term. It is unclear whether, under the stipulation, Amazon 

prevails on infringement if either construction is correct or 

only if both are correct. 

At oral argument, it became apparent that the parties 

have significant disagreements as to the effect of the stipulation—disagreements that render it impossible for this 

court to review the judgment. 

AlterWAN asserts that the judgment of non-infringement rests solely on the district court’s construction of 

“non-blocking bandwidth,” a term which appears both independently and in the district court’s construction of “cooperating service provider.” AlterWAN argues that the 

district court’s construction requires bandwidth to be available to the customer at all times, even when the Internet is 

inoperable. Because no system can provide such a service, 

Amazon cannot infringe. At oral argument, AlterWAN 

took the position that the “sole reason” Amazon does not 

infringe under the claim constructions at issue is because

of the exclusion of the caveat they had sought at claim construction (“while the network is operational”). This is so 

because “if the internet goes down, it doesn’t provide service.” Oral Arg. at 0:30–1:14; see also Oral Arg. at 31:02–

19 (“Q: Let’s adopt your construction of non-blocking bandwidth, which doesn’t have that limitation, it only requires 

that . . . available when the internet is operable, okay? Is 

your view that they infringe under that claim construction? 

A: Yes, Your Honor.”). In AlterWAN’s view, the core issue 

on appeal is whether the district court erred by failing to 

add the qualifier “while the network is operational” to its 

construction of “non-blocking bandwidth.” 

Amazon, on the other hand, contends that the judgment of non-infringement (as to the claims incorporating 

the term “cooperating service provider”) should be affirmed 

if the construction of “cooperating service provider” is affirmed, quite apart from the issue of internet availability. 

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10 ALTERWAN, INC. v. AMAZON.COM, INC. 

As explained at oral argument, Amazon contends that it

allows customers to pay for different port speeds, meaning 

that the customer gets the purchased speed, not “all the 

bandwidth [they] could want.” Oral Arg. at 20:45–21:01. 

Since Amazon does not ensure that bandwidth is always 

sufficient to meet the customer’s needs, Amazon does not 

infringe. Although Amazon defends the district court’s construction of “non-blocking bandwidth” and its rejection of 

the qualifier “while the network is operational,” Amazon

contends that any error in this respect would not affect the 

judgment of non-infringement. See Oral Arg. at 15:02–22

(“Q: What is the basis [of infringement]? . . . A: Amazon’s 

product does not provide sufficient bandwidth to meet everybody’s need, whether the internet is up or down.”). 

To add to the confusion, AlterWAN contends that it can 

establish infringement under the district court’s construction of the term “cooperating service provider” once the Internet availability language is included because the plain 

and ordinary meaning of the term simply means a service 

provider that cooperates. 

We have previously warned of the dangers of stipulating to non-infringement based on a district court’s claim 

constructions without indicating the exact basis for non-infringement. In Jang, the parties had entered into a stipulation that suffered two ambiguities. First, the stipulation 

did not identify which of the district court’s claim constructions actually affected the issue of infringement. 532 

F.3d at 1336. Second, the stipulation did not provide any 

factual context as to “how the disputed claim construction 

rulings relate to the accused products.” Id. at 1337. We

vacated and remanded, holding that “[a] judgment is reviewable only if it is possible for the appellate court to ascertain the basis for the judgment challenged on appeal.” 

Id. at 1334–35.

Here, as in Jang, we cannot “ascertain the basis for the 

judgment” of non-infringement, id., because the parties did 

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not adequately explain how the claim construction rulings 

related to the accused systems. See also Superior Indus. v. 

Masaba, Inc., 553 F. App’x 986, 989 (Fed. Cir. 2014). We 

must vacate the judgment and remand to the district court 

for further proceedings to clarify the parties’ non-infringement positions, and to determine whether a stipulation of 

non-infringement is even possible in the circumstances of 

this case. 

II

Since further proceedings are required, we think it useful and appropriate to clarify the meaning of the claim term

non-blocking bandwidth in one respect. The district court’s

construction, which effectively requires a system to provide 

bandwidth even when the Internet is inoperable, is not a 

reasonable construction in light of the specification since it 

requires the impossible. Amazon cites Chef America for the 

proposition that “[c]ourts may not redraft claims, whether 

to make them operable or to sustain their validity.” Appellee’s Br. 20 (quoting Chef Am., Inc. v. Lamb-Weston, Inc., 

358 F.3d 1371, 1374 (Fed. Cir. 2004)). In Chef America, the 

patentee claimed a process for making baked goods. 358 

F.3d at 1372. The claim limitation at issue was “heating 

the resulting batter-coated dough to a temperature in the 

range of about 400° F. to 850° F.” Id. at 1371. The patentee 

contended that the temperature range of “400° F. to 850° 

F.” referred to the temperature of the oven, rather than the 

temperature of the dough. Id. at 1371–72. This court disagreed, holding that the claims were unambiguous and declining to replace the term “to” with the term “at,” even 

though the claim, as written, led to an absurd result—the 

baked good being burned. 

Chef America does not require us to depart from common sense in claim construction. Here, the claim language 

itself does not unambiguously require bandwidth to be 

available even when the Internet is inoperable. See Ecolab, 

Inc. v. FMC Corp., 569 F.3d 1335, 1345 (Fed. Cir.), 

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12 ALTERWAN, INC. v. AMAZON.COM, INC. 

amended on reh’g in part, 366 F. App’x 154 (Fed. Cir. 2009). 

It is true that the specification defines “non-blocking bandwidth” as “bandwidth that will always be available and will 

always be sufficient.” ’478 patent, col. 4 l. 67–col. 5 l. 1. 

But this statement must be read in context.

The specification states that “[t]he wide area network 

technology described herein (referred to as AlterWANTM 

network) is an alternative wide area network that uses the 

internet as a backbone.” ’478 patent, col. 3, ll. 61–63. The 

specification describes several “quality of service” problems 

that arise from using the internet as a backbone, including 

latency problems, that is, “delay on critical packets getting 

from source to destination.” ’478 patent, col. 3 ll. 20–53. 

The patent’s solution to the latency problem is to provide 

“preplanned high bandwidth, low hop-count routing paths 

between pairs of customer sites that are geographically 

separated.” ’478 patent, col. 4 ll. 17–19. The specification 

describes the preplanned routing paths as a “key characteristic that all species within the genus of the invention

will share” and details its operation. ’478 patent, col. 4 ll. 

15–64. The specification then states: “In other words, the 

quality of service problem that has plagued prior attempts 

is solved by providing non-blocking bandwidth (bandwidth 

that will always be available and will always be sufficient) 

and predefining routes for the ‘private tunnel’ paths between points on the internet . . . .” ’478 patent, col. 4 l. 65–

col. 5 l. 3. 

The specification does not remotely suggest operability 

when the Internet is unavailable. Claims that are directed 

to transmission over the Internet cannot require such 

transmission when the Internet is not working. In light of 

the specification, “non-blocking bandwidth” is properly understood to address the problem of latency, rather than 

providing for bandwidth even in the scenario where the Internet is inoperable. We do not opine on what the meaning 

of non-blocking bandwidth is, other than it does not require 

bandwidth when the Internet is down. The district court 

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on remand will make an appropriate revision to this claim 

construction.

AlterWAN also challenges the district court’s construction of the “routing” claim term, a term that is not included 

in the stipulation. Although it can be appropriate to decide, 

on appeal, claim constructions not implicated by the district court’s judgment in limited circumstances, see 

Thorner v. Sony Comput. Ent. Am. LLC, 669 F.3d 1362, 

1369 (Fed. Cir. 2012), we decline to do so here. 

CONCLUSION

For the foregoing reasons, we vacate the stipulated 

judgment of non-infringement and remand the case for further proceedings consistent with this opinion.

VACATED AND REMANDED

COSTS

No costs. 

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