Computers in Communication Gordon Brebner
CONTENTS
Preface xiii
1 Introduction 1
1.1 Background 1
1.2 Uses of computer communications 4
1.2.1 Computer-oriented communication 4
1.2.2 Telecommunications 8
1.2.3 Radio and television broadcasting 10
1.2.4 Summary of uses of computer communications 11
1.3 Physical links 12
1.3.1 Physical media and their properties 14
1.3.2 Physical communication services 20
1.4 How computers communicate 26
1.4.1 Information, time and space 26
1.4.2 Agreement and implementation 27
1.4.3 Human influences 29
1.5 Chapter summary 31
1.6 Exercises and further reading 32
2 Information 35
2.1 Introduction 35
2.2 Agreement on information types 37
2.2.1 Absolute and relative information types 38
2.2.2 Examples of communicated information types 38
2.3 Implementation of required information types 45
2.3.1 Transformation of information 45
vii
viii CONTENTS
2.3.2 Representation of information 65
2.4 Chapter summary 74
2.5 Exercises and further reading 75
3 Time 80
3.1 Introduction 80
3.2 Agreement on time periods 83
3.2.1 Absolute and relative time measurement 83
3.2.2 Examples of communication time periods 85
3.3 Implementation of required time periods 92
3.3.1 Segmentation and concatenation 92
3.3.2 Flow control 97
3.3.3 Acknowledgement and error handling 103
3.4 Chapter summary 107
3.5 Exercises and further reading 108
4 Time Packages 110
4.1 Introduction 110
4.2 Unsegmented time package 112
4.2.1 Connectionless services 112
4.2.2 Examples of unsegmented time packages 114
4.3 Simple handshake time package 116
4.3.1 Examples of simple handshake time packages 118
4.4 Multi-stage handshake time package 120
4.4.1 Examples of multi-stage handshake services 121
4.5 Connection-oriented time package 125
4.5.1 Connection-oriented services 126
4.5.2 Examples of connection-oriented time packages 129
4.6 Chapter summary 134
4.7 Exercises and further reading 135
5 Space 138
5.1 Introduction 138
5.2 Agreement on spaces 140
5.2.1 Identifier schemes 140
5.2.2 Absolute and relative spaces 147
5.2.3 Examples of communication spaces 149
5.3 Implementation of required spaces 150
5.3.1 Filtering and switching 150
5.3.2 Splitting and multiplexing 159
5.4 Chapter summary 165
CONTENTS ix
5.5 Exercises and further reading 166
6 Message Broadcasting Networks 168
6.1 Introduction 168
6.1.1 Information basics 169
6.1.2 Time basics 171
6.1.3 Space basics 172
6.2 Multipeer channel implementation 173
6.2.1 Common medium 174
6.2.2 Chain or ring 174
6.2.3 Star or tree 176
6.3 Communication multiplexing 178
6.3.1 Isolated 179
6.3.2 Permission-based 181
6.3.3 Reservation-based 182
6.3.4 Physical division 183
6.4 Examples of guided technology network implementations
184
6.4.1 Ethernet 185
6.4.2 Token ring 190
6.4.3 FDDI and FDDI-II 194
6.4.4 Token bus 200
6.4.5 DQDB 204
6.4.6 100 BASE VG-AnyLAN 208
6.4.7 Discussion of examples 211
6.5 Unguided technology network implementations 212
6.6 Chapter summary 218
6.7 Exercises and further reading 218
7 Message Switching Networks 222
7.1 Introduction 222
7.1.1 Information basics 224
7.1.2 Time basics 225
7.1.3 Space basics 227
7.2 Channel implementation 229
7.3 Communication multiplexing 235
7.3.1 Isolated 237
7.3.2 Permission-based 238
7.3.3 Reservation-based 238
7.4 Examples of physical switching network implementations
239
7.4.1 Switched ethernet 240
7.4.2 Telephone system circuit switching 240
7.4.3 X.25 packet switching 241
7.4.4 Frame relay 244
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7.4.5 ATM cell relay 248
7.5 Examples of public switching network services 253
7.5.1 PSTN 254
7.5.2 CSPDN 254
7.5.3 PSPDN 254
7.5.4 N-ISDN 255
7.5.5 SMDS 255
7.5.6 B-ISDN 256
7.6 Example of a high-level switching network implementation
258
7.7 Chapter summary 263
7.8 Exercises and further reading 263
8 Inter-networks 267
8.1 Introduction 267
8.1.1 Information basics 269
8.1.2 Time basics 269
8.1.3 Space basics 271
8.2 Inter-network switching 274
8.3 Examples of inter-network implementations 276
8.3.1 IEEE 802 LAN bridging 276
8.3.2 The Internet 280
8.3.3 ISO inter-networking 302
8.4 Chapter summary 306
8.5 Exercises and further reading 307
9 Case Study 1: Accessing the WorldWideWeb 311
9.1 Introduction 311
9.2 The problem: information, time and space issues 314
9.3 Reliable end to end communication using TCP/IP 324
9.4 Home computer and the Internet 334
9.5 Within the Internet 340
9.6 WWW server and the Internet 347
9.7 Overall communications 349
9.8 Chapter summary 355
9.9 Exercises and further reading 355
10 Case Study 2: Controlling a manufacturing device 359
10.1 Introduction 360
10.2 The problem: information, time and space issues 362
10.3 FullMAP implementation 367
10.4 MiniMAP simplified implementation 384
10.5 Chapter summary 385
CONTENTS xi
10.6 Exercises and further reading 386
11 Case Study 3: Making a video telephone call 388
11.1 Introduction 388
11.2 The problem: information, time and space issues 391
11.3 Management of an ATM connection 397
11.4 Using an ATM connection 402
11.5 Overall B-ISDN implementation 405
11.6 Chapter summary 408
11.7 Exercises and further reading 408
12 Standardization 411
12.1 Introduction 412
12.2 Standards bodies 414
12.2.1 International Organization for Standardization (ISO)
415
12.2.2 International Telecommunication Union 417
12.2.3 Internet Society 418
12.2.4 Professional and manufacturer bodies 420
12.2.5 Summary of standardization bodies 423
12.3 ISO standards 424
12.3.1 Structure 424
12.3.2 Services and protocols 430
12.3.3 Management 433
12.3.4 Other standards 434
12.4 Internet standards 435
12.4.1 Structure 435
12.4.2 Protocols 438
12.5 ITU-T standards 441
12.6 IEEE 802 standards 444
12.7 Proprietary standards 445
12.7.1 IBM System Network Architecture 446
12.7.2 Digital Network Architecture 447
12.7.3 AppleTalk 448
12.7.4 Xerox Network Systems and descendents 449
12.8 Chapter summary 449
12.9 Exercises and further reading 450
Index 454
