United States Court of Appeals
for the Federal Circuit
__________________________
AKAMAI TECHNOLOGIES, INC.,
Plaintiff-Appellant,
AND
THE MASSACHUSETTS INSTITUTE OF
TECHNOLOGY,
Plaintiff-Appellant,
v.
LIMELIGHT NETWORKS, INC.,
Defendant-Cross-Appellant,
__________________________
2009-1372, -1380, -1416, -1417
__________________________
Appeals from the United States District Court for the
District of Massachusetts in Case Nos. 06-CV-11109 and
06-CV-11585, Judge Rya W. Zobel.
__________________________
Decided: December 20, 2010
__________________________
DONALD R. DUNNER, Finnegan, Henderson, Farabow,
Garrett & Dunner, LLP, of Washington, DC, argued for
all plaintiffs-appellants. With him on the brief were KARA
F. STOLL and ELIZABETH D. FERRILL. Of counsel on the
brief was ROBERT S. FRANK, JR., Choate, Hall & Stewart
LLP, of Boston, Massachusetts for The Massachusetts
AKAMAI TECH v. LIMELIGHT NETWORKS 2
Institute of Technology. Of counsel were G. MARK
EDGARTON and CARLOS PEREZ-ALBUERNE.
ALEXANDER F. MACKINNON, Kirkland & Ellis LLP, of
Los Angeles, California, argued for defendant-cross appel-
lant. With him on the brief were ROBERT G. KRUPKA, and
NICK G. SAROS. Of counsel on the brief was DION MESSER,
Limelight Networks, Inc., of Tempe, Arizona.
__________________________
Before RADER, Chief Judge, LINN and PROST, Circuit
Judges.
LINN, Circuit Judge.
Akamai Technologies, Inc. and the Massachusetts In-
stitute of Technology (collectively, “Akamai”) appeal the
district court’s judgment as a matter of law (“JMOL”)
overturning a jury verdict of infringement by Limelight
Networks, Inc. (“Limelight”) of claims 19-21 and 34 of
U.S. Patent No. 6,108,703 (the “’703 patent”). See Akamai
Techs., Inc. v. Limelight Networks, Inc., 614 F. Supp. 2d
90 (D. Mass. 2009) (“JMOL Opinion”). Akamai also
appeals the district court’s construction of claim 1 of U.S.
Patent No. 7,103,645 (the “’645 patent”) and claims 8, 18,
and 20 of U.S. Patent No. 6,553,413 (the “’413 patent”).
Limelight cross appeals the district court’s denial of
JMOL relating to the jury’s award of lost profits. See
Akamai Techs., Inc. v. Limelight Networks, Inc., Nos.
2009-1372, -1380, -1416, -1417, 2010 WL 331770 (Fed.
Cir. Jan. 27, 2010) (finding Limelight’s cross appeal in
this case proper as to the lost profits determination).
Because Limelight did not perform all of the steps of
the asserted method claims, and the record contains no
basis on which to attribute to Limelight the actions of its
customers who carried out the other steps, this court
3 AKAMAI TECH v. LIMELIGHT NETWORKS
affirms the finding of noninfringement and does not reach
Limelight’s cross-appeal regarding damages. This court
also affirms the district court’s judgment of noninfringe-
ment of the ’645 and ’413 patents based on its rulings on
claim construction.
BACKGROUND
I. The Technology and the Nature of the Dispute
Information is typically delivered over the Internet
from websites. Websites are collections of documents
written using a standard page description language
known as Hypertext Markup Language (“HTML”). Each
web page is a separate HTML file with an identifying
string of characters known as a Uniform Resource Locator
(“URL”). Typically, a full URL (e.g.,
“http://www.cafc.uscourts.gov/forms”) consists of several
elements: a protocol (e.g., “http://”); a domain name (also
referred to herein as a “hostname”) (e.g.,
“www.cafc.uscourts.gov”); and sometimes a path (e.g.,
“/forms”). A typical web page consists of a base HTML
document that includes text interspersed with various
types of content such as images, video, and
sound─referred to as objects. Most of these objects are
not incorporated into the web page in their entirety, but
instead are simply included as links, in the form of sepa-
rate URLs, which reference the actual object stored
elsewhere on the same computer or another computer in
the same domain (a group of networked computers that
share a common domain name). These objects are re-
ferred to in the patents as “embedded objects.” An em-
bedded object’s URL is typically the same as that of the
web page containing the embedded object, with
the object’s name appended thereto (e.g., “http://www.cafc.
uscourts.gov/forms/pic.jpg”).
AKAMAI TECH v. LIMELIGHT NETWORKS 4
The Internet maintains a Domain Name System
(“DNS”), which uses computers, known as domain name
servers (“DNS servers”), to convert the hostname of a
URL into a numeric Internet Protocol (“IP”) address,
which identifies one or more computers that store content
(“content servers”). This conversion process is referred to
as “resolving.” A user requesting a web page using a web
browser (e.g., Netscape Navigator® or Microsoft Internet
Explorer®) will receive an IP address from a local DNS
server that corresponds to the content server for the
requested web page. In response, the user’s computer
sends a request for the web page directly to that content
server using the IP address. The content server sends the
requested web page─the base HTML document and any
embedded objects’ URLs─to the user’s computer. The
user’s web browser then requests each embedded object
from the content provider’s server using that object’s URL
in the same manner that it requested the web page until
all of the objects have been retrieved and the web page is
fully displayed on the user’s computer.
This process of retrieving web content can be slow and
unreliable. For example, Internet congestion problems
may occur when a single content server receives many
simultaneous requests for the same web page─sometimes
referred to as “flash crowds.” In addition, users may
experience poor content delivery performance when the
user’s computer is located far away from the content
server it is accessing. One known solution to these con-
tent delivery problems is called mirroring, in which an
entire website is replicated on multiple servers in differ-
ent locations. Mirroring, however, has scalability prob-
lems, including costs required by the multiple hosting
facilities, additional overhead associated with keeping
mirror sites synchronized, and a ceiling on the number of
website copies that may be maintained concurrently. ’703
5 AKAMAI TECH v. LIMELIGHT NETWORKS
patent col.1 ll.34-61. 1 In response to these known prob-
lems with delivering content, Akamai sought to provide a
scalable solution that could efficiently deliver large
amounts of web content and handle flash crowds. Akamai
obtained the three patents at issue, which all share the
same specification and disclose a system for allowing a
content provider to outsource the storage and delivery of
discrete portions of its website content.
All three patents include method claims directed to a
content delivery service that delivers the base document
of a web site from a content provider’s computer while
individual embedded objects of the website are stored on
an object-by-object basis on a Content Delivery Network
(“CDN”). CDNs are systems of computers strategically
placed at various geographical locations to maximize the
efficient delivery of information over the Internet to users
accessing the network. The embedded objects are stored
on and served from the CDN’s “hosting” or “ghost” serv-
ers. Instead of maintaining identical copies of the entire
web site content at a single location or at multiple loca-
tions by mirroring as taught by the prior art, only embed-
ded objects are replicated on and served from a CDN. To
allow users accessing a content provider’s web page to
receive embedded objects from a CDN, the URL of the
embedded object must point to a CDN hosting or ghost
server instead of to a computer within the content pro-
vider’s domain. To this end, the specification of the
patents describes modifying the embedded object’s URL,
“to condition the URL to be served by the global hosting
servers.” ’703 patent col.6 ll.41-46. This process of modi-
fying an embedded object’s URL to link to an object on the
CDN is referred to as “tagging.”
1 Because the specifications of all three patents are
substantially identical, we refer throughout to the specifi-
cation as it appears in the ’703 patent.
AKAMAI TECH v. LIMELIGHT NETWORKS 6
Akamai and Limelight operate and compete in the
market for CDN services. Limelight’s accused service
delivers content providers’ embedded objects from its
CDN. According to Limelight’s contracts with its content
provider customers, to use Limelight’s CDN service, the
content provider must perform several steps. First, the
content provider must choose which embedded objects, if
any, it would like to be served from Limelight’s CDN. The
content provider must then tag the URL of each chosen
object as instructed by Limelight. Limelight then repli-
cates the properly tagged objects on some or all of its
servers and directs a user’s request for one of these ob-
jects to an appropriate Limelight server.
II. Proceedings Before the District Court
On June 23, 2006, Akamai sued Limelight in the
United States District Court for the District of Massachu-
setts asserting infringement of the ’645, ’703, and ’413
patents. After a trial on infringement of independent
claims 19 and 34 and dependent claims 20-21 of the ’703
patent, a jury returned a verdict of infringement and
awarded $40.1 million in lost profits and $1.4 million in
reasonable royalty damages. The two independent claims
asserted at trial cover methods that require tagging at
least some embedded objects in a content provider’s web
page so that requests for those objects resolve to a domain
name other than the content provider’s domain name.
Claim 19 also requires serving the requested web page
from the content provider’s domain. Claims 19 and 34
read as follows, with steps at the heart of this dispute
emphasized:
19. A content delivery service, comprising:
7 AKAMAI TECH v. LIMELIGHT NETWORKS
replicating a set of page objects across a wide
area network of content servers managed by a
domain other than a content provider domain;
for a given page normally served from the con-
tent provider domain, tagging the embedded ob-
jects of the page so that requests for the page
objects resolve to the domain instead of the content
provider domain;
responsive to a request for the given page re-
ceived at the content provider domain, serving the
given page from the content provider domain; and
serving at least one embedded object of the
given page from a given content server in the do-
main instead of from the content provider domain.
’703 patent col.19 ll.6-20.
34. A content delivery method, comprising:
distributing a set of page objects across a net-
work of content servers managed by a domain
other than a content provider domain, wherein
the network of content servers are organized into
a set of regions;
for a given page normally served from the con-
tent provider domain, tagging at least some of the
embedded objects of the page so that requests for
AKAMAI TECH v. LIMELIGHT NETWORKS 8
the objects resolve to the domain instead of the con-
tent provider domain;
in response to a client request for an em-
bedded object of the page:
resolving the client request as a function of a
location of the client machine making the request
and current Internet traffic conditions to identify
a given region; and
returning to the client an IP address of a
given one of the content servers within the given
region that is likely to host the embedded object
and that is not overloaded.
’703 patent col.20 ll.32-52.
It is undisputed that Limelight does not itself perform
every step of the asserted claims. JMOL Opinion at 116.
Limelight provides the information necessary for its
customers, the content providers, to modify their web
pages or Internet address routing information to use the
Limelight service. However, the content providers per-
form the actual tagging step (emphasized above) them-
selves. There are two tagging methods used by
Limelight’s customers. As described by the district court:
In the first method, the customer changes the
hostname address of one or more page objects in
the initial web page to point to Limelight’s servers
(the “prepend method”). In the second method,
the customer adds or changes alias information in
9 AKAMAI TECH v. LIMELIGHT NETWORKS
its DNS record so that the hostname addresses of
the page objects resolve to Limelight’s servers
without requiring any change to the customer’s
initial web page (the “CNAME method”).
JMOL Opinion at 117 n.23. The content provider also
serves the web page from its own domain. Limelight
performs the rest of the steps of the asserted claims. This
divided process is explicitly set forth in Limelight’s stan-
dard customer contract, which states:
Customer [i.e., content provider] shall be respon-
sible for identifying via the then current [Lime-
light] process all [URLs] of the Customer Content
to enable such Customer Content to be delivered
by [Limelight]
and
Customer shall provide [Limelight] with all coop-
eration and information necessary for [Limelight]
to implement the [Content Delivery Service].
J.A. 17807.
Because Limelight itself does not perform all the steps
of the asserted claims, Akamai presented a theory of joint
liability at trial. Akamai relied on the reasoning ex-
pressed by this court in BMC Resources that while
“[i]nfringement requires, as it always has, a showing that
a defendant has practiced each and every element of the
claimed invention,” joint liability may be found when one
party “control[s] or direct[s]” the activities of another
party. BMC Res., Inc. v. Paymentech, L.P., 498 F.3d 1373,
1380 (Fed. Cir. 2007). The district court, following BMC
Resources, instructed the jury that Limelight could only
be found to infringe if “the content provider, when [tag-
AKAMAI TECH v. LIMELIGHT NETWORKS 10
ging objects], acts under the direction and control 2 of
Limelight such that Limelight can properly be deemed to
be the one to do it.” JMOL Opinion at 118. The district
court added that the jury “should review the evidence,
decide how the Limelight systems work, how does the
interaction with the content provider work, and, specifi-
cally, does Limelight direct and control the modifications
or does the content provider carry out these tasks entirely
independently.” Id.
Following the verdict finding infringement, Limelight
moved for JMOL of noninfringement on the ground that
substantial evidence did not support the verdict that
Limelight directs or controls all the steps in the asserted
claims. Initially, the district court denied the motion
“because, unlike in BMC Resources, here there was evi-
dence that not only was there a contractual relationship
between Limelight and its customers, but that it provided
those customers with instructions explaining how to
utilize its content delivery service.” JMOL Opinion at
119. Subsequently, this court issued its decision in Muni-
auction, Inc. v. Thomson Corp., 532 F.3d 1318 (Fed. Cir.
2008), and Limelight moved for reconsideration. Muni-
auction, applying BMC Resources, held that an accused
infringer’s control over its customers’ access to an online
system, coupled with instructions on how to use that
system, was not enough to establish direct infringement.
Id. at 1328-30. On reconsideration, the district court
granted JMOL of noninfringement to Limelight holding
that there was “no material difference between Lime-
2 The district court initially instructed the jury that
Limelight must both direct and control the actions of the
Content Provider, but then issued a correcting instruction
that “[i]t is either direct or control, control or direct; it
doesn’t have to be both.” JMOL Opinion at 118 n.26.
11 AKAMAI TECH v. LIMELIGHT NETWORKS
light’s interaction with its customers and that of Thomson
in Muniauction.” JMOL Opinion at 122.
Akamai appeals and this court has jurisdiction under
28 U.S.C. § 1295(a)(1).
DISCUSSION
I. Joint Infringement of the ’703 Patent 3
On appeal, Akamai asserts that we should reverse the
district court’s JMOL of noninfringement of the ’703
patent because substantial evidence supports the jury’s
determination that Limelight exercises control or direc-
tion over the entire claimed process. Akamai attempts to
distinguish Muniauction, arguing that Limelight: (1)
creates and assigns a unique hostname for the content
provider; (2) provides explicit step-by-step instructions to
perform the tagging and serving claim steps; (3) offers
technical assistance to help content providers with their
performance of the claim steps; and (4) contractually
requires content providers to perform the tagging and
serving claim steps if they utilize the Limelight service.
Limelight responds that Akamai’s evidence is indistin-
guishable from that found legally insufficient in Muniauc-
tion and therefore we should affirm.
It is well settled that direct infringement requires a
single party to perform every step of a claimed method.
BMC Resources, 498 F.3d at 1378-79 (citing Warner-
Jenkinson Co., Inc. v. Hilton Davis Corp., 520 U.S. 17, 40
(1997)). In both BMC Resources and Muniauction this
court confronted the situation in which more than one
party is required to perform the steps of a claimed
3 Because Akamai waived any assertion of indirect
infringement before trial, the question before us is one of
direct infringement only. Feb. 26, 2008 Trial Tr. at 46:4-
22.
AKAMAI TECH v. LIMELIGHT NETWORKS 12
method. The court concluded that there can be no in-
fringement unless “one party exercises ‘control or direc-
tion’ over the entire process such that every step is
attributable to the controlling party.” Muniauction, 532
F.3d at 1329 (citing BMC Resources, 498 F.3d at 1380-81).
In assessing whether “control or direction” is present, the
court in BMC Resources made reference to the legal
principle that imposed “vicarious liability on a party for
the acts of another in circumstances showing that the
liable party controlled the conduct of the acting party.”
BMC Resources, 489 F.3d at 1379 (citing Engle v. Di-
nehart, 213 F.3d 639 (5th Cir. 2000) (unpublished deci-
sion); Restatement (Second) of Agency § 220 cmt. d)). The
court concluded that “[it] would be unfair indeed for the
mastermind in such situations to escape liability.” Id. at
1381. Moreover, the court in BMC Resources also ex-
plained that “[a] party cannot avoid infringement . . .
simply by contracting out steps of a patented process to
another entity.” Id.
While the “control or direction” test of BMC Resources
established a foundational basis on which to determine
liability for direct infringement of method claims by joint
parties, it left several questions unanswered, including
the question of whether the furnishing of instructions is
sufficient to attribute the actions of the instructed party
to the accused. Muniauction addressed the question
about instructions and, in concluding that the instruc-
tions in that case were not enough, reiterated the notion
of vicarious liability mentioned in BMC Resources. The
court in Muniauction held that the requisite level of
control or direction over the acts committed by a third
party is met in circumstances in which “the law would
traditionally hold the accused direct infringer vicariously
liable for the acts committed by another party.” 532 F.3d
at 1330. Thus, both BMC Resources and Muniauction set
13 AKAMAI TECH v. LIMELIGHT NETWORKS
forth relevant factors in assessing liability for joint in-
fringement.
While control or direction is a consideration, as is the
extent to which instructions, if any, may be provided,
what is essential is not merely the exercise of control or
the providing of instructions, but whether the relationship
between the parties is such that acts of one may be at-
tributed to the other. Implicit in this court’s holdings in
BMC Resources and Muniauction is that the performance
of a method step may be attributed to an accused in-
fringer when the relationship between the accused in-
fringer and another party performing a method step is
that of principal and agent, applying generally accepted
principles of the law of agency as explicated by the Su-
preme Court and the Restatement of Agency. The Re-
statement defines agency as “the fiduciary relationship
that arises when one person (a ‘principal’) manifests
assent to another person (an ‘agent’) that the agent shall
act on the principal’s behalf and subject to the principal’s
control, and the agent manifests assent or otherwise
consents so to act.” Restatement (Third) of Agency § 1.01.
For an agency relationship to exist, and thus, for in-
fringement to be found, both parties must consent that
the agent is acting on the principal’s behalf and subject to
the principal’s control. See Dixon v. United States, 465
U.S. 482, 505 (1984) (citing the Restatement (Second) of
Agency § 1 for the rule that an “agency relationship [is]
created when one person agrees with another ‘that the
other shall act on his behalf and subject to his control’”).
Similarly, also implicit in the court’s holdings in BMC
Resources and Muniauction, is that joint infringement
occurs when a party is contractually obligated to the
accused infringer to perform a method step.
In assessing infringement based on the actions of joint
parties, it is not enough to determine for whose benefit
AKAMAI TECH v. LIMELIGHT NETWORKS 14
the actions serve, for in any relationship there may be
benefits that inure in some respects to both parties. This
court therefore holds as a matter of Federal Circuit law
that there can only be joint infringement when there is an
agency relationship between the parties who perform the
method steps or when one party is contractually obligated
to the other to perform the steps. Neither is present here.
The court notes that the common law of agency en-
compasses not only the fiduciary relationship noted above,
but also some other relationships, which may include
those of independent contractors. United States v. Hud-
son, 491 F.3d 590, 595 (Fed. Cir. 2007) (“As a matter of
legal custom and tradition, . . . nothing about the title
independent contractor invariably precludes someone
from being an agent under appropriate circumstances.”);
Restatement (Third) of Agency § 1.01 cmt. c (“The com-
mon law of agency . . . additionally encompasses the
employment relation . . . . [T]he common term ‘independ-
ent contractor’ is equivocal in meaning and confusing in
usage because some termed independent contractors are
agents while others are nonagent service providers. . . .
This Restatement does not use the term ‘independent’
contractor.”); Restatement (Second) of Agency § 2(3) (“An
independent contractor . . . may or may not be an agent.”).
This same principle applies to the question of joint in-
fringement. A party that engages another to perform a
step of a claimed method as its agent cannot escape
liability simply by designating its agent an independent
contractor if all the elements that otherwise reflect an
agency relationship are present.
In this case, there is nothing to indicate that Lime-
light’s customers are performing any of the claimed
method steps as agents for Limelight. To the contrary,
Limelight’s CDN is a service similar to Thomson’s on-line
auction system in Muniauction, and Limelight’s relation-
15 AKAMAI TECH v. LIMELIGHT NETWORKS
ship with its customers is similar to Thomson’s relation-
ship with the bidders. In both cases, customers are
provided instructions on use of the service and are re-
quired to perform some steps of the claimed method to
take advantage of that service. In Muniauction, the
customers performed the step of bidding. Here, the
customers decide what content, if any, they would like
delivered by Limelight’s CDN and then perform the step
of “tagging” that content. Limelight’s customers also
perform the step of “serving” their own web pages.
Akamai argues that in Muniauction, the direction or
control provided by Thomson was “only tangentially
related to the claimed process” because it related to
controlling access to the auction system, not directing
users on what bid information to input. Akamai’s Princi-
pal Br. at 44. According to Akamai, here the control or
direction is directly related to the claimed step because
Limelight tells providers not only how to tag, but also
what hostname to use as a tag. Further, Akamai points
out that by including the word “direct” in the “control or
direct” test, this court in BMC Resources must have
meant the word “direct” to mean something other than
“control,” and this case “presents the ultimate in direc-
tion” because of the detailed instructions and technical
assistance provided to customers by Limelight. Akamai’s
Principal Br. at 42. However, the words in the BMC
Resources test must be read in the context of traditional
agency law. “An essential element of agency is the prin-
cipal’s right to control the agent’s actions. Control is a
concept that embraces a wide spectrum of meanings, but
within any relationship of agency the principal initially
states what the agent shall and shall not do, in specific or
general terms.” Restatement (Third) of Agency § 1.01
cmt. f. Like BMC Resources, the Restatement and the
Supreme Court refer to the words “control” and “direction”
AKAMAI TECH v. LIMELIGHT NETWORKS 16
when assessing whether an agency relationship exists,
but there is no indication that an agency relationship
arises when one party simply provides direction, no
matter how explicit, to another party. All the elements of
an agency relationship must be present. See Meyer v.
Holley, 537 U.S. 280, 286 (2003) (“The Restatement [ ]
specifies that the relevant principal/agency relationship
demands not only control (or the right to direct or control)
but also ‘the manifestation of consent by one person to
another that the other shall act on his behalf, and consent
by the other so to act.’”).
Akamai also argues that the relationship between
Limelight and its customers compels a finding of joint
infringement because Limelight “contracts out to content
providers the claim steps that it alone does not perform.”
This conclusion stems from Limelight’s standard form
contract that, according to Akamai, “obligates content
providers to perform the claim steps of tagging the em-
bedded objects and serving the tagged page so that re-
quests for the embedded objects resolve to Limelight’s
network instead of the content provider’s.” Akamai’s
Principal Br. at 40. For this argument, Akamai relies on
the statement in BMC Resources that “[a] party cannot
avoid infringement . . . simply by contracting out steps of
a patented process to another entity.” BMC Resources,
498 F.3d at 1381. Akamai’s reliance on this statement is
misplaced.
As discussed above, Limelight’s customers decide
what content, if any, they choose to have delivered by
Limelight’s CDN and only then perform the “tagging” and
“serving” steps. The form contract does not obligate
Limelight’s customers to perform any of the method steps.
It merely explains that the customer will have to perform
the steps if it decides to take advantage of Limelight’s
service. See Muniauction, 532 F.3d at 1329 (“[M]ere
17 AKAMAI TECH v. LIMELIGHT NETWORKS
‘arms-length cooperation’ will not give rise to direct
infringement by any party.”). What is critical here is
whether the evidence shows that the relationship between
Limelight and its customers is such that the steps in
question are performed by the customers as agents of
Limelight or under a contractual obligation and are, thus,
properly attributable to Limelight. It is true that Lime-
light’s agreement calls for its customers to assign a
unique hostname, requires content providers to perform
certain claim steps if they choose to use Limelight’s
service, and provides instructions and offers technical
assistance for performing those steps. However, none of
those points establishes either Limelight’s control over its
customers or its customers’ consent to Limelight’s control.
To the contrary, the agreement merely provides the
customers with the tools to allow them to exercise their
independent discretion and control over how and in what
respect they implement the system. Limelight’s custom-
ers did not perform the actions of tagging and serving as
Limelight’s agents and were not contractually obligated to
perform those actions. Instead, the evidence leaves no
question that Limelight’s customers acted principally for
their own benefit and under their own control.
While acknowledging the difficulty of proving in-
fringement of claims that must be infringed by multiple
parties, this court has noted that such concerns “can
usually be offset by proper claim drafting. A patentee can
usually structure a claim to capture infringement by a
single party.” BMC Resources, 498 F.3d at 1381. Akamai
recognizes and, indeed, asserts that the other two patents
at issue in this case (the ’645 and ’413 patents), which
share the same specification, do not implicate this joint
infringement issue because of the way the asserted claims
were drafted. Oral Arg. 10:35-11:10, available at
http://oralarguments.cafc.uscourts.gov. This court also
AKAMAI TECH v. LIMELIGHT NETWORKS 18
observes that in addition to initially structuring a claim to
capture infringement by a single party, patentees may be
able to correct a claim that can only be infringed by
multiple parties by seeking a reissue patent. See Mark A.
Lemley et al., Divided Infringement Claims, 33 AIPLA
Q.J. 255, 278-79 (2005).
Here, the asserted claims were drafted so as to re-
quire the activities of both Limelight and its customers for
a finding of infringement. Thus, Akamai put itself in a
position of having to show that the allegedly infringing
activities of Limelight’s customers were attributable to
Limelight. Akamai did not meet this burden because it
did not show that Limelight’s customers were acting as
agents of or were contractually obligated to Limelight
when performing the tagging and serving steps. Thus,
the district court properly granted JMOL of noninfringe-
ment to Limelight.
* * *
Limelight argues as an alternative ground for affir-
mance that Akamai presented no substantial evidence
that Limelight or its customers actually performed the
tagging limitation as properly construed. Because we find
that the district court properly granted JMOL of nonin-
fringement on the ground stated, we need not and do not
address this argument. Likewise, we do not reach Lime-
light’s conditional cross-appeal of the damages award
alleging that Akamai failed to present economic proof of a
causal link between Limelight’s infringement and any
Akamai lost sales.
II. Claim Construction of the ’645 and ’413 Patents
After the district court’s claim construction order,
Akamai Technologies, Inc. v. Limelight Networks, Inc.,
494 F. Supp. 2d 34, 39 (D. Mass. 2007) (“Claim Construc-
19 AKAMAI TECH v. LIMELIGHT NETWORKS
tion Order”), Akamai stipulated that it could not prove
infringement of the ’645 patent under the district court’s
construction. The district court thus entered judgment of
noninfringement. The district court subsequently entered
summary judgment of noninfringement of claims 8, 18,
and 20 of the ’413 patent. Akamai appeals the district
court’s construction of several terms in the ’645 and ’413
patents. While Limelight does not concede that the ’645
and ’413 patents do not implicate a joint infringement
issue similar to that found in the ’703 patent above, both
parties agree that even if such an issue does exist, it is
not properly before the court in this appeal. Oral Arg.
10:35-11:10; 30:40-31:40 (Limelight’s counsel stating that
the joint infringement issues for the ’645 and ’413 patents
were not developed at the trial court). Thus, we decide
Akamai’s appeal of the district court’s construction of
several terms in the asserted claims of the ’645 and ’413
patents independent of any potential joint infringement
issues.
We review claim construction de novo. Cybor Corp. v.
FAS Techs., Inc., 138 F.3d 1448, 1451 (Fed. Cir. 1998) (en
banc). “We begin a claim construction analysis by consid-
ering the language of the claims themselves.” Edwards
Lifesciences LLC v. Cook Inc., 582 F.3d 1322, 1327 (Fed.
Cir. 2009). However, “the written description can provide
guidance as to the meaning of the claims, thereby dictat-
ing the manner in which the claims are to be construed,
even if the guidance is not provided in explicit definitional
format.” Scimed Life Sys., Inc. v. Advanced Cardiovascu-
lar Sys., Inc., 242 F.3d 1337, 1344 (Fed. Cir. 2001).
A. The Technical Setting
As part of a system for efficient content delivery, the
’645 and ’413 patents describe a framework including a
set of “hosting” or “ghost” servers used to store and deliver
AKAMAI TECH v. LIMELIGHT NETWORKS 20
a website’s embedded objects. ’703 patent col.3 ll.4-7. To
determine the location of a hosting computer on which a
particular object is stored, the framework includes a
second set of servers that are configured with functional-
ity that is similar to, but not exactly the same as, a typical
Internet DNS server, such that the servers resolve URLs
specifically for the CDN. The specification refers to this
second set of servers as “top-level” DNS servers. Id. col.3
ll.17-21, 31. The specification also describes a third set of
servers that provide “low-level DNS” functionality. Id.
col.3 ll.22-24. Together, the top-level and low-level serv-
ers form an “alternative domain name system.” According
to the patents’ preferred embodiment, when a user’s
machine requests a web page from a content provider, the
web page base document is delivered to the user’s com-
puter from the content server in the traditional manner
described above. Id. col.3 ll.24-27. Any embedded objects
in that web page that are stored on the CDN’s hosting
servers, however, are located using the invention’s
framework. First, the top-level DNS server determines
the user’s location in the network and uses that informa-
tion to identify a list of low-level DNS servers. Id. col.3
ll.29-33, 60-61. The top-level DNS server then redirects
the request for the embedded object to one of the identi-
fied low-level DNS servers that, in turn, resolves the
request into an IP address for the appropriate hosting
server that delivers the object to the user’s computer. Id.
col.3 ll.33-37. The specification does not limit the frame-
work to two levels of DNS servers, but describes “a hier-
archy of DNS servers that consisting [sic] of several
levels.” Id. col.3 ll.37-41. In addition, the top-level and
low-level DNS functionality may be combined into a
single DNS level. Id. col.5 ll.54-57.
The specification also describes load balancing across
the set of hosting servers. Id. col.3 ll.66-67. Load balanc-
21 AKAMAI TECH v. LIMELIGHT NETWORKS
ing is the process of equalizing the workload on multiple
computers. The specification describes a load balancing
technique based on distributing the embedded object
requests. This technique can be included in the tagging
process by modifying the embedded object URL using the
hostname of a “virtual server.” Id. col.4 ll.1-5. A virtual
server is simply a reference to a hosting server whose
physical location is not determined until a user attempts
to access a specific object. This allows users to retrieve
the objects stored on hosting servers efficiently based on a
number of continually changing factors (e.g., network
traffic, user location). Thus, upon retrieval of a modified
web page by a user, the hosting framework maintained by
the CDN will resolve the virtual server hostname in the
modified URL into the IP address of the appropriate
hosting server from which to retrieve the object.
Claim 1 of the ’645 patent provides:
In a wide area network in which an Internet do-
main name system (DNS) is useable to resolve
DNS queries directed to participating content
provider content that is available from participat-
ing content provider sites, a method of content de-
livery wherein participating content providers
identify content to be delivered by a service pro-
vider from a set of content servers that are dis-
tinct from the participating content provider sites
and associated with the service provider, wherein
a given object of a participating content provider is
associated with an alphanumeric string, the
method comprising:
having the service provider establish an alter-
native domain name system (DNS), distinct from
the Internet domain name system and any client
AKAMAI TECH v. LIMELIGHT NETWORKS 22
local name server, and having authority to resolve
the alphanumeric strings associated with the ob-
jects identified by the participating content pro-
viders so that the objects identified by the
participating content providers are available to be
served from the service provider’s content servers,
the service provider’s alternative domain name
system having one or more DNS levels, wherein at
least one DNS level comprises a set of one or more
name servers;
for each of one or more participating content
providers, delivering a given object on behalf of
the participating content provider, wherein the
given object is delivered by the following steps;
responsive to a DNS query to the given ob-
ject’s associated alphanumeric string, the DNS
query originating from a client local name server,
receiving the DNS query at a given name server of
a lowest level of the one or more DNS levels in the
service provider’s alternative domain name sys-
tem, the given name server that receives the DNS
query being close to the client local name server as
determined by given location information;
having the given name server that receives
the DNS query resolve the alphanumeric string
into an IP address that the given name server
then returns to the client local name server,
wherein the alphanumeric string is resolved with-
out reference to a filename for the given object,
wherein the IP address returned as a result of the
23 AKAMAI TECH v. LIMELIGHT NETWORKS
resolution is associated with a content server
within a given subset of the set of content servers,
the subset of the set of content being associated
with the given name server, the content server as-
sociated with the IP address returned by the given
name server being selected according to a load
sharing algorithm enforced across the subset of
the set of content servers associated with the
given name server;
at the content server associated with the IP
address, receiving a request for the given object,
the request having the filename associated
therewith;
if the given object is available for delivery
from the content server associated with the IP ad-
dress, serving the given object from the content
server.
’645 patent col.17 ll.39-col.18 ll.29 (emphases added).
Claim 8 is representative of the asserted claims of the
’413 patent. It provides:
AKAMAI TECH v. LIMELIGHT NETWORKS 24
A method of content delivery wherein participat-
ing content providers identify content to be deliv-
ered by a content delivery network service
provider from a set of content servers associated
with the content delivery network service pro-
vider, wherein a given object of a participating
content provider is associated with a [URL] that
includes, in addition to a filename, an alphanu-
meric string, comprising:
having the content delivery network service
provider establish a domain name system (DNS)
having authority to resolve the alphanumeric
strings in the URLs of the objects identified by the
participating content providers, the content deliv-
ery network server provider’s domain name sys-
tem having one or more DNS levels, wherein at
least one DNS level comprises a set of one or more
name servers;
for each of one or more participating content
providers, delivering a given object on behalf of
the participating content provider, wherein the
given object is delivered by the following steps;
responsive to a DNS query, selecting a given
one of the name servers in the content delivery
network service provider’s domain name system;
at the given one of the name servers, resolving
the alphanumeric string to an IP address, wherein
25 AKAMAI TECH v. LIMELIGHT NETWORKS
the alphanumeric string is resolved without refer-
ence to the filename for the given object;
at a server associated with the IP address, the
server being one of the set of content servers, re-
ceiving a request for the given object, the request
having the filename associated therewith;
from the server, serving the given object; and
caching the given object at the server so that
the given object is available for delivery from the
server for a given time period in the event that a
new DNS query to resolve the alphanumeric
string is received at the domain name system and
is resolved to the IP address of the server.
’413 patent col.18 ll.14-51 (emphases added).
B. Associated with an Alphanumeric String
Akamai appeals the construction of the term “a given
object of a participating content provider is associated
with an alphanumeric string” in the preamble of claim 1
of the ’645 patent. 4 The district court construed the
limitation to require that the alphanumeric string include
the embedded object’s original URL (the URL including
the hostname of the computer on which the actual object
resided within the content provider’s domain). Claim
Construction Order at 39. The court reasoned that the
4 Neither party contends that the term in question
is not a limitation because it is part of the preamble.
AKAMAI TECH v. LIMELIGHT NETWORKS 26
written description portion of the ’645 patent “describes
the invention as associating a particular object of a con-
tent provider with an alphanumeric string consisting of a
virtual server hostname prepended onto the URL for the
object.” Id. at 40. The court found that “[t]he specification
discloses no other way that an object is associated with an
alphanumeric string, nor is there any suggestion or
teaching that an association which did not include the
URL for the embedded object could be used in an em-
bodiment of the invention.” Id. The district court de-
clined as overly broad Akamai’s proposed construction of
the term “associated” according to its dictionary definition
of “brought into some kind of relationship with.”
Akamai contends that the court imported a limitation
from the specification into the claims and thereby im-
properly limited the scope of the claims to the specifica-
tion’s preferred embodiment. According to Akamai,
nothing in the claim language supports requiring that the
alphanumeric string include the original URL. Akamai
relies on the parties’ stipulation that “alphanumeric
string” is “a character string up to 24 characters drawn
from the alphabet (a-z), digits (0-9), minus signs (-), and
periods (.).” Stipulated Order Establishing the Construc-
tions for Certain Claim Terms as Agreed Upon by the
Parties at 3, Akamai Techs., Inc. v. Limelight Networks,
Inc., No. 06-CV-11109 (D. Mass. Apr. 24, 2007). Akamai
asserts that the specification and prosecution history do
not define “associated” as having any meaning other than
its ordinary meaning. Thus, Akamai argues that the
ordinary meaning of the words in the claim compel a
broad interpretation without the limitation introduced by
the district court. Akamai also argues that the specifica-
tion very clearly indicates that including the object’s
original URL in the alphanumeric string is merely the
preferred method. Akamai contends that one of ordinary
27 AKAMAI TECH v. LIMELIGHT NETWORKS
skill in the art would understand that other tagging
methods may be used to associate an alphanumeric string
with the object.
In addition, Akamai points to the prosecution history,
other claim limitations in the ’645 patent, and the use of
“alphanumeric string” in claim 18 of the ’413 patent as
evidence contradicting the district court’s construction.
Akamai notes that (1) none of the examples of alphanu-
meric strings cited by Akamai during prosecution in-
cluded the original URL; (2) other claim limitations of the
’645 patent use the term “alphanumeric string” as a
virtual server hostname, not a URL; and (3) the preamble
of claim 18 of the ’413 patent requires a URL to include
an alphanumeric string, not the other way around.
Limelight responds that the district court correctly
limited the claim term to include the object’s original URL
because it reflects the ’645 patent’s explicit description of
the invention. Reiterating the points made by the district
court, Limelight asserts that the patents consistently
describe “the invention” as associating an alphanumeric
string with an object by prepending a virtual server
hostname to the original URL that identifies the object in
the absence of the CDN. Limelight adds that including
the original URL in the alphanumeric string is not merely
a preferred embodiment in the patents because all the
examples in the patents contain the object’s original URL.
This court agrees with Limelight and the district
court that the claim term “a given object of a participating
content provider is associated with an alphanumeric
string” limits tagged alphanumeric strings to those
strings including the object’s original URL. Here, as in
Honeywell International, Inc. v. ITT Industries, Inc., 452
F.3d 1312, 1318 (Fed. Cir. 2006), alphanumeric strings
including the object’s original URL were not merely
AKAMAI TECH v. LIMELIGHT NETWORKS 28
discussed as a preferred embodiment. Instead, the writ-
ten description specifically refers to strings including the
object’s original URL as “the invention”:
According to the present invention, load balancing
across the set of hosting servers is achieved in
part through a novel technique for distributing
the embedded object requests. In particular, each
embedded object URL is preferably modified by
prepending a virtual server hostname into the
URL. More generally, the virtual server host-
name is inserted into the URL.
’645 patent col. 4 ll.13-19.
According to the invention, the embedded object
URL is first modified, preferably in an off-line
process, to condition the URL to be served by the
global hosting servers.
Id. col.6 ll.54-57.
Thus, according to the present invention, a virtual
server hostname is prepended into the URL for a
given embedded object . . . .
Id. col.7 ll.36-38.
With the above as background, the inventive
global hosting framework is now described in the
context of a specific example. . . . Instead of re-
29 AKAMAI TECH v. LIMELIGHT NETWORKS
turning the usual page, according to the inven-
tion, the Web site returns a page with embedded
object URLs that are modified according to the
method illustrated in the flowchart of FIG. 4.
Id. col.7 l.49-col.8 l.2
If, however, no copy of the data on the ghost ex-
ists, a copy is retrieved from the original server or
another ghost server. Note that the ghost knows
who the original server was because the name was
encoded into the URL that was passed to the
ghost from the browser.
Id. col.12 ll.54-60.
The specification does include language indicating
that the patentee intended certain aspects of the descrip-
tion to represent preferred, rather than required, ele-
ments of the invention. See, e.g., ’645 patent col.4 ll.15-17
(“[E]ach embedded object URL is preferably modified by
prepending a virtual server hostname into the URL.”); id.
col.6 ll.57-58 (“A flowchart illustrating the preferred
method for modifying the object URL is illustrated in FIG.
4.”). This court also acknowledges that much of the
language describing a string including a URL as “the
invention” occurs within the section entitled “Detailed
Description of the Preferred Embodiment” or in the de-
scription of Figure 4, which is referred to as a “preferred
method for modifying the object URL.” However, the
specification as a whole makes clear that including the
object’s original URL is the only method to achieve the
AKAMAI TECH v. LIMELIGHT NETWORKS 30
claimed association between an alphanumeric string and
the embedded object. Indeed, it is the only method de-
scribed. Netword, LLC v. Centraal Corp., 242 F.3d 1347,
1352 (Fed. Cir. 2001) (“Although the specification need
not present every embodiment or permutation of the
invention and the claims are not limited to the preferred
embodiment of the invention . . . neither do the claims
enlarge what is patented beyond what the inventor has
described as the invention.”) (internal citations omitted).
See also Bell Atl. Network Servs., Inc. v. Covad Commc’ns
Grp., Inc., 262 F.3d 1258, 1271 (Fed. Cir. 2001) (“W]hen a
patentee uses a claim term throughout the entire patent
specification, in a manner consistent with only a single
meaning, he has defined that term ‘by implication.’”)
(quoting Vitronics Corp. v. Conceptronic, Inc., 90 F.3d
1576, 1582 (Fed. Cir. 1996)). Moreover, the specification
specifically limits the object’s modified URL to either
prepending or inserting a virtual server hostname into
the URL. ’645 patent col.4 ll.15-19 (“In particular, each
embedded object URL is preferably modified by prepend-
ing a virtual server hostname into the URL. More gener-
ally, the virtual server hostname is inserted into the
URL.”). Both of these methods include the original URL
of the object in the modified string. Finally, the specifica-
tion describes the proper functioning of the invention as
motivation for including the object’s original URL in the
modified string, “the ghost knows who the original server
was because the name was encoded into the URL that
was passed to the ghost from the browser.” Id. col.12
ll.56-58.
This court is not persuaded by Akamai’s argument
that the patentee established a broader scope during
prosecution or that other uses of the term “alphanumeric
string” compel a broader interpretation. Akamai argues
that during prosecution the patentee made it clear that
31 AKAMAI TECH v. LIMELIGHT NETWORKS
an alphanumeric string can be comprised of just a host-
name as opposed to requiring the inclusion of an entire
URL. Akamai refers to the patentee’s description of an
examiner interview in a preliminary amendment. The
remarks describe the interpretation of the phrase “alpha-
numeric string” and cite “numerous examples of such
strings, such as . . . ‘a1234.g.akamaitech.net,’” in the
written description. Id. col.7 ll.14-15. However, in the
specification, the reference to the indicated hostname is in
the context of determining a virtual server hostname for
ultimate inclusion in the tagged string. The specification
does not indicate that this virtual hostname can eventu-
ally be the entire string. Instead, the specification clearly
describes that the hostname will be “prepended into the
URL for the given embedded object” once the hostname is
determined. See, e.g., id. col.6 ll.63-64. In fact, all the
examples in the specification indicate that the ultimate
tagged string contains the object’s original URL. ’645
patent col.8 ll.24-25; id. col.8 ll.56-57; id. col.9 ll.25-26.
Even if we agreed with Akamai that the patentee indi-
cated in the prosecution history that the alphanumeric
string associated with an object could include only a
hostname, this is not enough to overcome the clear de-
scription of the invention in the specification. See Honey-
well, 452 F.3d at 1319 (“Where, as here, the written
description clearly identifies what his invention is, an
expression by a patentee during prosecution that he
intends his claims to cover more than what his specifica-
tion discloses is entitled to little weight.”); Biogen, Inc. v.
Berlex Labs., 318 F.3d 1132, 1140 (Fed. Cir. 2003) (stating
that “[r]epresentations during prosecution cannot enlarge
the content of the specification.”). Akamai’s arguments
that other uses of “alphanumeric string” in the ’645 and
’413 patents require a broad interpretation such that the
string may include only a hostname are likewise not
persuasive. None of the uses of “alphanumeric string” in
AKAMAI TECH v. LIMELIGHT NETWORKS 32
either patent clearly limits the contents to just a host-
name. In fact, Akamai does not explain how a string
made up of just a virtual server hostname would be
“associated” with the original object even under the
broadest definition of that term.
Akamai argues that the district court’s requirement
that the alphanumeric string include an entire URL is
nonsensical because DNS servers resolve hostnames, not
URLs. Akamai also asserts that the district court’s
statement that “[t]he URL of the object is necessary to the
inventive global framework in order to retrieve the object
from the content provider’s server if no copy exists on a
ghost [i.e., content] server” in its claim construction order,
Claim Construction Order at 40, demonstrates a “funda-
mental misunderstanding of the requirements of the
invention.” Akamai’s Principal Br. at 57. According to
Akamai, this statement ignores that the specification
describes retrieving any missing content from either the
content provider’s original server or another content
server in the CDN. None of these arguments are persua-
sive. At no place does the specification indicate that the
entire string must be used by the DNS server. Even if
only the hostname is used by the DNS during the resolv-
ing step, this does not mean that an alphanumeric string
cannot contain other information not used by the DNS
during this step. Indeed, this must be the case since the
specification explicitly notes that “the ghost knows who
the original server was because the name was encoded
into the URL that was passed to the ghost from the
browser.” ’645 patent col.12 ll.56-58.
C. Selection by the Alternative Domain Name System
Akamai also appeals the district court’s construction
of “the given name server that receives the DNS query
being close to the client local name server as determined
33 AKAMAI TECH v. LIMELIGHT NETWORKS
by given location information” in claim 1 of the ’645
patent and “selecting a given one of the name servers in
the content delivery network” in claims 8, 18, and 20 of
the ’413 patent. The district court interpreted both limi-
tations to require that the name server be selected by the
alternative domain name system. 5 Claim Construction
Order, at 42, 45. The court found that the specification
compelled this interpretation because “[r]ead in light of
the specification, the invention claims an alternate DNS
system that selects a DNS server in response to a user
request based on the location of the user.” Id. at 43.
Akamai, citing DSW, Inc. v. Shoe Pavilion, Inc., 537 F.3d
1342, 1347 (Fed. Cir. 2008), argues that the district court
improperly incorporated a structural limitation─the
alternative domain name system─into method claims.
Moreover, Akamai asserts that claim 1 of the ’645 patent
5 The claim limitations and their associated con-
struction differ slightly for the ’645 and ’413 patents. For
the ’645 patent, the limitation “the given name server
that receives the DNS query being close to the client local
name server as determined by given location information”
was construed by the district court to be “the particular
name server that receives the DNS query is selected by
the alternative domain name system and is close in
Internet terms to the client local name server.” Claim
Construction Order at 42. Claims 8 and 18 of the ’413
patent include the limitation “responsive to a DNS query,
selecting a given one of the name servers in the content
delivery network,” which is construed as “in response to a
DNS query, the [CDN’s] [DNS] selects a particular name
server.” Id. at 45. Claim 20 of the ’413 patent includes
the limitation “responsive to a DNS query received from a
client local name server, selecting a given one of the name
servers in the [CDN],” which is construed as “in response
to a DNS query received from a client local name server,
the [CDN’s] [DNS] selects a particular name server.” Id.
at 45. These distinctions are not germane to the issue
presented in this appeal.
AKAMAI TECH v. LIMELIGHT NETWORKS 34
does not use the term selecting at all. Akamai points out
that claim 1 only requires that the CDN’s DNS server
receiving a DNS query be close to the client’s local name
server. In addition, Akamai argues that nothing in the
’413 patent claim language, specification, or prosecution
history supports the court’s requirement of selection by
the alternative domain name system. Limelight responds
that the district court did not import a new structural
limitation because claim 1 expressly requires an alterna-
tive domain name system.
This court is not persuaded by Akamai’s argument.
DSW is inapposite. In DSW this court reversed the
district court’s claim construction importing a limitation
from a preferred embodiment because the claim language
was unambiguously broader than the preferred embodi-
ment, not because it imported structural limitations into
a method claim. Id. at 1347. Method claims often include
structural details. See e.g., Microprocessor Enhancement
Corp. v. Tex. Instruments, Inc., 520 F.3d 1367, 1374 (Fed.
Cir. 2008) (“Method claim preambles often recite the
physical structures of a system in which the claimed
method is practiced, and claim 1 is no different.”); Eaton
Corp. v. Rockwell Int’l Corp., 323 F.3d 1332, 1342 (Fed.
Cir. 2003) (construing a method claim as including “steps
that require the operation or manipulation of the particu-
lar structure identified and described by the preamble”).
All of the asserted claims in both the ’645 patent and the
’413 patent explicitly refer to the alternative domain
name system as a detail associated with the claimed
method. ’645 patent col.17 ll.50-51 (“having the service
provider establish an alternative domain name system
(DNS)”); ’413 patent col.18 ll.22-23, col.19 ll.44-45, col.20
ll.25-26 (“having the content delivery network service
provider establish an alternative domain name system
(DNS)”). Therefore, the structural element of the alterna-
35 AKAMAI TECH v. LIMELIGHT NETWORKS
tive DNS framework was explicitly and properly included
in the claims.
Akamai also asserts that the district court’s interpre-
tation improperly limits the inventive framework to a
multi-level DNS system. Akamai points out that because
the patents explicitly allow for a framework with a one-
level DNS framework, a multi-level restriction is unduly
limiting. ’703 patent col.5 ll.56-57 (“Alternatively, there
may be a single DNS level that combines the functionality
of the top-level and low-level servers.”).
The district court responded to this exact argument in
its claim construction order. Specifically, the court ex-
plained that because the specification states that “the
functionality of the top and low-level servers” may be
combined in “a single DNS level,” the specification re-
quires that a single-level DNS system accomplish the
same steps as the two-level system described in the
preferred embodiment. Claim Construction Order at 45.
Thus, the district court’s construction does support a
single-level DNS system, and is not limited to a multi-
level DNS system. As the district court recognized, the
steps described in the preferred embodiment─(1) a top-
level DNS server of the CDN selects a close-by low-level
DNS server and redirects the user to that server and (2)
the user’s local DNS server requests the object’s IP ad-
dress from the low-level server─can be accomplished by
one DNS server. Id. at 46 (citing ’413 patent col.9 ll.44-
50). Specifically, the district court explained:
In a single-level DNS embodiment, as suggested
by the specification, the user’s local name server
would still contact a content delivery provider’s
top-level name server to resolve the IP address of
a server to serve an object. This name server,
however, would then directly communicate with a
AKAMAI TECH v. LIMELIGHT NETWORKS 36
particular local name server, based on the user’s
location, to resolve the server’s IP address and re-
turn it to the user, rather than require the user to
conduct a second lookup. Thus, the user would
obtain the IP address of the appropriate ghost
server with only a single DNS request, however
the selection of a particular name server would
still be the result of a DNS lookup by the service
provider’s DNS system. Such an embodiment
would satisfy the claimed “one” level of DNS, yet
not be in conflict with [the district court’s adopted]
claim construction.
Id. at 45-46.
This explanation is entirely consistent with the speci-
fication’s description of the invention and effectively
counters Akamai’s argument that the court’s construction
improperly limits the invention to a multi-level DNS
system. Akamai also asserts, however, that one of these
“other techniques” could be substituted for the top-level
DNS servers in order to implement a one-level DNS
framework. Thus, according to Akamai, the patent, but
not the district court’s construction, allows for a one-level
DNS framework in which “other techniques,” such as
“Anycasting,” would be used to select the ultimate CDN
DNS server─instead of a top-level DNS server─because
“the specification encompassed techniques known in the
prior art.” Akamai’s Br. at 61 (citing BJ Servs. Co. v.
Halliburton Energy Servs., Inc., 338 F.3d 1368, 1372 (Fed.
Cir. 2003). This court does not agree that the patent’s
description allows for such a broad reading of the claims.
The patent disclosure supports only one method for choos-
ing the ultimate CDN DNS server─the alternative DNS
system. There is no support in the specification for any
method of choosing a particular name server other than
by a DNS lookup and no disclosure that would have
37 AKAMAI TECH v. LIMELIGHT NETWORKS
suggested to a person of ordinary skill in the art that
anything other than a DNS lookup should be contem-
plated. There is no evidence that, given the lack of de-
tailed disclosure in the patent’s language, a person of skill
in the art would have looked to other known techniques to
implement this portion of the claimed invention.
In fact, the patent repeatedly defines using DNS
lookup for choosing the ultimate CDN DNS server as the
“invention.” As noted by the district court, the specifica-
tion describes “the present invention” as “manipulat[ing]
the DNS system so the name is resolved to one of the
ghosts that is near the client.” ’703 patent col.9 ll.26-28.
In addition, under the heading entitled “Brief Summary of
the Invention,” the specification states that “[t]o locate the
appropriate hosting servers to use, the top-level DNS
server determines the user’s location in the network to
identify a given low-level DNS server to respond to the
request for the embedded object.” ’703 patent col.3 ll.29-
33.
Akamai conceded that under the district court’s con-
struction, Limelight does not infringe the ’645 patent.
Akamai also does not argue that Limelight would infringe
the ’413 patent under this construction. Therefore, this
court is left to conclude that the district court properly
entered judgment in favor of Limelight on the issue of
infringement.
CONCLUSION
For the foregoing reasons, this court affirms the dis-
trict court’s grant of Limelight’s motion for JMOL of
noninfringement of the ’703 patent. This court also
affirms the district court’s entry of judgment of nonin-
fringement of the ’645 and ’413 patents.
AKAMAI TECH v. LIMELIGHT NETWORKS 38
AFFIRMED