Designing and Deploying 802.11n Wireless Networks

Introduction xxvPart I Fundamental ConceptsChapter 1 Introduction to Wireless LANs 1Wireless LAN Markets and Applications 1                Retail 2                Warehousing 3                Healthcare 4                Hospitality 9                Voice over WLAN 9                Video Surveillance 11                Home and Small Office 12                General Enterprise Systems 13                Location-Aware Wireless Applications 13Benefits of Wireless Networks 15                Mobility 15                Installation in Difficult-to-Wire Areas 16                Increased Reliability 17                Reduced Installation Time 17                Long-Term Cost Savings 17                Productivity Gain Is the Answer 18Wireless Network Technologies 19                IEEE 802.11 (Wi-Fi) 20                Initial 802.11 20                802.11a 21                802.11b 21                802.11g 22                802.11n 23                Comparison of 802.11 Standards 24                Wi-Fi Certification 24Other Wireless Network Technologies 26                IEEE 802.16 (WiMAX) 26                IEEE 802.15 (Bluetooth) 30                IEEE 802.15.4 (ZigBee) 32                Certified Wireless USB 33Wireless LANs: A Historical Perspective 34                The Early Days 34                Initial 802.11 Standardization 35                802.11n Standardization 36Chapter 2 Radio Wave Fundamentals 39Radio Wave Attributes 39                Amplitude 40                Frequency 40                Phase 41RF System Components 41                RF Transceiver 41                RF Modulation 43                Amplitude Shift-Keying 43                Frequency Shift-Keying 44                Phase Shift-Keying 45                Quadrature Amplitude Modulation 45                Spread Spectrum 45                Orthogonal Frequency-Division Multiplexing 48RF Signal Propagation 48                Attenuation 48                Free Space Loss 49                Physical Obstacles 50                Multipath Propagation 51                Noise and Signal-to-Noise Ratio 51RF Mathematics 53                Converting Units 53Chapter 3 Wireless LAN Types and Components 55Types of Wireless LANs 55                Ad Hoc Wireless LANs 55                Infrastructure Wireless LANs 57                Mesh Wireless Networks 59Wireless LAN Components 62                Client Devices 62                Client Radio 63                Industry Standard Architecture 65                Peripheral Component Interconnect 66                Mini-PCI 66                PC Card 66                ExpressCard 67                CompactFlash 67                Universal Serial Bus 67                Access Points 68                Autonomous Access Points 68                Controller-Based Access Points 69                Wi-Fi Routers 69                Mesh Nodes 72                Antennas 72                RF Amplifiers 74                Repeaters 75                Bridges 75Network Infrastructure Components 77                Network Distribution Systems 77                Switches 77                Optical Fiber 79                Power over Ethernet 79                Application Connectivity Software 82                Terminal Emulation 82                Browser-Based Approaches 83                Direct Database Interfaces 84                Wireless Middleware 84Chapter 4 Wireless LAN Implications 87Security Vulnerabilities 87                Passive Monitoring 88                Unauthorized Access 91                Denial of Service 95Radio Signal Interference 97                Microwave Oven Interference 99                Cordless Phone Interference 101                Bluetooth Interference 103                Neighboring Wireless LAN Interference 105Impacts of Multipath Propagation 108                Roaming Issues 109                Battery Limitations 110                Interoperability Problems 111                Installation Issues 112Part II The 802.11 StandardChapter 5 Introduction to IEEE 802.11 and Related Standards 115The Importance of Standards 115                Types of Standards 115                Institute for Electrical and Electronic Engineers 117                Benefits of the 802.11 Standard 117                Appliance Interoperability 118                Fast Product Development 119                Stable Future Migration 119                Price Reductions 119                Avoiding Silos 119The IEEE 802 LAN Standards Family 120                802.11 MAC Sublayer 121                802.11 Physical Layer 123                IEEE 802.2 123                Unacknowledged Connectionless Service 124                Connection-Oriented Service 125                Continuous ARQ 126                Stop-and-Wait ARQ 127                Acknowledged Connectionless Service 128IEEE 802.11 Features 129                Station Services 130                Authentication 130                Deauthentication 131                Privacy 131                Distribution System Services 131                Association 131                Disassociation 131                Distribution 131                Integration 132                Reassociation 132                Station States and Corresponding Frame Types 132Chapter 6 IEEE 802.11 Medium Access Control (MAC) Layer 135Primary 802.11 MAC Layer Functions 135                Data Delivery 136                Medium Access 137                Distributed Coordination Function 138                Hybrid Coordination Function 139                Error Recovery 140                Data Frame Acknowledgments 140                Dynamic Rate Switching 141                Data Frame Aggregation 142                MSDU Aggregation 143                MPDU Aggregation 143                Data Frame Fragmentation 143                Encryption 145                Wired Equivalent Privacy 145                Temporal Key Integrity Protocol 146                Advanced Encryption Standard 146                Multicasting 147Connectivity 148                Scanning for Networks 149                Authentication 151                Open System Authentication 151                Shared Key Authentication 152                IEEE 802.1X Port-Based Authentication 153                Association 154                Reassociation 155Timing and Synchronization 156                Short IFS 156                PCF IFS 157                DCF IFS 157                Extended IFS 157RTS/CTS 158                Power Management 159802.11 MAC Frame Structures 160                Protocol Version Field 160                Type Field 161                Subtype Field 161                To DS Field 161                From DS Field 161                More Frag Field 161                Retry Field 163                Power Management Field 163                More Data Field 164                Protected Frame Field 164                Order Field 164                Duration/ID Field 164                Address 1, 2, 3, and 4 Fields 164                Sequence Control Field 165                QoS Control Field 166                HT Control Field 166                Frame Body Field 166                Frame Check Sequence Field 166MAC Frame Types 166                Management Frames 167                Association Request Frame 167                Association Response Frame 167                Reassociation Request Frame 167                Reassociation Response Frame 167                Probe Request Frame 168                Probe Response Frame 168                Beacon Frame 168                ATIM Frame 170                Disassociation Frame 170                Authentication Frame 170                Deauthentication Frame 170                Action Frame 170                Action No ACK Frame 171                Management Frame Body Contents 171                Control Frames 172                Control Wrapper Frame 172                Block ACK Request Frame 172                Block ACK Frame 172                Power-Save Poll Frame 173                Request-to-Send Frame 173                Clear-to-Send Frame 173                Acknowledgment Frame 173                Contention-Free End Frame 173                CF End + CF ACK Frame 173                Data Frames 174Interoperability 174Chapter 7 IEEE 802.11 Physical Layers 177802.11 Physical Layer Architecture 177                PLCP Sublayer 177                PMD Sublayer 178802.11 Physical Layer Functions 179                Carrier-Sense Function 179                Transmit Function 179                Receive Function 180Legacy 802.11 Physical Layers 180                Frequency-Hopping Spread-Spectrum PHY 180                Direct-Sequence Spread-Spectrum PHY 182                Infrared PHY 185                Orthogonal Frequency Division Multiplexing PHY (802.11a) 185                High-Rate Direct-Sequence Spread-Spectrum PHY (802.11b) 188                Extended-Rate PHY (802.11g) 190HT-OFDM (802.11n) 190                MIMO Concepts 190                Transmit Beamforming 190                Spatial Multiplexing 191                Channel Bonding 193                802.11n Modulation 194Interoperability 198Part III Wireless Network DesignChapter 8 Planning a Wireless LAN Deployment 201Project Management Principles 202Wireless LAN Deployment Planning Steps 204Step 1: Defining the Project Scope 204                Project Charter 204                Assumptions 204                Constraints 205Step 2: Developing the Work Breakdown Structure 206                Requirements Definition Phase 206                Design Phase 207                Implementation Phase 209                Operations and Maintenance Phase 211Step 3: Identifying Staffing 214Step 4: Creating a Schedule 217Step 5: Developing a Budget 218                Preliminary Requirements and Design 218                Hardware and Software Costs 219                Deployment Services Costs 221                Ongoing Operations and Maintenance Costs 223Step 6: Evaluating Risks 225Step 7: Analyzing Feasibility 227                Costs 228                Benefits 228                Impacts on Users 229                Impacts on Existing Systems 229                Making the Decision to Proceed 229Executing the Project 232                The Kick-Off Meeting 232                Periodic Activities 233Evaluating the Outcome of the Project 233Chapter 9 Defining Requirements for a Wireless LAN 237Requirements Attributes 238Requirements Definition Steps 238Step 1: Gathering Information 239                Interviewing Users 239                Interviewing IT Staff 240                Reviewing the Existing Infrastructure and Systems 240Step 2: Analyzing Requirements 241                Application Requirements 241                Client Device Requirements 243                Signal Coverage Requirements 244                Utilization Requirements 246                Mobility Requirements 248                Continuous Movement 248                Portable Access 249                Stationary Access 249                Security Requirements 250                Sensitivity of Information and Systems 250                Organization Security Policies 251                Network Access Privileges 251                Existing Security Mechanisms 252                Scalability Requirements 253                Existing Network Infrastructure Requirements 254                Integration Requirements 255                Environmental Requirements 256                Building Construction and Obstacles 256                Floor Plans 256                Temperature and Humidity 256                Durability 257                Aesthetic Requirements 258Step 3: Documenting Requirements 259Step 4: Obtaining Requirements Approval 260Chapter 10 System Architecture Considerations 263Architectural Considerations 264Wireless Access Networks 264                Autonomous Access Point Architecture 265                Controller-Based Access Point Architecture 267                Mesh Network Architecture 269                Ad Hoc Architecture 270                2.4 GHz Versus 5 GHz 272                Geographical Location Considerations 272                Performance Considerations 272                Existing Client Device Considerations 273                Facility Size Considerations 273                Radio Signal Interference Considerations 273                Hybrid Frequency Band Considerations 274                Common Infrastructure Considerations 274                Migration Considerations 276                Redundancy Considerations 277                Controller Redundancy 277                Access Point Redundancy 279Distribution Systems 282                Switch Considerations 282                PoE Considerations 282Voice over WLAN Systems 284                Single-Site Architecture 284                Multisite WAN with Centralized Call Processing 285                Multisite WAN with Distributed Call Processing 287Application Connectivity 289                Terminal Emulation Considerations 289                Browser-Based Connectivity Considerations 292                Direct Database Considerations 293                Wireless Middleware Considerations 294Chapter 11 Range, Performance, and Roaming Considerations 299Range Versus Performance 299Range Considerations 300                Signal Coverage Requirements 300                Radio Frequency Bands 301                Transmit Power Settings 302                Transmission Channel Settings 303                Data Rate Settings 304                Antennas 306                Amplifiers 307                Repeaters 308                Physical Obstacles 309                Radio Signal Interference 309Performance Considerations 311                Throughput Versus Data Rate 312                Radio Frequency Bands 313                Transmit Power Settings 313                Transmission Channel Settings 314                Data Rate Settings 315                Antennas 315                Amplifiers 316                Radio Signal Interference 316                Channel Width Settings 316                Signal Coverage 317                Fragmentation Settings 317                RTS/CTS Settings 318                Bandwidth Control Mechanisms 319                Microcell Deployment Strategies 319Roaming Considerations 321                Roaming Levels 322                Access Point Roaming 322                Subnet Roaming 323                Wireless ISP Roaming 324                Wireless IP Phone Roaming 324                Mobility Settings 325Chapter 12 Radio Frequency Considerations 327Frequency Band Selection 327                2.4-GHz Frequency Band 327                5-GHz Frequency Band 328Transmission Channel Settings 328                Manual Channel Settings 328                Single-Level Facilities 329                Multilevel Facilities 330                Adaptive Channel Settings 332Difficult-to-Cover Areas 333                Signal Coverage in Elevators 333                Signal Coverage in Stairwells 336                Signal Coverage in Parking Areas 336Radio Signal Interference Reduction 337Chapter 13 Security Considerations 339Security Elements 339Encryption 340Authentication 342                EAP Methods 342                Authentication Servers 344                Guest Access 345Rogue Access Point Detection 346RF Shielding 347Wireless Security Polices 349Part IV Wireless Network Installation and TestingChapter 14 Test Tools 353Tool Considerations 353Spectrum Analyzers 354                Real-Time Fast Fourier Transform 354                FFT Duty Cycle 356                Swept Spectrogram 357                Active Devices 357                Recording Spectrum Data 358Signal Coverage Testers 358                Heat Maps 358                Positioning 360                Passive Versus Active Modes 361                Simulation 361                Free Signal Coverage Tester: NetStumbler 361Wireless Protocol Analyzers 362                Filtering Frames 363                Recording Traces 363                Free Protocol Analyzer: WireShark 364Chapter 15 Performing a Wireless Site Survey 367Wireless Site Survey Considerations 368Reviewing Requirements 369Selecting Site Survey Tools 370Obtaining Floor Diagrams 371Inspecting the Facility 372Assessing the Existing Network Infrastructure 372                Communications Rooms 372                Switches and Power over Ethernet 373                WAN 373Identifying Potential Radio Signal Interference 373Defining Signal Values for Acceptable Signal Coverage 376                Minimum Received Signal Strength 376                Minimum SNR 376                Uplink Versus Downlink Signal Values 377Identifying Optimum Access Point Antenna Installation Locations 379                Propagation Testing 379                Test Access Point Configuration 379                Antenna Considerations 379                Identifying Test Locations 380                Measuring Test Signals 381                Assessing Propagation Test Results 382                Cell Overlap Considerations 383                Annotate Access Point Antenna Installation Locations 384Writing an RF Site Survey Report 385Chapter 16 Installing and Configuring a Wireless LAN 387Wireless LAN Installation Considerations 387Planning the Installation 388                Developing an Installation Plan 388                Points of Contact 388                Safety Tips 389                Installation Procedures 389                Required Facility Changes 390                Tools 390                Reference to Design Documentation 390                Schedule 390                Resources 391                Budget 391                Risks 391                Coordinating the Installation 391Staging the Components 392Installing Ethernet Switches and Cabling 393Installing Access Points 394                Mounting Practices 394                Antenna Alignment 395                Configuration Setting Access 396                Firmware 396                Access Point Configuration Settings 396                802.11n Enable 396                SSID 396                DTIM Interval 397                Beacon Interval 397                Radio Frequency Bands 398                Transmit Power 398                Transmission Channel 399                Data Rates 399                Antenna Diversity 399                Channel Width 401                Fragmentation Threshold 401                RTS/CTS Threshold 402Testing the Installation 402Documenting the Installation 403Chapter 17 Testing a Wireless LAN 405Wireless LAN Testing Considerations 405Signal Coverage Testing 406                Wireless Site Survey Coverage Testing 406                As-Installed Coverage Testing 407                Consider Beacon Rates 407Performance Testing 408                Association Tests 408                Registration Tests 409                Network Connection Tests 409                Authentication Tests 410                Application Connection Tests 410                Application Tests 410                Load Tests 411In-Motion Testing 412Security Vulnerability Testing 413                Security Settings Verification 413                Penetration Testing 414                Private-Side Testing 414                Public-Side Testing 414Acceptance/Verification Testing 415Simulation Testing 416Prototype Testing 417Pilot Testing 418Test Documentation 419Part V Operational Support ConsiderationsChapter 18 Managing a Wireless LAN 421Operational Support Considerations 421Help Desk 422                Connection Problems 422                Poor Signal Coverage 423                Poor Performance 423                System Status 423                Additional Considerations 423Network Monitoring 424                Performance Monitoring 424                Access Point Monitoring 424                Configuration Monitoring 425                Security Policy Management 425                Installation Control Policies 425                Monitoring Policies 425                Periodic Testing Policies 426Maintenance 426                Inoperative Access Points 426                Poor Performance 426                Poor Signal Coverage 426                Broken Hardware 427                Firmware Updates 427                Signal Coverage Verification 427                Access Point Inspections 428                Troubleshooting 428                Sparing 428Engineering 428                Advanced Problem Resolution 429                Coverage Expansion 429                Capacity Increases 429                Firmware Review 429                Technology Upgrades 430                Design Review 430Configuration Management 430                Change-Control Processes 430                Security Management 431                Review Existing Security Policies 432                Review the System Architecture 432                Review Management Tools and Procedures 432                Interview Users 433                Verify Configurations of Wireless Devices 433                Investigate Physical Installations of Access Points 433                Identify Rogue Access Points 433                Perform Penetration Tests 434                Analyze Security Gaps 434                Recommend Improvements 434Trouble Ticket Coordination 435                Help Desk Group 435                Desktop Support Group 436                Network Support Group 436Preparing for the Transfer to Operational Mode 436Chapter 19 Troubleshooting a Wireless LAN 439Troubleshooting Methodology 439                Identify the Problem 439                Identify the Underlying Cause of the Problem 440                Fix the Problem 440Connection Problems 440                Insufficient Signal Coverage 441                Radio Signal Interference 442                Access Point Failure 442                Incompatible Client Radio 442                Faulty Firmware 443                Incorrect Client Radio Configuration 443Performance Problems 444                Insufficient Signal Coverage 444                Radio Signal Interference 444                Faulty Firmware 445                Nonoptimal Client Radio Configuration 445                Nonoptimal Access Point Configuration 445                Misaligned Antennas 446                High Utilization 447Chapter 20 Preparing Operational Support Staff 449Support Staff Considerations 449Availability of Existing Staff 450Experience Requirements 450Education and Training Requirements 451                Vendor-Neutral Training 451                Vendor-Specific Training 452                College Education 452Certifications 452Staffing Sources 453Glossary 4559781587058899, TOC, 5/7/10