cnai contents

Table of Contents For

Computer Networks And Internets

4th Edition

Preface xxvii

PART I Using And Building Internet Applications 39

Chapter 1 Introduction 1

1.1	Growth Of Computer Networking 1
1.2	Complexity In Network Systems 2
1.3	Mastering The Complexity 2
1.4	Concepts And Terminology 3
1.5	The Value Of Hands-On Experience 3
1.6	Organization Of The Text 3
1.7	Summary 4

Chapter 2 Motivation And Tools 7

2.1	Introduction 7
2.2	Resource Sharing 7
2.3	Growth Of The Internet 8
2.4	Probing The Internet 11
2.5	Interpreting A Ping Response 12
2.6	Tracing A Route 14
2.7	Summary 15
	Exercises 15

Chapter 3 Network Programming And Applications 19

3.1	Introduction 19
3.2	Network Communication 20
3.3	Client-Server Computing 20
3.4	Communication Paradigm 21
3.5	An Example Application Program Interface 21
3.6	An Intuitive Look At The API 22
3.7	Definition Of The API 22
	3.7.1	The Await_Contact Function 23
	3.7.2	The Make_Contact Function 23
	3.7.3	The Appname_To_Appnum Function 23
	3.7.4	The Cname_To_Comp Function 24
	3.7.5	The Send Function 24
	3.7.6	The Recv And Recvln Functions 24
	3.7.7	The Send_Eof Function 25
	3.7.8	Summary Of API Types 25
3.8	Code For An Echo Application 25
	3.8.1	Example Echo Server Code 26
	3.8.2	Example Echo Client Code 28
3.9	Code For A Chat Application 31
	3.9.1	Example Chat Server Code 31
	3.9.2	Example Chat Client Code 33
3.10	Code For A Web Application 35
	3.10.1	Example Web Client Code 36
	3.10.2	Example Web Server Code 38
3.11	Managing Multiple Connections With The Select Function 43
3.12	Summary 43
	Exercises 44

PART II Data Transmission 45

Chapter 4 Transmission Media 47

4.1	Introduction 47
4.2	Copper Wires 47
4.3	Glass Fibers 49
4.4	Radio 50
4.5	Satellites 50
4.6	Geosynchronous Satellites 51
4.7	Low Earth Orbit Satellites 52
4.8	Low Earth Orbit Satellite Arrays 52
4.9	Microwave 53
4.10	Infrared 53
4.11	Light From A Laser 54
4.12	Summary 54
	Exercises 54

Chapter 5 Local Asynchronous Communication (RS-232) 57

5.1	Introduction 57
5.2	The Need For Asynchronous Communication 58
5.3	Using Electric Current To Send Bits 58
5.4	Standards For Communication 59
5.5	Baud Rate, Framing, And Errors 61
5.6	Half And Full Duplex Asynchronous Communication 62
5.7	Limitations Of Real Hardware 63
5.8	Hardware Bandwidth And The Transmission Of Bits 64
5.9	The Effect Of Noise On Communication 64
5.10	Significance For Data Networking 65
5.11	Summary 66
	For Further Study 66
	Exercises 67

Chapter 6 Long-Distance Communication (Carriers, Modulation, And Modems) 69

6.1	Introduction 69
6.2	Sending Signals Across Long Distances 69
6.3	Modem Hardware Used For Modulation And Demodulation 73
6.4	Leased Analog Data Circuits 73
6.5	Optical, Radio Frequency, And Dialup Modems 74
6.6	Carrier Frequencies And Multiplexing 76
6.7	Baseband And Broadband Technologies 77
6.8	Wavelength Division Multiplexing 78
6.9	Spread Spectrum 78
6.10	Time Division Multiplexing 79
6.11	Summary 79
	Exercises 80

PART III Packet Transmission 81

Chapter 7 Packets, Frames, And Error Detection 83

7.1	Introduction 83
7.2	The Concept Of Packets 83
7.3	Packets And Time-Division Multiplexing 85
7.4	Packets And Hardware Frames 86
7.5	Byte Stuffing 87
7.6	Transmission Errors 89
7.7	Parity Bits And Parity Checking 89
7.8	Probability, Mathematics, And Error Detection 90
7.9	Detecting Errors With Checksums 91
7.10	Detecting Errors With Cyclic Redundancy Checks 92
7.11	Combining Building Blocks 94
7.12	Burst Errors 95
7.13	Frame Format And Error Detection Mechanisms 95
7.14	Summary 96
	Exercises 97

Chapter 8 LAN Technologies And Network Topology 101

8.1	Introduction 101
8.2	Direct Point-to-Point Communication 102
8.3	Shared Communication Channels 104
8.4	Significance Of LANs And Locality Of Reference 104
8.5	LAN Topologies 105
	8.5.1	Star Topology 105
	8.5.2	Ring Topology 106
	8.5.3	Bus Topology 107
	8.5.4	The Reason For Multiple Topologies 107
8.6	Example Bus Network: Ethernet 108
	8.6.1	History Of The Ethernet 108
	8.6.2	Ethernet Transmission And Manchester Encoding 108
	8.6.3	Sharing On An Ethernet 109
8.7	Carrier Sense On Multi-Access Networks (CSMA) 110
8.8	Collision Detection And Backoff With CSMA/CD 110
8.9	802.11b Wireless LANs And CSMA/CA 112
8.10	Another Example Bus Network: LocalTalk 113
8.11	Ring Topology And Token Passing 114
8.12	Self-Healing Token Passing Networks 115
8.13	Example Star Network: ATM 117
8.14	Summary 118
	Exercises 119

Chapter 9 Hardware Addressing And Frame Type Identification 123

9.1	Introduction 123
9.2	Specifying A Recipient 124
9.3	How LAN Hardware Uses Addresses To Filter Packets 124
9.4	Format Of A Physical Address 126
9.5	Broadcasting 127
9.6	Multicasting 128
9.7	Multicast Addressing 129
9.8	Identifying Packet Contents 130
9.9	Frame Headers And Frame Format 130
9.10	An Example Frame Format 131
9.11	Using Networks That Do Not Have Self-Identifying Frames 133
9.12	Network Analyzers, Physical Addresses, Frame Types 135
9.13	Summary 136
	For Further Study 137
	Exercises 138

Chapter 10 LAN Wiring, Physical Topology, And Interface Hardware 141

10.1	Introduction 141
10.2	Speeds Of LANs And Computers 141
10.3	Network Interface Hardware 142
10.4	The Connection Between A NIC And A Network 144
10.5	Original Thick Ethernet Wiring 144
10.6	Connection Multiplexing 146
10.7	Thin Ethernet Wiring 147
10.8	Twisted Pair Ethernet 148
10.9	Advantages And Disadvantages Of Wiring Schemes 150
10.10	The Topology Paradox 152
10.11	Network Interface Cards And Wiring Schemes 152
10.12	10/100 Network Interfaces And Autonegotiation 154
10.13	Categories Of Wire 154
10.14	Wiring Schemes And Other Network Technologies 155
10.15	Summary 156
	For Further Study 156
	Exercises 157

Chapter 11 Extending LANs: Fiber Modems, Repeaters, Bridges, and Switches 159

11.1	Introduction 159
11.2	Distance Limitation And LAN Design 159
11.3	Fiber Optic Extensions 160
11.4	Repeaters 161
11.5	Bridges 164
11.6	Frame Filtering 165
11.7	Startup And Steady State Behavior Of Bridged Networks 166
11.8	Planning A Bridged Network 166
11.9	Bridging Between Buildings 167
11.10	Bridging Across Longer Distances 168
11.11	A Cycle Of Bridges 170
11.12	Distributed Spanning Tree 171
11.13	Switching 172
11.14	Combining Switches And Hubs 173
11.15	Bridging And Switching With Other Technologies 173
11.16	Summary 174
	Exercises 175

Chapter 12 Long-Distance And Local Loop Digital Technologies 177

12.1	Introduction 177
12.2	Digital Telephony 177
12.3	Synchronous Communication 179
12.4	Digital Circuits, NIUs, And DSU/CSUs 180
12.5	Telephone Standards 181
12.6	DS Terminology And Data Rates 182
12.7	Lower Capacity Circuits 183
12.8	Intermediate Capacity Digital Circuits 183
12.9	Highest Capacity Circuits 184
12.10	Optical Carrier Standards 185
12.11	The C Suffix 185
12.12	Synchronous Optical NETwork (SONET) 185
12.13	The Local Subscriber Loop 187
12.14	ISDN 187
12.15	Asymmetric Digital Subscriber Line Technology 188
12.16	Other DSL Technologies 191
12.17	Cable Modem Technology 192
12.18	Upstream Communication 193
12.19	Hybrid Fiber Coax 194
12.20	Fiber To The Curb 195
12.21	Head-End And Tail-End Modems 195
12.22	Wireless Alternatives For Special Cases 196
12.23	Broadcast Satellite Systems 196
12.24	Summary 198
	Exercises 199

Chapter 13 WAN Technologies And Routing 201

13.1	Introduction 201
13.2	Large Networks And Wide Areas 201
13.3	Packet Switches 202
13.4	Forming A WAN 203
13.5	Store And Forward 204
13.6	Physical Addressing In A WAN 205
13.7	Next-Hop Forwarding 205
13.8	Source Independence 207
13.9	Relationship Of Hierarchical Addresses To Routing 207
13.10	Routing In A WAN 208
13.11	Use Of Default Routes 210
13.12	Routing Table Computation 211
13.13	Shortest Path Computation In A Graph 211
13.14	Distributed Route Computation 213
13.15	Distance Vector Routing 213
13.16	Link-State Routing (SPF) 216
13.17	Example WAN Technologies 216
	13.17.1	ARPANET 216
	13.17.2	X.25 216
	13.17.3	Frame Relay 217
	13.17.4	SMDS 217
	13.17.5	ATM 218
13.18	Summary 218
	Exercises 219

Chapter 14 Connection-Oriented Networking And ATM 221

14.1	Introduction 221
14.2	A Single, Global Network 221
14.3	ISDN And ATM 222
14.4	ATM Design And Cells 222
14.5	Connection-Oriented Service 224
14.6	VPI\\|/\\|VCI 224
14.7	Labels And Label Switching 225
14.8	An Example Trip Through An ATM Network 226
14.9	Permanent Virtual Circuits 227
14.10	Switched Virtual Circuits 228
14.11	Quality Of Service 229
14.12	The Motivation For Cells And Label Switching 229
	14.12.1	Cells vs. Packets. 229
	14.12.2	Label Switching Vs. Routing 230
14.13	ATM Data Transmission And AAL5 230
14.14	Critique Of ATM 231
14.15	MultiProtocol Label Switching (MPLS) 232
14.16	Summary 233
	Exercises 233

Chapter 15 Network Characteristics: Ownership, Service Paradigm, And Performance 235

15.1	Introduction 235
15.2	Network Ownership 236
	15.2.1	Private Networks 236
	15.2.2	Public Networks 236
15.3	Privacy And Public Networks 237
15.4	Advantages And Disadvantages 237
15.5	Virtual Private Networks 238
15.6	Guaranteeing Absolute Privacy 239
15.7	Service Paradigm 239
15.8	Connection-Oriented Service Paradigm 240
	15.8.1	Continuous And Bursty Traffic 240
	15.8.2	Simplex And Full Duplex Connections 240
	15.8.3	Connection Duration And Persistence 240
	15.8.4	Service Guarantees 241
	15.8.5	Stream Or Message Interface 241
15.9	Connectionless Service Paradigm 241
15.10	Interior And Exterior Service Paradigms 241
15.11	Comparison Of Service Paradigms 242
15.12	Examples Of Service Paradigms 242
15.13	Addresses And Connection Identifiers 243
15.14	Network Performance Characteristics 244
	15.14.1	Delay 244
	15.14.2	Throughput 245
	15.14.3	The Relationship Between Delay And Throughput 246
	15.14.4	Delay-Throughput Product 247
15.15	Jitter 247
	15.15.1	Isochronous Networks 248
	15.15.2	Asynchronous Networks 248
15.16	Summary 248
	Exercises 249

Chapter 16 Protocols And Layering 251

16.1	Introduction 251
16.2	The Need For Protocols 251
16.3	Protocol Suites 252
16.4	A Plan For Protocol Design 253
16.5	The Seven Layers 253
16.6	Stacks: Layered Software 255
16.7	How Layered Software Works 257
16.8	Multiple, Nested Headers 258
16.9	The Scientific Basis For Layering 258
16.10	Techniques Protocols Use 259
	16.10.1	Sequencing For Out-Of-Order Delivery 259
	16.10.2	Sequencing To Eliminate Duplicate Packets 261
	16.10.3	Retransmitting Lost Packets 261
	16.10.4	Avoiding Replay Caused By Excessive Delay 262
	16.10.5	Flow Control To Prevent Data Overrun 262
	16.10.6	Mechanisms To Avoid Network Congestion 266
16.11	The Art Of Protocol Design 268
16.12	Summary 268
	Exercises 269

PART IV Internetworking 271

Chapter 17 Internetworking: Concepts, Architecture, and Protocols 273

17.1	Introduction 273
17.2	The Motivation For Internetworking 273
17.3	The Concept Of Universal Service 274
17.4	Universal Service In A Heterogeneous World 274
17.5	Internetworking 275
17.6	Physical Network Connection With Routers 275
17.7	Internet Architecture 276
17.8	Achieving Universal Service 277
17.9	A Virtual Network 277
17.10	Protocols For Internetworking 279
17.11	Significance Of Internetworking And TCP/IP 279
17.12	Layering And TCP/IP Protocols 280
17.13	Host Computers, Routers, And Protocol Layers 281
17.14	Summary 282
	Exercises 282

Chapter 18 IP: Internet Protocol Addresses 285

18.1	Introduction 285
18.2	Addresses For The Virtual Internet 285
18.3	The IP Addressing Scheme 286
18.4	The IP Address Hierarchy 287
18.5	Original Classes Of IP Addresses 287
18.6	Computing The Class of An Address 289
18.7	Dotted Decimal Notation 290
18.8	Classes And Dotted Decimal Notation 291
18.9	Division Of The Address Space 291
18.10	Authority For Addresses 292
18.11	A Classful Addressing Example 292
18.12	Subnet And Classless Addressing 293
18.13	Address Masks 294
18.14	CIDR Notation 295
18.15	A CIDR Address Block Example 295
18.16	CIDR Host Addresses 296
18.17	Special IP Addresses 297
	18.17.1	Network Address 297
	18.17.2	Directed Broadcast Address 297
	18.17.3	Limited Broadcast Address 297
	18.17.4	This Computer Address 298
	18.17.5	Loopback Address 298
18.18	Summary Of Special IP Addresses 298
18.19	The Berkeley Broadcast Address Form 299
18.20	Routers And The IP Addressing Principle 299
18.21	Multi-Homed Hosts 301
18.22	Summary 301
	Exercises 302

Chapter 19 Binding Protocol Addresses (ARP) 305

19.1	Introduction 305
19.2	Protocol Addresses And Packet Delivery 306
19.3	Address Resolution 306
19.4	Address Resolution Techniques 307
19.5	Address Resolution With Table Lookup 308
19.6	Address Resolution With Closed-Form Computation 309
19.7	Address Resolution With Message Exchange 310
19.8	Address Resolution Protocol 311
19.9	ARP Message Delivery 312
19.10	ARP Message Format 313
19.11	Sending An ARP Message 314
19.12	Identifying ARP Frames 315
19.13	Caching ARP Responses 315
19.14	Processing An Incoming ARP Message 316
19.15	Layering, Address Resolution, Protocol Addresses 317
19.16	Summary 318
	Exercises 318

Chapter 20 IP Datagrams And Datagram Forwarding 321

20.1	Introduction 321
20.2	Connectionless Service 321
20.3	Virtual Packets 322
20.4	The IP Datagram 323
20.5	Forwarding An IP Datagram 324
20.6	IP Addresses And Routing Table Entries 325
20.7	The Mask Field And Datagram Forwarding 326
20.8	Destination And Next-Hop Addresses 326
20.9	Best-Effort Delivery 327
20.10	The IP Datagram Header Format 328
20.11	Summary 329
	Exercises 329

Chapter 21 IP Encapsulation, Fragmentation, And Reassembly 333

21.1	Introduction 333
21.2	Datagram Transmission And Frames 333
21.3	Encapsulation 334
21.4	Transmission Across An Internet 335
21.5	MTU, Datagram Size, And Encapsulation 336
21.6	Reassembly 338
21.7	Identifying A Datagram 338
21.8	Fragment Loss 339
21.9	Fragmenting A Fragment 339
21.10	Summary 340
	Exercises 340

Chapter 22 The Future IP (IPv6) 343

22.1	Introduction 343
22.2	The Success Of IP 343
22.3	The Motivation For Change 344
22.4	A Name And A Version Number 345
22.5	IPv6 Features 345
22.6	IPv6 Datagram Format 346
22.7	IPv6 Base Header Format 346
22.8	How IPv6 Handles Multiple Headers 348
22.9	Fragmentation, Reassembly, And Path MTU 349
22.10	The Purpose Of Multiple Headers 350
22.11	IPv6 Addressing 351
22.12	IPv6 Colon Hexadecimal Notation 352
22.13	Summary 353
	Exercises 353

Chapter 23 An Error Reporting Mechanism (ICMP) 355

23.1	Introduction 355
23.2	Best-Effort Semantics And Error Detection 355
23.3	Internet Control Message Protocol 356
23.4	ICMP Message Transport 359
23.5	Using ICMP Messages To Test Reachability 360
23.6	Using ICMP To Trace A Route 360
23.7	The Last Address Printed By Traceroute 361
23.8	Using ICMP For Path MTU Discovery 362
23.9	Summary 363
	Exercises 363

Chapter 24 UDP: Datagram Transport Service 365

24.1	Introduction 365
24.2	The Need For End-To-End Transport Protocols 365
24.3	The User Datagram Protocol 366
24.4	The Connectionless Paradigm 367
24.5	Message-Oriented Interface 367
24.6	UDP Communication Semantics 368
24.7	Arbitrary Interaction 368
24.8	Support For Unicast, Multicast, And Broadcast 369
24.9	Endpoint Identification With Protocol Port Numbers 369
24.10	UDP Datagram Format 370
24.11	The UDP Checksum And The Pseudo Header 370
24.12	UDP Encapsulation 371
24.13	Summary 371
	Exercises 372

Chapter 25 TCP: Reliable Transport Service 375

25.1	Introduction 375
25.2	The Need For Reliable Transport 375
25.3	The Transmission Control Protocol 376
25.4	The Service TCP Provides To Applications 376
25.5	End-To-End Service And Datagrams 377
25.6	Achieving Reliability 378
25.7	Packet Loss And Retransmission 379
25.8	Adaptive Retransmission 380
25.9	Comparison Of Retransmission Times 381
25.10	Buffers, Flow Control, And Windows 381
25.11	Three-Way Handshake 383
25.12	Congestion Control 384
25.13	TCP Segment Format 385
25.14	Summary 386
	Exercises 386

Chapter 26 Network Address Translation 389

26.1	Introduction 389
26.2	The Requirement For Unique Addresses 389
26.3	Network Address Translation Technology 390
26.4	NAT Topology 390
26.5	Possible Implementations Of NAT 391
26.6	Basic Address Translation 391
26.7	Translation Table 392
26.8	NAPT And TCP Splicing 393
26.9	Other Variants: Twice NAT And CAT 394
26.10	NAT Software And Systems For Use At Home 394
26.11	Summary 395
	For Further Study 395
	Exercises 395

Chapter 27 Internet Routing 399

27.1	Introduction 399
27.2	Static Vs. Dynamic Routing 399
27.3	Static Routing In Hosts And A Default Route 400
27.4	Dynamic Routing And Routers 401
27.5	Routing In The Global Internet 402
27.6	Autonomous System Concept 403
27.7	The Two Types Of Internet Routing Protocols 404
	27.7.1	Interior Gateway Protocols (IGPs) 404
	27.7.2	Exterior Gateway Protocols (EGPs) 404
	27.7.3	When EGPs And IGPs Are Used 404
	27.7.4	Optimal Routes, Routing Metrics, and IGPs 405
27.8	Routes And Data Traffic 406
27.9	The Border Gateway Protocol (BGP) 406
27.10	The Routing Information Protocol (RIP) 408
27.11	RIP Packet Format 409
27.12	The Open Shortest Path First Protocol (OSPF) 410
27.13	An Example OSPF Graph 411
27.14	OSPF Areas 412
27.15	Multicast Routing 412
	27.15.1	IP Multicast Semantics 412
	27.15.2	IGMP 413
	27.15.3	Forwarding And Discovery Techniques 414
	27.15.4	Multicast Protocols 415
27.16	Summary 416
	Exercises 416

PART V Network Applications 419

Chapter 28 Client-Server Interaction 421

28.1	Introduction 421
28.2	The Functionality Application Software Provides 422
28.3	The Functionality An Internet Provides 422
28.4	Making Contact 423
28.5	The Client-Server Paradigm 423
28.6	Characteristics Of Clients And Servers 424
28.7	Server Programs And Server-Class Computers 424
28.8	Requests, Responses, And Direction Of Data Flow 425
28.9	Transport Protocols and Client-Server Interaction 425
28.10	Multiple Services On One Computer 426
28.11	Identifying A Particular Service 427
28.12	Multiple Copies Of A Server For A Single Service 427
28.13	Dynamic Server Creation 428
28.14	Transport Protocols And Unambiguous Communication 428
28.15	Connection-Oriented And Connectionless Transport 429
28.16	A Service Reachable Through Multiple Protocols 430
28.17	Complex Client-Server Interactions 430
28.18	Interactions And Circular Dependencies 431
28.19	Summary 431
	Exercises 432

Chapter 29 The Socket Interface 435

29.1	Introduction 435
29.2	Application Program Interface 435
29.3	The Socket API 436
29.4	Sockets And Socket Libraries 436
29.5	Socket Communication And UNIX I/O 437
29.6	Sockets, Descriptors, And Network I/O 438
29.7	Parameters And The Socket API 438
29.8	Procedures That Implement The Socket API 439
	29.8.1	The Socket Procedure 439
	29.8.2	The Close Procedure 439
	29.8.3	The Bind Procedure 439
	29.8.4	The Listen Procedure 441
	29.8.5	The Accept Procedure 441
	29.8.6	The Connect Procedure 442
	29.8.7	The Send, Sendto, And Sendmsg Procedures 443
	29.8.8	The Recv, Recvfrom, And Recvmsg Procedures 444
29.9	Read And Write With Sockets 445
29.10	Other Socket Procedures 445
29.11	Sockets, Threads, And Inheritance 446
29.12	Summary 446
	Exercises 447

Chapter 30 Example Of A Client And A Server 449

30.1	Introduction 449
30.2	Connection-Oriented Communication 449
30.3	An Example Service 450
30.4	Command-Line Arguments For The Example Programs 450
30.5	Sequence Of Socket Procedure Calls 450
30.6	Code For Example Client 452
30.7	Code For Example Server 455
30.8	Stream Service And Multiple Recv Calls 457
30.9	Socket Procedures And Blocking 458
30.10	Size Of The Code And Error Reporting 458
30.11	Using The Example Client With Another Service 459
30.12	Using Another Client To Test The Server 459
30.13	Summary 460
	Exercises 460

Chapter 31 Naming With The Domain Name System 463

31.1	Introduction 463
31.2	Structure Of Computer Names 464
31.3	Geographic Structure 466
31.4	Domain Names Within An Organization 466
31.5	Domain Names That Begin With www 469
31.6	The DNS Client-Server Model 469
31.7	The DNS Server Hierarchy 470
31.8	Server Architectures 470
31.9	Locality Of Reference And Multiple Servers 472
31.10	Links Among Servers 472
31.11	Resolving A Name 472
31.12	Optimization Of DNS Performance 474
31.13	Types Of DNS Entries 475
31.14	Aliases Using The CNAME Type 475
31.15	An Important Consequence Of Multiple Types 476
31.16	Abbreviations And The DNS 476
31.17	Summary 477
	Exercises 477

Chapter 32 Electronic Mail Representation And Transfer 481

32.1	Introduction 481
32.2	The Electronic Mail Paradigm 481
32.3	Electronic Mailboxes And Addresses 482
32.4	Electronic Mail Message Format 483
32.5	Carbon Copies 485
32.6	Multipurpose Internet Mail Extensions 485
32.7	E-mail And Application Programs 487
32.8	Mail Transfer 487
32.9	The Simple Mail Transfer Protocol 488
32.10	Optimizing For Multiple Recipients On A Computer 489
32.11	Mail Exploders, Lists, And Forwarders 490
32.12	Mail Gateways 491
32.13	Automated Mailing Lists 492
32.14	Mail Relays And E-mail Addresses 492
32.15	Mailbox Access 493
32.16	Dialup Connections And POP 495
32.17	Summary 495
	Exercises 496

Chapter 33 IP Telephony (VoIP) 499

33.1	Introduction 499
33.2	The Motivation And Challenge Of IP Telephony 499
33.3	Encoding, Transmission, And Playback 500
33.4	Signaling Systems And Protocols 501
33.5	A Basic IP Telephone System 501
33.6	Interoperation With Other Telephone Systems 502
33.7	Alternative Terminology And Concepts 503
	33.7.1	SIP Terminology And Concepts 503
	33.7.2	H.323 Terminology And Concepts 504
	33.7.3	ISC Terminology And Concepts 504
33.8	Proposed Protocols And Layering 505
33.9	H.323 Characteristics 505
33.10	H.323 Layering 506
33.11	SIP Characteristics And User Identification 507
33.12	SIP Methods 507
33.13	An Example SIP Session 508
33.14	Telephone Number Mapping And Routing 509
33.15	IP Telephones And Electrical Power 509
33.16	Summary 510
	For Further Study 510
	Exercises 511

Chapter 34 File Transfer And Remote File Access 513

34.1	Introduction 513
34.2	Generalized File Transfer 513
34.3	The File Transfer Protocol 514
34.4	FTP General Model And User Interface 515
34.5	FTP Commands 515
34.6	Connections, Authorization, And File Permissions 516
34.7	Anonymous File Access 517
34.8	File Transfer In Either Direction 517
34.9	Wildcard Expansion In File Names 518
34.10	File Name Translation 518
34.11	Changing Directories And Listing Contents 518
34.12	File Types And Transfer Modes 519
34.13	Example FTP Session 520
34.14	Verbose Output 522
34.15	Client-Server Interaction In FTP 522
34.16	Control And Data Connections 523
34.17	Data Connections And End Of File 524
34.18	Trivial File Transfer Protocol 524
34.19	Network File System 525
34.20	Summary 526
	Exercises 526

Chapter 35 World Wide Web Pages And Browsing 529

35.1	Introduction 529
35.2	Browser Interface 529
35.3	Hypertext And Hypermedia 530
35.4	Document Representation 530
35.5	HTML Format And Representation 531
35.6	Example HTML Formatting Tags 532
35.7	Headings 533
35.8	Lists 533
35.9	Embedding Graphics Images In A Web Page 534
35.10	Identifying A Page 535
35.11	Hypertext Links From One Document To Another 535
35.12	Client-Server Interaction 536
35.13	Web Document Transfer And HTTP 537
35.14	Browser Architecture 538
35.15	Optional Clients 539
35.16	Caching In Web Browsers 541
35.17	HTTP Support For Caching 542
35.18	Alternative Transfer Protocols 542
35.19	Other Markup Languages 542
35.20	Summary 543
	Exercises 543

Chapter 36 Dynamic Web Document Technologies (CGI, ASP, JSP, PHP, ColdFusion) 547

36.1	Introduction 547
36.2	Three Basic Types of Web Documents 547
36.3	Advantages And Disadvantages Of Each Document Type 548
36.4	Implementation Of Dynamic Documents 550
36.5	The CGI Standard 550
36.6	Output From A CGI Program 550
36.7	An Example CGI Program 551
36.8	Parameters And Environment Variables 553
36.9	State Information And Cookies 554
36.10	A CGI Script With Long-Term State Information 555
36.11	A CGI Script With Short-Term State Information 556
36.12	Forms And Interaction 559
36.13	Server-Side Scripting Technologies 560
36.14	Summary 561
	Exercises 562

Chapter 37 Active Web Document Technologies (Java, JavaScript) 565

37.1	Introduction 565
37.2	Continuous Update With Server Push And Client Pull 565
37.3	Active Documents And Server Overhead 566
37.4	Active Document Representation And Translation 566
37.5	Java Technology 568
37.6	The Java Programming Language 568
	37.6.1	Language Characteristics 568
	37.6.2	Similarities to C++ 569
37.7	The Java Runtime Environment 569
	37.7.1	Machine Independence And Portability 570
37.8	The Java Library 571
37.9	A Graphics Toolkit 572
37.10	Using Java Graphics On A Particular Computer 573
37.11	Java Interpreters And Browsers 574
37.12	Compiling A Java Program 574
37.13	An Example Applet 575
37.14	Invoking An Applet 577
37.15	Example Of Interaction With A Browser 578
37.16	Errors And Exception Handling 580
37.17	JavaScript Technology 580
37.18	Alternatives 582
37.19	Summary 583
	Exercises 583

Chapter 38 RPC and Middleware 587

38.1	Introduction 587
38.2	Programming Clients And Servers 587
38.3	Remote Procedure Call Paradigm 588
38.4	RPC Paradigm 589
38.5	Communication Stubs 591
38.6	External Data Representation 592
38.7	Middleware And Object-Oriented Middleware 593
	38.7.1	ONC RPC 593
	38.7.2	DCE\\|/\\|RPC 594
	38.7.3	MSRPC 594
	38.7.4	CORBA 594
	38.7.5	MSRPC2 594
	38.7.6	COM\\|/\\|DCOM 595
	38.7.7	Java RMI 595
	38.7.8	Jini 595
	38.7.9	SOAP 595
	38.7.10	UDDI 596
	38.7.11	XML 596
38.8	Summary 596
	Exercises 597

Chapter 39 Network Management (SNMP) 599

39.1	Introduction 599
39.2	Managing An Internet 599
39.3	The Danger Of Hidden Failures 600
39.4	Network Management Software 600
39.5	Clients, Servers, Managers, And Agents 600
39.6	Simple Network Management Protocol 601
39.7	Fetch-Store Paradigm 602
39.8	The MIB And Object Names 602
39.9	The Variety Of MIB Variables 603
39.10	MIB Variables That Correspond To Arrays 603
39.11	Summary 604
	Exercises 605

Chapter 40 Network Security 607

40.1	Introduction 607
40.2	Secure Networks And Policies 607
40.3	Aspects Of Security 608
40.4	Responsibility And Control 609
40.5	Integrity Mechanisms 609
40.6	Access Control And Passwords 610
40.7	Encryption And Confidentiality 610
40.8	Public Key Encryption 611
40.9	Authentication With Digital Signatures 611
40.10	Internet Firewall Concept 612
40.11	Packet Filtering Using Ports 614
40.12	Using Packet Filters To Create A Firewall 615
40.13	Virtual Private Networks 616
40.14	Tunneling 617
40.15	Security Technologies 618
40.16	Summary 619
	Exercises 620

Chapter 41 Initialization (Configuration) 623

41.1	Introduction 623
41.2	Bootstrapping Protocol Software 623
41.3	Protocol Parameters 624
41.4	Protocol Configuration 624
41.5	Examples Of Items That Need To Be Configured 624
41.6	Configuration From Stable Storage 625
41.7	The Need To Automate Protocol Configuration 626
41.8	Methods For Automated Protocol Configuration 626
41.9	The Address Used To Find An Address 627
41.10	A Sequence Of Protocols Used During Bootstrap 628
41.11	Bootstrap Protocol (BOOTP) 628
41.12	Dynamic Host Configuration Protocol (DHCP) 630
41.13	Optimizations In DHCP 631
41.14	Indirect Server Access Through A Relay 632
41.15	DHCP Message Format 632
41.16	DHCP And Domain Names 633
41.17	Summary 634
	Exercises 635

Table of Contents For Computer Networks And Internets 4th Edition

Preface xxvii

PART I Using And Building Internet Applications 39

Chapter 1 Introduction 1

Chapter 2 Motivation And Tools 7

Chapter 3 Network Programming And Applications 19

PART II Data Transmission 45

Chapter 4 Transmission Media 47

Chapter 5 Local Asynchronous Communication (RS-232) 57

Chapter 6 Long-Distance Communication (Carriers, Modulation, And Modems) 69

PART III Packet Transmission 81

Chapter 7 Packets, Frames, And Error Detection 83

Chapter 8 LAN Technologies And Network Topology 101

Chapter 9 Hardware Addressing And Frame Type Identification 123

Chapter 10 LAN Wiring, Physical Topology, And Interface Hardware 141

Chapter 11 Extending LANs: Fiber Modems, Repeaters, Bridges, and Switches 159

Chapter 12 Long-Distance And Local Loop Digital Technologies 177

Chapter 13 WAN Technologies And Routing 201

Chapter 14 Connection-Oriented Networking And ATM 221

Chapter 15 Network Characteristics: Ownership, Service Paradigm, And Performance 235

Chapter 16 Protocols And Layering 251

PART IV Internetworking 271

Chapter 17 Internetworking: Concepts, Architecture, and Protocols 273

Chapter 18 IP: Internet Protocol Addresses 285

Chapter 19 Binding Protocol Addresses (ARP) 305

Chapter 20 IP Datagrams And Datagram Forwarding 321

Chapter 21 IP Encapsulation, Fragmentation, And Reassembly 333

Chapter 22 The Future IP (IPv6) 343

Chapter 23 An Error Reporting Mechanism (ICMP) 355

Chapter 24 UDP: Datagram Transport Service 365

Chapter 25 TCP: Reliable Transport Service 375

Chapter 26 Network Address Translation 389

Chapter 27 Internet Routing 399

PART V Network Applications 419

Chapter 28 Client-Server Interaction 421

Chapter 29 The Socket Interface 435

Chapter 30 Example Of A Client And A Server 449

Chapter 31 Naming With The Domain Name System 463

Chapter 32 Electronic Mail Representation And Transfer 481

Chapter 33 IP Telephony (VoIP) 499

Chapter 34 File Transfer And Remote File Access 513

Chapter 35 World Wide Web Pages And Browsing 529

Chapter 36 Dynamic Web Document Technologies (CGI, ASP, JSP, PHP, ColdFusion) 547

Chapter 37 Active Web Document Technologies (Java, JavaScript) 565

Chapter 38 RPC and Middleware 587

Chapter 39 Network Management (SNMP) 599

Chapter 40 Network Security 607

Chapter 41 Initialization (Configuration) 623

Appendix 1 Glossary Of Networking Terms And Abbreviations 637

Appendix 2 The ASCII Character Set 683

Appendix 3 Address Masks In Dotted Decimal 685

Appendix 4 How To Use The CD-ROM Included With This Book 687

Bibliography 693

Index 701

Table of Contents For

Computer Networks And Internets

4th Edition