通信网：基本概念与主体结构（英文影印版）

. 2.1 examples of layering
2.2 the osi reference model
2.2.1 unified view of layers, protocols. and services
2.2.2 the seven-layer model
2.3 overview of tcp/ip architecture
2.3.1 tcp/ip protocol: how the layers work together
2.4 the berkeley api
2.4.1 socket system calls
2.4.2 network utillity functions
2.5 application protocols and tcp/ip utilities
2.5.l telnet
2.5.2 file transfer protocol
2.5.3 ip utilities
summary
checklist of important terms
further reading
problems
3 digital transmission fundamentals
3.i digital representation of information
3.1.l binary representations of different information types
3.1.2 network requirements of different information types
3.2 why digital communications?
3.2.1 basic properties of digital transmission systems
3.3 characterization of communication channels
3.3.1 frequency domain characterization
3.3.2 time domain characterization
3.4 fundamental limits in digital transmission
3.4.1 the nyquist signaling rate
3.4.2 the shannon channel capacity
3.5 line coding
3.6 modems and digital modulation
3.6.1 signal constellations and telephone modem standards
3.7 properties of media and digital transmission systems
3.7.1 twisted pair
3.7.2 coaxial cable
3.7.3 optical fiber
3.7.4 radio transmission
3.7.5 infrared light
3.8 error detection and correction
3.8.1 error detection
3.8.2 two-dimensional parity checks
3.8.3 internet checksum
3.8.4 polynomial codes
3.8.5 standardized polynomial codes
3.8.6 error detecting capability of a polynomial code
3.8.7 linear codes
3.8.8 error correction
summary
checklist of important terms
further reading
problems
appendix 3a: asynchronous data transmission
appendix 3b: fourier series
4 transmission systems and the telephone network
4.1 multiplexing
4.1.1 frequency-division multiplexing
4.1.2 time-bivision multiplexing
4.2 sonet
4.2.1 sonet multiplexing
4.2.2 sonet frame structure
4.3 wavelength-division multiplexing

.　　 Chapter 4 discusses digital transmission systems and the telephone network. The first few sections deal with properties of current and emerging optical networks. The digital multiplexing hierarchy and the SONETstandard are introduced. We develop the fault recovery features of SONETrings and we emphasize the capability of SONET optical networks to create arbitrary logical topologies under software control.We then introduce wavelength division multiplexing and explain how WDMoptical networks share the flexible network configuration features of SONET. The design of circuit switches for traditional telephone networks and for future optical networks is discussed next. The latter sections deal weth telephone networks, with a focus on the signaling system that enables telephone service and associated enhanced services,e.g.,caller ID,800-call.We consider the telephone network and the layered architecture of its signaling system. We discuss the frequency reuse concept and tts application in telephone and satellite cellular networks.
　　 Chapter 5 is the usual place to discuss data link controls. Instead of dealing immediately with this topic, we first introduce the notions of peer-to-peer protocols and service models. ARQ protocols that provide relable transger service are developed in detail as specific examples of peer-to-peer protocols. The detailed discussion givees the student an appreciation of what is involved in implementing a protocol. The end-to-end and hop-by-hop approaches to deploying peer-to-peer protocols are compared, and additional examples of peer-to-peer protocols are introduced for flow control and for timing recovery. We also preview the reliable stream service provided by TCP. The details of HDLC and PPP data link standards are then presented. Finally we discuss the sharing of adata link by multiple packet flows and introduce the notion of multiplexing gain.
　　 Chapter 6 deals with the transfer information across shared media, usingLANs and wireless networks as specific examples. We begin with an introductionto broadcast networks and to approaches to sharing a medium. We explain thefunction of LANs and their placement in the OSI reference model. We considerrandom access as well as scheduling approaches to transferring packets across ashared medium. We examine the impact of delay-bandwidth product on perfor-mance, and we show why this dictates the evolution of Ethernet from a sharedmedium access technique to a switched technique. In addition to token ring andFDDI LANs, we also present a full discussion of the IEEE 802.I l wireless LANstandard. We also discuss FDMA, TDMA,and CDMA channelization approaches to sharing media and we show their application in various existingcellular radio networks. We have taken great care to make the difficult topic ofCDMA accessible to the student.
　　 Chapter 7 deals with packet switching networks. To provide a context for thechapter we begin by presenting an end-to-end view of packet transfer across theInternet. We then develop the notions of datagram and virtual-circuit packetswitching, using IP and ATM as examples. We introduce basic designapproaches to packet switches and routers. Shortest-path algorithms and thelink state and distance vector approaches to selecting routes in a network arepresented next. ATM and the concept of label switching are introduced, and therelationship between QualitY-of-Service and traffic shaping, scheduling and calladmission control is developed. The chapter includes a discussion of TCP andATM congestion control.
　　 Key Arehiteetures and Advanced Topics
　　 The third section shows how the fundamental networking concepts are embodiedin two key network architectures, ATM and TCP/IP. The section also deals withthe interworking of ATM and TCP/IP, as well as with enhancements to TCP/IPto provide secure and more responsive communications.
　　 Chapter 8 presents a detailed discussion of TCP/IP protocols. We examinethe structure of the IP layer and the details of IP addressing, routing, andfragmentation and reassembly. We discuss the motivation and present the fea-tures of IPv6. we introduce UDP, and examine in detail how TCP providesreliable stream service and How control end-to-end across a connectionlesspacket network. RIP, OSPF, and BGP are introduced as protocols for synthesiz-ing routing tables in the Internet. Multicast routing is also introduced.
　　 Chapter 9 deals with the architecture of ATM networks. The ATM layer isexplained, and QualitY-of-Service and the ATM network service categories arepresented. The various types of ATM adaptation layer protocols are discussednext. ATM signaling and PNNI routing are introduced.
　　 Chapter 10 deals with the interworking of IP and ATM and with proposedenhancements to IP. We consider the various approaches for operating IP over
　　 ATM networks. We then introduce Multiprotocol Label Switching which is themost promising example for operating IP over ATM and other link layer pro-tocols. Finally we introduce RSVP, Integrated Services IP, and DifferentiatedServices IP which together provide mechanisms for providing Quality-of-Serviceover IP.
　　 Chapter 11 provides an introduction to network security protocols. Thevarious categories of threats that can arise in a network are used to identifyvarious types of security requirements. Secret key and public key cryptographyare introduced and their application to providing security is discussed. Wedevelop protocols that provide security across insecure networks and we intro-duce protocols for establishing security associations and for managing keys.These general protocols are then related to the IP security protocols and totransport layer security protocols.
　　 Chapter 12 deals with multimedia information and networking. We beginwith an introduction to the properties of image, audio, and video signals. Wediscuss the various compression schemes that are applied to obtain efficientdigital representations, and we describe the relevant compressioa standards.We then introduce the RTP protocol for transmitting real-time informationacross the Internet. Finally, we close the loop in the discussion of "plain oldtelephone service" by reviewing the various signaling protocols that are beingdeveloped to support multimedia communications in general, and IP telephonyin particular, over the Internet.
　　 The book ends with an Epilogue that discusses trends in network architec-ture and identifies several areas that are likely to influence the development offuture networks.
　　 Appendices
　　 Appendix A deals with network performance models. Network performance isan integral part of network design and operation. In the text we use quantitativeexamples to illustrate the tradeoffs involved in various situations. We believe thatan intuition for performance issues can be developed without delving into theunderlying mathematics. Delay and loss petformance results are introduced inthe sections that deal with multiplexing, trunking, and medium access control. Inthese sections, the dynamics of the given problem are described and the keyperformance results are presented. The purpose of Appendix A is to developthe analysis of the performance models that are cited in the text. These analysesmay be incorporated into more advanced courses on communication networks.
　　 Appendix B provides an introduction to network management. The basicfunctions and structure of a network management system are introduced as wellas the Simple Network Management Protocol (SNMP). We present the rules fordescribing management information, as well as the collection of objects, calledManagement Information Base, that are managed. by SNMP. We also introduceremote monitoring (RMON which offers extensive network diagnostic, plan-ning, and performance information.
　　 HOW TO USE THIS BOOK
　　 The book was designed to snpport a variety of introductory courses on computer and communication networks. By appropriate choice of sections, the instructor can make adjustments to provide a desired focus or to account for the background of the students. Chapter l to Chapter 8 contain the core material (and more) that is covered in the typical introductory course on computer networks. For example, at the University of Toronto a 40 lecture-hour introductory undergraduate course in computer networks covers the following: Chapter 1 (all); Chapter 2 (all) including a series of lab exercises using sockets; Chapter 3 (sections 3.l, 3.2, 3.5, 3.6, 3.8.l to 3.8.5); Chapter 4 (sections 4.l to 4.3); Chapter 5 (all); Chapter 6 (sections 6.l to 6.4, 6.6.I, 6.6.2); Chapter 7 (all); and Chapter 8 (sections 8. I to 8.5). For courses that spend more time on the material in Chapter 8 or later, the material from Chapters 3 and 4 can be dropped altogether. The book contains enough material for a two-semester course sequence that provides an introductory course on computer networks followed by a course on emerging network protocols.
　　 PEDAGOGICAL ELEMENTS
　　 The book contains the following pedagogical elements:
　　 Numerous Figures. Network diagrams, time diagrams, performance graphs, state transition diagrams are essential to effectively convey concepts in networking. The 574 figures in the book are based on a set of Microsoft PowerPoint" course presentations that depend heavily on visual representation of concepts. A set of these presentation charts is available to instructors.
　　 Numerous Examples. The discussion of fundamental concepts is accompanied with examples illustrating the use of the concept in practice. Numerical examples are included in the text wherever possible.
　　 Text Boxes. Commentaries in text boxes are used to discuss network trends and interesting developments, to speculate about future developments, and to motivate new topics.
　　 Problems. The authors firmly believe that learning must involve problem solving. The book contains 589 problems. Each chapter includes problems with a range of difficulties from simple application of concepts to exploring, developing or elaborating various concepts and issues. Quantitative problems range from simple calculations to brief case studies exploring various aspects of certain algorithms, techniques, or networks. Simple programming exercises involving sockets and TCP/IP utilities are included where appropriate.
　　 An Instructor's Solutions Alanual is available from McGraw-Hill.
　　 Chapter Introductions. Each chapter includes an introduction previewing the material covered in the chapter and in the context of the "big picture".
　　 Chapter Summaries and Checklist of Important Terms. Each chapter includes a summary that reiterates the most important concepts. A checklist of important terms will aid the student in reviewing the material.
　　 References. Each chapter includes a list of references. Given the introductory nature of the text, references concentrate on pointing to more advanced materials. Reference to appropriate Internet Engineering Taskforce (IETF) RFCs and research papers is made where appropriate, especially with more recent topics.
　　 A web site. The following Web site contains links to the on-line version of the solutions manual, the Powerpoint slides', author information, and other related information: www.mhhe.com/leon-garcia.
　　 ACKNOWLEDGMENTS
　　 The material in the book was developed over many years in introductory as wellas advanced courses in networking, both in regular undergraduate and graduateprograms as well as in programs with an orientation towards professional prac-tice. We acknowledge the feedback from the many students who participated inthese courses and who used various versions of the manuscript. In particular wethank the students from CETYS University. We also acknowledge the input ofthe graduate students who served as teaching assistants in these courses, espe-cially Dennis Chan, Yasser Rasheed, Mohamed Arad, Massoud Hashemi,Hasan Naser, and Andrew Jun.
　　 We thank Anindo Banerjea, Raouf Boutaba, Michael Kaplan, and Gillian_Woodruff for many exciting conversations on networking. Anindo and Raoufgraciously provided some of the material that is presented in Chapter 2. Wewould also like to thank Anwar Elwalid and Debasis Mitra for their continuedenconragement and interest in the book. We thank Yau-Ren Jenq for reviewingthe fair queueing discussions in detail.
　　 We are especially grateful to Irene ICatzela for testing the manuscript in hercourses. We also thank Ray Pickholtz for testing various versions of the text,including the beta version, and for his many valuable suggestions and his con-tinued encouragement.
　　 We thank the reviewers for their many useful comments on the variousversions of the manuscript: Subrata Banerjee (Stevens Institute ofTechnology), John A. Copeland (Georgia Institute of Technology), MarioOerla (UCLA), Rohit Goyal (Ohio State University), Gary Harkin (MontanaState University), Melody Moh (San Jose State University), Kihong Park(Purdue University-West Lafayette), Raymond L. Pickholtz (The GeorgeWashington University), Chunming Qiao (SUNY Buffalo), Arunabha Sen (Arizona State University), Stuart Tewksbury (West Virginia University), and Zhi-li Zhang (University of Minnesota).
　　 We would also like to acknowledge the many friends from Nortel Networks for showing us the many facets of networking. We thank Sidney Yip for opening tbe door to many years of interaction. We also thank Richard Vickers, Marek Wernik, and Jim Yan for many illuminating conversations over the years. We especially thank Tony Yuen for sharing his vast knowledge of the networking industry and for continuously showing how the big picture is actually bigger!
　　 We thank Eric Munson from McGraw-Hill for persuading us to take the plunge with this project, and Betsy Jones, Executive Editor, for providing decisive support at key times. In addition we thank the production team at McGrawHill for their patience, ideas, and continued support, especially Kelley Butcher and Jim Labeots.
　　 IW would like to thank to his wife Liesye for the constant enconragement and for putting up with him during the many nights and weekends spent writing the book, especially during the final stages.
　　 Finally, ALG would like to thank his soulmate, Karen Carlyle, who went beyond the usual putting up with an author's neglect, to assuming the role of project manager, designer, transcriber and real-time editor for the book.
　　 With the help of the many reviewers, professors, and students who have used early versions of this book we have tried to make the complex and fiuid topic of network architecture as approachable, up-to-date and error-free as possible. We welcome all comments and suggestions on how to improve the text. Please contact us via the text's website with any ideas you may have.
　　 Alberto Leon-Garcia
　　 Indra Widjaja