Computer Networking: A Top-Down Approach Featuring the Internet

679 Pages·2000·9.987 MB·English

by  Keith W. Ross

Computer Networking

Computer Networking: A

Top-Down Approach
Featuring the Internet

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Table of Contents
Computer Networking
A Top-Down Approach Featuring the Internet
James F. Kurose and Keith W. Ross
Preface
Link to the Addison-Wesley WWW site for this book
Link to overheads for this book
Online Forum Discussion About This Book - with Voice!
1. Computer Networks and the Internet
1. What is the Internet?
2. What is a Protocol?
3. The Network Edge
4. The Network Core
Interactive Programs for Tracing Routes in the Internet
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Java Applet: Message Switching and Packet Switching
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5. Access Networks and Physical Media
6. Delay and Loss in Packet-Switched Networks
7. Protocol Layers and Their Service Models
8. Internet Backbones, NAPs and ISPs
9. A Brief History of Computer Networking and the Internet
10. ATM
11. Summary
12. Homework Problems and Discussion Questions
2. Application Layer
1. Principles of Application-Layer Protocols
2. The World Wide Web: HTTP
3. File Transfer: FTP
4. Electronic Mail in the Internet
Table of Contents
5. The Internet's Directory Service: DNS
Interactive Programs for Exploring DNS
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6. Socket Programming with TCP
7. Socket Programming with UDP
8. Building a Simple Web Server
9. Summary
10. Homework Problems and Discussion Questions
3. Transport Layer
1. Transport-Layer Services and Principles
2. Multiplexing and Demultiplexing Applications
3. Connectionless Transport: UDP
4. Principles of Reliable of Data Transfer
Java Applet: Flow Control in Action
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5. Connection-Oriented Transport: TCP
6. Principles of Congestion Control
7. TCP Congestion Control
8. Summary
9. Homework Problems and Discussion Questions
4. Network Layer and Routing
1. Introduction and Network Service Model
2. Routing Principles
3. Hierarchical Routing
4. Internet Protocol
Java Applet: IP Fragmentation
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5. Routing in the Internet
6. What is Inside a Router?
7. IPv6
8. Multicast Routing
9. Summary
10. Homework Problems and Discussion Questions
5. Link Layer and Local Area Networks
1. The Data Link Layer: Introduction, Services
2. Error Detection and Correction
3. Multiple Acces Protocols and LANs
4. LAN Addresses and ARP
5. Ethernet
CSMA/CD Applet
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6. Hubs, Bridges and Switches
7. Wireless LANs: IEEE 802.11
8. The Point-to-Point Protocol
9. ATM
10. X.25 and Frame Relay
11. Summary
12. Homework Problems and Discussion Questions
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Table of Contents
6. Multimedia Networking
1. Multimedia Networking Applications
2. Streaming Stored Audio and Video
3. Making the Best of the Best-Effort Service: An Internet Phone Example
4. RTP
5. Beyond Best Effort
6. Scheduling and Policing Mechanisms for Providing QoS Guarantees
7. Integrated Services
8. RSVP
9. Differentiated Services
10. Summary
11. Homework Problems and Discussion Questions
7. Security in Computer Networks
1. What is Network Security?
2. Principles of Cryptography
3. Authentication: Who are You?
4. Integrity
5. Key Distribution and Certification
6. Secure E-Mail
7. Internet Commerce
8. Network-Layer Security: IPsec
1999 Panel Discussion on Internet Security
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9. Summary
10. Homework Problems and Discussion Questions
8. Network Management
1. What is Network Managmenet?
2. The Infrastructure for Network Management
3. The Internet Network Management Framework
4. ASN.1
5. Firewalls
6. Summary
7. Homework Problems and Discussion Questions
Appendix
Lab: Building a multi-threaded Web server in Java
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Lab: Building a mail user agent in Java
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Lab: Implementing a reliable transport protocol
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Lab: Implementing a distributed, asynchronous distance vector routing algorithm
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Table of Contents
Some relevant online audio material:
Unix Network Programming, Jim Kurose
Introduction to Computer Networks, Jim Kurose
Internet Protocols, Keith Ross
Distribution of Stored Information in the Web, Keith Ross
Asynchronous learning links:
The Web of Asynchronous Learning Networks

Copyright 1996-2000 James F. Kurose and Keith W. Ross
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preface
Preface and Acknowledgments
Welcome to our online textbook, Computer Networking: A Top-Down Approach. We ( Jim Kurose,
Keith Ross, and Addison-Wesley-Longman) think you will find this textbook to be very different than
the other computer networking books that are currently available. Perhaps the most unique and
innovative feature of this textbook is that it is online and accessible through a Web browser. We
believe that our online format has several things going for it. First, an online text can be accessed from
any browser in the world, so a student (or any other reader) can gain access to the book at anytime from
anyplace. Second, as all of us Internet enthusiasts know, much of the best material describing the
intricacies of the Internet is in the Internet itself. Our hyperlinks, embedded in a coherent context,
provide the reader direct access to some of the best sites relating to computer networks and Internet
protocols. The links do not only point to RFCs but also to sites that are more pedagogic in nature,
including home-brewed pages on particular aspects of Internet technology and articles appearing in
online trade magazines. Being online also allows us to include many interactive features, including
direct access to the Traceroute program, direct access to search engines for Internet Drafts, Java applets
that animate difficult concepts, and (in the near future) direct access to streaming audio. Being online
enables us to use more fonts and colors (both within the text and in diagrams), making the text both
perky and cheerful. Finally, an online format will allow us to frequently release new editions (say, every
year), which will enable the text to keep pace with this rapidly changing field.
Another unusual feature of the text is its Internet focus. Most of the existing textbooks begin with a
broader perspective and address the Internet as just as one of many computer network technologies. We
instead put Internet protocols in the spotlight, and use the Internet protocols as motivation for studying
some of the more fundamental computer networking concepts. But why put the Internet in the spotlight,
why not some other networking technology such as ATM? Most computer networking students have had
already significant "hands on" experience with the Internet (e.g., surfing the Web and sending e-mail at
the very least) before taking a course on computer networks. We have found that modern-day students in
computer science and electrical engineering, being intensive users of the Internet, are enormously
curious about what is under the hood of the Internet. Thus, it is easy to get students excited about
computer networking when using the Internet as your guiding vehicle. A second reason for the Internet
focus is that in recent years computer networking has become synonymous with the Internet. This wasn't
the case five-to-ten years ago, when there was a lot of talk about ATM LANs and applications direclty
interfacing with ATM (without passing through TCP/IP). But we have now reached the point where just
about all data traffic is carried over the Internet or intranets. Furthermore, streaming audio and video
have recently become commonplace in the Internet, and someday telephony may be too. Because our
book has an Internet focus, it is organized around a five-layer Internet architecture rather than around the
more traditional seven-layer OSI architecture.
Another unique feature of this book is that it is also top-down in how the content is organized. As we
mentioned above, this text, as almost all computer networks textbooks, uses a layered architectural
model to organize the content. However, unlike other texts, this text begins at the application-layer and
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works its way down the protocol stack. The rationale behind this top-down organization is that once one
understands the applications, one can then understand the network services needed to support these
applications. One can then, in turn, examine the various ways in which such services might be provided/
implemented by a network architecture. Covering applications early thus provides motivation for the
remainder of the text.
An early emphasis on application-layer issues differs from the approaches taken in most other texts,
which have only a small (or nonexistent) amount of material on network applications, their
requirements, application-layer paradigms (e.g., client/server), and the application programming
interfaces (e.g., sockets). Studying application-layer protocols first allows students to develop an
intuitive feel for what protocols are (the role of message exchange and the actions taken on events) in
the context of network applications (e.g., the Web, FTP and e-mail) which they use daily. Furthermore,
the inclusion of a significant amount of material at the application layer reflects our own belief that there
has been, and will continue to be, a significant growth in emphasis (in the research community, and in
industry) in the higher levels of network architecture. These higher layers -- as exemplified by the Web
as an application layer protocol -- is the true ``growth area'' in computer networking.
This textbook also contains material on application programming development - material not covered
in depth by any introductory computer networks textbook. (While there are books devoted to network
programming, e.g., the texts by Stevens, they are not introductory networking textbooks.) There are
several compelling reasons for including this material. First, anyone wanting to write a network
application must know about socket programming - the material is thus of great practical interest.
Second, early exposure to socket programming is valuable for pedagogical reasons as well - it allows
students to write actual network application-level programs and gain first-hand experience with many of
this issues involved in having multiple geographically distributed processes communicate. We present
the material on application programming in a Java context rather than a C context, because socket
programming in Java is simpler, and allows students to quickly see the forest through the trees.
It has been said that computer networking textbooks are even more boring than accounting texts.
Certainly, one seed of truth in the statement is that many books are simply a compendium of facts about
a myriad of computer networking technologies and protocols, such as packet formats or service
interfaces (and given the wealth of protocol standards, there is no shortage of such facts!). What is
missing in such accounting-like textbooks is an identification of the important, underlying issues that
must be solved by a network architecture, and a methodical study of the various approaches taken
towards addressing these issues. Many texts focus on what a network does, rather than why. Addressing
the principles, rather than just the dry standards material, can make a textbook more interesting and
accessible. (A sense of humor, use of analogies, and real-world examples also help.)
The field of networking is now mature enough that a number of fundamentally important issues can be
identified. For example, in the transport layer, the fundamental issues include reliable communication
over an unreliable channel, connection establishment/teardown and handshaking, congestion and flow
control, and multiplexing. In the routing layer, two fundamentally important issues are how to find
``good'' paths between two routers, and how to deal with large, heterogeneous systems. In the data link
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layer, a fundamental problem is how to share a multiple access channel. This text identifies
fundamental networking issues as well as approaches towards addressing these issues. We believe
that the combination of using the Internet to get the student's foot in door and then emphasizing the
issues and solution approaches will allow the student to quickly understand just about any networking
technology. For example, reliable data transfer is a fundamental issue in both the transport and data link
layer. Various mechanisms (e.g., error detection, use of timeouts and retransmit, positive and negative
acknowledgments, and forward error correction) have been designed to provide reliable data transfer
service. Once one understands these approaches, the data transfer aspects of protocols like TCP and
various reliable multicast protocols can been seen as case studies illustrating these mechanisms.
How an Instructor Can Use this Online Book
This online book can be used as the textbook for a course on computer networking just like any other
textbook. The instructor can assign readings and homework problems, and base lectures on the material
within the text. However, the textbook is also ideally suited for asynchronous online courses. Such
courses are particularly appealing to students who commute to school or have difficulty scheduling
classes due to course time conflicts. The authors already have significant experience in leading
asynchronous online courses, using an earlier draft of this online text. They have found that one
successful asynchronous format is to have students do weekly asynchronous readings (and listenings!)
and to have students participate in weekly newsgroup discussions about the readings. Students can have
a virtual presence by sharing the URLs of the their personal Web pages with the rest of the class.
Students can even collaborative on joint projects, such as research papers and network application
development, asynchronously over the Internet. Readers are encouraged to visit the following sites
which are devoted to asynchronous online education:
The Web of Asynchronous Learning Networks
Journal of Asynchronous Learning Networks
Asynchronous Learning Networks Magazine

Acknowledgments
Lot's of people have given us invaluable help on this project since it began in 1996. For now, we simply
say "Thanks!" and list some of the names alphabetically.
Paul Amer
Daniel Brushteyn
John Daigle
Wu-chi Feng
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Albert Huang
Jussi Kangasharju
Hyojin Kim
Roberta Lewis
William Liang
Willis Marti
Deep Medhi
George Polyzos
Martin Reisslein
Despina Saparilla
Subin Shrestra
David Turner
Ellen Zegura
Shuchun Zhang
and all the UPenn, UMass and Eurecom students that have suffered through earlier drafts!
(List is incomplete. Will be adding names shortly.)

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Instructor Overheads: Computer Networking: A Top Down Approach Featuring the Internet
Computer Networking
A Top-Down Approach Featuring the Internet
James F. Kurose and Keith W. Ross
Instructor Overheads
You'll find links below to overheads (powerpoint files, compressed postscript and PDF format) for the textbook,
Computer Networking: A Top-Down Approach Featuring the Internet, by Jim Kurose and Keith Ross, published by
Addison Wesley Longman. If you want to find out more about the book, you can check out the on-line version of
the text at http://gaia.cs.umass.edu/kurose/Contents.htm or at http://www.seas.upenn.edu/~ross/book/Contents.htm.
The publisher's WWW site for the book is http://www.awlonline.com/kurose/
Note that the overheads below are being made available in powerpoint format (as well as postscript and pdf, shortly)
so that instructors can modify the overheads to suit their own teaching needs. While we hope that many instructors
will make use of the overheads (regardless of whether or not our text is used for the course), we ask that you use the
overheads for educational purposes only. Please respect the intellectual property represented in the overheads and do
not use them for your own direct commercial benefit.
Questions or comments to Jim Kurose or Keith Ross
Chapter 1: Computer Networks and the Internet
chapter1a.ppt (Part 1, powerpoint format, 1.178M, last update: 21-Dec-99))
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chapter1b.ppt (Part 2, powerpoint format, 215K, last update: 21-Dec-99)
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Chapter 2: The Application Layer
chapter2a.ppt (Part 1, powerpoint format, 568K, last update: 21-Dec-99)
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chapter2b.ppt (Part 2, powerpoint format, 276K, last update: 21-Dec-99)
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