Designing and Deploying 802.11 Wireless Networks

Name: Designing and Deploying 802.11 Wireless Networks | A Practical Guide to Implementing 802.11n and 802.11ac Wireless Networks For Enterprise-Based Applications
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A Practical Guide to Implementing 802.11n and 802.11ac Wireless Networks For Enterprise-Based Applications

Jim Geier(Autor*in)

Cisco Press

2. Auflage

Erschienen am 29. April 2015

512 Seiten

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Beschreibung

Designing and Deploying 802.11 Wireless Networks

Second Edition

A Practical Guide to Implementing 802.11n and 802.11ac Wireless Networks For Enterprise-Based Applications

Plan, deploy, and operate high-performance 802.11ac and 802.11n wireless networks

The new 802.11ac standard enables WLANs to deliver significantly higher performance. Network equipment manufacturers have refocused on 802.11ac- and 802.11n-compliant solutions, rapidly moving older versions of 802.11 toward "legacy" status. Now, there's a complete guide to planning, designing, installing, testing, and supporting 802.11ac and 802.11n wireless networks in any environment, for virtually any application.

Jim Geier offers practical methods, tips, and recommendations that draw on his decades of experience deploying wireless solutions and shaping wireless standards. He carefully introduces 802.11ac's fundamentally different design, site survey, implementation, and network configuration techniques, helping you maximize performance and avoid pitfalls.

Geier organizes each phase of WLAN deployment into clearly defined steps, making the entire planning and deployment process easy to understand and execute. He illuminates key concepts and methods through realistic case studies based on current Cisco products, while offering tips and techniques you can use with any vendor's equipment. To build your skills with key tasks, you'll find several hands-on exercises relying on free or inexpensive tools.

Whether you're deploying an entirely new wireless network or migrating from older equipment, this guide contains all the expert knowledge you'll need to succeed.

Jim Geier has 30 years of experience planning, designing, analyzing and implementing communications, wireless, and mobile systems. Geier is founder and Principal Consultant of Wireless-Nets, Ltd., providing wireless analysis and design services to product manufacturers. He is also president, CEO, and co-founder of Health Grade Networks, providing wireless network solutions to hospitals, airports, and manufacturing facilities. His books include the first edition of Designing and Deploying 802.11n Wireless Networks (Cisco Press); as well as Implementing 802.1X Security Solutions and Wireless Networking Handbook. Geier has been active in the IEEE 802.11 Working Group and Wi-Fi Alliance; has chaired the IEEE Computer Society (Dayton Section) and various conferences; and served as expert witness in patent litigation related to wireless and cellular technologies.

Review key 802.11 concepts, applications, markets, and technologies
Compare ad hoc, mesh, and infrastructure WLANs and their components
Consider the impact of radio signal interference, security vulnerabilities, multipath propagation, roaming, and battery limitations
Thoroughly understand today's 802.11 standards in the context of actual network deployment and support
Plan your deployment: scoping, staffing, schedules, budgets, risks, feasibility analysis, and requirements
Architect access networks and distribution system for maximum reliability, manageability, and performance
Make the right tradeoffs and decisions to optimize range, performance, and roaming
Secure WLANs via encryption, authentication, rogue AP detection, RF shielding, and policies
Master design and site survey tools and methods for planning 802.11ac networks and migrations
Efficiently install and test any 802.11ac or 802.11n wireless network
Establish specialized support for wireless networks, including help desk operations
Systematically troubleshoot connectivity, performance, and roaming issues
Design efficient mesh networks and city-wide deployments

Weitere Details

Weitere Ausgaben

Person

Inhalt

Introduction xxv

Part I: Fundamental Concepts

Chapter 1 Introduction to Wireless LANs 1

Wireless LAN Markets and Applications 1

Retail 2

Warehousing 2

Healthcare 4

Hospitality 5

Voice over WLAN 5

Video Surveillance 6

Home and Small Office 7

General Enterprise Systems 8

Location-Aware Wireless Applications 8

Benefits of Wireless Networks 10

Mobility 10

Installation in Difficult-to-Wire Areas 11

Increased Reliability 11

Reduced Installation Time 12

Long-Term Cost Savings 12

Productivity Gain Is the Answer 12

Wireless LAN Technologies 14

Initial 802.11 16

802.11a 16

802.11b 16

802.11g 17

Current Standards: 802.11n and 802.11ac 18

Comparison of 802.11 Standards 19

Wi-Fi Certification 19

Wireless LANs: A Historical Perspective 21

The Early Days 21

Initial 802.11 Standardization 22

802.11n and 802.11ac Standardization 23

Summary 25

Chapter 2 Radio Wave Fundamentals 27

Radio Wave Attributes 27

Amplitude 28

Frequency 28

Phase 29

RF System Components 29

RF Transceiver 29

RF Modulation 30

Amplitude-Shift Keying 31

Frequency-Shift Keying 32

Phase-Shift Keying 33

Quadrature Amplitude Modulation 33

Spread Spectrum 33

Orthogonal Frequency-Division Multiplexing 36

RF Signal Propagation 36

Attenuation 37

Free Space Loss 37

Physical Obstacles 38

Multipath Propagation 39

Noise and Signal-to-Noise Ratio 39

RF Mathematics 41

Converting Units 41

Summary 42

Chapter 3 Wireless LAN Types and Components 43

Types of Wireless LANs 43

Ad Hoc Wireless LANs 43

Infrastructure Wireless LANs 45

Wireless Mesh Networks 48

Wireless LAN Components 50

Client Devices 50

Client Radio 51

Industry Standard Architecture 53

Peripheral Component Interconnect 54

Mini-PCI 54

PC Card 54

ExpressCard 55

CompactFlash 55

Universal Serial Bus 55

Access Points 56

Autonomous Access Points 56

Controller-Based Access Points 57

Wi-Fi Routers 58

Mesh Nodes 60

Antennas 60

RF Amplifiers 62

Repeaters 63

Bridges 64

Network Infrastructure Components 65

Network Distribution Systems 65

Switches 65

Optical Fiber 67

Power over Ethernet 67

Application Connectivity Software 70

Terminal Emulation 70

Browser-Based Approaches 71

Direct Database Interfaces 72

Wireless Middleware 72

Summary 74

Chapter 4 Wireless LAN Implications 75

Security Vulnerabilities 75

Passive Monitoring 76

Unauthorized Access 79

Unauthorized Access Leads to Compromise of Financial Data 82

Denial-of-Service Attacks 83

Radio Signal Interference 85

Microwave Oven Interference 86

Cordless Phone Interference 88

Bluetooth Interference 90

Neighboring Wireless LAN Interference 92

Impacts of Multipath Propagation 95

Roaming Issues 96

Battery Limitations 97

Interoperability Problems 98

Installation Issues 98

Summary 99

Part II: The 802.11 Standard

Chapter 5 Introduction to IEEE 802.11 and Related Standards 101

The Importance of Standards 101

Types of Standards 102

Institute of Electrical and Electronics Engineers 103

Benefits of the 802.11 Standard 104

Appliance Interoperability 104

Fast Product Development 105

Stable Future Migration 105

Price Reductions 106

Avoiding Silos 106

The IEEE 802 LAN Standards Family 107

802.11 MAC Sublayer 109

802.11 Physical Layer 110

IEEE 802.2 110

Unacknowledged Connectionless Service 111

Connection-Oriented Service 112

Continuous ARQ 113

Stop-and-Wait ARQ 114

Acknowledged Connectionless Service 115

IEEE 802.11 Features 116

Station Services 117

Authentication 117

Deauthentication 118

Privacy 118

Distribution System Services 118

Association 118

Disassociation 118

Distribution 118

Integration 119

Re-association 119

Station States and Corresponding Frame Types 119

Summary 121

Chapter 6 IEEE 802.11 Medium Access Control (MAC) Layer 123

Primary 802.11 MAC Layer Functions 123

Data Delivery 124

Medium Access 125

Distributed Coordination Function 126

Hybrid Coordination Function 127

Error Recovery 129

Data Frame Acknowledgements 129

Dynamic Rate Switching 130

Data Frame Aggregation 131

MSDU Aggregation 132

MPDU Aggregation 132

Data Frame Fragmentation 132

Encryption 134

Wired Equivalent Privacy 134

Temporal Key Integrity Protocol 135

CCMP 136

Multicasting 136

Connectivity 138

Scanning for Networks 138

Authentication 140

Open System Authentication 140

Shared Key Authentication 141

IEEE 802.1X Port-Based Authentication 142

Associating with the Access Point 143

4-Way Handshake 145

Timing and Synchronization 145

Short IFS 146

PCF IFS 146

DCF IFS 147

Extended IFS 147

RTS/CTS 147

Power Management 149

802.11 MAC Frame Structures 150

Protocol Version Field 150

Type Field 150

Subtype Field 151

To DS Field 152

From DS Field 152

More Frag Field 152

Retry Field 153

Power Management Field 153

More Data Field 153

Protected Frame Field 153

Order Field 153

Duration/ID Field 153

Address 1, 2, 3, and 4 Fields 154

Sequence Control Field 154

QoS Control Field 155

HT Control Field 155

Frame Body Field 155

Frame Check Sequence Field 155

MAC Frame Types 156

Management Frames 156

Association Request Frame 156

Association Response Frame 156

Re-association Request Frame 157

Re-association Response Frame 157

Probe Request Frame 157

Probe Response Frame 157

Beacon Frame 157

ATIM Frame 159

Disassociation Frame 159

Authentication Frame 159

Deauthentication Frame 160

Action Frame 160

Action No ACK Frame 160

Management Frame Body Contents 160

Control Frames 162

Control Wrapper Frame 162

Block ACK Request Frame 162

Block ACK Frame 162

Power-Save Poll Frame 162

Request-to-Send Frame 162

Clear-to-Send Frame 162

Acknowledgement Frame 163

Contention-Free End Frame 163

CF End + CF ACK Frame 163

Data Frames 163

Interoperability 164

Summary 165

Chapter 7 IEEE 802.11 Physical (PHY) Layers 167

802.11 Physical Layer Architecture 167

PLCP Sublayer 168

PMD Sublayer 168

802.11 Physical Layer Functions 169

Carrier Sense Function 169

Transmit Function 169

Receive Function 170

Legacy 802.11 Physical Layers 170

Frequency-Hopping Spread Spectrum PHY 170

Direct-Sequence Spread Spectrum PHY 172

Infrared PHY 175

Orthogonal Frequency-Division Multiplexing PHY (802.11a) 175

High-Rate Direct-Sequence Spread Spectrum PHY (802.11b) 178

Extended-Rate PHY (802.11g) 180

High-Throughput (802.11n) 180

MIMO Concepts 180

Transmit Beamforming 180

Spatial Multiplexing 181

Channel Bonding 183

802.11n Modulation 184

Interoperability 188

Very High-Throughput 6 GHz (802.11ac) 188

RF Channel Bandwidth 188

Multi-User MIMO 189

Interoperability 189

Summary 190

Part III: Wireless Network Design

Chapter 8 Planning a Wireless LAN Deployment 191

Project Management Principles 191

Wireless LAN Deployment Planning Steps 193

Step 1: Defining the Project Scope 194

Project Charter 194

Assumptions 194

Constraints 194

Step 2: Developing the Work Breakdown Structure 196

Requirements Definition Phase 196

Design Phase 197

Implementation Phase 199

Operations and Maintenance Phase 201

Step 3: Identifying Staffing 204

Step 4: Creating a Schedule 206

Step 5: Developing a Budget 207

Preliminary Requirements and Design 207

Hardware and Software Costs 208

Deployment Services Costs 211

Ongoing Operations and Maintenance Costs 212

Step 6: Evaluating Risks 215

Step 7: Analyzing Feasibility 217

Costs 217

Benefits 218

Impacts on Users 218

Impacts on Existing Systems 219

Making the Decision to Proceed 219

Executing the Project 221

The Kickoff Meeting 222

Evaluating the Outcome of the Project 223

Summary 225

Chapter 9 Defining Requirements for a Wireless LAN 227

Requirements Attributes 227

Requirements Definition Steps 228

Step 1: Gathering Information 229

Interviewing Users 229

Interviewing IT Staff 230

Reviewing the Existing Infrastructure and Systems 230

Step 2: Analyzing Requirements 231

Application Requirements 231

Client Device Requirements 233

Signal Coverage Requirements 234

Utilization Requirements 236

Mobility Requirements 238

Security Requirements 240

Scalability Requirements 243

Existing Network Infrastructure Requirements 244

Environmental Requirements 245

Aesthetic Requirements 248

Step 3: Documenting Requirements 248

Step 4: Obtaining Requirements Approval 249

Summary 250

Chapter 10 System Architecture Considerations 251

Architectural Considerations 251

Wireless Access Networks 252

Autonomous Access Point Architecture 253

Controller-Based Access Point Architecture 254

Mesh Network Architecture 256

Ad Hoc Architecture 258

2.4-GHz Versus 5-GHz 259

Geographic Location Considerations 260

Performance Considerations 260

Existing Client Device Considerations 260

Facility Size Considerations 260

Radio Signal Interference Considerations 261

Hybrid Frequency Band Considerations 261

Common Infrastructure Considerations 262

Migration Considerations 264

Redundancy Considerations 264

Controller Redundancy 264

Access Point Redundancy 267

Distribution Systems 269

Switch Considerations 269

PoE Considerations 269

Voice over WLAN Systems 271

Single-Site Architecture 271

Multisite WAN with Centralized Call Processing 272

Multisite WAN with Distributed Call Processing 274

Application Connectivity 277

Terminal Emulation Considerations 277

Browser-Based Connectivity Considerations 279

Direct Database Considerations 280

Wireless Middleware Considerations 282

Summary 285

Chapter 11 Range, Performance, and Roaming Considerations 287

Range Versus Performance 287

Range Considerations 288

Signal Coverage Requirements 288

Radio Frequency Bands 289

Transmit Power Settings 290

Transmission Channel Settings 291

Data Rate Settings 292

Antennas 294

Amplifiers 295

Repeaters 296

Physical Obstacles 297

Radio Signal Interference 297

Performance Considerations 299

Throughput Versus Data Rate 299

Radio Frequency Bands 300

Transmit Power Settings 300

Transmission Channel Settings 301

Data Rate Settings 302

Antennas 302

Amplifiers 303

Radio Signal Interference 304

Channel Width Settings 304

Signal Coverage 305

Fragmentation Settings 305

RTS/CTS Settings 306

Bandwidth Control Mechanisms 306

Microcell Deployment Strategies 307

Roaming Considerations 309

Roaming Levels 309

Access Point Roaming 310

Subnet Roaming 310

Wireless ISP Roaming 312

Wireless IP Phone Roaming 312

Mobility Settings 313

Summary 313

Chapter 12 Radio Frequency Considerations 315

Frequency Band Selection 315

2.4-GHz Frequency Band 315

5-GHz Frequency Band 316

Transmission Channel Settings 316

Manual Channel Settings 316

Single-Level Facilities 317

Multilevel Facilities 319

Adaptive Channel Settings 321

Difficult-to-Cover Areas 321

Signal Coverage in Elevators 322

Signal Coverage in Stairwells 324

Signal Coverage in Parking Areas 324

Radio Signal Interference Reduction 325

Summary 326

Chapter 13 Security Considerations 327

Security Elements 327

Encryption 328

Authentication 330

EAP Methods 331

Authentication Servers 332

Guest Access 333

Rogue Access Point Detection 334

RF Shielding 335

Wireless Security Policies 337

Summary 339

Part IV: Wireless Network Installation and Testing

Chapter 14 Test Tools 341

Tool Considerations 341

Spectrum Analyzers 342

Real-Time Fast Fourier Transform 342

FFT Duty Cycle 344

Swept Spectrogram 345

Active Devices 345

Recording Spectrum Data 346

Signal Coverage Testers 346

Heat Maps 346

Positioning 347

Passive Versus Active Modes 349

Simulation 349

Free Signal Coverage Tester: NetStumbler 349

Wireless Protocol Analyzers 350

Filtering Frames 351

Recording Traces 352

Free Protocol Analyzer: WireShark 352

Summary 354

Chapter 15 Performing a Wireless Site Survey 355

Wireless Site Survey Considerations 356

Reviewing Requirements 357

Selecting Site Survey Tools 358

Obtaining Floor Diagrams 359

Inspecting the Facility 360

Assessing the Existing Network Infrastructure 360

Communications Rooms 360

Switches and Power over Ethernet 361

WAN 361

Identifying Potential Radio Signal Interference 361

Defining Signal Values for Acceptable Signal Coverage 364

Minimum Received Signal Strength 364

Minimum SNR 364

Uplink Versus Downlink Signal Values 365

Identifying Optimum Access Point Antenna Installation Locations 367

Propagation Testing 367

Test Access Point Configuration 367

Antenna Considerations 368

Identifying Test Locations 369

Measuring Test Signals 371

Assessing Propagation Test Results 372

Cell Overlap Considerations 374

Annotating Access Point Antenna Installation Locations 375

Writing an RF Site Survey Report 376

Summary 377

Chapter 16 Installing and Configuring a Wireless LAN 379

Wireless LAN Installation Considerations 379

Planning the Installation 380

Developing an Installation Plan 380

Points of Contact 380

Safety Tips 381

Installation Procedures 381

Required Facility Changes 382

Tools 382

References to Design Documentation 382

Schedule 383

Resources 383

Budget 383

Risks 383

Coordinating the Installation 383

Staging the Components 384

Installing Access Points 386

Mounting Practices 386

Antenna Alignment 387

Configuring Access Points 387

Configuration Setting Access 388

Firmware 388

Access Point Configuration Settings 388

802.11n/ac Enable 388

SSID 389

Beacon Interval 389

Radio Frequency Bands 390

Transmit Power 390

Transmission Channel 391

Data Rates 392

Antenna Diversity 392

Channel Width 393

Fragmentation Threshold 394

RTS/CTS Threshold 394

Testing the Installation 395

Documenting the Installation 395

Summary 396

Chapter 17 Testing a Wireless LAN 397

Wireless LAN Testing Considerations 397

Signal Coverage Testing 398

Wireless Site Survey Coverage Testing 398

As-Installed Coverage Testing 399

Considering Beacon Rates 399

Performance Testing 400

Association Tests 401

Registration Tests 401

Authentication Tests 401

Network Connection Tests 402

Application Connection Tests 402

Application Tests 402

Load Tests 403

In-Motion Testing 404

Security Vulnerability Testing 405

Security Settings Verification 405

Penetration Testing 405

Private-Side Testing 405

Public-Side Testing 406

Acceptance/Verification Testing 407

Simulation Testing 408

Prototype Testing 409

Pilot Testing 409

Test Documentation 410

Summary 411

Part V: Operational Support Considerations

Chapter 18 Managing a Wireless LAN 413

Operational Support Considerations 413

Help Desk 414

Connection Problems 414

Poor Signal Coverage 415

Poor Performance 415

System Status 415

Additional Considerations 415

Network Monitoring 416

Performance Monitoring 416

Access Point Monitoring 416

Configuration Monitoring 417

Security Policy Management 417

Installation Control Policies 417

Monitoring Policies 418

Periodic Testing Policies 418

Maintenance 418

Inoperative Access Points 418

Poor Performance 418

Poor Signal Coverage 419

Broken Hardware 419

Firmware Updates 419

Signal Coverage Verification 420

Access Point Inspections 420

Troubleshooting 420

Sparing 420

Engineering 421

Advanced Problem Resolution 421

Coverage Expansion 421

Capacity Increases 422

Firmware Review 422

Technology Upgrades 422

Design Review 422

Configuration Management 422

Change-Control Processes 423

Security Management 424

Reviewing Existing Security Policies 424

Reviewing the System Architecture 425

Reviewing Management Tools and Procedures 425

Interviewing Users 425

Verifying Configurations of Wireless Devices 425

Investigating Physical Installations of Access Points 426

Identifying Rogue Access Points 426

Performing Penetration Tests 426

Analyzing Security Gaps 427

Recommending Improvements 427

Trouble Ticket Coordination 427

Help Desk Group 428

Desktop Support Group 428

Network Support Group 428

Preparing for the Transfer to Operational Mode 429

Summary 429

Chapter 19 Troubleshooting a Wireless LAN 431

Troubleshooting Methodology 431

Identifying the Problem 431

Identifying the Underlying Cause of the Problem 432

Fixing the Problem 432

Connection Problems 432

Insufficient Signal Coverage 433

Radio Signal Interference 434

Access Point Failure 434

Incompatible Client Radio 434

Faulty Firmware 435

Incorrect Client Radio Configuration 435

Performance Problems 436

Insufficient Signal Coverage 436

Radio Signal Interference 436

Faulty Firmware 437

Non-optimal Client Radio Configuration 437

Non-optimal Access Point Configuration 437

Misaligned Antennas 438

High Utilization 439

Summary 439

Chapter 20 Preparing Operational Support Staff 441

Support Staff Considerations 441

Availability of Existing Staff 442

Experience Requirements 442

Education and Training Requirements 443

Vendor-Neutral Training 443

Vendor-Specific Training 443

College Education 444

Certifications 444

Staffing Sources 445

Summary 445

Glossary 447

Index 455

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