Modeling Communication Networks and Protocols (eBook)

Contents 6
1 Introduction 12
1.1 A Historical Note 13
1.2 Event-Driven Simulation: A Crash Course 16
1.2.1 Events 17
1.2.2 The Car Wash Model 18
1.2.3 Discrete Time 23
1.2.4 Nondeterminism and the Time Grain 27
1.3 An Overview of SMURPH 30
1.3.1 Reactive Systems: Execution Modes 31
1.3.2 Organization of the Package 33
References 35
2 Examples 37
2.1 The Car Wash Redux 37
2.1.1 The Washer Process 38
2.1.2 The Entrance Process 43
2.1.3 Completing the Program 45
2.1.4 About Time 47
2.1.5 Presenting the Results 49
2.1.6 Running the Model 49
2.1.7 In Real Time 51
2.2 The Alternating-Bit Protocol 54
2.2.1 The Protocol 55
2.2.2 Stations and Packet Buffers 57
2.2.3 The Sender’s Protocol 59
2.2.4 The Recipient’s Protocol 65
2.2.5 Wrapping It Up 68
2.2.6 Running the Model 74
2.3 A PID Controller 79
2.3.1 PID Control in a Nutshell 80
2.3.2 Building the Controller 83
2.3.3 Playing with the Controller 92
2.4 A Wireless Network Model 98
2.4.1 The ALOHA Network 99
2.4.2 The Protocol Specification 100
2.4.3 The Hub Station 104
2.4.4 The Terminals 112
2.4.5 The Channel Model 115
2.4.6 Wrapping It Up 126
2.4.7 Experimenting with the Model 130
References 142
3 Basic Operations and Types 144
3.1 Numbers 144
3.1.1 Simple Integer Types 144
3.1.2 Time in SMURPH 146
3.1.3 Type BIG and Its Range 150
3.1.4 Arithmetic Operations 151
3.1.5 Constants 152
3.1.6 Other Non-standard Numerical Types 153
3.2 Auxiliary Operation and Functions 155
3.2.1 Random Number Generators 155
3.2.2 Input/Output 159
3.2.3 The XML Parser 162
3.2.4 Operations on Flags 166
3.2.5 Type Boolean 167
3.2.6 Pools 167
3.2.7 Error Handling 168
3.2.8 Identifying the Experiment 169
3.2.9 Telling the Time and Date 169
3.2.10 Decibels 170
3.3 SMURPH Types 171
3.3.1 Type Hierarchy 171
3.3.2 Object Naming 172
3.3.3 Type Derivation 175
3.3.4 Multiple Inheritance 177
3.3.5 Abstract Types 179
3.3.6 Announcing Types 179
3.3.7 Subtypes with Empty Local Attribute Lists 180
3.3.8 Object Creation and Destruction 180
References 182
4 The Virtual Hardware 183
4.1 Stations 184
4.1.1 Declaring Station Types 184
4.1.2 Creating Station Objects 185
4.1.3 The Current Station 187
4.2 Links 187
4.2.1 Propagation of Signals in Links 187
4.2.2 Creating Links 188
4.3 Ports 190
4.3.1 Creating Ports 190
4.3.2 Connecting Ports to Links 192
4.3.3 Setting Distance Between Ports 193
4.4 Radio Channels 195
4.4.1 Signals, Attenuation, Interference 197
4.4.2 Creating Radio Channels 200
4.4.3 The List of Assessment Methods 201
4.5 Transceivers 206
4.5.1 Creating Transceivers 206
4.5.2 Interfacing and Configuring Transceivers 209
Reference 214
5 The Execution Framework 215
5.1 Processes 215
5.1.1 Activity Interpreters: The Concept 215
5.1.2 Declaring Process Types 216
5.1.3 Creating and Terminating Processes 218
5.1.4 Process Operation 221
5.1.5 The Code Method 223
5.1.6 The Process Environment 225
5.1.7 Process as an Activity Interpreter 227
5.1.8 The Root Process 228
5.2 Signal Passing 231
5.2.1 Regular Signals 231
5.2.2 Priority Signals 233
5.3 The Timer AI 234
5.3.1 Wait Requests 235
5.3.2 Operations 237
5.3.3 Clock Tolerance 238
5.3.4 The Visualization Mode 240
5.4 The Monitor AI 241
5.4.1 Wait Requests 242
5.4.2 Signaling Monitor Events 242
6 The Client 245
6.1 General Concepts 245
6.2 Message and Packet Types 247
6.3 Packet Buffers 250
6.4 Station Groups 252
6.5 Communication Groups 254
6.6 Traffic Patterns 256
6.6.1 Defining Traffic Types 256
6.6.2 Creating Traffic Patterns 257
6.6.3 Modifying the Standard Behavior of Traffic Patterns 263
6.6.4 Intercepting Packet and Message Deallocation 267
6.6.5 Message Queues 269
6.7 Inquiries 270
6.7.1 Acquiring Packets for Transmission 271
6.7.2 Testing for Packet Availability 274
6.8 Wait Requests 274
7 Links and Ports 277
7.1 Activities 277
7.1.1 Activity Processing in Links 278
7.1.2 Starting and Terminating Activities 279
7.1.3 Wait Requests and Events 282
7.1.4 Collisions 286
7.1.5 Event Priorities 286
7.1.6 Receiving Packets 288
7.2 Port Inquiries 290
7.2.1 Inquiries About the Present 290
7.2.2 Inquiries About the Past 292
7.2.3 Inquiries About the Future 293
7.3 Faulty Links 295
7.4 Cleaning After Packets 297
References 299
8 Radio Channels and Transceivers 300
8.1 Interpreting Activities in Radio Channels 300
8.1.1 The Stages of Packet Transmission and Perception 301
8.1.2 Criteria of Event Assessment 302
8.1.3 Neighborhoods 303
8.1.4 Event Assessment 304
8.1.5 Interference Histograms 306
8.1.6 Event Reassessment 308
8.1.7 The Context of Assessment Methods 309
8.1.8 Starting and Terminating Packet Transmission 310
8.2 Packet Perception and Reception 311
8.2.1 Wait Requests and Events 312
8.2.2 Event Priorities 317
8.2.3 Receiving Packets 317
8.2.4 Hooks for Handling Bit Errors 318
8.2.5 Transceiver Inquiries 323
8.3 Cleaning After Packets 328
Reference 328
9 Mailboxes 329
9.1 General Concepts 329
9.2 Fifo Mailboxes 330
9.2.1 Declaring and Creating Fifo Mailboxes 330
9.2.2 Wait Requests 333
9.2.3 Operations on Fifo Mailboxes 336
9.2.4 The Priority Put Operation 341
9.3 Barrier Mailboxes 343
9.3.1 Declaring and Creating Barrier Mailboxes 343
9.3.2 Wait Requests 344
9.3.3 Operations on Barrier Mailboxes 345
9.4 Bound Mailboxes 345
9.4.1 Binding Mailboxes 346
9.4.2 Device Mailboxes 348
9.4.3 Client Mailboxes 350
9.4.4 Server Mailboxes 351
9.4.5 Unbinding and Determining the Bound Status 354
9.4.6 Wait Requests 355
9.4.7 Operations on Bound Mailboxes 356
9.5 Journaling 361
9.5.1 Declaring Mailboxes to Be Journaled 361
9.5.2 Driving Mailboxes from Journal Files 362
9.5.3 Journaling Client and Server Mailboxes 363
10 Measuring Performance 365
10.1 Type RVariable 365
10.1.1 Creating and Destroying Random Variables 366
10.1.2 Operations on Random Variables 366
10.2 Client Performance Measures 368
10.2.1 Random Variables 368
10.2.2 Counters 369
10.2.3 Virtual Methods 370
10.2.4 Resetting Performance Measures 371
10.3 Link Performance Measures 373
10.4 RFChannel Performance Measures 374
10.5 Terminating Execution 375
10.5.1 Maximum Number of Received Messages 377
10.5.2 Virtual Time Limit 377
10.5.3 CPU Time Limit 377
10.5.4 The Exit Code 378
Reference 378
11 Tools for Testing and Debugging 379
11.1 User-Level Tracing 379
11.2 Simulator-Level Tracing 382
11.3 Observers 383
References 387
12 Exposing Objects 388
12.1 General Concepts 388
12.2 Making Objects Exposable 389
12.3 Programming Exposures 392
12.4 Invoking Exposures 398
12.5 Standard Exposures 400
12.5.1 Timer Exposure 403
12.5.2 Mailbox Exposure 404
12.5.3 RVariable Exposure 405
12.5.4 Client and Traffic Exposure 406
12.5.5 Port Exposure 409
12.5.6 Link Exposure 410
12.5.7 Transceiver Exposure 412
12.5.8 RFChannel Exposure 413
12.5.9 Process Exposure 415
12.5.10 Kernel Exposure 416
12.5.11 Station Exposure 418
12.5.12 System Exposure 421
12.5.13 Observer Exposure 422
Appendix A: Library Models of Wireless Channels 424
A.1 The Base Model 424
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A.1.1 The Mapper Classes 425
A.1.2 Channel Separation 428
A.1.3 The Functions of the Base Model 429
A.2 The Shadowing Model 433
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A.2.1 Model Parameters 434
A.2.2 Event Assessment 435
A.3 The Sampled Model 437
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A.3.1 Model Parameters 437
A.3.2 The RSSI Samples 438
A.3.3 Computing the Attenuation 441
A.4 The Neutrino Model 442
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A.4.1 Model Parameters 443
A.4.2 Event Assessment 443
Appendix B: SMURPH Under Linux and Windows 445
B.1 Package Structure 446
B.2 Installation 448
B.3 Running DSD 451
B.4 Comments on Windows 452
B.5 Creating Executable Programs in SMURPH 453
B.6 Running the Program 457
Appendix C: DSD: The Dynamic Status Display Program 461
C.1 Basic Principles 461
C.2 The Monitor 462
C.3 Invoking DSD 464
C.4 Window Templates 466
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C.4.1 Template Identifiers 466
C.4.2 Template Structure 467
C.4.3 Special Characters 468
C.4.4 Exception Lines 470
C.4.5 Replication of Layout Lines 470
C.4.6 Window Height 470
C.4.7 Regions 471
C.4.8 Field Attributes 471
C.5 Requesting Exposures 473
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C.5.1 The Hierarchy of Exposable Objects 474
C.5.2 Navigating the Ownership Tree 475
C.6 Exposure Windows 476
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C.6.1 Basic Operations 477
C.6.2 Stepping 477
C.6.3 Segment Attributes 479
C.7 Other Commands 479
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C.7.1 Display Interval 480
C.7.2 Disconnection and Termination 480
C.7.3 Shortcuts 481
Bibliography 482
Index 483