UNITED STATES PATENT AND TRADEMARK OFFICE
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`
`Limelight Networks, Inc.,
`Petitioner
`
`v.
`
`Akamai Technologies, Inc.,
`Patent Owner.
`
`
`
`
`
`
`Patent No. 7,693,959 to Leighton et al.
`
`IPR Case No. IPR2017-00249
`
`Declaration of Michael J. Freedman, Ph.D.
`
`
`
`1
`
`
`
`
`
`Petitioner Limelight - LN1003
`
`

`
`TABLE OF CONTENTS
`
`TABLE OF CONTENTS
`
`II.
`
`RETENTION & COMPENSATION ........................................................... ..8
`
`III. MATERIAL CONSIDERED ....................................................................... ..8
`
`IV.
`
`OVERVIEW AND LEGAL STANDARDS ................................................ ..9
`
`V.
`
`DESCRIPTION OF THE RELEVANT FIELD AND THE
`
`RELEVANT TIME FRAME ..................................................................... .. 10
`
`VI.
`
`LEVEL OF ORDINARY SKILL IN THE ART ........................................ ..11
`
`VII. OVERVIEW OF THE ’959 PATENT ....................................................... ..13
`
`Declaration of Michael J. Freedman, Ph.D. ........................................................... 1 
`Declaration of Michael J. Freedman, Ph.D .......................................................... ..1
`BACKGROUND AND QUALIFICATIONS ................................................ 4 
`I. 
`BACKGROUND AND QUALIFICATIONS .............................................. ..4
`I.
`RETENTION & COMPENSATION ............................................................. 8 
`II. 
`III.  MATERIAL CONSIDERED ......................................................................... 8 
`IV.  OVERVIEW AND LEGAL STANDARDS .................................................. 9 
`V. 
`DESCRIPTION OF THE RELEVANT FIELD AND THE
`RELEVANT TIME FRAME ....................................................................... 10 
`LEVEL OF ORDINARY SKILL IN THE ART .......................................... 11 
`VI. 
`VII.  OVERVIEW OF THE ’959 PATENT ......................................................... 13 
`A.  The Challenged Claims ................................................................................ 15 
`A.
`The Challenged Claims .............................................................................. .. 15
`1.  Claim 1 ......................................................................................................... 15 
`2.  Claim 2 ......................................................................................................... 16 
`3.  Claim 4 ......................................................................................................... 17 
`4.  Claim 9 ......................................................................................................... 17 
`5.  Claim 10 ....................................................................................................... 17 
`6.  Claim 11 ....................................................................................................... 17 
`7.  Claim 12 ....................................................................................................... 17 
`8.  Claim 15 ....................................................................................................... 18 
`9.  Claim 16 ....................................................................................................... 18 
`10.  Claim 26 ....................................................................................................... 18 
`11.  Claim 28 ....................................................................................................... 18 
`12.  Claim 58 ....................................................................................................... 18 
`VIII.  BACKGROUND TECHNOLOGIES .......................................................... 19 
`A.  HTTP and URLs ........................................................................................... 19 
`B.  DNS, DNS resolution, and local name servers ............................................ 20 
`B. DNS, DNS resolution, and local name servers .......................................... ..2O
`IX. 
`THE SCOPE AND CONTENT OF THE PRIOR ART ............................... 28 
`
`VIII. BACKGROUND TECHNOLOGIES ........................................................ .. 19
`
`1. Claim 1 ....................................................................................................... ..15
`
`2. Claim 2 ....................................................................................................... .. 16
`
`3. Claim 4 ....................................................................................................... .. 17
`
`4. Claim 9 ....................................................................................................... .. 17
`
`5. Claim 10 ..................................................................................................... ..17
`
`6. Claim 11 ..................................................................................................... .. 17
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`7. Claim 12 ..................................................................................................... ..17
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`8. Claim 15 ..................................................................................................... ..18
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`9. Claim 16 ..................................................................................................... ..18
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`10. Claim 26 ..................................................................................................... ..18
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`11. Claim 28 ..................................................................................................... ..18
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`12. Claim 58 ..................................................................................................... ..18
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`A. HTTP and URLs ......................................................................................... .. 19
`
`IX.
`
`THE SCOPE AND CONTENT OF THE PRIOR ART ............................. ..28
`
`2
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`

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`A.  U.S. Patent No. 6,154,777 (“Ebrahim-777”) [Ex. 1004] ............................. 28 
`B.  Rabinovich-Memo [Ex. 1005] ...................................................................... 32 
`C.  U.S. Patent No. 6,167,427 (“Rabinovich-427”) [Ex. 1006] ......................... 33 
`X. 
`CLAIM CONSTRUCTION ......................................................................... 34 
`XI.  UNPATENTABILITY BASED ON PRIOR ART
`IN THE
`PRESENT PROCEEDINGS ........................................................................ 37 
`A.  Ground 1: Ebrahim-777 in view of Rabinovich-427 and the
`Rabinovich-Memo ........................................................................................ 37 
`1.  Motivation to combine the prior art ............................................................. 38 
`2.  Claim-by-claim Analysis .............................................................................. 41 
`
`
`3
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`

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`I, Michael Freedman, Ph.D., declare as follows:
`
`I.
`
`1.
`
`BACKGROUND AND QUALIFICATIONS
`
`Counsel for Limelight Networks, Inc. (“Limelight”) has retained me as an
`
`expert to offer my opinion regarding the validity of U.S. Patent No. 7,693,959
`
`(“’959 patent”).
`
`2.
`
`I submit this declaration based on my personal knowledge and in support of
`
`Limelight’s inter partes review petition regarding the ’959 patent.
`
`3.
`
`I am a trained Computer Scientist and Engineer. I began programming
`
`online services in 1995, and received a Bachelor’s degree in 2001 and Master’s
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`degree in 2002 from the Massachusetts Institute of Technology, both in Computer
`
`Science and Engineering. I subsequently received a Ph.D. in Computer Science
`
`from New York University in 2007. During 2005 through 2007, I spent my
`
`doctoral studies as a research scholar at Stanford University. Since 2007, I have
`
`been a professor of computer science at Princeton University, initially as an
`
`Assistant Professor (2007-2013), then as a tenured Associate Professor (2013-
`
`2015), and most recently as a Full Professor. I am also currently the co-founder
`
`and CEO of Iobeam, a startup company building a cloud-hosted data analysis
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`platform for sensor and device data. My curriculum vitae is attached as Appendix
`
`A.
`
`4. My research interests and experience primarily focus on Internet services,
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`distributed systems, networking, and security. Since the year 2000, I have
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`published over 75 peer-reviewed journal, conference, and workshop papers in
`
`these topics. According to my recent review of Google Scholar, these peer-
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`reviewed papers have been cited more than 9000 times. A list of my publications
`
`is provided in Appendix A. Of particular note here, I have published multiple
`
`papers concerning web proxies and content delivery networks (CDNs), DNS
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`services, server selection, distributed systems, Internet architecture, and network
`
`and communication protocols.
`
`5.
`
`At Princeton, I teach courses at both the undergraduate level in distributed
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`systems and networking, as well as graduate courses in computer systems and
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`networking. These courses include topics relevant to the ’959 patent, including
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`HTTP, web proxies, CDNs, DNS, distributed systems, Internet architecture and
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`routing, network and communication protocols, and server, middlebox, and
`
`gateway technologies.
`
`6.
`
`I have been on the technical program committee for numerous conferences
`
`with peer-reviewed proceedings, including the main academic computer science
`
`venues for networking (SIGCOMM), network systems (NSDI), and systems (OSDI
`
`and SOSP). I have been the technical program chair of multiple conferences,
`
`including the ACM Symposium on Cloud Computing (SOCC). I have served as a
`
`reviewer for numerous leading journals, including Communications of the ACM,
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`5
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`

`
`Transactions on Computer Systems (TOCS), and Transactions on Networking
`
`(TON).
`
`7.
`
`I have also served as a consultant and advisor for companies such as Netflix,
`
`CloudFlare, Blockstack Labs, the Institute for Defense Analyses, Intelligent
`
`Automation, and Quova. I am also the named inventor on U.S. Patent Nos.
`
`8,204,982 and 8,463,904, which deal with methods to detect network proxies and
`
`middleboxes, often coupled with
`
`technologies around
`
`IP-address-based
`
`geolocation.
`
`8.
`
`In my career, I have received numerous national awards for my work. Of
`
`particular note, I received the Presidential Early Career Award for Scientists and
`
`Engineers (PECASE), given by the White House’s Office of Science and
`
`Technology Policy. In receiving this award, I was one of 20 individuals nominated
`
`by the National Science Foundation. I have also been awarded National Science
`
`Foundation’s CAREER Award, the Office of Naval Research’s Young Investigator
`
`Award, an Alfred P. Sloan Research Fellowship, membership in the Computer
`
`Science Study Group of the U.S. Department of Defense’s Defense Advanced
`
`Research Projects Agency (DARPA), and multiple “Best Research Paper”-type
`
`awards from leading international conferences and symposia.
`
`9.
`
` My research and development has also led to deployed systems and
`
`industrial impact in Web and Internet services, as well as in the networking field.
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`For example, I designed, programmed, deployed, and operated an open Web
`
`content delivery system, CoralCDN, that had been publicly available between 2004
`
`and 2015, serving millions of unique users per day. I also designed, built, and
`
`operated two subsequent server-selection systems: OASIS devised efficient
`
`mechanisms to map the Internet topology cooperatively to determine geographic
`
`proximity, offering locality-based DNS service for thousands of service replicas
`
`for more than a dozen distributed services between 2005 and 2009; DONAR
`
`solved locality- and load-aware cost optimizations for server selection, providing
`
`DNS- and HTTP-based name resolution for services on the Measurement Lab
`
`testbed from 2009-2013, including those powering the Federal Communications
`
`Commission’s Consumer Broadband Test. My research on IP geolocation and
`
`intelligence for Web services led me to co-found Illuminics Systems, which was
`
`acquired by Quova (now part of Neustar) in 2006. My work on programmable
`
`enterprise networking helped form the basis for the OpenFlow / software-defined
`
`networking (SDN) architecture that was standardized by the Open Networking
`
`Foundation (an organization comprised of most major telecommunications
`
`companies, networking vendors, and Internet and Online Service Providers).
`
`10.
`
`I am particularly familiar with the design, deployment, and selection of
`
`Internet proxies, e.g., network-facing machines that interpose themselves on end-
`
`to-end traffic between clients and servers to provide additional functionality (such
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`as content caching and connection pooling). CoralCDN, for example, provided
`
`HTTP proxy-based content caching to both reduce load on Internet websites and
`
`speed up client access, while CoralCDN’s DNS service, as well as the OASIS and
`
`DONAR systems, performed locality- and load-aware proxy selection for clients.
`
`11. As can be seen from the above outline of my Educational Background and
`
`Employment, I have extensive experience in the fields of filesystems, web proxies
`
`and CDNs, DNS services, server selection, distributed systems, Internet
`
`architecture and routing, network and communication protocols, and server,
`
`middlebox, and gateway technologies. I deal frequently with the issues that are
`
`discussed in the ’959 patent.
`
`II. RETENTION & COMPENSATION
`
`12.
`
`I have been retained as an independent expert on behalf of Limelight for this
`
`matter. I am being compensated at my customary rate for the services I am
`
`providing in this case. The compensation is not contingent upon my performance,
`
`the outcome of this Inter Partes Review or any other proceeding, or any issues
`
`involved in or related to this Inter Partes Review, nor do I have a financial interest
`
`in the parties to this case.
`
`III. MATERIAL CONSIDERED
`
`13. The analysis provided in this Declaration is based on my education as
`
`well as my experience in the field. In addition to relying upon my knowledge based
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`
`on written materials and other information that was known in 1998, I have
`
`considered the exhibits to this Petition. A list of materials that I have considered for
`
`my analysis is attached as Appendix B.
`
`IV. OVERVIEW AND LEGAL STANDARDS
`
`14.
`
`I have been asked to provide opinions regarding the validity of claims
`
`of the ’959 patent in light of several prior art patents and publications.
`
`15.
`
`It is my understanding that a claimed invention is unpatentable under
`
`35 U.S.C. § 103 if the differences between the invention and the prior art are such
`
`that the subject matter as a whole would have been obvious at the time the alleged
`
`invention was made to a POSITA. This is sometimes described as “obviousness.”
`
`I understand that an obviousness analysis takes into account the level of ordinary
`
`skill in the art, the scope and content of the prior art, and the differences between
`
`the prior art and the claimed subject matter.
`
`16.
`
`It is my understanding that the Supreme Court, in KSR Int’l Co. v.
`
`Teleflex Inc., 550 U.S. 398 (2007) and other cases, has recognized several
`
`rationales for combining references or modifying a reference to show obviousness
`
`of the claimed subject matter. Some of these rationales include the following:
`
`combining prior art elements according to known methods to yield predictable
`
`results; simple substitution of one known element for another to obtain predictable
`
`results; a predictable use of prior art elements according to their established
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`functions; applying a known technique to a known device to yield predictable
`
`results; choosing from a finite number of identified, predictable solutions, with a
`
`reasonable expectation of success; and some teaching, suggestion, or motivation in
`
`the prior art that would have led a POSITA to modify the prior art or combine prior
`
`art teachings to arrive at the claimed invention. I also understand that a POSITA is
`
`a person of ordinary ingenuity and creativity, not an automaton.
`
`V. DESCRIPTION OF THE RELEVANT FIELD AND THE RELEVANT
`TIME FRAME
`
`17.
`
`I have carefully reviewed the specification, drawings, and claims of the ’959
`
`patent.
`
`18. Based on my review of these materials, and the materials listed in Appendix
`
`B, I believe that the relevant field for purposes of the ’959 patent is content storage
`
`and delivery over the Internet:
`
`“1. Technical Field
`
`This invention relates generally to information retrieval in a computer
`
`network. More particularly, the invention relates to a novel method of
`
`hosting and distributing content on the Internet that addresses the problems
`
`of Internet Service Providers (ISPs) and Internet Content Providers.” (Ex.
`
`1001 at 1:20-25).
`
`I have been informed that the relevant timeframe runs up to July 1998.
`
`19. As described above and in my C.V., I have extensive experience in the
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`10
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`

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`relevant technical field. Based on my experience and expertise in this field, I have
`
`an understanding of the relevant field in the relevant timeframe.
`
`VI. LEVEL OF ORDINARY SKILL IN THE ART
`
`20.
`
`I understand that my analysis and opinions expressed in this declaration
`
`must be rendered based on the perspective of a POSITA at the time of the
`
`invention. I also understand that a POSITA is a hypothetical person who is
`
`presumed to have known the relevant art at the time of the alleged invention
`
`claimed in the ’959 patent.
`
`21.
`
`I further understand that in determining the level of ordinary skill in the art, I
`
`am to consider factors including:
`
`(a) the type of problems encountered in the art or field of invention,
`
`(b) prior art solutions to those problems,
`
`(c) the rapidity with which innovations are made,
`
`(d) sophistication of the technology, and
`
`(e) the educational level of active workers in the field.
`
`22.
`
`I understand that a POSITA is a person of ordinary creativity, but not an
`
`automaton, and that a POSITA can often fit multiple patents or prior art references
`
`together like pieces of a puzzle as a result of this ordinary creativity. I also
`
`understand that I may consider the inferences and creative steps that a POSITA
`
`would employ. In addition, I understand that a POSITA would necessarily have
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`been capable of understanding the scientific and engineering principles applicable
`
`to the pertinent art.
`
`23.
`
`I also understand that when I consider what would have been obvious to a
`
`POSITA, I am not considering what would have been obvious to me at the time,
`
`nor to the inventors, judges, laymen, those skilled in other arts, or to geniuses in
`
`the art.
`
`24.
`
`In my opinion, a POSITA working in the field of content delivery over the
`
`Internet at the time of the invention (see § IV) would have been familiar with
`
`common techniques for storing and delivering content over the Internet. For
`
`example, storage service providers and global traffic management/load balancing
`
`services were well-known before July, 1998. (Ex. 1001 at 1:46-61 (web hosting
`
`farms providing content storage/delivery services).
`
` Client-server systems
`
`operating on the Internet using known server and client devices were also well-
`
`known prior to July, 1998. (Id. at 4:64-5:29).
`
`25. Software and protocols for delivering content over the Internet was also
`
`well-known and understood by those of ordinary skill. For example, Hypertext
`
`Transfer Protocol (HTTP) and Hypertext Markup Language (HTML) (id. at 1:27-
`
`45), Uniform Resource Locators (URLs) (id. at 1:35-38), and Domain Name
`
`Service (DNS) (id. at 10:10-16 (describing standard features of DNS), 12:9-16
`
`(describing caching as a part of the standard DNS system)), were in widespread
`
`12
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`

`
`use on the Internet and well-known to persons of ordinary skill before July, 1998.
`
`26.
`
`In my experience working and teaching in the field, most persons of
`
`ordinary skill in the art had at least a bachelor’s degree in Computer Science,
`
`Computer Engineering, or the equivalent. This was a rapidly-developing and
`
`highly technical field where that educational background would have been
`
`important.
`
`27.
`
`In addition to education, in my experience, a person of ordinary skill in the
`
`art had worked in the field for several years and had experience working with
`
`Internet content delivery.
`
`28. Thus, it is my opinion that a POSITA in the field of the ’959 patent would
`
`have at least a Bachelor’s degree in Computer Science, Computer Engineering, or
`
`the equivalent, and several years of experience in the field of distributed systems,
`
`name services, or Internet content delivery.
`
`29. My opinions have been rendered based on the perspective of a POSITA.
`
`VII. OVERVIEW OF THE ’959 PATENT
`
`30. The ’959 patent’s claims relate to a method and system for delivering
`
`content over the Internet. Internet content was known to include HTML files and
`
`embedded objects such as images, audio, video, and other HTML files, and this
`
`content was delivered over the Internet using known techniques that included
`
`HTTP, HTML, and URLs:
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`13
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`

`
`“In the Web environment, client machines effect transactions to Web
`servers using the Hypertext Transfer Protocol (HTTP), which is a
`known application protocol providing users access to files (e.g., text,
`graphics, images, sound, video, etc.) using a standard page description
`language known as Hypertext Markup Language (HTML). HTML
`provides basic document formatting and allows the developer to
`specify ‘links’ to other servers and files. In the Internet paradigm, a
`network path to a server is identified by a so-called Uniform Resource
`Locator (URL) having a special syntax for defining a network
`connection.” (Ex. 1001 at 1:28-38 (emphasis added) (Ex. 1001 at
`1:28-38; see also id. at 4:65-5:9 (describing FIG. 1) & 5:30-39
`(describing FIG. 2)).
`
`31. The claims of the ’959 patent, included below in § VII.A, involve a “content
`
`delivery network” or “CDN.” These terms are not used at all in the specification
`
`of the ’959 patent, but the claims show that a CDN includes two well-known types
`
`of servers: content servers and name servers.
`
`32. The ’959 patent explains that content servers are not limited to any particular
`
`type of server, and that content servers may consist of ordinary components
`
`including a processor, operating system (such as UNIX or Windows), and a web
`
`server application. (Ex. 1001 at 6:9-13).
`
`33. The ’959 patent also explains that name servers were well-known and
`
`commonly used as part of the Domain Name System (“DNS”). (See, e.g., Ex.
`
`1001 at 10:10-14, 12:9-16). I describe DNS and Name Servers in more detail in §
`
`14
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`

`
`VIII regarding Background Technologies.
`
`34. Thus, a POSITA was familiar with the subject matter of the ’959 patent
`
`before July, 1998. (See also Ex. 1001 at 1:46-52 & 1:62-2:3).
`
`A. The Challenged Claims
`
`35.
`
`I understand that the claims at issue, i.e. the Challenged Claims, are claims
`
`1, 2, and 9 of the ’959 patent. The Challenged Claims, annotated for ease of
`
`reference, are set forth below:
`
`1.
`
`Claim 1
`
`[Claim 1-Preamble] 1. A computer-implemented method of delivering
`text, graphics, images, downloads, audio or video on behalf of
`multiple content providers, comprising:
`
`[1a] operating content delivery network (CDN) content servers in
`multiple locations, each location with connectivity to one or more
`networks;
`
`[1b] operating multiple CDN name servers;
`
`[1c] receiving a first domain name service (DNS) query at a first CDN
`name server, the first DNS query including a data string of the form
`“string1 string2 string3”, where:
`
`[1c-i] string3 is a generic top level domain (gTLD),
`
`[1c-ii] string2 is separated from string3 by a period and is a name
`maintained by a service provider that operates the CDN content
`servers and the CDN name servers, and
`
`15
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`

`
`[1c-iii] string1 is separated from string2 by a period and comprises
`one or more sub-strings, where each sub-string is comprised of one of:
`letters, numbers, and combinations of letters and numbers, and any
`pair of sub-strings in string 1 are separated by a period;
`
`[1d] having the first CDN name server respond to the first DNS query
`by sending a response that includes a first set of one or more IP
`addresses, where a first end user request for content directed to one of
`the IP addresses of the first set causes the service provider to deliver
`the content to a first end user from a first CDN content server;
`
`[1e] receiving a second DNS query at a second CDN name server, the
`second DNS query also including the same data string that is received
`by the first CDN name server; and
`
`[1f] having the second CDN name server respond to the second DNS
`query by sending a response that includes a second set of one or more
`IP addresses, wherein a second end user request for content directed to
`one of the IP addresses of the second set causes the service provider to
`deliver the content to a second end user from a second CDN content
`server;
`
`[1g] the second set of one or more IP addresses differing from the first
`set of one or more IP addresses based on where the first and second
`DNS queries originate.
`
`2.
`
`Claim 2
`
`[Claim 2] The method as described in claim 1 wherein the CDN name
`servers are deployed at the multiple locations, and wherein the first
`
`16
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`

`
`and second DNS queries are received from respective first and second
`local DNS name servers.
`
`3.
`
`Claim 4
`
`[Claim 4] The method as described in claim 1 wherein the first CDN
`content server is closer to the first end user than is the second CDN
`content server.
`
`4.
`
`Claim 9
`
`[Claim 9] The method as described in claim 1 wherein the multiple
`locations are part of a network associated with the service provider.
`
`5.
`
`Claim 10
`
`[Claim 10] The method as described in claim 1 wherein the multiple
`CDN name servers are an authority for string2.string3.
`
`6.
`
`Claim 11
`
`[Claim 11] The method as described in claim 1 wherein the portion
`string2.string3 of the data string is used by the service provider for
`two or more content providers that use the CDN content servers to
`deliver their respective content.
`
`7.
`
`Claim 12
`
`[Claim 12] The method as described in claim 1 wherein the content
`requested by the first end user and the content requested by the second
`end user are one of the following: (a) the same content, (b) different
`content from the same content provider, and (c) different content from
`different content providers.
`
`17
`
`

`
`8.
`
`Claim 15
`
`[Claim 15] The method as described in claim 4 wherein the first CDN
`content server is not overloaded.
`
`9.
`
`Claim 16
`
`[Claim 16] The method as described in claim 15 wherein the first
`CDN content server is likely to have the content requested by the first
`end user.
`
`10. Claim 26
`
`[Claim 26] The method as described in claim 1 where the data string
`includes a value that encodes information about the content.
`
`11. Claim 28
`
`[Claim 28] The method as described in claim 1 wherein the content
`requested by the first end user is an embedded object.
`
`12. Claim 58
`
`[Claim 58-Preamble] A system for content delivery operated by a
`content delivery network (CDN) service provider for multiple content
`providers, comprising:
`
`[58a] a plurality of CDN content servers organized into sets; and
`
`[58b] a CDN name service having a set of name servers, the CDN
`name service receiving first and second DNS queries and returning a
`response to each of the first and second DNS queries;
`
`[58c] where the first DNS query includes a name that points to the
`CDN, the name of the form “string 1 string2 string3”, where:
`
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`

`
`[58c-i] string3 is a generic top level domain (gTLD),
`
`[58c-ii] string2 is separated from string3 by a period and is a name
`maintained by the CDN service provider, and
`
`[58c-iii] string 1 is separated from string2 by a period and comprises
`one or more sub-strings, where each sub-string is comprised of one of:
`letters, numbers, and combinations of letters and numbers, and any
`pair of sub-strings in string1 are separated by a period;
`
`[58d] where the second DNS query also includes the name;
`
`[58e] where a response to the first DNS query leads to a first subset of
`CDN content servers;
`
`[58f] where a response to the second DNS query leads to a second
`subset of CDN content servers; and
`
`[58g] where information within the responses to the first and second
`DNS queries varies based on where the respective first and second
`DNS queries originate.
`
`VIII. BACKGROUND TECHNOLOGIES
`A. HTTP and URLs
`
`36. The Internet uses various naming schemes to identify resources, including IP
`
`addresses and domain names. Computers that are connected to the Internet have
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`an IP address assigned to their network interfaces, such as “1.2.3.4.” Domain
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`names, such as “www.example.com” are human-readable and easy to remember,
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`while IP addresses are not. DNS provides a service that maps domain names to IP
`
`addresses, so that humans can use domains names while computer programs, after
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`using DNS to resolve a name to an IP address, can access remote resources at their
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`appropriate IP addresses. An entity called the Internet Assigned Numbers
`
`Authority (“IANA”) oversees global IP address allocation and management of the
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`DNS Root Zone, including maintaining the official list of the “top-level” domains
`
`such as “.com”, “.org”, “.net”, “.edu”, and the like.
`
`37. The World Wide Web, for example, names resources using URLs such as
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`“http://www.example.com/a/b/”. (Id. at § 3). The URL provides the browser
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`several pieces of information, including: the protocol to use (“http://”), the domain
`
`of the web server(s) associated with the request (“www.example.com”), and the
`
`path associated with the request (“/a/b/”).
`
`38. A user’s web browser then extracts the domain name from this URL, uses
`
`DNS to resolve this domain name to an IP address, then sends an HTTP request
`
`containing this URL to this IP address (which corresponds to a web server or web
`
`proxy).
`
`B. DNS, DNS resolution, and local name servers
`
`39. Before sending an HTTP request for a URL, a web browser first needs to
`
`learn the IP address of the server associated with the URL’s domain or hostname,
`
`e.g., the IP address of the domain “www.example.com.” It does so by resolving
`
`the domain name through the Domain Name System (DNS), which provides name
`
`resolution for the Internet in a decentralized fashion. There is not a single database
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`that maintains a mapping from all domain names to their corresponding network
`
`addresses. Rather, DNS is organized around the notion of hierarchical,
`
`administrative delegation. DNS is specified in two specifications from 1987, and
`
`these specifications specific well-known
`
`techniques
`
`for organizing and
`
`manipulating domain names. (See, e.g., RFC 1034 [Ex. 1007] at §§ 3.1-3.5 &
`
`4.2.2; RFC 1035 [Ex. 1008] at §§ 2 & 3).
`
`40. For example, once the fictional company “Example, Inc.” successfully
`
`applies to own the domain name “example.com,” it has the ability to host a website
`
`accessible to end users at the URL “http://www.example.com/”, as well as to create
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`subdomains
`
`of
`
`that
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`domain,
`
`e.g.,
`
`“www.example.com”
`
`and
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`“images.example.com.” (RFC 1034 [Ex. 1007] at §§ 3.1-3.5). It also defines
`
`which DNS servers are responsible for providing authoritative name resolution for
`
`its domain and subdomain(s). (Id. at 2.4).
`
`41. This process introduces the notion of different DNS record types. These
`
`record types include NameServer (NS) records, which define the names of
`
`nameservers that can provide authoritative answers for a domain, e.g., an NS
`
`record specifies that “ns.example.com” is an authoritative nameserver for
`
`“example.com.” (Id. at §§ 2.4, 6.2 (showing query examples)). Address (A)
`
`records provide a mapping
`
`from domains
`
`to network addresses, e.g.,
`
`“www.example.com” has an IP address 1.2.3.4. This information about a
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`domain’s authoritative nameservers is communicated to its parent domain, e.g., the
`
`domain registrar used by Example, Inc. will detail information about example.com
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`to the .com nameservers.
`
`42. DNS resolution
`
`therefore
`
`involves
`
`the process of finding (1)
`
`the
`
`authoritative nameserver(s) for a domain, and then (2) the IP address for the
`
`requested domain.
`
`43. To discover the initial NS record for a given domain name, DNS takes
`
`advantage of its hierarchical delegation and a process known as iterative
`
`resolut