IN THE UNITED STATES DISTRICT COURT
`FOR THE EASTERN DISTRICT OF TEXAS
`MARSHALL DIVISION
`
`ESTECH SYSTEMS, INC.,
`
`
`
`Plaintiff,
`
`v.
`
`
`
`C.A. 2:20-cv-00123-JRG (lead case)
`
`JURY TRIAL DEMANDED
`
`TARGET CORPORATION,
`
`PLAINSCAPITAL BANK,
`
`C.A. 2:20-cv-00122-JRG
`
`BOKF, NATIONAL ASSOCIATION,
`
`C.A. 2:20-cv-00126-JRG
`
`BBVA USA, and
`
`WELLS FARGO & COMPANY, AND
`WELLS FARGO BANK, N.A.,
`
`C.A. 2:20-cv-00127-JRG
`
`C.A. 2:20-cv-00128-JRG
`
`Defendants.
`
`
`
`
`
`
`
`
`
`EXPERT REPORT OF DR. SHUKRI SOURI REGARDING
`INVALIDITY OF THE ASSERTED PATENTS
`
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`I.
`
`INTRODUCTION .................................................................................................................. 3
`
`II. EXPERIENCE ........................................................................................................................ 3
`
`III. LEGAL STANDARDS .......................................................................................................... 6
`
`IV. US PATENT NO. 8,391,298 ................................................................................................ 11
`
`A. TECHNICAL BACKGROUND ....................................................................................... 11
`
`B. OVERVIEW OF US PATENT NO. 8,391,298 ................................................................ 17
`
`C. OVERVIEW OF PRIOR ART REFERENCES ............................................................... 22
`
`D. GROUND 1 – LUDWIG IN COMBINATION WITH REID .......................................... 40
`
`E. GROUND 2 – LUDWIG IN COMBINATION WITH HORI ......................................... 88
`
`F. GROUND 3 – WILSON AND GUY COMBINED WITH HORI ................................. 107
`
`V. US PATENT NO. 7,068,684 .............................................................................................. 139
`
`A. TECHNICAL BACKGROUND ..................................................................................... 139
`
`B. OVERVIEW OF US PATENT NO. 7,068,684 .............................................................. 145
`
`C. OVERVIEW OF THE PRIOR ART REFERENCES .................................................... 150
`
`D. GROUND 1 – CHIU ....................................................................................................... 161
`
`E. GROUND 2 – CHIU AND BUSTINI ............................................................................ 187
`
`F. GROUND 3 – LECOMTE AND BECHTOLSHEIM .................................................... 220
`
`G. GROUND 4 – CHIU IN COMBINATION WITH KRAMER ...................................... 242
`
`H. GROUND 5 – CHIU AND BUSTINI IN COMBINATION WITH KRAMER ............ 245
`
`I. GROUND 6 – LECOMTE AND BECHTOLSHEIM IN COMBINATION WITH
`KRAMER ............................................................................................................................... 247
`
`VI. US PATENT NO. 6,067,349 .............................................................................................. 249
`
`A. TECHNICAL BACKGROUND ..................................................................................... 249
`
`B. OVERVIEW OF US PATENT NO. 6,067, 349 ............................................................. 254
`
`C. OVERVIEW OF PRIOR ART REFERENCES ............................................................. 260
`
`D. GROUND 1 – ROGERS ................................................................................................. 273
`
`E. GROUND 2 – ITOH IN COMBINATION WITH KLAUSNER .................................. 290
`
`F. GROUND 3 – YUE IN COMBINATION WITH KLAUSNER .................................... 322
`
`VII. US PATENT NO. 7,123,699 .............................................................................................. 353
`
`A. TECHNICAL BACKGROUND ..................................................................................... 353
`
`B. OVERVIEW OF US PATENT NO. 7,123,699 .............................................................. 362
`
`C. OVERVIEW OF PRIOR ART REFERENCES ............................................................. 371
`
`D. GROUND 1 – BOWATER ............................................................................................. 383
`
`E. GROUND 2 – BOWATER IN COMBINATION WITH DAVIS ................................. 420
`
`F. GROUND 3 – BETTIS ................................................................................................... 436
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`G. GROUND 4 – BETTIS IN COMBINATION WITH DAVIS........................................ 466
`
`VIII. DECLARATION ................................................................................................................ 480
`
`APPENDIX A ................................................................................................................................. i
`
`
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`I.
`
`1.
`
`INTRODUCTION
`
`Exponent, Inc. (“Exponent”) has been retained by K&L Gates, LLP (“K&L Gates”) on
`
`behalf of Cisco System, Inc. (“Cisco”) to provide technical services and independent opinions on
`
`certain issues relating to the United States patent no. 8,391,298 (“the ’298 patent”), United States
`
`patent no. 7,068,684 (“the ’684 patent”), United States patent no. 6,067,349 (“the ’349 patent”),
`
`and United States patent no. 7,123,699 (“the ’699 patent”) (collectively the “Asserted Patents”).
`
`2.
`
`In particular, I, Shukri Souri, was requested to review the subject material of the patents
`
`listed above, along with certain of the claims therein, and opine as to whether the requirements of
`
`these claims are disclosed by various prior art references. The opinions and comments formulated
`
`during this assessment are based on observations and information available at the time of the
`
`investigation. The findings presented herein are made to a reasonable degree of scientific certainty.
`
`I have made every effort to accurately and completely investigate all areas of concern identified
`
`during our investigation. I reserve the right to supplement this report if and when new information
`
`becomes available after this report is signed, including, but not limited to, additional discovery or
`
`documents, opinions of the court, and the opinions and testimony of other experts in this case. I
`
`reserve the right to respond to any opinions offered by other experts and to any testimony offered
`
`at trial. And, I reserve the right to create graphics or demonstratives to support my opinions if
`
`called to testify at a hearing.
`
`II. EXPERIENCE
`
`3.
`
`I am a salaried employee of Exponent. Exponent charges $650 per hour for my time plus
`
`expenses for work performed in connection with this project. I have received no additional
`
`compensation for work in this case, and my compensation does not depend upon the contents of
`
`this report, any testimony I may provide, or the ultimate outcome of the case.
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`4.
`
`Exponent is an engineering and science consulting firm headquartered at 149
`
`Commonwealth Drive, Menlo Park, California, 94025. Exponent has been retained by counsel for
`
`Cisco in this matter to provide independent technical expert consulting services. I, Shukri Souri,
`
`am the investigator for the subject matter in this report.
`
`5.
`
`I am a Principal and a Corporate Vice President at Exponent. I am based in, and Director
`
`of, Exponent’s New York office. I am also the Director of Exponent’s Electrical Engineering and
`
`Computer Science practice.
`
`6.
`
`I received my B.A. (Honors) and M.A. in Engineering Science from Oxford University,
`
`United Kingdom; my Master’s degree in Electrical Engineering from Stanford University,
`
`California; and my Ph.D. in Electrical Engineering, also from Stanford University, California.
`
`7.
`
`Before returning to Stanford for my Ph.D., I was a member of the staff at Raychem’s
`
`Corporate Research and Development Laboratories, where I designed and built electronic systems
`
`to target safe operation of commercial and industrial equipment. My work resulted in patents
`
`awarded by the United States, European, Japanese, and World Intellectual Property Organization
`
`patent offices.
`
`8.
`
`Prior to Exponent, I co-founded two software firms, arcadiaOne, Inc. (“arcadiaOne”) and
`
`Merenga, Inc., where I directed development teams and contributed to architecture and design,
`
`source code development, testing, and deployment of enterprise-level software. At arcadiaOne, I
`
`was an Engineering Manager with responsibilities for the development of software for the
`
`synchronous transfer of digital assets between enterprises, such as from content providers to
`
`content portals over arcadiaOne’s real-time messaging platform. At Merenga, Inc., I was Chief
`
`Executive Officer and President with responsibilities for the firm’s operations in delivering an
`
`Internet platform for the optimization of asset allocation to investors.
`
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`9.
`
`I have also worked with government institutions to advise on technological investigations
`
`and challenges. In 2012, I was selected to participate in a United States National Academy of
`
`Engineering Frontiers of Engineering Symposium to help address future technological challenges
`
`facing society. In 2010, I advised members of the United States Congress in their Investigation
`
`into Instances of Sudden Unintended Acceleration in Toyota Made Vehicles, as instituted by the
`
`Committee on Energy and Commerce in the House of Representatives. I led Exponent’s computer
`
`systems and software investigation of Toyota vehicles allegedly experiencing unintended
`
`acceleration.
`
`10. My experience with telephony, Internet communications technologies, messaging
`
`platforms, and software development spans over 25 years, during which time I have worked on
`
`telecommunications equipment, computer systems for real-time messaging, and software systems
`
`for Internet communications, including quantitative information and rich media streaming such as
`
`audio and video. My focus has been on the reliability and safety of such software systems,
`
`particularly as it relates to precision, accuracy, and robustness. Often, these are complex systems
`
`with integration challenges and involving fault tolerance.
`
`11. My knowledge of programming languages includes C, C++, Java, Matlab, Python, Fortran,
`
`APL, and HP-BASIC, among others. I am currently a Senior Member of the Institute of Electrical
`
`and Electronics Engineers (“IEEE”) and a Member of the Institution of Engineering and
`
`Technology in the United Kingdom.
`
`12.
`
`Additional details about my background and expertise, including publications, are further
`
`described in my professional resume, which is attached as Appendix A to this report.
`
`13. Materials I have considered in relation to this report include the Asserted Patents and
`
`associated prosecution histories, the prior art references relied upon within this report, and other
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`cited documents as indicated in footnotes. In forming my opinions, I have relied upon my
`
`education, knowledge of telecommunications and associated networking technology, and related
`
`experience.
`
`III. LEGAL STANDARDS
`
`14.
`
`I am not a lawyer, and am not opining regarding legal matters. I have been informed by
`
`counsel that the property right protected by a patent is defined by the claims of the patent, which
`
`appear as numberered paragprahs at the end of the text. Each claim stands on its own when
`
`determining infringement and invalidity. These are the “metes and bounds” that define the scope
`
`of the property rights. Thus, the first steps in analyzing infrigment or validity of a patent claim
`
`begins with an analysis of the claim itself, also referred to as “claim construction.”
`
`15.
`
`After reviewing the language used in the claim, the patent specification and prosecution
`
`history are reviewed to ensure that they do not alter the way one skilled in the art would understand
`
`a claim limitation. At times, the specification might provide further clarification as to the meaning
`
`of a claim limitation—including its plain and ordinary meaning as viewed from the the perspective
`
`of the skilled artisan at the time of the patent’s effective filing date. I have been asked to assume
`
`the Asserted Patents are entitled to the filing date on its cover. These dates provide the temproral
`
`context from which the claims are interpreted. I note the ’699 and ’298 Patents are continuations-
`
`in-part of the earlier filed ’684 Patent and that each adds additional subject matter, including
`
`figures, to the disclosure of the earlier filed ’684 Patent. However, as set forth in greater detail
`
`below, whether these two continuations in part are entitled to the earlier filing date of the ’684
`
`Patent or their own respective filing dates, my opinions do not change.
`
`16.
`
`To understand the perspective of the skilled artisan, one must determine the field of the art
`
`to which the patent pertains, and then the background of one of ordinary skill in the art. The person
`
`of ordinary skill in the art (“POSITA”) is a hypothetical person who is presumed to have known
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`the relevant art at the time of the invention. Factors that may be considered in determining the
`
`level of ordinary skill in the art may include: (1) type of problems encountered in the art; (2) prior
`
`art solutions to those problems; (3) rapidity with which innovations are made; (4) sophistication
`
`of the technology; and (5) educational level of active workers in the field.
`
`17.
`
`In additon to claim language, patent specification and prosecution history—which are the
`
`preferred sources for claim construction—outside sources may be referenced to construe claim
`
`terms. I understand this evidence to be extrinsic evidence (e.g., dictionary meanings). I have
`
`included a claim construction section below for each patent and have applied the constructions
`
`therein as applicable. If no construction was provided, I have applied the “plain and ordinary
`
`meaning” of the term as judged by how a POSTA would understand the term as of the effective
`
`filing date of the patent in view of the specification, prosecution history, and claim language itself.
`
`18.
`
`It is my understanding that there are two ways that prior art references can render a patent
`
`claim invalid: anticipation and obviousness. Counsel has informed me all issued claims of a patent,
`
`including those I have reviewed for this report, are presumed valid. I have further been informed
`
`that, in order to establish a patent claim is invalid, the defendant has to establish, by clear and
`
`convincing evidence, that the claim is invalid. Counsel has told me that clear and convincing
`
`means it is highly probable that the claim is invalid. In other words, when balancing the evidence,
`
`clear and convincing evidence requires that the scale tip heavily toward invalidity. I have further
`
`been told that this burden is not as high as “beyond a reasonable doubt,” which is a higher
`
`evidentiary burden applicable in criminal cases.
`
`19.
`
`I understand that there is a set process to determine anticipation (i.e., the claimed invention
`
`is not new or not novel under section 102 of the Patent Act). I understand that anticipation requires
`
`that: 1) the claims of a patent are properly construed, and 2) the claim language is then compared
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`to the prior art on a limitation-by-limitation basis. If the prior art references contain all the elements
`
`of the claim language (explicitly or inherently), arranged as in the claims, that is considered
`
`anticipation. For example, if a claim simply specifies the limitation A, B and C arranged as
`
`required by the claim, the claim is anticipated. For a prior art reference to “teach” the limitations
`
`of a claims, a person of ordinary skill in the art must recognize the limitations as disclosed,
`
`expressly or inherently, in that single reference and, to the extet the claim specifies a relationship
`
`between the limitations, the disclosed limitations must be in the same relationship between the
`
`limitations.
`
`20.
`
`I understand that an invention is obvious when the differences between the subject matter
`
`sought to be patented and the prior art are such that the subject matter as a whole would have been
`
`obvious at the time of the invention to a POSITA. For this reason, I have been asked to consider
`
`the level of ordinary skill in the field that someone would have had at the time of the claimed
`
`invention.
`
`21.
`
`Counsel instructed me that in an obviousness determination the factors to consider are: 1)
`
`the scope and content of the prior art (some of this prior art is presented herein, and other content
`
`of such prior art comes from my decades of experience in the industry), 2) the differences between
`
`the prior art and the asserted claims (of which, as set forth in greater detail below is minimal), 3)
`
`the level of ordinary skill in the pertinent art (as set forth in each patent-specific section below),
`
`and 4) the existence of secondary considerations of non-obviousness. Secondary considerations
`
`include: a long-felt need; commercial success; unexpected results; praise of the invention;
`
`licensing; copying; failure of others; and skepticism by experts. At this point, I have not considered
`
`any evidence of secondary considerations as none has been provided to me. I reserve my right to
`
`assess and respond to any such evidence should it become part of the record.
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`22.
`
`Counsel also instructed me that an obviousness inquiry may involve assessing the
`
`motivation of a POSITA to combine references. For a claim to be obvious, all limitations of the
`
`claimed invention must be present in two or more prior art references, or in prior art references
`
`combined with the common knowledge of a skilled artisan. Thus, if a claim specifies the
`
`limitations A, B, C, and only one references show A and B, then C must be disclosed in a separate
`
`reference, or, alternatively, must be part of the common knowledge of one of ordinary skill in the
`
`art. Further, the prior art references themselves may provide a suggestion, motivation, or reason to
`
`combine, but such a basis for combination need not come from the references themselves.
`
`However, I have been instructed that an explicit teaching, suggestion, or motivation need not be
`
`present in a reference to support combinability of references.
`
`23.
`
`It is also my understanding through Counsel that the combination of familiar elements
`
`according to known methods is likely to be obvious when it does no more than yield predictable
`
`results. It is further my understanding that a proper obviousness analysis focuses on what was
`
`known or obvious to a POSITA, not just the patentee.
`
`24.
`
`I have been told that combinations of the prior art should be analyzed based on the mindset
`
`of a POSITA at the time the invention was made. Counsel has advised me that in rendering my
`
`opinions, I should cast my mind back to the time the patent was filed to occupy the mind of one
`
`skilled in the art at that time who is presented only with the references, and who is normally guided
`
`by the then-accepted wisdom in the art.
`
`25.
`
`I understand that I am to perform the task referenced in the preceding paragraph without
`
`using “hindsight” reasoning. For example, it is improper to use the claim as a template for piecing
`
`together components (or steps) found in separate prior art reference. Instead, I was asked to
`
`consider the feasibility and combinability of references through the eyes of a POSITA—using
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`common knowledge at the relevant time periods for the various patents I have been asked to
`
`analyze. As I describe below, the individual references contain statements and teachings that
`
`motivate those of ordinary skill in the art to look to the other references in the combinations I was
`
`asked to consider.
`
`26.
`
`I understand that relevant considerations for combining references include at least the
`
`following:
`
`(A) Combining prior art elements according to known methods to yield predictable results;
`
`(B) Simple substitution of one known element for another to obtain predictable results;
`
`(C) Use of known techniques to improve similar devices, methods, or products in the same way;
`
`(D) Applying a known technique to a known device, method, or product ready for improvement
`
`to yield predictable results;
`
`(E) “Obvious to try,” which is choosing from a finite number of identified, predictable solutions
`
`with a reasonable expectation of success;
`
`(F) Known work in one field of endeavor may prompt variations of it for use in either the same
`
`field or a different one based on design incentives or other market forces if the variations are
`
`predictable to a POSITA; and
`
`(G) Some teaching, suggestion, or motivation in the prior art that would have led a POSITA to
`
`modify the prior art reference or to combine prior art reference teachings to arrive at the claimed
`
`invention.
`
`27.
`
`I have kept these considerations in mind when offering the opinions below regarding
`
`combinability, as well as when interpreting the scope and content of the references.
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`IV. US PATENT NO. 8,391,298
`
`A. TECHNICAL BACKGROUND
`
`28.
`
`The subject matter of the ’298 patent relates to a phone directory for use with a Voice over
`
`Internet Protocol (“VoIP”) telephone system. VoIP is a method for transmitting voice
`
`communication, or other multimedia information that is intended to be consumed in real-time,
`
`through computer networks using the Internet Protocol (“IP”). The use of computer networks—
`
`which typically involves the Internet for communication beyond a single local area network
`
`(“LAN”)—provides an alternative to using the public switched telephone network, which is
`
`typically used by traditional telephones for transmitting standard telephone signals.
`
`29.
`
`Since the claims relevant to this report place limitations upon how a phone directory for a
`
`telecommunications system is implemented throughout a network, such as placing restrictions
`
`upon the network architecture associated with such a directory, it is useful to discuss some
`
`technical background relevant to computer networking.
`
`30.
`
`In general, in the context of telecommunications, a network is comprised of a group of
`
`devices that are connected via appropriate physical infrastructure and that use a set of common
`
`protocols to communicate. For example, a typical computer network includes various connected
`
`computers (e.g., personal computers, network telephony devices, or the like) that each have
`
`suitable communication hardware for transmitting and receiving information to and from a
`
`network (e.g., ethernet hardware or wireless antennas); using this communication hardware, the
`
`computers connect to the network via a router, hub, or switch device that facilitates communication
`
`between the various connected computers. In some small networks, such as a small office or an
`
`individual dwelling, there may be a single router, hub, or switch device to which all the computers
`
`within the network connect; alternatively, for networks that span a larger local area—such as
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`throughout an office building—there may be multiple routers, hubs, or switch devices, with each
`
`computer connecting to the most accessible such device to access the network.
`
`31.
`
`Networks that are largely self-contained (i.e., that define their own set of localized network
`
`addresses and span a relatively small physical region) are generally referred to as LANs. Within a
`
`LAN, devices communicate with each other either using a peer-to-peer system, which is common
`
`for small LANs such as a single home network, or using a client/server model, which is common
`
`for medium or larger LANs such as in an office building, on a school campus, or the like. In a
`
`peer-to-peer LAN, the router, hub, or switch device enables communication between connected
`
`computers by directly transmitting signals between the sender and destination computers: in effect,
`
`the LAN router, hub, or switch handles delivery of information sent from a computer by directing
`
`it to the intended recipient. In contrast, a client/server-based LAN includes at least one server
`
`within the LAN to which the other devices connect, and which hosts network resources to facilitate
`
`communication between the connected devices.1 The connected computers then access network
`
`functionality using the client-server model where an application running on an individual computer
`
`(i.e., the client) makes requests for service to a different networked computer that provides this
`
`service (i.e., the server).
`
`32.
`
`A LAN can also include hardware for facilitating communication with computers that are
`
`connected to other networks that are not directly part of the LAN. For example, a LAN can include
`
`one or more modems, or other such access gateway devices, that enable connection to another
`
`LAN. Such access gateway devices, which are sometimes referred to as edge routers, are similar
`
`to a router device that coordinates communication with an individual LAN, but rather than connect
`
`individual computers to a LAN, an access gateway device connects to other access gateways on
`
`
`1 https://www.tomshardware.com/reviews/local-area-network-wi-fi-wireless,3020-2.html. Accessed December 16,
`2020.
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`different LANs to provide a means for inter-LAN communication.2 In general, an arrangement
`
`where LANs are coupled together to form a larger network of networks is known as a wide-area
`
`network (“WAN”).3 Indeed, the Internet is an example of a WAN that is publicly accessible and
`
`global in scale: a computer within a LAN, such as a home network, or an office LAN, may connect
`
`to the Internet via a router and then access other distant computers (which may be within their own
`
`LAN) that are also connected to the Internet.
`
`33.
`
`Thus, in the context of telecommunications, key networking hardware includes: 1) a
`
`mechanism for each connected device to transmit and receive signals; 2) at least one or more
`
`routers, hubs, or switch devices that enable the other devices to connect to the LAN; 3) additional
`
`local servers to host network resources within the LAN if applicable; and, 4) network access
`
`gateways for accessing one or more WANs to enable communication with other devices that are
`
`outside of the LAN.
`
`34.
`
`Although there are many architectures that can be used to implement a network, each of
`
`which may have a specific hardware configuration and corresponding set of situation-dependent
`
`advantages or disadvantages, a typical computer network with which an ordinary network engineer
`
`would be familiar is likely to involve multiple LANs connected to each other by at least one WAN,
`
`and potentially many WANs. Communication between computers within the same LAN is
`
`generally handled locally by a router device or server that is in the LAN, wherein the router device
`
`or server facilitates delivery of transmitted information from the sending computer to the intended
`
`destination computer. Communication between computers that are in different LANs requires an
`
`
`2 In small LANs, such as an individual home network comprising one or a few devices, the router that coordinates
`the LAN can also provide access to a WAN. For example, a home router device may provide both the routing
`functionality for an associated home LAN and also comprise a modem device for facilitating connection to the
`Internet.
`3 https://www.comptia.org/content/guides/what-is-a-wide-area-network. Accessed December 16, 2020.
`
`2007846.001 - 5130
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`13
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`Ex. 2003
`Cisco Systems, Inc. v. Estech Systems, Inc.
`
`

`

`
`
`additional layer of coordination to facilitate transmission between the LANs via a WAN: the
`
`sender’s communication is first transmitted to the LAN’s local access gateway device, and this
`
`local access gateway transmits the information to a distant access gateway within the destination
`
`LAN, which then handles transmitting the information to the intended destination computer that
`
`is part of this destination LAN. These network architectures and components were all considered
`
`generic and conventional, and would have been well-known to a POSITA as of the filing date of
`
`all of the Asserted Patents.
`
`35.
`
`In addition to a mechanism to physically distribute information between connected devices,
`
`network communication requires the use of suitable communication protocols to enable encoding
`
`of information and to ensure the network infrastructure can properly handle delivery of this
`
`information to its destination. Of particular relevance to the field of VoIP communication systems
`
`is the IP, which is a primary communication protocol within the IP suite.4 Similar to the Open
`
`Systems Interconnection model (“OSI model”),5 the IP suite is a conceptual model and a set of
`
`communication protocols used for transmission of information throughout computer networks.
`
`The IP is located within the Internet layer of the IP suite, which is broadly comparable to the
`
`Network layer of the OSI model,6 and defines packet structures for encapsulating payload data
`
`along with header information that specifies the network location of the sender and recipient with
`
`source and destination IP addresses, respectively.
`
`36.
`
`The Internet layer of the IP suite is used in conjunction with the Transport layer, which
`
`facilitates delivery of IP packets between different network locations and adds various
`
`
`4 In addition to use for traffic on the Internet, the IP is widely used throughout other LANs and WANs that
`connect computer devices.
`5 See ISO/IEC 7498-1, “Information technology – Open Systems Interconnection – Basic Reference Model: The
`Basic Model,” Second edition, 1994.
`6 See https://www.electronicdesign.com/unused/article/21800810/whats-the-difference-between-the-osi-
`sevenlayer-network-model-and-tcpip. Accessed December 16, 2020.
`
`2007846.001 - 5130
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`14
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`Ex. 2003
`Cisco Systems, Inc. v. Estech Systems, Inc.
`
`

`

`
`
`functionality for establishing connections between the source and destination and managing the
`
`flow, reliability, and other such performance characteristics of communication between these
`
`locations. For example, the most common Transport layer protocol for Internet communication is
`
`the Transmission Control Protocol (“TCP”), which is used to divide information into a sequence
`
`of many IP packets to be transmitted from the source, and to properly order packets and reconstruct
`
`information from packets received at a destination. The use of IP with TCP is often referred to as
`
`“TCP/IP” communication, where TCP is used to divide information into many IP packets for
`
`transmission from a source, and to facilitate various error checking and data integrity functionality
`
`when assembling the received information at the destination, such as correctly sequencing packets
`
`that arrive out of order and re-requesting missing packets.
`
`37.
`
`For VoIP applications, however, much of the error correction functionality provided by the
`
`TCP may be undesirable due to the real-time nature of how the received signal may be consumed.
`
`For example, if a received transmission is being converted into an audio signal in real-time, there
`
`may be no benefit to re-requesting a missing packet because by the time such a re-request is
`
`fulfilled, the data may no longer be required. Thus, for VoIP or other real-time multimedia
`
`transmissions, the User Datagram Protocol (“UDP”), which provides some data integrity ch