计算机网络：系统方法（英文版·原书第6版）

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。

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)