Ⅰ COMPUTER COMMUNICATIONS AND NETWORK BASICS 1
1 Overview of Computer Communications and Networking 2
1.1 What Does Computer Communications and Networking Technologies Mean? 3
1.2 What Is a Computer Network？ 4
Network Members:Devices,Nodes,and Hosts 4
Network Media and Communication Protocols 5
1.3 Types of Computer Networks 7
Classifying Networks by the Area They Encompass 7
Classifying Networks by Their Topology 9
Switched Networks 14
1.4 Network Addressing,Routing,Reliability,Interoperability,and Security 16
Addressing 16
Routing 17
Reliability 17
Interoperability 18
Security 18
1.5 Network Standards 19
De Jure Standards 20
De Facto Standards 20
Proprietary Standards 21
Consortia Standards 21
Internet Standards Development 22
1.6 The Telephone System and Data Communications 23
The Invention of the Telephone 23
The Evolution of the Telephone Industry and AT&T 24
The AT&T Breakup of 1984 25
The Telecommunications Act of 1996 26
Data Communications versus Telecommunications 27
1.7 Organization of the Book 28
End-of-Chapter Commentary 29
Chapter Review Moterials 30
2 Essential Terms and Concepts 33
2.1 Network Applications and Application Protocols 34
2.2 Computer Communications and Networking Models 37
Decentralized Systems 37
CentralizedSystems 38
Distributed Systems 38
Client/Server Model 40
Peer-to-Peer Model 41
Web-Based Model 43
Emerging File-Sharing Model Servant 44
2.3 Communication Service Methods and Data Transmission Modes 45
Serial and Parallel Communications 45
Synchronous,Asynchronous,and Isochronous Communications 46
Simplex and Duplex Communications 48
2.4 Analog and Digital Communications 49
Analog Communications 49
Digital Communications 51
2.5 Speed and Capacity of a Communications Channel 54
Bandwidth andData Rate 54
Throughput 55
Noise 55
2.6 Multiplexing and Switching 59
Multiplexing 59
Switching 62
2.7 Network Architecture and the OSI Reference Model 65
The OSI Model 65
OSI Service Types 67
OSI Today 70
End-of-Chapter Commentary 71
Chapter Review Materials 72
3 Analog and Digital Communications Concepts 76
3.1 Representing Data as Analog Signals 77
Converting Analog Data to Analog Signals 77
Converting Digital Data to Analog Signals 79
3.2 Representing Data as Digital Signals 87
Converting Analog Data to Digital Signals 87
Converting Digital Data to Digital Signals 90
3.3 Data Rate and Baud Rate Redux 92
3.4 Digital Carrier Systems 93
T1 and DS Circuits 93
Fractional T1 95
SONET and OC Circuits 98
End-of-Chapter Commentary 100
Chapter Review Materials 100
Ⅱ Physical,Data Link,and Network Layer Concepts 107
4 Physical Layer Concepts 108
4.1 What Is the Physical Layer? 109
4.2 The Physical and Electrical Characteristics of Wire 110
Physical Characteristics 111
Electrical Characteristics 114
4.3 Copper Media 116
Unshielded and Shielded Twisted-Pair Cable 116
IBM Cable 118
Coaxial Cable 119
Twin Axial Cable 120
4.4 Fiber-Optic Media 120
4.5 Wireless Communications 124
Radio Transmission 124
Infrared Transmission 127
Wireless LAN Standards 128
4.6 Satellite Communications 129
4.7 Structured Cabling Systems 133
End-of-Chapter Commentary 135
Chapter Review Materials 135
5 Data Link Layer Concepts and IEEE LAN Standards 139
5.1 What Is the Data Link Layer? 140
Overview 140
The IEEE and the Data Link Layer 141
5.2 The Logical Link Control(LLC)Sublayer 142
Framing 142
Flow Control 146
Error Control 152
5.3 The Media Access Control(MAC)Sublayer 158
Random Access Protocols 158
Token Passing Protocols 161
Random Access versus Token Passing Protocols 162
5.4 Data Prioritization and Quality of Service 163
End-of-Chapter Commentary 166
Chapter Review Materials 166
6 Network Hardware Components(Layers 1 and 2) 170
6.1 What Are Connectors? 171
Overview 171
UTP Cable Connectors 171
Coaxial Cable Connectors 172
Fiber-Optic Cable Connectors 173
Other Connectors 173
6.2 Transceivers and Media Converters 174
Transceivers 174
Media Converters 176
6.3 Repeaters 177
Repeaters versus Hubs 177
6.4 Network Interface Cards and PC Cards 179
Network Interface Cards 179
PC Cards 181
6.5 Bridges 182
Overview 182
Bridge Standards 183
Bridges versus Repeaters 187
6.6 Switches 188
Store-and-Forward Switch 188
Cut-Through Switch 189
Hybrid Switch 190
Switch Performance 190
End-of-Chapter Commentary 192
Chapter Review Materials 192
7 Internetworking and Network Layer Concepts and Components 195
7.1 Internetworking Concepts 196
7.2 The Network Layer and Routing Concepts 200
Network Layer Overview 200
Routing Protocol Concepts 202
Routing Algorithms 205
7.3 Sample Routing Protocols 208
Autonomous Systems and Interior and Border Gateway Protocols 208
RIP 208
RIP-2 211
OSPF 212
Other Routing Protocols 214
Classless Interdomain Routing 215
7.4 Routers and Switches 215
Overview(Review)of Switches and Switching 215
Layer-2 and Layer-3 Switches versus Routers 216
Layer-4 Switching 217
IP Switching 217
Brouter versus Router 218
7.5 Virtual Private Networks(VPNs) 218
VPN Strategies 218
VPN Benefits 221
End-of-Chapter Commentary 223
Chapter Review Materials 223
8 The Internet and TCP/IP 229
8.1 What Is the Internet? 230
8.2 Internet History 231
ARPANET 231
BITNET,CSNET,and UUCP 231
NSFNET 233
A Commercial Internet 236
The Current Public Internet 237
Other Internet Backbone Initiatives 238
8.3 Internet Administration 240
Governance and Organization 240
Standards Development 241
Internet Security 242
8.4 What Is TCP/IP? 243
A Brief History 243
The TCP/IP Model versus the OSI Model 245
8.5 TCP/IP's Transport and Network Layer Protocols 248
Overview of Internet-Based Communications and the Role of UDP,TCP,IP,and Port Numbers 248
The User Datagram Protocol(UDP) 249
The Transport Control Protocol(TCP) 252
The Internet Protocol(IP) 260
8.6 IP Addresses 263
IPv4 263
Subnetting IPv4 Addresses 265
IP Address Resolutions:DNS 270
IP Address and Name Assignment 273
8.7 IPv6 274
The Need for IPv6 274
I Pv6 versus IPv4 275
I Pv6 Addresses 278
I Pv6 Migration 280
8.8 TCP/IP Application Level Protocols 281
Electronic Mail:SMTP,MIME,and POP 281
The TELNET Protocol 291
The File Transfer Protocol(FTP) 293
The Hypertext Transfer Protocol(HTTP) 295
End-of-Chapter Commentary 304
Chapter Review Materials 304
Ⅲ Local and Wide Area Networking Technologies 311
9 Ethernet and IEEE 802.3 Networks 312
9.1 The History of Ethernet 313
In the Beginning 313
Ethernet versus IEEE 802.3 314
9.2 10-MBPS Ethernet/802.3 LANS 316
Physical and Data Link LayerInformation 316
The Concept of Network Diameter and Collision Domain 321
The 5-4-3 Repeater Placement Rule 324
Workarounds to the 5-4-3 Repeater Placement Rule 325
Performance Issues 326
9.3 Switched Ethernet,Full-Duplex Ethernet,and Virtual LANs 328
The Concept of Segmentation 328
Switched Ethernet 330
Full-Duplex Ethernet 335
Virtual Local Area Networks(VLANs) 336
9.4 100-MBPS Ethernet LANs 337
Fast Ethernet 338
100VG-AnyLAN 342
9.5 Gigabit Ethernet 346
Overview 346
IEEE 802.3z:Gigabit Ethernet over Fiber 348
IEEE 802.3ab:Gigabit Ethernet over Copper 350
Gigabit Ethernet versus Asynchronous TransferMode (ATM) 351
Gigabit Ethernet's Bottom Line 352
Is Faster Better? 353
Ethernet as a WAN Protocol:IEEE 802.3ae—10-Gigabit Ethernet 353
9.6 Other Ethernet-Related Projects 354
End-of-Chapter Commentary 355
Chapter Review Materials 355
10 Token Ring 361
10.1 What Is Token Ring? 362
10.2 Physical Layer Specifications 364
10.3 Frame Formats 365
The Token Frame 365
The Data Frame 366
10.4 Priority and Reservation 368
10.5 Monitor Stations 369
10.6 Second-Generation Token Ring 370
Switched Token Ring 370
Dedicated Token Ring 372
Full-Duplex Token Ring 373
High-Speed Token Ring 373
10.7 Token Ring versus Token Bus 374
End-of-Chapter Commentary 375
Chapter Review Materials 375
11 Fiber Distributed Data Interface(FDDI) 378
11.1 What Is FDDI? 379
11.2 Physical Layer Specifications 381
11.3 Frame Formats and Medium Access Specifications 382
Frame Formats 382
MAC Sublayer:FDDI versus Token Ring 384
Operation 385
11.4 Configuration and Design Issues 386
11.5 Interconnecting FDDI with Ethernet/802.3 or ATM Networks 388
11.6 The Future of FDDI 390
End-of-Chapter Commentary 390
Chapter Review Materials 391
12 Integrated Services Digital Network(ISDN) 393
12.1 What Is ISDN? 394
History 394
Standards 396
12.2 ISDN Components 398
Modules,Equipment,and Adapters 398
Interfaces 399
12.3 ISDN Channel Types 400
B Channel 401
D Channel 401
H Channel 402
12.4 Basic and Primary Rate Interfaces 402
Basic Rate Interface(BRI) 402
Primary Rate Interface(PRI) 403
12.5 ISDN Protocols 404
Overview 404
Link Access Protocol-D Channel(LAP-D) 405
12.6 ISDN Features,Services,and Applications 406
Service Profile Identification(SPID)Numbers 406
Line and Feature Sets 406
Teleservices 407
ISDN versus Regular Phone Service 407
ISDN and the Internet 408
LAN-to-LAN Connections 409
12.7 Other ISDN Initiatives 410
Always On/Dynamic ISDN 410
Broadband ISDN 411
End-of-Chapter Commentary 411
Chapter Review Materials 412
13 Frame Relay 416
13.1 What Is Frame Relay? 417
13.2 Frame Relay Circuits 420
Permanent Virtual Circuit(PVC) 420
Committed Information Rate(CIR) 422
CIR and Oversubscription 423
Switched Virtual Circuit(SVC) 426
13.3 Technical Overview and Data Link Layer Issues 427
Basic Operation 427
Frame Relay Frames 428
Data Link Connection Identifier(DLCI) 430
Congestion Control and Management 432
Link Management 434
13.4 Additional Frame Relay Information 434
Voice Over Frame Relay 434
Frame Relay versus Other LAN-to-LAN Technologies 436
Frame Relay in the News 436
End-of-Chapter Commentary 437
Chapter Review Materials 437
14 Switched Multimegabit Data Service(SMDS) 441
14.1 What Is SMDS? 442
Overview 442
History 443
Development Rationale 443
14.2 SMDS Technical Overview 444
Physical Layer Specifications 444
Data Link Layer Specifications:DQDB 446
14.3 The SMDS Interface Protocol(SIP) 447
14.4 SMDS Addressing 451
14.5 SMDS versus Other LAN-to-LAN Technologies 452
SMDS versus Frame Relay and ATM 452
14.6 Status of SMDS Today 453
End-of-Chapter Commentary 455
Chapter Review Materials 455
15 Asynchronous Transfer Mode(ATM) 458
15.1 What Is ATM? 459
Overview 459
History 459
15.2 General Concepts and Operation 461
General Concepts 461
Operation 461
15.3 ATM Interface Standards 463
15.4 ATM Cells,Virtual Connections,and Addressing 465
ATM Cells 465
Virtual Connections 467
Addressing 469
15.5 ATM Adaptation Layer(AAL) 470
15.6 ATM and Convergence Technology 472
15.7 ATM versus Other Technologies and Services 473
ATM versus Fast and Gigabit Ethernet 473
ATM versus Frame Relay 474
ATM versus SONET 475
ATM as an Emulated LAN Technology 475
End-of-Chapter Commentary 477
Chapter Review Materials 477
Ⅳ Related Networking Concepts,Applications,and Technologies 477
16 Dialup and Home Networking 482
16.1 What Is Dialup Networking? 483
Terminal Dialup Connection 483
Network Dialup Connection 485
16.2 Analog Modem Concepts 485
Overview 485
Modem Standards 486
DCE,DTE,Compression,and Error Control 486
56K Modems 489
16.3 DSL Service 490
Overview 490
DSL Transmission Rates and Circuit Quality 492
Types of DSL Service 494
16.4 Cable Modems 498
16.5 Home Networking Concepts and Issues 501
Connecting to the Internet 502
Interconnecting More Than One Home Computer 504
The Home Network Infrastructure 505
Home Network Security 505
Potential Problems When Configuring a Home Network 506
End-of-Chapter Commentary 507
Chapter Review Materials 508
17 Network Security Issues 512
17.1 What Is Network Security? 513
17.2 Threat Assessment 513
Identifying Critical Assets 514
Who Covets Your Assets? 516
Risk Analysis 517
War Games 518
Documentation 518
17.3 Network Attacks and Security Measures Considerations 518
Examples of Network Attacks 518
Denial of Service(DoS)Attacks 519
Obstacles to Implementing Network Security 521
Security Measures Considerations 521
17.4 Firewalls 524
Overview 524
Type of Firewalls 524
Firewalls and Multiprotocol Environments 526
Firewall Implementation Considerations 527
17.5 Encryption Methods 528
Overview 528
Public Key Infrastructure(PKI) 530
Data Encryption Standard(DES) 530
Pretty Good Privacy(PGP) 531
RSA 532
17.6 Authentication and Access Control Measures 537
Digital Certificates 538
SmartCards 538
Kerberos 539
17.7 Virtual Private Networks and Internet Security 539
VPN Security Protocols 540
The IP Security Protocol(IPSec) 541
Protecting VPN Connections 544
End-of-Chapter Commentary 545
Chapter Review Materials 545
18 Network Convergence 549
18.1 What Is Network Convergence? 550
Overview 550
Convergence Is More Than Combining Voice and Data 552
18.2 Networking Issues and Convergence 554
Network Media and Convergence 554
Network Applications and Convergence 556
Convergence and Multimedia Networking 557
18.3 Effects of Network Convergence on Businesses 559
Convergence Effects on Legacy Networks and Systems 559
Convergence Effects on Computing and Networking Styles 560
Convergence Effects on Network Performance and Growth Rate 561
Organizational Changes and Convergence 562
Network Management and Convergence 563
Convergence and the Internet with Corporate Network Applications 564
18.4 Convergence at Home 565
End-of-Chapter Commentary 566
Chapter Review Materials 567
A Vendor Ethernet/802.3 Prefixes 570
B Using Parity for Single-Bit Error Correction 571
C Guidelines for Installing UTP Cable 574
D Network Design and Analysis Guidelines;Network Politics 576
E X.25 582
Glossary 587
Index 617