UNITED STATES PATENT AND TRADEMARK OFFICE
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`
`Juniper Networks, Inc. & Palo Alto Networks, Inc.,
`Petitioners,
`
`v.
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`Packet Intelligence LLC,
`Patent Owner.
`
`
`In re Inter Partes Review of:
`U.S. Patent No. 6,651,099; 6,665,725; 6,771,646; 6,839,751; and 6,954,789
`
`DECLARATION OF KEVIN C. ALMEROTH, PH.D.
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`TABLE OF CONTENTS
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`I.
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`Introduction .......................................................................................................... 1
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`II. Background and Qualifications ........................................................................... 1
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`III. Compensation ...................................................................................................... 9
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`IV. Materials Reviewed ............................................................................................. 9
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`V. Overview of Basic Network Principles ............................................................. 10
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`A. The OSI Model ............................................................................................... 17
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`B. Data Encapsulation ......................................................................................... 18
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`C. Prior Art Network Monitors ........................................................................... 21
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`VI. Claim Construction ............................................................................................ 23
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`A. Person of Ordinary Skill in the Art ................................................................ 23
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`B. “conversational flow” ..................................................................................... 23
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`VII.
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`Riddle .......................................................................................................... 26
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`A. Overview ........................................................................................................ 26
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`B. Opinions Regarding Riddle’s Traffic Classes ................................................ 27
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`C. Opinions Regarding Riddle’s Service Aggregate Traffic Classes ................. 30
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`D. Opinions Regarding Riddle’s Recognition of PointCast Traffic ................... 32
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`VIII. Yu ............................................................................................................... 33
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`A. Overview ........................................................................................................ 33
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`B. Yu Does Not Teach Conversational Flows .................................................... 34
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`IX. RFC 1945 ........................................................................................................... 35
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`A. Overview ........................................................................................................ 35
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`B. RFC 1945 Does Not Teach Conversational Flows ........................................ 35
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`I, Kevin C. Almeroth, declare as follows:
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`I. Introduction
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`1. My name is Kevin C. Almeroth. I have been retained by Heim, Payne
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`& Chorush LLP, on behalf of Packet Intelligence LLC, and I am submitting this
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`declaration to offer my independent expert opinion concerning certain issues raised
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`in the seven co-pending Petitions for Inter Partes Review (“Petition”) regarding five
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`related patents. Specifically, Petitioners filed seven (7) IPR Petitions: (1) IPR2020-
`
`00335 concerning U.S. Patent No. 6,651,099, (2) IPR2020-00336 concerning U.S.
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`Patent No. 6,665,725, (3) IPR2020-00337 concerning U.S. Patent No. 6,771,646, (4)
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`IPR2020-00338 concerning U.S. Patent No. 6,839,751, (5) IPR2020-00339
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`concerning U.S. Patent No. 6,954,789, (6) IPR2020-00485 concerning U.S. Patent
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`No. 6,651,099, and (7) IPR2020-00486 concerning U.S. Patent No. 6,954,789
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`(collectively, the “Asserted IPRs” and “Challenged Patents”, respectively).
`
`II. Background and Qualifications
`
`2.
`
`I hold three degrees from the Georgia Institute of Technology: (1) a
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`Bachelor of Science degree in Information and Computer Science (with minors in
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`Economics, Technical Communication, American Literature) earned in June, 1992;
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`(2) a Master of Science degree in Computer Science (with specialization in
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`Networking and Systems) earned in June, 1994; and (3) a Doctor of Philosophy
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`(Ph.D.) degree in Computer Science (Dissertation Title: Networking and System
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`Support for the Efficient, Scalable Delivery of Services in Interactive Multimedia
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`System, minor in Telecommunications Public Policy) earned in June, 1997.
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`3.
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`One of the major themes of my research has been the delivery of
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`multimedia content and data between computing devices and users. In my research
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`I have looked at large-scale content delivery systems and the use of servers located
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`in a variety of geographic locations to provide scalable delivery to hundreds, even
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`thousands, of users simultaneously. I have also looked at smaller-scale content
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`delivery systems in which content, including interactive communication like voice
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`and video data, is exchanged between computers and portable computing devices.
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`As a broad theme, my work has examined how to exchange content more efficiently
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`across computer networks, including the devices that switch and route data traffic.
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`More specific topics include the scalable delivery of content to many users, mobile
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`computing, satellite networking, delivering content to mobile devices, and network
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`support for data delivery in wireless and sensor networks.
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`4.
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`Beginning in 1992, when I started graduate school, the focus of my
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`research was on the provision of interactive functions (VCR-style functions like
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`pause, rewind, and fast-forward) for near video-on-demand systems in cable
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`systems, in particular, how to aggregate requests for movies at a cable head-end and
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`then how to satisfy a multitude of requests using one audio/video stream broadcast
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`to multiple receivers simultaneously. Continued evolution of this research has
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`resulted in the development of new techniques to scalably deliver on-demand
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`content, including audio, video, web documents, and other types of data, through the
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`Internet and over other types of networks, including over cable systems, broadband
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`telephone lines, and satellite links.
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`5.
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`An important component of my research from the very beginning has
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`been investigating the challenges of communicating multimedia content between
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`computers and across networks. Although the early Internet was designed mostly
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`for text-based non-real time applications, the interest in sharing multimedia content
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`quickly developed. Multimedia-based applications ranged from downloading
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`content to a device to streaming multimedia content to be instantly used. One of the
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`challenges was that multimedia content is typically larger than text-only content but
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`there are also opportunities to use different delivery techniques since multimedia
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`content is more resilient to errors. I have worked on a variety of research problems
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`and used a number of systems that were developed to deliver multimedia content to
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`users.
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`6.
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`In 1994, I began to research issues associated with the development and
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`deployment of a one-to-many communication facility (called “multicast”) in the
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`Internet (first deployed as the Multicast Backbone, a virtual overlay network
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`supporting one-to-many communication). Some of my more recent research
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`endeavors have looked at how to use the scalability offered by multicast to provide
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`streaming media support for complex applications like distance learning, distributed
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`collaboration, distributed games, and large-scale wireless communication. Multicast
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`has also been used as the delivery mechanism in systems that perform local filtering
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`(i.e., sending the same content to a large number of users and allowing them to filter
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`locally content in which they are not interested).
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`7.
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`Starting in 1997, I worked on a project to integrate the streaming media
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`capabilities of the Internet together with the interactivity of the web. I developed a
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`project called the Interactive Multimedia Jukebox (IMJ). Users would visit a web
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`page and select content to view. The content would then be scheduled on one of a
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`number of channels, including delivery to students in Georgia Tech dorms delivered
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`via the campus cable plant. The content of each channel was delivered using
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`multicast communication.
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`8.
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`In the IMJ, the number of channels varied depending on the capabilities
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`of the server including the available bandwidth of its connection to the Internet. If
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`one of the channels was idle, the requesting user would be able to watch their
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`selection immediately. If all channels were streaming previously selected content,
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`the user's selection would be queued on the channel with the shortest wait time. In
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`the meantime, the user would see what content was currently playing on other
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`channels, and because of the use of multicast, would be able to join one of the
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`existing channels and watch the content at the point it was currently being
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`transmitted.
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`9.
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`The IMJ service combined the interactivity of the web with the
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`streaming capabilities of the Internet to create a jukebox-like service. It supported
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`true Video-on-Demand when capacity allowed, but scaled to any number of users
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`based on queuing requested programs. As part of the project, we obtained
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`permission from Turner Broadcasting to transmit cartoons and other short-subject
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`content. We also attempted to connect the IMJ into the Georgia Tech campus cable
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`television network so that students in their dorms could use the web to request
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`content and then view that content on one of the campus's public access channels.
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`10. More recently, I have also studied issues concerning how users choose
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`content, especially when considering the price of that content. My research has
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`examined how dynamic content pricing can be used to control system load. By
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`raising prices when systems start to become overloaded (i.e., when all available
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`resources are fully utilized) and reducing prices when system capacity is readily
`
`available, users' capacity to pay as well as their willingness can be used as factors in
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`stabilizing the response time of a system. This capability is particularly useful in
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`systems where content is downloaded or streamed on-demand to users.
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`11. As a parallel research theme, starting in 1997, I began researching
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`issues related to wireless devices and sensors. In particular, I was interested in
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`showing how to provide greater communication capability to "lightweight devices,"
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`i.e., small form-factor, resource-constrained (e.g., CPU, memory, networking, and
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`power) devices. Starting by at least 2004 I researched techniques to wirelessly
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`disseminate information, for example advertisements, between users using ad hoc
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`networks. In the system, called Coupons, an incentive scheme is used to encourage
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`users to relay information, including advertisements, to other nearby users.
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`12. Starting in 1998, I published several papers on my work to develop a
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`flexible, lightweight, battery-aware network protocol stack. The lightweight
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`protocols we envisioned were similar in nature to protocols like Universal Plug and
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`Play (UPnP) developed by the Digital Living Network Alliance (DLNA).
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`13. From this initial work, I have made wireless networking, including ad-
`
`hoc and mesh networks, and wireless devices, one of the major themes of my
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`research. One topic includes development of applications for mobile devices, for
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`example, virally exchanging and tracking "coupons" through "opportunistic contact"
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`(i.e., communication with other devices coming into communication range with a
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`user). Other topics include building network communication among a set of mobile
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`devices unaided by any other kind of network infrastructure. Yet another theme is
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`monitoring wireless networks, in particular different variants of IEEE 802.11
`
`compliant networks, to (1) understand the operation of the various protocols used in
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`real-world deployments, (2) use these measurements to characterize use of the
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`networks and identify protocol limitations and weaknesses, and (3) propose and
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`evaluate solutions to these problems.
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`14. Protecting networks, including their operation and content, has been an
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`underlying theme of my research almost since the beginning. Starting in 2000, I have
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`been involved in several projects that specifically address security, network
`
`protection, and firewalls. After significant background work, a team on which I was
`
`a member successfully submitted a $4.3M grant proposal to the Army Research
`
`Office (ARO) in the Department of Defense to propose and develop a high-speed
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`intrusion detection system. Once the grant was awarded, we spent several years
`
`developing and meeting the milestones of the project. I have also used firewalls in
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`developing techniques for the classroom to ensure that students are not distracted by
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`online content.
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`15. As an important component of my research program, I have been
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`involved in the development of academic research into technology available in the
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`market place. One aspect of this work is my involvement in the Internet Engineering
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`Task Force (IETF) including many content delivery related working groups like the
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`Audio Video Transport (AVT) group, the MBone Deployment (MBONED) group,
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`Source Specific Multicast (SSM) group, the Inter- Domain Multicast Routing
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`(IDMR) group, the Reliable Multicast Transport (RMT) group, the Protocol
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`Independent Multicast (PIM) group, and others. I have also served as a member of
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`the Multicast Directorate (MADDOGS), which oversaw the standardization of all
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`things related to multicast in the IETF. Finally, I was the Chair of the Internet2
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`Multicast Working Group for seven years.
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`16.
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`I am an author or co-author of approximately 200 technical papers,
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`published software systems, IETF Internet Drafts and IETF Request for Comments
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`(RFCs).
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`17. My involvement in the research community extends to leadership
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`positions for several journals and conferences. I am the co-chair of the Steering
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`Committee for the ACM Network and System Support for Digital Audio and Video
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`(NOSSDAV) workshop and on the Steering Committees for the International
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`Conference on Network Protocols (ICNP), ACM Sigcomm Workshop on
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`Challenged Networks (CHANTS), and IEEE Global Internet (GI) Symposium. I
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`have served or am serving on the editorial boards of IEEE/ACM Transactions on
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`Networking, IEEE Transactions on Mobile Computing, IEEE Transactions on
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`Networks and System Management, IEEE Network, ACM Computers in
`
`Entertainment, AACE Journal of Interactive Learning Research (JILR), and ACM
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`Computer Communications Review.
`
`18.
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`I have co-chaired a number of conferences and workshops including
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`the IEEE International Conference on Network Protocols (ICNP), ACM
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`International Conference on Next Generation Communication (CoNext), IEEE
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`Conference on Sensor, Mesh and Ad Hoc Communications and Networks (SECON),
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`International Conference on Communication Systems and Networks (COMSNETS),
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`IFIP/IEEE International Conference on Management of Multimedia Networks and
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`Services (MMNS), the International Workshop On Wireless Network Measurement
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`(WiNMee), ACM Sigcomm Workshop on Challenged Networks (CHANTS), the
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`Network Group Communication (NGC) workshop, and the Global Internet
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`Symposium; and I have been on the program committee of numerous conferences.
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`19. Furthermore, in the courses I teach, the class spends significant time
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`covering all aspects of the Internet including each of the layers of the Open System
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`Interconnect (OSI) protocol stack commonly used in the Internet. These layers
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`include the physical and data link layers and their handling of signal modulation,
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`error control, and data transmission. I also teach DOCSIS, DSL, and other
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`standardized protocols for communicating across a variety of physical media
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`including cable systems, telephone lines, wireless, and high-speed Local Area
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`Networks (LANs). I teach the configuration and operation of switches, routers, and
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`gateways including routing and forwarding and the numerous respective protocols
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`as they are standardized and used throughout the Internet. Topics include a wide
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`variety of standardized Internet protocols at the Network Layer (Layer 3), Transport
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`Layer (Layer 4), and above.
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`20.
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`In addition to having co-founded a technology company myself, I have
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`worked for, consulted with, and collaborated with companies such as IBM, Hitachi
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`Telecom, Digital Fountain, RealNetworks, Intel Research, Cisco Systems, and
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`Lockheed Martin.
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`21.
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`I am a Member of the Association of Computing Machinery (ACM)
`
`and a Fellow of the Institute of Electrical and Electronics Engineers (IEEE).
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`22. Additional details about my employment history, fields of expertise,
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`and publications are further included in my curriculum vitae, attached as Exhibit
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`2043.
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`III. Compensation
`
`23.
`
`I am being compensated as an expert witness in this matter at $700 per
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`hour in addition to out-of-pocket expenses. I have received no additional
`
`compensation for my work on this matter and my compensation does not depend,
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`and has not ever depended in any way, on my opinion as expressed in this
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`Declaration, in any testimony that I may give, or on the outcome of this case.
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`IV. Materials Reviewed
`
`24.
`
`I have reviewed the following materials in connection with the
`
`preparation of this Declaration:
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`• Provisional Patent Application No. 60/141,903 (Ex. 1016);
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`• U.S. Patent No. 6,651,099 (Ex. 1001) and its file history (Ex. 1017);
`
`• U.S. Patent No. 6,665,725 (Ex. 1002) and its file history (Ex. 1018);
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`• U.S. Patent No. 6,771,646 (Ex. 1003) and its file history (Ex. 1019);
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`• U.S. Patent No. 6,839,751 (Ex. 1004) and its file history (Ex. 1021);
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`• U.S. Patent No. 6,954,789 (Ex. 1005) and its file history (Ex. 1022);
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`• U.S. Patent No. 6,412,000 (“Riddle”) (Ex. 1008);
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`• U.S. Patent No. 6,625,150 (“Yu”) (Ex. 1011);
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`• RFC 1945 (Ex. 1010);
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`• The Petitions for Inter Partes Review for IPR2020-00335, IPR2020-
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`00336, IPR2020-00337, IPR2020-00338, IPR2020-00339, IPR2020-
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`00485, and IPR2020-00486; and
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`• Declaration of Dr. Jon B. Weissman (Ex. 1006).
`
`V. Overview of Basic Network Principles
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`25. As basic background, one of the most widely used computer networks
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`is the Internet. The Internet has been around for several decades. Many trace the
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`origins of the Internet to the ARPANET (the Advanced Research Projects Agency
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`Network), which dates back to the late 1960s. While the origins of the Internet were
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`humble, it has grown into a massive, highly sophisticated network for highly
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`complex and highly varied forms of communication. One of the major leaps in the
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`Internet's evolution did not occur until the early 1990s and the sale of the NSFnet
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`Backbone to MCI, spurring commercialization of the Internet and interest in the
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`World Wide Web (WWW). These changes were significant contributors towards the
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`Internet becoming more widely available and usable.
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`26. Originally useful mainly for the exchange of text documents through
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`email (using the Simple Mail Transfer Protocol, or SMTP) or file exchange (using a
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`protocol like the File Transfer Protocol, or FTP), the Internet has evolved to support
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`more complex data including multiple media types (e.g., pictures, audio, video),
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`hence the concept of “multimedia.” Coupled with new and improved delivery
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`capabilities and increased ways of offering information to users, the ways in which
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`the Internet could be used increased dramatically during the 1990s. These factors led
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`to numerous technical innovations in the way data was made available to users.
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`27. One of the more important capabilities that existed within the Internet
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`was that it was acting as an information repository whereby servers held information
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`and clients would make requests for that information. The Internet was also evolving
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`such that, instead of servers holding important information, it was other users who
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`held the information. In some cases, instead of information stored in documents, it
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`was the users themselves who were the object of contact, for example, in multimedia
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`conferencing. As described in more detail below, an underlying and long-standing
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`challenge in the Internet was identifying the right address to use in contacting other
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`users or servers.
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`28. A large amount of Internet communication takes place using a
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`client/server paradigm. That is, content servers hold information desired by users.
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`Through their clients, users make requests for this information, and the server
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`responds by providing the requested information. Such a paradigm is used in, for
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`example, the World Wide Web (WWW). In other applications, like email, servers
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`are responsible for accepting, storing, and forwarding email.
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`29. Two principles upon which applications and the underlying network
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`infrastructure are based are the use of layered communication to break the task of
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`data delivery into more manageable sub-tasks, and the use of protocols to establish
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`rules for how data is communicated.
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`30. Generally, a protocol is a set of rules that defines how a set of functions
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`will be performed. Protocols are important within networks since the two sides of a
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`communication must act in the same, predictable way for data to be successfully
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`delivered. For example, the HyperText Transfer Protocol (HTTP) defines both how
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`requests/responses for objects are to be made and the syntax of request/response
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`messages. The way in which data is exchanged is as important as the format of the
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`data when it is exchanged. Called syntax, protocol specifications typically include
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`the way information in a message is formatted. By clearly describing a protocol's
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`communication rules and syntax, ambiguities and errors can be avoided.
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`31. Protocols are then combined, based on the layer at which each operates,
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`to perform the functions necessary to deliver data between sources and destinations.
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`In many cases, there is one protocol responsible for the functions of not one, but
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`sometimes multiple layers. Each layer and its corresponding protocol perform a set
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`of functions based on widely, but not universally, agreed upon guidelines. As data
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`is prepared for transmission by an application, it is sent through a set of layers. Each
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`layer performs specified functions. For some of the layers, there is a corresponding
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`protocol and a corresponding protocol header that is added to the application's data.
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`32. To help understand the process and give direction to the flow of data,
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`the layers are “stacked” one on the other, from the highest layer (the application
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`layer) to the lowest layer (the physical layer). Data, therefore, flows “down” the
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`stack from the application layer of the transmitting host, across the network, and
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`“up” a corresponding stack at the receiver.
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`33. Over the years, there have been several efforts to “standardize” the
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`layers and the functions performed by each. One example is the International
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`Standards Organization's (ISO) Open System Interconnect (OSI). The OSI stack has
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`seven layers and the general functions of each layer are well-known. ISO's OSI stack
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`model is an older example dating back to the mid-1980s. A more recent example is
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`the “TCP/IP stack,” also called the “Internet stack.” It integrated the functionality of
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`two of the layers from the OSI stack (Presentation and Session Layers) into the
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`Application Layer and better maps to the Internet's currently used protocols, e.g., IP,
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`UDP, and TCP.
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`34. Of the layers in the TCP/IP stack, the “highest” layer is the application
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`layer and includes protocols like the HyperText Transfer Protocol (HTTP) and the
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`Simple Mail Transfer Protocol (SMTP). There are dozens of application layer
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`protocols, each typically corresponding to a specific application.
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`35. The Hypertext Transfer Protocol (or “HTTP”) is an example of a well-
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`known application (layer 7) protocol. HTTP version 1.1 was published as RFC 2068
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`in January 1997. As an application layer protocol, HTTP is a set of rules for carrying
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`application-specific data between a source and a destination (for example, carrying
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`HTTP protocol headers and world wide web data between a web browser and a web
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`site server). Because most Internet traffic uses both IP and TCP, Internet traffic is
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`often described as “TCP over IP” or simply “TCP/IP.” When that traffic happens to
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`also use HTTP as the application layer protocol, it is often described as “HTTP over
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`TCP/IP.”
`
`36. The next layer is the transport layer. The two most common protocols
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`are the Transmission Control Protocol (TCP) and the User Datagram Protocol
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`(UDP). Where the UDP protocol only provides support for “ports,” TCP provides
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`better support for reliable data delivery through acknowledgements, in-order packet
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`delivery, connections, as well as congestion control, and similar to UDP, port
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`numbers. The vast majority of content delivered over the Internet uses one of these
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`two protocols as its transport layer protocol.
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`37. The Transmission Control Protocol, referred to as “TCP,” is one of the
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`main protocols used to send and receive information over the Internet. TCP is well
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`known in the computer networking industry—one early TCP rule set was published
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`as a Request for Comment (or “RFC”) by the Internet Engineering Task Force
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`(“IETF”) in September 1981 (RFC 793). That rule set was based on an even earlier
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`rule set published in December 1974 as RFC 675. TCP is an example of a transport
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`(layer 4) protocol in the OSI model. TCP is responsible for adding reliability and
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`ordering to the stream of network information—for example, the packets of
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`information sent using IP as the network-layer protocol may not arrive at the
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`destination in the same order intended by the sender of the message. TCP sets rules
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`for breaking up and transmitting the message so that the recipient is able to reliably
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`receive and reassemble the message. Another common analogy from the physical
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`world is the example of sending a multi-page letter through the mail by separately
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`numbering page and mailing each page in its own envelope. IP, like the postal
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`service, will route the envelope-like packets to the destination, but TCP (like the
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`numbering of the individual pages) sets the rules to allow the recipient to verify that
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`all of the pages have been received and to reassemble the pages in the right order.
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`38. TCP describes, for example, how two devices on the Internet may
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`establish a connection over which TCP data packets may be communicated between
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`them. By way of a negotiation process known as a three-way handshake, such a
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`connection can be established between two nodes, and once that connection
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`establishment phase completes, data transfer can begin. Typically, a TCP connection
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`is managed by a device operating system, so that applications such as a web browser,
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`or a web server like a CDN caching server, can pass data to the operating system’s
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`TCP protocol “stack” and the operating system will manage transmission of that data
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`to the receiver, and will pass received data from the other device up to the application
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`layer.
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`39. The next layer down, and the cornerstone of the Internet, is the Internet
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`layer. The corresponding protocol, the Internet Protocol (IP), provides end-to-end
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`delivery. Using the IP address and a variety of support protocols (e.g., routing
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`protocols), routers in the Internet are able to choose the next path towards a
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`destination, thereby robustly moving packets closer to their destination. From a lay
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`perspective, the most common transport protocol, TCP, along with IP, form the core
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`of Internet communications. Hence, the Internet's protocols are commonly called
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`“TCP/IP.”
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`40. The Internet Protocol (or “IP”) is an example of a well-known network
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`(layer 3) protocol. IPv4 was published as RFC 760 in January 1980 while its
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`successor IPv6 was published as RFC 2460 in December 1998. The IP protocol
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`describes a set of rules for dividing a message into multiple parts (called “IP
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`packets”) and then transmitting those packets from an IP sender to an IP destination
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`across multiple routers or other links in a computer network. Each packet of
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`information includes an IP address for its destination, analogous to sending a letter
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`through the mail by placing the letter inside an envelope that has the recipient’s
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`physical address written on the face of the letter. The Data Link Layer (DLL) and
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`the Physical Layer are often closely coupled. The reason is that the function of the
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`DLL is to move bits across one physical hop between devices that form part of an
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`end-to-end path. A DLL protocol is typically designed for a specific physical
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`medium, though there are often many different protocols that can be used for a given
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`medium. Physical Layer protocols are responsible for converting digital bits into the
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`analog transmission signal specific to the particular medium being used for
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`communication. It is therefore clear why there is a close relationship between a DLL
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`protocol and the Physical Layer: both work for a specific medium and together move
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`data across a single hop along a path from a source to a destination’s postal address
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`printed on it.
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`41. Often overlooked in the transmission of data is that DLL protocols and
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`their headers-only survive across a single hop. Once data is delivered across the hop,
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`the DLL layer header is removed, leaving the IP header exposed, and then based on
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`the next hop to the destination, a new DLL protocol header is added-this one specific
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`to the new medium the packet is to traverse. This process is repeated for each hop
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`along the path from a source to a destination.
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`42. As mentioned above, while the stack concept is a popular metaphor to
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`help understand how network communication occurs, no reference model is perfect,
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`and each model serves as a guideline. Protocols, for example, may perform functions
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`of other layers, and still be accepted as valid protocols. Even in these cases, the
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`abstraction provided by the general principle of layering and abstraction are
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`sufficient to enable data transmission to take place successfully.
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`43.
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`In client/server based architectures that use a particular protocol to
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`support a specific application, the protocol is usually implemented in both the client
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`and the server. Thus, for example, there is an HTTP client (i.e., a web browser) and
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`an HTTP server. The client and server communicate over the network using
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`additional protocols focused on the actual delivery of data.
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`A. The OSI Model
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`44.
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`Information is transmitted across networks, such as the Internet, as data
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`packets. Data packets are formatted in compliance with established rules known as
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`protocols. To facilitate communications across various networks, the International
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`Standards Organization (“ISO”) developed the Open Systems Interconnection
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`(“OSI”) model. The OSI model defines a framework for
`
`implementing
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`communications between any two network devices and divides the communication
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`process into seven layers as shown below:
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`’099 Patent at 9:37-50.
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`45. Each layer provides specific functions to support the layers above it.
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`The Application layer (layer 7) is the highest layer, while