数据通信与网络教程 英文版PDF电子书下载

CHAPTER 1 INTRODUCTION TO COMMUNICATIONS,STANDARDS,AND PROTOCOLS 1

1.1 VVHY STUDY COMMUNICATIONS? 1

A Brief History 1

Applications 3

Issues 6

1.2 COMPUTER NETWORKS 7

Common Bus Topology 9

StarTopology 10

Ring Topology 11

Fully Connected Topology 12

Combined Topologies 13

1.3 STANDARDS AND STANDARDS ORGANIZATIONS 14

The Need for Standards 14

Agencies 15

1.4 OPEN SYSTEMS AND THE OSI MODEL 17

Overview of the Model 20

Physical Layer 23

Data Link Layer 28

Network Layer 30

Transport Layer 32

Session Layer 38

Presentation Layer 42

Application Layer 45

Summary 46

1.5 THE FUTURE OF DATA COMMUNICATIONS 47

REVIEW QUESTIONS 51

EXERCISES 53

REFERENCES 54

CHAPTER 2 TRANSMISSION FUNDAMENTALS 56

2.1 COMMUNICATIONS MEDIA 57

Conductive Metal 59

Optical Fiber 62

Wireless Communications 66

Summary 81

Telephone System 83

2.2 COMMUNICATION SERVICES AND DEVICES 83

Integrated Services Digital Network 87

Cellular Phones 88

FaX Machines 90

2.3 CODES 92

ASCII Code 93

EBCDIC Code 94

Baudot,Morse,and BCD Codes 97

2.4 ANALOG AND DIGITAL SIGNALS 101

Digital Encoding Schemes 102

Analog Signals 105

Bit Rate 110

2.5 MODULATION AND DEMODULATION 115

Digital-to-Analog Conversion 116

Analog-to-Digital Conversion 121

2.6 MODEMS AND MODEM STANDARDS 124

Signal Constellation 126

Intelligent(Hayes Compatible)Modems 130

Cable Modems 131

NulI Modems 135

2.7 SUMMARY 135

REVIEW QUESTIONS 137

EXERCISES 139

REFERENCES 143

CHAPTER 3 DATA COMMUNICATION 145

Serial and Parallel Transmission 146

3.1 TRANSMISSION MODES 146

Asynchronous and Synchronous Transmission 147

Simplex,Half-Duplex,and Full-Duplex Communications 150

3.2 INTERFACE STANDARDS 151

RS-232 Interface 152

RS-232 Subsets 155

Null Modems 156

RS-449 Interface 157

X.21 Interface 159

3.3 MULTIPLEXING 161

Frequency-Division Multiplexing 163

Time-Division Multiplexing 165

Statistical Multiplexers 167

T-l Carrier 169

3.4 CONTENTION PROTOCOLS 172

Aloha Protocols 174

Carrier Sense Multiple Access 177

Collision Detection 180

Token Passing 183

Summary of Protocols 187

3.5 DATA COMPRESSION 188

Huffman Code 189

Run-Length Encoding 192

Relative Encoding 194

Lempel-Ziv Encoding 195

Image Compression 201

JPEG 203

MPEG 211

Summary of Compression Techniques 216

3.6 SUMMARY 217

REVIEW QUESTIONS 218

EXERCISES 220

REFERENCES 224

CHAPTER 4 DATA SECURITY AND INTEGRITY 226

4.1 I NTRODUCTION 226

Parity Checking Analysis 228

4.2 PARITY CHECKING 228

Double-Bit Error Detection 229

Burst Error Detection 229

4.3 CYCLIC REDUNDANCY CHECKS 231

Polynomial Division 232

How CRC Works 233

Analysis of CRC 235

CRC Implementation Using Circular Shifts 239

Single-Bit Error Correction 241

4.4 HAMMING CODES 241

Multiple-Bit Error Correction 244

Comparison of Error Detection and Error Correction 244

4.5 ENCRYPTION AND DECRYPTION 245

Caesar Cipher 247

Polyalphabetic Cipher 248

Transposition Cipher 250

Bit-Level Ciphering 251

Data Encryption Standard 252

Clipper Chip 256

Key Distribution and Protection 260

Merkle's Puzzles 260

Shamir's Method 261

4.6 PUBLIC KEY ENCRYPTION 262

RSA Algorithm 264

Digital Signatures 266

Authentication Using Hash-Based Schemes 268

Encryption Potpourri 272

Summary of Encryption Methods 272

4.7 VIRUSES,WORMS,AND HACKERS 275

Infecting Files 275

Memory-Resident Viruses 276

Virus Evolution 277

Virus Sources 281

The Internet Worm 281

Computer Hackers 283

4.8 SUMMARY 284

REVIEW QUESTIONS 286

EXERCISES 288

REFERENCES 291

CHAPTER 5 PROTOCOLCONCEPTS 293

5.1 INTRODUCTION 293

5.2 BASIC FLOW CONTROL 295

Signaling 295

Frame-Oriented Control 297

Protocol Efficiency 301

5.3 SLIDING WINDOW PROTOCOLS 304

Frame Format 306

Go-back-n Protocol 307

Selective Repeat Protocol 314

Sliding Window Protocol Efficiency 322

Summary of Protocols 324

5.4 PROTOCOL CORRECTNESS 325

Finite State Machines 325

Petri Nets 331

5.5 DATA LINK CONTROL PROTOCOLS 336

High-Level Data Link Control(HDLC) 336

Other Bit-Oriented Protocols 344

Binary Synchronous Communications Protocol 345

Summary:Data Link Protocols 349

5.6 CASE STUDY:KERMIT 350

Frame Format 351

Protocol 352

Commands 354

5.7 SUMMARY 356

REVIEW QUESTIONS 357

EXERCISES 359

REFERENCES 363

CHAPTER 6 LOCAL AREA N ETWORKING 364

6.1 NETWORK TOPOLOGIES 364

6.2 ETHERNET:IEEE STANDARD 802.3 367

Ethernet Components 368

Relation to OSI 368

Cable Specifications 371

Connecting Segments 373

Frame Format 374

Efficiency 375

6.3 TOKEN RING:IEEE STANDARD 802.5 379

Token and Frame Formats 381

Reserving and Claiming Tokens 383

Ring Maintenance 389

Efficiency 391

Other Ring Networks 392

6.4 TOKEN Bus:IEEE STANDARD 802.4 397

Token Bus Operations 399

Lost Tokens 402

Ring Initialization 403

Prioritizing Frames 404

6.5 INTERCONNECTING LANS 407

Layer 1 Connections 409

Layer 2 Connections 410

Bridging Different Types of LANs 411

Bridge Routing 413

Summary 426

6.6 CASE STUDY:NOVELL NETWARE 427

NetWare Configuration 427

Running Novell NetWare 429

Security and Integrity 431

Selected Novell Commands 434

Login Scripts 436

6.7 SUMMARY 439

REVIEW QUESTIONS 440

EXERCISES 443

REFERENCES 446

CHAPTER 7 WIDE AREA NETWORKING 448

7.1 INTRODUCTION 448

7.2 NETWORK ROUTING 451

Routing Tables 452

Types of Routing 453

Dijkstra's Algorithm 456

Bellman-Ford Algorithm 459

Link State Routing 466

Hierarchical Routing 467

Routing Information Protocol 470

Open Shortest Path First 471

？order Gateway Protocol 472

Congestion and Deadlock 473

Summary of Routing Techniques 473

7.3 PUBLIC DATA NETWORKS:THE X SERIES PROTOCOLS 478

Packet-Switched Network Modes 479

X.25 Public Data Network Interface Standard 481

Triple-X Standard for Non-X.25 Devices 486

7.4 INTERNET PROTOCOLS 490

Overview of TCP/IP 491

Internet Addressing 493

Domain Name System 495

IP Packets 497

Fragmentation 500

IP Routing 501

Intemet Control Message Protocol 504

IPv6 506

7.5 TRANSPORT PROTOCOLS 515

Transmission Control Protocol 518

OSI Transport Protocols 529

User Datagram Protocol 529

7.6 SOCKET PROGRAMMING 531

Sockets 532

Client/Server Model 532

Socket Data Structures 533

Socket Commands 535

Client/Server Example 535

7.7 SUMMARY 548

REVIEW QUESTIONS 551

EXERCISES 553

REFERENCES 557

CHAPTER 8 ADDITIONAL NETWORK PROTOCOLS 559

8.1 INTERNET APPLICATIONS 559

Virtual Terminal 559

Telnet 560

File Transfers 564

Simple Mail Transfer Protocol 571

Simple Network Management Protocol 573

8.2 WORLD WIDE WEB 576

Web Page Access 577

Hypertext Markup Language 579

HTML Forms 582

JavaScript and Client-side Programming 587

Common Gateway Interface and Server-side Programming 592

8.3 ELECTRONIC MAIL:X.400 AND X.500 STANDARDS 597

X.400 Mail Standards 598

X.500 Directory Service 606

8.4 INTEGRATED SERVICES DIGITAL NETWORK 610

Summary 610

ISDN Services 612

ISDN Architecture 613

Protocols 615

Broadband ISDN 624

8.5 ASYNCHRONOUS TRANSFER MODE 625

Benefits of Small Fixed-Size Cells 626

Overview of ATM Network 628

Switching 629

Reference Model 631

Cell Definition 633

Virtual Circuits and Paths 636

Connection Management 637

Adaptation Layers 639

8.6 SYSTEMS NETWORK ARCHITECTURE 646

Lower Layers Physical Link Control 647

Path Control 648

Transmission Conteol 654

Data Flow Control 657

Higher Layers 659

REVIEW QUESTIONS 661

EXERCISES 663

REFERENCES 665

GLOSSARY 667

ACRONYMS 695

INDEX 699