Source: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-ca13-15-01992/USCOURTS-ca13-15-01992-0/pdf.json

Nature of Suit Code: 830
Nature of Suit: Patent
Cause of Action: 

---

United States Court of Appeals 

for the Federal Circuit ______________________ 

COMCAST IP HOLDINGS I LLC,

Plaintiff-Appellee

v.

SPRINT COMMUNICATIONS COMPANY, L.P., 

SPRINT SPECTRUM LP, NEXTEL OPERATIONS, 

INC.,

Defendants-Appellants

______________________ 

2015-1992

______________________ 

Appeal from the United States District Court for the 

District of Delaware in No. 1:12-cv-00205-RGA, Judge 

Richard G. Andrews.

______________________ 

Decided: March 7, 2017 

______________________ 

MATTHEW B. LEHR, Davis Polk & Wardwell LLP, 

Menlo Park, CA, argued for plaintiff-appellee. Also represented by ANTHONY I. FENWICK, GARETH DEWALT, DAVID 

LISSON. 

BRIAN CHARLES RIOPELLE, McGuire Woods LLP, 

Richmond, VA, argued for defendants-appellants. Also 

represented by DAVID EVAN FINKELSON, BRIAN DAVID 

SCHMALZBACH; RACHELLE HARLEY THOMPSON, Raleigh, 

NC. 

Case: 15-1992 Document: 44-2 Page: 1 Filed: 03/07/2017
2 COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 

 Before O’MALLEY, REYNA, and CHEN, Circuit Judges.

CHEN, Circuit Judge. 

Comcast IP Holdings I LLC (Comcast) sued Sprint 

Communications Company LP, Sprint Spectrum L.P., and 

Nextel Operations, Inc. (collectively, Sprint) for infringement of, among other patents, U.S. Patent Nos. 8,170,008, 

7,012,916, and 8,204,046 (collectively, Low Patents), 

which are generally directed to the use of computer network technology to facilitate a telephone call (phone call 

or call). After a jury trial, the jury found that Sprint’s 

handling of certain phone calls infringed claims 1, 13, and 

27 of the ’008 Patent, claim 45 of the ’916 Patent, and 

claims 90 and 113 of the ’046 Patent, and awarded Comcast a $7.5 million damages award. The district court 

then denied Sprint’s motion for judgment as a matter of 

law (JMOL), or in the alternative, for a new trial, and 

added prejudgment interest to the damages award. 

Sprint has appealed various rulings from the district 

court. Because we see no error in these rulings, we affirm

the district court’s entry of judgment against Sprint. 

BACKGROUND

A. The Claimed Inventions

The Low Patents are in the same patent family1 and 

are generally directed to methods of using Domain Name 

System (DNS) technology, such as the Internet, to initiate 

and route a phone call through a switched telecommunication system. 

One example of a switched telecommunication system 

is a public switched telephone network (PSTN), which 

 

1 The Low Patents share the same specification so 

we cite to the ʼ008 Patent for convenience.

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COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 3

provides for a bearer channel (i.e., “interconnection”) 

between two telephones “according to a called-party 

telephone number input at the calling-party telephone.” 

ʼ008 Patent col. 2 ll. 13–17; see also id. col. 1 ll. 31–41

(defining a switched telecommunication system as “a 

system comprising a bearer network with switches for 

setting up a bearer channel through the network”). A 

PSTN is shown in Figure 1.

Id. fig. 1. In Figure 1

customer premises equipment, CPE[] 10 (such as 

standard analogue telephones . . . . ) are connected 

through an access network 11 to switching points, 

SPs 12. The SPs 12 form nodes in an interexchange network 13 made up of interconnecting 

trunks 14 and SPs that are controlled by control 

entities 15 in the SPs. The control effected by the 

control entities 15 is determined by signalling inputs received from the CPEs and other SPs, and 

involves call setup, maintenance and clearance to 

provide the desired bearer channel between calling CPE and called CPE. Conceptually, the PSTN

may be thought of as a bearer network and a control (signalling) network, the function of the latter 

being to effect call control through the bearer 

network, namely the control of setup, maintenance and take down of bearer channels through 

the bearer network; in practice, the bearer and 

signalling networks may use the same physical 

circuits and even the same logical channels.

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4 COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 

Id. col. 2 ll. 19–35.

The Low Patents also explain that a “communication 

system” generally has “a broader meaning than switched 

telecommunication system” and “include[s] datagrambased communication systems where each data packet is 

independently routed through a bearer network without 

following a predetermined bearer channel.” Id. col. 1 ll. 

50–55. One example of a datagram-based communication 

system is the Internet. See, e.g., Appellant Br. at 40.

Asserted claim 1 is representative of the claimed invention in the ’008 Patent:

1. A method, comprising:

receiving, over a switched telecommunication system, a request;

determining, responsive to the request, a 

call destination using domain name system signaling; and 

initiating a call through the switched telecommunication system between a calling 

party and the call destination that was determined as a result of said domain name 

system signaling.

Id. col. 32 ll. 46–55. 

Asserted claims 45 and claim 90 below are representative of the claimed inventions for the ’916 Patent 

and the ’046 Patent. 

45. A method of accessing communications data 

for contacting a target entity, said method comprising:

forming, from a number string identifying 

the target entity, a domain name by a process including parsing at least a substanCase: 15-1992 Document: 44-2 Page: 4 Filed: 03/07/2017
COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 5

tial portion of the number string into at 

least a part of said domain name;

supplying the domain name formed to a 

DNS-type database system and receiving 

back a resource record including an URI

[uniform resource identifier] for locating 

communications data associated with the 

domain name; and

using the URI received back to access said 

communications data. 

’916 Patent col. 36 ll. 56–67. 

90. A method, comprising:

forming, by at least one computing device, 

from a number string identifying a target 

entity, a domain name by a process including parsing at least a portion of the number string into at least a part of said 

domain name; and

supplying, by the at least one computing 

device, the domain name to a database 

and receiving back from that database a 

resource record including a uniform resource identifier (URI) of the target entity. 

’046 Patent col. 45 l. 65–col. 46 l. 6.

B. The Accused Methods

The six accused methods are ways in which Sprint 

connects a calling party with a called party (call flows), 

and there is no dispute as to how these accused call flows 

operate. 

Comcast accused three call flows of infringing the ’008 

Patent. See Appellant Br. at 15. These calls generally 

begin on Sprint’s wireless cellular network that uses a 

standard known as Code Division Multiple Access, or 

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6 COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 

“CDMA” (CDMA Network). The calls then travel through 

an Internet Protocol Multimedia Subsystem network 

(IMS Network). “The IMS Network includes an IMS core, 

which is a collection of servers on a packet-based network 

used to route and process signaling traffic” for the calls. 

Id. at 16 n.7. 

When a call enters the IMS core, it does so through a 

media gateway controller, or “MGC.” Id. at 18. Once the 

call enters the IMS core, “a network element named a call 

session control function (‘CSCF’) uses [DNS] signaling to 

determine an IP address used to route the call to a session 

border controller (‘SBC’).” Id. at 18–19. “The SBC is 

another server on the IMS core.” Id. at 19. From there, 

the call is routed outside of the IMS core, and then back 

into the IMS core to another MGC. Id. “The MGC is not 

specific to any particular telephone number or service 

provider.” Id. From the MGC, the call is ultimately 

routed to the called party. Id.

Comcast accused another three call flows of infringing 

the ’916 Patent and the ’046 Patent. Id. at 15. Common 

to these call flows are their use of a process referred to as 

“ENUM” to route calls through the IMS core. “That 

method starts with a [called] telephone number, removes 

any special characters, reverses the numbers, places a dot 

between each number, and adds ‘e.164.arpa’ to the end” of 

the number.” Id. at 27.

C. Procedural Background

Comcast asserted claims 1, 13, and 27 of the ’008 Patent, claim 45 of the ’916 Patent, and claims 90 and 113 of 

the ’046 Patent against Sprint in the District of DelaCase: 15-1992 Document: 44-2 Page: 6 Filed: 03/07/2017
COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 7

ware.2 The parties disputed the claim constructions for, 

among other terms, the term “switched telecommunication system” in the ’008 Patent and the term “parsing” in 

the ’916 Patent and the ’046 Patent. For the term 

“switched telecommunication system,” the parties disagreed as to whether such a system could include elements 

of a datagram-based system. J.A. at 3. The district court 

concluded that “[a] system with elements of both switches 

and a ‘datagram-based system’ is not necessarily outside 

the scope of a ‘switched telecommunication system.’” Id.

at 4. “A ‘communication system’ is still a broader concept 

than a ‘switched telecommunication system’ even where 

the ‘switched telecommunication system’ has elements of 

a ‘datagram-based system,’ because a ‘switched telecommunication system’ at a minimum must have switches 

and function on a bearer network.” Id. 

As for the term “parsing,” the district court determined that “parsing” was an automated process because it 

necessarily required a computer. See id. at 39. And the 

parties agreed that the term must include “analyzing a 

string according to a set of rules of a grammar.” Id. at 40. 

But they differed on whether the relevant prosecution 

histories of the ’916 Patent and the ’046 Patent demonstrated disavowals of claim scope so as to limit the term 

“parsing.” See id. The district court saw no clear disavowals of claim scope in the prosecution histories. Id. 

After a six-day jury trial, the jury found that all of the 

asserted claims of the Low Patents were infringed by 

their respective accused call flows and awarded Comcast 

a lump sum payment of $7.5 million in damages. Id. at 

49. Sprint then moved for JMOL, as well as for a new 

 

2 Other patents from the Low family were also asserted against Sprint, but they are irrelevant to this 

appeal as they were not part of the trial. 

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8 COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 

trial, on several bases. See id. at 48–69. For example, 

Sprint argued that there was insufficient evidence to 

support the jury’s verdict as to the ’008 Patent because 

Comcast’s evidence, in the form of expert testimony from 

Dr. Eric Burger, only demonstrated that “any destination 

along the way in route of a call” could be a “call destination,” and wrongly suggested that there could be “multiple 

destinations” along a call flow. Id. at 53–54. Sprint 

insisted this understanding of “call destination” was 

flawed because the claim term can only refer to “the 

absolute final point in the call flow, or the receiving 

phone,” otherwise the term would be superfluous. Id. at 

52, 54. 

The district court disagreed with Sprint. The district 

court noted that the jury was instructed to apply the 

common meaning of “call destination” in rendering its 

verdict as neither party asked for a construction of the 

claim term. Id. at 53 & n.1. The district court explained 

that the jury could have reasonably concluded—based on 

Comcast’s expert—that “there are intermediate ‘call 

destinations’” along the accused call flows. Id. at 54. It 

further explained that the jury could have “reasonably 

look[ed] at the claims and conclude[d] that the word ‘a’ 

before the first use of the term call destination implied 

that there could be more than one destination . . . .” Id. 

Sprint likewise contended that there was insufficient 

evidence to prove that Sprint’s accused call flows infringed the asserted claims of the ’916 Patent and the ’046 

Patent because Comcast did not demonstrate that the 

“parsing” limitation was met. Id. at 57–58. The court 

disagreed again, citing testimony from Dr. Burger. See id.

at 59–60.

Moreover, Sprint took exception to the district court’s 

decision to tack on prejudgment interest to the $7.5 

million damages award. Id. at 65. Sprint maintained 

that prejudgment interest should only be calculated from 

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COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 9

the time of first infringement of each patent until judgment, rather than from the time of the relevant hypothetical negotiation—here 2006—until judgment. Id. More 

specifically, Sprint insisted that prejudgment interest 

should not be applied to the damages relevant to the 

infringement of the ’008 Patent and the ’046 Patent 

because those patents had not yet been issued in 2006 

(the time when the ’916 Patent was issued)—they were 

only issued in 2012. Id. at 65–66. 

The district court rejected Sprint’s argument, observing that “both sides’ experts opined that the reasonable 

royalty should be a lump sum resulting from a single 

hypothetical negotiation that took place in 2006” if Sprint 

were found to infringe all three patents. Id. at 66 (citing 

trial transcript). Based on that agreement, the district 

court concluded that “[a] hypothetical negotiation in 2006 

would include each of the asserted patents, even if they 

issued later, and the resulting negotiation would include 

the fact that two of the patents issued later.” Id. (citing 

ResQNet.com, Inc. v. Lansa, Inc., 594 F.3d 860, 872 (Fed. 

Cir. 2010)). Moreover, because of the agreed-upon methodology of using a lump sum award for infringement of all 

of the patents, the district court noted the practical problem of assessing prejudgment interest on a per patent 

basis where the lump sum verdict did not apportion the 

damages for each patent. See id.

Sprint has filed a timely appeal. We have jurisdiction 

pursuant to 28 U.S.C. § 1295(a)(1) (2012). 

STANDARDS OF REVIEW

The law of the regional circuit controls our standard 

of review for the denial of a motion for JMOL.3 E.g., 

 

3 In moving for a new trial before the district court, 

Sprint merely rehashed its arguments for why it deserved

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10 COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 

MobileMedia Ideas LLC v. Apple Inc., 780 F.3d 1159, 1164 

(Fed. Cir. 2015). In the Third Circuit, review of such a 

denial is without deference. See, e.g., Rinehimer v. Cemcolift, Inc., 292 F.3d 375, 383 (3d Cir. 2002). We “review 

the record in the light most favorable to the prevailing 

party ‘unless the record is critically deficient of that 

minimum quantum of evidence from which a jury might 

reasonably afford relief.’” Potence v. Hazleton Area Sch. 

Dist., 357 F.3d 366, 370 (3d Cir. 2004) (quoting Rotondo v. 

Keene Corp., 956 F.2d 436, 438 (3d Cir. 1992)).

The proper construction of a patent’s claims is an issue of Federal Circuit law, and we apply the framework 

set forth in Teva Pharmaceuticals USA, Inc. v. Sandoz, 

Inc., __ U.S. __, __, 135 S. Ct. 831, 840–42 (2015). E.g., 

Power Integrations, Inc. v. Fairchild Semiconductor Int’l, 

Inc., 843 F.3d 1315, 1326 (Fed. Cir. 2016). Under that 

framework, intrinsic evidence and the ultimate construction of claim terms are reviewed de novo, and underlying 

factual determinations concerning extrinsic evidence are 

reviewed for clear error. See id. “Where an infringement 

verdict relies on incorrect construction of the disputed 

claim terms, this court may grant JMOL or order a new 

trial to correct the error, depending on the degree of 

difference between the incorrect construction and the 

correct construction.” Finisar Corp. v. DirecTV Grp., Inc., 

523 F.3d 1323, 1333 (Fed. Cir. 2008). “If no reasonable 

jury could have found infringement under the proper 

claim construction, this court may reverse a district 

court’s denial of JMOL without remand.” Id. (citing

 

judgment as a matter of law. Because we assess those 

arguments in the context of its JMOL motion, we need not 

address them again in the context of its motion for a new 

trial.

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COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 11

Harris Corp. v. Ericsson Inc., 417 F.3d 1241, 1255–57 

(Fed. Cir. 2005)).

Determination of infringement is a question of fact, 

which, in the context of a jury trial, we review for substantial evidence. Union Carbide Chems. & Plastics Tech. 

Corp. v. Shell Oil Co., 308 F.3d 1167, 1177 (Fed. Cir. 

2002) (citing B. Braun Med., Inc. v. Abbott Labs., 124 F.3d 

1419, 1423 (Fed. Cir. 1997)). 

DISCUSSION 

A. Construction of “Switched Telecommunication System” in the Asserted Claims of the ʼ008 Patent

Sprint contends that the proper construction of 

“switched telecommunication system” must be one that 

excludes any element of a datagram-based system, so as 

to render it consistent with the “fundamental requirement” of the ʼ008 Patent, which is that a phone call must 

“travel[] over a predetermined bearer channel all the way

from the caller to the call destination.” Appellant Br. at

32–33 (emphasis added). Sprint’s insistence is not only 

unpersuasive, but also irrelevant because the infringement verdict would remain unaffected even under its 

narrower construction.

We may affirm the jury’s findings on infringement if 

substantial evidence appears in the record supporting the 

jury’s verdict, and if correction of errors in claim construction would not have changed the verdict, given the evidence presented. See Teleflex, Inc. v. Ficosa N. Am. Corp., 

299 F.3d 1313, 1328 (Fed. Cir. 2002) (citing Weinar v. 

Rollform Inc., 744 F.2d 797, 808 (Fed. Cir. 1984)). Prejudicial error here requires “sufficient evidence . . . to support a finding of non-infringement under a correct 

instruction.” CytoLogix Corp. v. Ventana Med. Sys., Inc., 

424 F.3d 1168, 1174 (Fed. Cir. 2005) (alteration omitted) 

(quoting Ecolab, Inc. v. Paraclipse, Inc., 285 F.3d 1362, 

1374 (Fed. Cir. 2002)). 

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12 COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 

Here, even if “switched telecommunication system” 

were construed so as to exclude any element of a datagram-based system, Sprint has not demonstrated how the 

relevant accused call flows do not infringe the ’008 Patent. 

In other words, Sprint has not shown prejudice. Sprint 

does not dispute that its CDMA Network is where a call is 

initiated or set up and that the CDMA Network is a 

switched telecommunication system having no datagrambased elements. See Appellant Br. at 39–40. 

Moreover, adoption of Sprint’s construction would not 

permit it to argue that the ’008 Patent requires a call to 

travel “exclusively” over a switched telecommunication 

system. See id. at 16 (“None of the accused call flows 

travels exclusively over a switched network or predetermined bearer channels. Instead, each starts on Sprint’s 

CDMA network, travels through Sprint’s . . . IMS . . . 

network (a packet-based network), and eventually returns 

to the CDMA network or the CDMA air interface for 

routing to the called handset.” (footnotes omitted)). The 

claim language does not demand this. Claims 1 and 13 

only require “initiating a call through the switched telecommunication system,” ’008 Patent col. 32 ll. 46–55; id.

col. 33 ll. 31–40 (emphasis added), and claim 27 only 

requires “setting up a call through the switched telecommunication system,” id. col. 34 ll. 39–47 (emphasis added). These claims do not state that after a call is either 

initiated or set up through a switched telecommunication 

system, the call must also travel exclusively on that 

system to a particular destination. 

The specification also does not support the construction that Sprint desires. It reveals that the ’008 Patent is 

not directed to methods of transmitting an entire call

from a calling party’s phone to the called party’s phone; 

rather, it is directed to methods, consistent with the claim 

language, for initiating or setting up a call intended for

transmission to a called party. See id. col. 1 ll. 27–30 

(“The present invention relates to a method of accessing 

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COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 13

service resource items that are intended to be used in 

setting up bearer channels through a switched telecommunications system.” (emphasis added)). And figure 15 in 

the specification expressly contemplates a call that does 

not travel exclusively on a switched telecommunication 

system. See id. fig. 15; see also id. col. 27 ll. 10–14.

To support its theory that the ’008 Patent requires a 

call to travel exclusively on a switched telecommunication 

system, Sprint relies on the specification’s explanation 

that datagram-based elements are “logically distinct” 

from the switched telecommunication system. See Appellant Br. at 35–36 (citing ’008 Patent col. 11 l. 65–col. 12 l. 

2). The specification explains that “[t]he intention of 

requiring the computer network to be logically distinct 

from the [switched] telecommunication[] system is to 

exclude computer networks that are dedicated to the 

management or monitoring of the bearer network and 

effectively form part of the [switched] telecommunication[] system itself.” ’008 Patent col. 11 ll. 50–55. This 

explanation, however, does not suggest that a call either 

initiated or set up on a switched telecommunication 

system cannot traverse any datagram-based elements 

once it leaves the system. 

Accordingly, we sustain the jury’s verdict of infringement of claims 1, 13, and 27 of the ’008 Patent because 

there is substantial evidence that the relevant accused 

call flows were either initiated or set up on a switched 

telecommunication system. 

B. Sufficiency of Evidence for “Call Destination” Limitation in Asserted Claims 1 and 13 and “Identifier 

of a Second Party” Limitation in Asserted Claim 27 

of the ’008 Patent

Sprint next complains that there was insufficient evidence for the jury to find that the “call destination” limitation of claims 1 and 13 of the ’008 Patent—which the 

jury was instructed to apply its plain and ordinary meanCase: 15-1992 Document: 44-2 Page: 13 Filed: 03/07/2017
14 COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 

ing because neither party asked for a construction—was 

met by the relevant accused call flows. See Appellant Br. 

at 41–50. According to Sprint, Comcast only presented 

evidence that a call destination was any point on a call 

flow, but a call destination must be the “final point on the 

path of a call.” Id. at 43. We disagree with Sprint as 

there is substantial evidence to support the jury’s finding 

that the relevant accused call flows met the “call destination” limitation. 

Sprint “is essentially [proffering] a claim construction 

argument regarding the meaning of the term [‘call destination’] . . . in the guise of a challenge to the sufficiency of 

the evidence of infringement.” ePlus, Inc. v. Lawson 

Software, Inc., 700 F.3d 509, 520 (Fed. Cir. 2012). Sprint 

invites the court to construe the meaning of a call destination as the final point on the path of a call. But if Sprint 

“desired such a narrow definition, it could (and should) 

have sought a construction to that effect.” ePlus, 700 F.3d 

at 520; see also Hewlett-Packard Co. v. Mustek Sys., Inc., 

340 F.3d 1314, 1321 (Fed. Cir. 2003) (“[W]here the parties 

and the district court elect to provide the jury only with 

the claim language itself, and do not provide an interpretation of the language in the light of the specification and 

the prosecution history, it is too late at the JMOL stage to 

argue for or adopt a new and more detailed interpretation 

of the claim language and test the jury verdict by that 

new and more detailed interpretation. The verdict must 

be tested by the charge actually given and by giving the 

ordinary meaning of the language of the jury instruction.”). “In the absence of such a construction, however, 

the jury was free to rely on the plain and ordinary meaning of the term . . . .” ePlus, 700 F.3d at 520. And Sprint 

“has not met its burden of showing that it has the only 

reasonable view of the claim [limitation] . . . .” Avid Tech., 

Inc. v. Harmonic, Inc., 812 F.3d 1040, 1048 (Fed. Cir. 

2016). As the district court correctly explained, the jury 

could have “reasonably look[ed] at the claims and conCase: 15-1992 Document: 44-2 Page: 14 Filed: 03/07/2017
COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 15

clude[d] that the word ‘a’ before the first use of the term 

call destination implied that there could be more than one 

destination” rather than exclusively referring to the call’s 

final destination. J.A. at 54. 

In light of this, the jury reasonably relied on 

Dr. Burger’s testimony that the relevant accused call 

flows were routed to at least one call destination. 

Dr. Burger testified that the various servers inside the 

IMS core, such as the MGC and the SBC, were call destinations because the CSCF routed calls to those servers. 

Id. at 4439, 4541–42. This testimony from Dr. Burger did 

not, as Sprint suggests, invite the jury to find that any 

point along the accused call flows was a “call destination.” 

These were specific servers in the IMS core. 

Sprint’s complaints regarding the “identifier of a second party” limitation in claim 27 of the ’008 Patent4 are 

similar to those that it lodges against the “call destination” limitation in claims 1 and 13. See Appellant Br. at 

45. But for the reasons we reject that a “call destination” 

must be the final point on a path of a call, we also reject 

 

4 Claim 27 reads: 

A method, comprising: 

receiving a request from a first party; 

determining by a computer, responsive to 

the request, an identifier of a second party 

using domain name system signaling; 

setting up a call through the switched telecommunication system between the first 

party and the second party that was determined as a result of said domain name 

system signaling.

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16 COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 

that an “identifier of a second party” must be a “unique 

identifier of a second party.” First, if Sprint wanted this 

restrictive construction of the term, it should have sought 

one. But it never did and now is too late. See ePlus, 700 

F.3d at 520; see also Hewlett-Packard, 340 F.3d at 1321. 

Second, the jury reasonably relied on Dr. Burger’s testimony that the term means “how you get to [a] second 

party” and that DNS signaling in the IMS core determined an identifier of a second party, which could include 

the SBC inside the IMS core. See J.A. at 4539–41.

Because substantial evidence demonstrates that the 

“call destination” limitation in claims 1 and 13 and the 

“identifier of a second party” limitation in claim 27 were

met, we sustain the jury’s verdict that Sprint infringed 

these claims of the ’008 Patent. 

C. Construction of “Parsing” in Asserted Claims of the 

’916 Patent and the ’046 Patent

Sprint also attacks the district court’s claim construction of the term “parsing” in the asserted claims of the 

’916 Patent and the ’046 Patent. See Appellant Br. at 50–

57. Specifically, Sprint faults the district court for refusing to find disclaimers in the prosecution histories and 

imposing limitations on the scope of “parsing.” Id. at 50. 

But Sprint fails to identify any prejudice associated with 

the district court’s claim construction as it never explains 

in its opening brief how its purportedly correct and narrower claim construction would have affected the infringement verdict. See CytoLogix, 424 F.3d at 1174. 

Sprint notes that page fifty of its opening brief explained how it was prejudiced. Reply Br. at 21 n.7 (citing 

Appellant Br. at 50). We disagree. For example, Sprint 

does not explain how the relevant accused call flows do 

not practice the asserted claims under its narrower claim 

construction. Sprint has thus waived any arguments 

concerning how it was prejudiced by a broader construction of “parsing.” See SmithKline Beecham Corp. v. 

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Apotex Corp., 439 F.3d 1312, 1319 (Fed. Cir. 2006) (“Our 

law is well established that arguments not raised in the 

opening brief are waived.” (citation omitted)); see also

Fresenius USA, Inc. v. Baxter Int’l, Inc., 582 F.3d 1288, 

1304 (Fed. Cir. 2009) (“[The appellant] failed to clearly 

explain what result would occur if this court adopted [the 

appellant’s] proposed claim constructions. [The appellant] gave this court little guidance and cited no record 

support regarding why a modified claim construction 

would affect the infringement judgment, the validity 

judgment, or both. For that reason alone, we may decline 

to consider [the appellant’s] claim construction arguments.”). Consequently, we sustain the jury’s verdict that 

Sprint infringed the asserted claims of the ’916 Patent 

and the ’046 Patent. 

Even without the waiver, we agree with the district 

court’s construction of “parsing,” and its rejection of 

Sprint’s prosecution disclaimer arguments concerning this

term. “[F]or prosecution disclaimer to attach, our precedent requires that the alleged disavowing actions or 

statements made during prosecution be both clear and 

unmistakable.” Omega Eng’g, Inc. v. Raytek Corp., 334 

F.3d 1314, 1325–26 (Fed. Cir. 2003). Where the prosecution history is ambiguous or susceptible to “multiple 

reasonable interpretations” as to any alleged disavowal, 

we decline to find prosecution disclaimer. Cordis Corp. v. 

Medtronic AVE, Inc., 339 F.3d 1352, 1359 (Fed. Cir. 

2003); Omega Eng’g, 334 F.3d at 1325. 

The district court construed “parsing” as “[a]n automated process of analyzing a string according to a set of 

rules of a grammar.” J.A. at 40. But Sprint seeks a 

narrower construction, contending that during the reexaminations of the ’916 Patent and the ’046 Patent, “Comcast distinguished ‘parsing’ from ‘predetermined 

association’ and other processes such as ‘mapping,’ 

‘lookup,’ and ‘translating’” to avoid having the asserted 

claims rejected. Appellant Br. at 52. While Comcast did 

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18 COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 

make statements indicating that such processes are not 

the same as “parsing,” when read in context, we do not 

read those statements as necessarily excluding any form 

of these processes from “parsing.” See, e.g., Lucent Techs., 

Inc. v. Gateway, Inc., 525 F.3d 1200, 1211–12 (Fed. Cir. 

2008) (“[T]he arguments made by the applicants during 

prosecution clearly distinguish the claimed method from 

that of [the prior art], but do not constrain the definition 

of [the disputed claim term] as urged by the defendants.”). 

Accordingly, we see no reason to disturb the district 

court’s claim construction or the jury verdict. 

D. Prejudgment Interest 

After an infringement finding, “the court shall 

award . . . damages adequate to compensate for the infringement . . . together with interest and costs . . . .” 35 

U.S.C. § 284 (2012). “[P]rejudgment interest should be 

awarded under § 284 absent some justification for withholding such an award.” Gen. Motors Corp. v. Devex Corp., 

461 U.S. 648, 657 (1983); see also Energy Transp. Grp., 

Inc. v. William Demant Holding A/S, 697 F.3d 1342, 1358 

(Fed. Cir. 2012). We review the district court’s award of 

prejudgment interest for an abuse of discretion. Gen. 

Motors Corp., 461 U.S. at 657; see also Energy Transp. 

Grp., 697 F.3d at 1358. 

Sprint contends that the district court erroneously 

charged Comcast prejudgment interest from 2006 forward 

even though neither the ’008 Patent nor the ’046 Patent 

had issued at that point. Appellant Br. at 57–64. Specifically, because neither of those two patents had issued yet, 

there could be no infringement as a matter of law for 

them in 2006. In Sprint’s view, accordingly, the district 

court’s award of prejudgment interest was an abuse of 

discretion because the court should have calculated prejudgment interest from the time of first infringement of 

each of the three infringed patents until judgment. In 

other words, Sprint contends the district court should 

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have apportioned the prejudgment interest calculations 

based on the royalty periods covered by the individual 

patents. See id. While in other contexts Sprint’s contentions might be well taken, they are not here. 

The parties’ experts agreed that any damage award 

should take the form of a lump sum royalty payment. 

And, the jury was told that the lump sum royalty payment should run from the date of the earliest relevant 

hypothetical negotiation. Specifically, Comcast’s damages 

expert, Ms. Carla Mulhern, explained to the jury how it 

was to calculate damages as follows:

Q. So when would this hypothetical negotiation 

have taken place had it actually taken place?

A. The hypothetical negotiation is set at the time 

of first infringement. So, in this case, it’s a little 

complicated because we have multiple patents. 

So if the ’916 [P]atent is found to be infringed by 

Sprint, the hypothetical negotiation would have 

occurred at the time of first infringement of the 

’916 [P]atent, which is in late 2006. . . . 

If Sprint is not found to have infringed the ’916 

[P]atent, but only either the ’046 or ’008 patents, 

which issued much later, then the hypothetical 

negotiation would occur in 2012 at the time of 

first infringement of those patents.

J.A. at 4593–94. Sprint’s damages expert Dr. Debra Aron 

agreed with Ms. Mulhern’s statements on the timing of 

the hypothetical negotiation: 

Q. You agree with Ms. Mulhern that if the ’916 

[P]atent or any combination of patents that includes the ’916 [Patent] is found to be infringed, 

then the appropriate date for the hypothetical negotiation for all infringed patents in this case is 

late 2006; correct?

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20 COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 

A. Yes, that’s right.

Q. And the analysis that both you and Ms. Mulhern have done, you understand is directed to a 

lump sum royalty through the time of trial; correct?

A. That’s what it should be, yes. 

Q. And you and she agree on that point; correct?

A. I think we agree on that point. 

Id. at 4974–75. The jury was also told that the hypothetical negotiators would have employed the “book of wisdom,” looking forward in time from the date of the first 

hypothetical negotiation to account for “all information 

that would have been relevant to the parties in coming to 

and arriving at a deal.” Id. at 66; id. at 4594–95. Both 

experts agreed that this information would have included 

the issuance of any later patent relating to the same 

technology. Id. at 4593–95; id. at 5002–03.

As the verdict form reflects, the jury found that claims 

in all three of the Low patents were infringed. Id. at 46–

47. And as it was invited to do, the jury then awarded 

Comcast a lump sum royalty in the amount of $7.5 million. Id. at 47. That award necessarily was predicated on 

a hypothetical negotiation occurring in 2006. Because the 

jury found the ’916 Patent infringed and the hypothetical 

negotiation to have occurred in 2006 there was only one 

damage award for the district court to consider when 

assessing the dollar figure against which prejudgment 

interest should be measured and the date from which it 

was to run. There was, accordingly, neither a basis for 

the district court to apportion prejudgment interest nor a

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COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO. 21

need for the district court to undertake such apportionment.5 

Prejudgment interest runs from the earliest date of 

infringement for any patent issued at the time of the 

hypothetical negotiation; here, the ’916 Patent indisputably had been issued by 2006. We see no abuse of discretion in the district court’s assessment of prejudgment 

interest against Sprint based on the entire royalty award. 

See Bio-Rad Labs., Inc. v. Nicolet Instrument Corp., 807 

F.2d 964, 969 (Fed. Cir. 1986) (“[T]he purpose of prejudgment interest . . . is ‘to ensure that the patent owner is 

placed in as good a position as he would have been had 

the infringer entered into a reasonable royalty agreement.’” (quoting Gen. Motors Corp., 461 U.S. at 655)); cf.

Stickle v. Heublein, Inc., 716 F.2d 1550, 1561 n.8 (Fed. 

Cir. 1983) (“Since the parties treated the mechanical and 

process patents as a unitary licensing property, we need 

not consider damages for infringement of each patent 

individually. Under other circumstances it may well be 

necessary to determine damages separately for each such 

patent since a patent owner has every right to demand 

royalties for each patent he holds.”).

CONCLUSION

For the preceding reasons, we AFFIRM the judgment 

entered by the district court. 

 

5 The district court properly rejected Sprint’s suggestion that it could have determined what portion of the 

jury’s award was attributable to each patent, based on the 

damages methodology employed by Ms. Mulhern. See

J.A. at 66. The jury’s award was less than half of what 

Ms. Mulhern proposed, thereby indicating that the jury 

did not actually follow her proposal. See Appellee Br. at 

60 (citing J.A. at 47, 4635).

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