本书是计算机网络领域的经典教材，被哈佛大学、斯坦福大学、卡内基·梅隆大学、康奈尔大学、普林斯顿大学等众多名校采用。第6版延续了之前版本的特色，采用系统方法，反对严格的分层。新版添加了丰富的实例，增加或扩展了接入网络技术、虚拟局域网、软件定义网络、可靠的端到端传输、拥塞控制机制、协议缓冲区、HTTP/2、现代网络管理系统等内容，关注云、虚拟网络覆盖、去中心化身份管理和区块链等新技术。本书既适合作为高等院校计算机相关专业的教材，也适合广大技术人员参考。

无

计算机\网络

第6版对云技术给予了极大的关注，并且讨论了与安全相关的信任、身份和区块链等问题。然而，如果回看第1版，你会发现其中的基本概念是相同的。本书正是网络这个故事的现代版本，包含众多与时俱进的新实例和新技术。
—— David D. Clark　麻省理工学院

无论是第一次向本科生介绍网络，还是扩大研究生的知识面，这些学生需要了解的知识都可以在本书中找到。多年来，我一直信任第5版，现在很高兴将我的学生和他们即将创造的未来网络“托付”给第6版。
—— Christopher (Kit) Cischke　密歇根理工大学

本书不仅描述“怎么做”，而且解释“为什么”，以及同样重要的“为什么不”。这是一本能够帮助学生建立工程直觉的书，并且培养学生就设计或选择下一代系统做出正确决策的能力，在技术快速变革的时代，这一点至关重要。
—— Roch Guerin　宾夕法尼亚大学

作者在不牺牲技术严谨性的情况下，将网络简化为简单且易于组织和呈现的概念。本书在网络架构设计的基本原则和构建于其上的应用程序之间取得了平衡，对网络课程的学生和教师来说是必不可少的资源。
—— Arvind Krishnamurthy　华盛顿大学

教授计算机网络课程多年，阅读了几乎每一本教材，我可以负责任地说，没有哪本书比这本书更好。虽然分层方法对于初学者学习网络基础知识非常有用（本书也可以这样使用），但系统方法才是我在课堂上所采用的，也是深受认可的，它帮助学生完成了从学习到实践的过程。
—— G. Aaron Wilkin　罗斯·霍尔曼理工学院

Foreword ix
Foreword to the First Edition xi
Preface xiii
1 Foundation 1
Problem: Building a Network 1
1.1 Applications 2
1.1.1 Classes of Applications 3
1.2 Requirements 6
1.2.1 Stakeholders 7
1.2.2 Scalable Connectivity 8
1.2.3 Cost-Effective Resource Sharing 13
1.2.4 Support for Common Services 17
1.2.5 Manageability 22
1.3 Architecture 23
1.3.1 Layering and Protocols 24
1.3.2 Encapsulation 28
1.3.3 Multiplexing and Demultiplexing 30
1.3.4 Seven-Layer OSI Model 31
1.3.5 Internet Architecture 33
1.4 Software 36
1.4.1 Application Programming Interface (Sockets) 37
1.4.2 Example Application 40
1.5 Performance 43
1.5.1 Bandwidth and Latency 44
1.5.2 Delay × Bandwidth Product 49
1.5.3 High-Speed Networks 50
1.5.4 Application Performance Needs 52
Perspective: Feature Velocity 55
Broader Perspective 56
Exercises 57
2 Direct Links 67
Problem: Connecting to a Network 67
2.1 Technology Landscape 68
2.2 Encoding 74
2.3 Framing 78
2.3.1 Byte-Oriented Protocols (PPP) 79
2.3.2 Bit-Oriented Protocols (HDLC) 81
2.3.3 Clock-Based Framing (SONET) 83
2.4 Error Detection 87
2.4.1 Internet Checksum Algorithm 89
2.4.2 Cyclic Redundancy Check 91
2.5 Reliable Transmission 97
2.5.1 Stop-and-Wait 98
2.5.2 Sliding Window 100
2.5.3 Concurrent Logical Channels 112
2.6 Multiaccess Networks 113
2.6.1 Physical Properties 114
2.6.2 Access Protocol 115
2.6.3 Longevity of Ethernet 120
2.7 Wireless Networks 121
2.7.1 Basic Issues 123
2.7.2 802.11/Wi-Fi 127
2.7.3 Bluetooth (802.15.1) 135
2.8 Access Networks 137
2.8.1 Passive Optical Network 138
2.8.2 Cellular Network 139
Perspective: Race to the Edge 145
Broader Perspective 147
Exercises 147
3 Internetworking 163
Problem: Not All Networks Are Directly Connected 163
3.1 Switching Basics 164
3.1.1 Datagrams 166
3.1.2 Virtual Circuit Switching 168
3.1.3 Source Routing 179
3.2 Switched Ethernet 182
3.2.1 Learning Bridges 183
3.2.2 Implementation 184
3.2.3 Spanning Tree Algorithm 186
3.2.4 Broadcast and Multicast 192
3.2.5 Virtual LANs (VLANs) 193
3.3 Internet (IP) 195
3.3.1 What Is an Internetwork? 195
3.3.2 Service Model 198
3.3.3 Global Addresses 206
3.3.4 Datagram Forwarding in IP 208
3.3.5 Subnetting and Classless Addressing 211
3.3.6 Address Translation (ARP) 219
3.3.7 Host Configuration (DHCP) 222
3.3.8 Error Reporting (ICMP) 226
3.3.9 Virtual Networks and Tunnels 226
3.4 Routing 230
3.4.1 Network as a Graph 232
3.4.2 Distance-Vector (RIP) 234
3.4.3 Link State (OSPF) 242
3.4.4 Metrics 252
3.5 Implementation 256
3.5.1 Software Switch 256
3.5.2 Hardware Switch 258
3.5.3 Software-Defined Networks 262
Perspective: Virtual Networks All the Way Down 265
Broader Perspective 267
Exercises 267
4 Advanced Internetworking 291
Problem: Scaling to Billions 291
4.1 Global Internet 292
4.1.1 Routing Areas 294
4.1.2 Interdomain Routing (BGP) 297
4.2 IP Version 6 308
4.2.1 Historical Perspective 309
4.2.2 Addresses and Routing 310
4.2.3 Packet Format 315
4.2.4 Advanced Capabilities 317
4.3 Multicast 319
4.3.1 Multicast Addresses 321
4.3.2 Multicast Routing (DVMRP, PIM, MSDP) 322
4.4 Multiprotocol Label Switching 334
4.4.1 Destination-Based Forwarding 336
4.4.2 Explicit Routing 342
4.4.3 Virtual Private Networks and Tunnels 344
4.5 Routing Among Mobile Devices 348
4.5.1 Challenges for Mobile Networking 349
4.5.2 Routing to Mobile Hosts (Mobile IP) 352
Perspective: The Cloud Is Eating the Internet 359
Broader Perspective 360
Exercises 361
5 End-to-End Protocols 369
Problem: Getting Processes to Communicate 369
5.1 Simple Demultiplexor (UDP) 371
5.2 Reliable Byte Stream (TCP) 374
5.2.1 End-to-End Issues 374
5.2.2 Segment Format 377
5.2.3 Connection Establishment and Termination 380
5.2.4 Sliding Window Revisited 385
5.2.5 Triggering Transmission 392
5.2.6 Adaptive Retransmission 395
5.2.7 Record Boundaries 399
5.2.8 TCP Extensions 400
5.2.9 Performance 403
5.2.10 Alternative Design Choices (SCTP, QUIC) 405
5.3 Remote Procedure Call 410
5.3.1 RPC Fundamentals 411
5.3.2 RPC Implementations (SunRPC, DCE, gRPC) 419
5.4 Transport for Real-Time (RTP) 432
5.4.1 Requirements 434
5.4.2 RTP Design 437
5.4.3 Control Protocol 441
Perspective: HTTP Is the New Narrow Waist 445
Broader Perspective 447
Exercises 447
6 Congestion Control 461
Problem: Allocating Resources 461
6.1 Issues in Resource Allocation 462
6.1.1 Network Model 463
6.1.2 Taxonomy 467
6.1.3 Evaluation Criteria 470
6.2 Queuing Disciplines 473
6.2.1 FIFO 474
6.2.2 Fair Queuing 476
6.3 TCP Congestion Control 481
6.3.1 Additive Increase/Multiplicative Decrease 482
6.3.2 Slow Start 485
6.3.3 Fast Retransmit and Fast Recovery 490
6.3.4 TCP CUBIC 494
6.4 Advanced Congestion Control 495
6.4.1 Active Queue Management (DECbit, RED, ECN) 495
6.4.2 Source-Based Approaches (Vegas, BBR, DCTCP) 504
6.5 Quality of Service 512
6.5.1 Application Requirements 513
6.5.2 Integrated Services (RSVP) 519
6.5.3 Differentiated Services (EF, AF) 530
6.5.4 Equation-Based Congestion Control 536
Perspective: Software-Defined Traffic Engineering 539
Broader Perspective 540
Exercises 541
7 End-to-End Data 555
Problem: What Do We Do With the Data? 555
7.1 Presentation Formatting 557
7.1.1 Taxonomy 558
7.1.2 Examples (XDR, ASN.1, NDR, Protobufs) 562
7.1.3 Markup Languages (XML) 569
7.2 Multimedia Data 573
7.2.1 Lossless Compression Techniques 575
7.2.2Image Representation and Compression (GIF, JPEG) 577
7.2.3 Video Compression (MPEG) 585
7.2.4 Transmitting MPEG Over a Network 590
7.2.5 Audio Compression (MP3) 595
Perspective: Big Data and Analytics 597
Broader Perspective 599
Exercises 599
8 Network Security 607
Problem: Security Attacks 607
8.1 Trust and Threats 608
8.2 Cryptographic Building Blocks 610
8.2.1 Principles of Ciphers 610
8.2.2 Secret-Key Ciphers 613
8.2.3 Public-Key Ciphers 615
8.2.4 Authenticators 618
8.3 Key Predistribution 622
8.3.1 Predistribution of Public Keys 622
8.3.2 Predistribution of Secret Keys 627
8.3.3 Diffie–Hellman Key Exchange 628
8.4 Authentication Protocols 631
8.4.1 Originality and Timeliness Techniques 632
8.4.2 Public-Key Authentication Protocols 633
8.4.3 Secret-Key Authentication Protocols 635
8.5 Example Systems 639
8.5.1 Pretty Good Privacy (PGP) 640
8.5.2 Secure Shell (SSH) 642
8.5.3 Transport Layer Security (TLS, SSL, HTTPS) 645
8.5.4 IP Security (IPsec) 650
8.5.5 Wireless Security (802.11i) 653
8.5.6 Firewalls 656
Perspective: Blockchain and a Decentralized Internet 661
Broader Perspective 663
Exercises 663
9 Applications 671
Problem: Applications Need Their Own Protocols 671
9.1 Traditional Applications 672
9.1.1 Electronic Mail (SMTP, MIME, IMAP) 674
9.1.2 World Wide Web (HTTP) 682
9.1.3 Web Services 691
9.2 Multimedia Applications 701
9.2.1 Session Control and Call Control (SDP, SIP, H.323) 702
9.2.2 Resource Allocation for Multimedia Applications 712
9.3 Infrastructure Applications 718
9.3.1 Name Service (DNS) 718
9.3.2 Network Management (SNMP, OpenConfig) 729
9.4 Overlay Networks 734
9.4.1 Routing Overlays 736
9.4.2 Peer-to-Peer Networks 744
9.4.3 Content Distribution Networks 758
Perspective: The Cloud Is the New Internet 765
Broader Perspective 766
Exercises 766
Solutions to Select Exercises 773
Glossary 785
Index 805