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Designing and Deploying 802.11n Wireless Networks
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Designing and Deploying 802.11n Wireless Networks

by Jim Geier
 

See All Formats & Editions

ISBN-10: 1587058898

ISBN-13: 9781587058899

Pub. Date: 06/17/2010

Publisher: Cisco Press

Gain a practical understanding of the underlying concepts of the 802.11n standard and the methodologies for completing a successful wireless network installation

Practical, start-to-finish guidance for successful deployment of 802.11n wireless LANs

With the ratification of the 802.11n wireless LAN standard, thousands of companies are moving rapidly

Overview

Gain a practical understanding of the underlying concepts of the 802.11n standard and the methodologies for completing a successful wireless network installation

Practical, start-to-finish guidance for successful deployment of 802.11n wireless LANs

With the ratification of the 802.11n wireless LAN standard, thousands of companies are moving rapidly toward implementation. However, 802.11n is very different from legacy 802.11a, 802.11b, and 802.11g wireless standards, and successful deployment requires new knowledge and techniques. In this book, leading wireless expert Jim Geier systematically presents all the information and guidance that network architects, engineers, administrators, and managers need to maximize the performance and business value of new 802.11n networks.

Drawing on extensive experience with real-world 802.11n deployments, Geier guides you through the entire project lifecycle: planning, design, installation, testing, monitoring, and support. Each phase of wireless LAN deployment is organized into clearly defined steps, and multiple case studies and hands-on exercises show how to apply each technique.

You’ll find practical guidance for deploying in enterprises without existing wireless infrastructure, as well as migrating from legacy 802.11a, 802.11b, or 802.11g networks. For convenient reference, Geier also provides an extensive, up-to-date wireless networking glossary.

Jim Geier founded Wireless-Nets, Ltd., and serves as its principal consultant. His 25 years of experience include analysis, design, implementation, installation, and support of wireless network-based solutions for cities, enterprises, airports, manufacturers, warehouses, hospitals, and other facilities worldwide. He is author of more than a dozen books, including Wireless Networks - First Step and Deploying Voice over Wireless LANs (Cisco Press) and Implementing 802.1X Security Solutions. He has been active with the IEEE 802.11 Working Group developing international wireless LAN standards, and chaired the IEEE International Conference on Wireless LAN Implementation.

  • Understanding 802.11n MAC, physical layer, and related standards
  • Designing 802.11n wireless networks for diverse scenarios: considering architecture, range, performance, roaming, and RF issues
  • Migrating from 802.11a, 802.11b, and 802.11g wireless networks
  • Choosing the right tools and equipment, and using them effectively
  • Planning effectively: scoping projects; creating work breakdown structures; organizing teams, schedules, and budgets; defining requirements, and more
  • Securing WLANs via encryption, authentication, rogue access point detection, RF shielding, and polices
  • Performing site surveys and identifying optimum access point locations
  • Installing and configuring wireless LANs: planning, staging, deployment, documentation, and more
  • Systematic testing to improve signal coverage, performance, and security
  • Managing wireless LANs: help desk support, network monitoring, maintenance, engineering, configuration management, security, tools, and more
  • Troubleshooting 802.11n networks: identifying issues with connectivity, performance, and more

Product Details

ISBN-13:
9781587058899
Publisher:
Cisco Press
Publication date:
06/17/2010
Series:
Networking Technology Series
Pages:
497
Product dimensions:
7.50(w) x 9.20(h) x 1.30(d)

Table of Contents

Introduction xxv

Part I Fundamental Concepts

Chapter 1 Introduction to Wireless LANs 1

Wireless 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 13

Benefits 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 18

Wireless 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 24

Other Wireless Network Technologies 26

IEEE 802.16 (WiMAX) 26

IEEE 802.15 (Bluetooth) 30

IEEE 802.15.4 (ZigBee) 32

Certified Wireless USB 33

Wireless LANs: A Historical Perspective 34

The Early Days 34

Initial 802.11 Standardization 35

802.11n Standardization 36

Chapter 2 Radio Wave Fundamentals 39

Radio Wave Attributes 39

Amplitude 40

Frequency 40

Phase 41

RF 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 48

RF Signal Propagation 48

Attenuation 48

Free Space Loss 49

Physical Obstacles 50

Multipath Propagation 51

Noise and Signal-to-Noise Ratio 51

RF Mathematics 53

Converting Units 53

Chapter 3 Wireless LAN Types and Components 55

Types of Wireless LANs 55

Ad Hoc Wireless LANs 55

Infrastructure Wireless LANs 57

Mesh Wireless Networks 59

Wireless 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 75

Network 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 84

Chapter 4 Wireless LAN Implications 87

Security Vulnerabilities 87

Passive Monitoring 88

Unauthorized Access 91

Denial of Service 95

Radio Signal Interference 97

Microwave Oven Interference 99

Cordless Phone Interference 101

Bluetooth Interference 103

Neighboring Wireless LAN Interference 105

Impacts of Multipath Propagation 108

Roaming Issues 109

Battery Limitations 110

Interoperability Problems 111

Installation Issues 112

Part II The 802.11 Standard

Chapter 5 Introduction to IEEE 802.11 and Related Standards 115

The 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 119

The 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 128

IEEE 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 132

Chapter 6 IEEE 802.11 Medium Access Control (MAC) Layer 135

Primary 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 147

Connectivity 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 155

Timing and Synchronization 156

Short IFS 156

PCF IFS 157

DCF IFS 157

Extended IFS 157

RTS/CTS 158

Power Management 159

802.11 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 166

MAC 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 174

Interoperability 174

Chapter 7 IEEE 802.11 Physical Layers 177

802.11 Physical Layer Architecture 177

PLCP Sublayer 177

PMD Sublayer 178

802.11 Physical Layer Functions 179

Carrier-Sense Function 179

Transmit Function 179

Receive Function 180

Legacy 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) 190

HT-OFDM (802.11n) 190

MIMO Concepts 190

Transmit Beamforming 190

Spatial Multiplexing 191

Channel Bonding 193

802.11n Modulation 194

Interoperability 198

Part III Wireless Network Design

Chapter 8 Planning a Wireless LAN Deployment 201

Project Management Principles 202

Wireless LAN Deployment Planning Steps 204

Step 1: Defining the Project Scope 204

Project Charter 204

Assumptions 204

Constraints 205

Step 2: Developing the Work Breakdown Structure 206

Requirements Definition Phase 206

Design Phase 207

Implementation Phase 209

Operations and Maintenance Phase 211

Step 3: Identifying Staffing 214

Step 4: Creating a Schedule 217

Step 5: Developing a Budget 218

Preliminary Requirements and Design 218

Hardware and Software Costs 219

Deployment Services Costs 221

Ongoing Operations and Maintenance Costs 223

Step 6: Evaluating Risks 225

Step 7: Analyzing Feasibility 227

Costs 228

Benefits 228

Impacts on Users 229

Impacts on Existing Systems 229

Making the Decision to Proceed 229

Executing the Project 232

The Kick-Off Meeting 232

Periodic Activities 233

Evaluating the Outcome of the Project 233

Chapter 9 Defining Requirements for a Wireless LAN 237

Requirements Attributes 238

Requirements Definition Steps 238

Step 1: Gathering Information 239

Interviewing Users 239

Interviewing IT Staff 240

Reviewing the Existing Infrastructure and Systems 240

Step 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 258

Step 3: Documenting Requirements 259

Step 4: Obtaining Requirements Approval 260

Chapter 10 System Architecture Considerations 263

Architectural Considerations 264

Wireless 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 279

Distribution Systems 282

Switch Considerations 282

PoE Considerations 282

Voice over WLAN Systems 284

Single-Site Architecture 284

Multisite WAN with Centralized Call Processing 285

Multisite WAN with Distributed Call Processing 287

Application Connectivity 289

Terminal Emulation Considerations 289

Browser-Based Connectivity Considerations 292

Direct Database Considerations 293

Wireless Middleware Considerations 294

Chapter 11 Range, Performance, and Roaming Considerations 299

Range Versus Performance 299

Range 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 309

Performance 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 319

Roaming Considerations 321

Roaming Levels 322

Access Point Roaming 322

Subnet Roaming 323

Wireless ISP Roaming 324

Wireless IP Phone Roaming 324

Mobility Settings 325

Chapter 12 Radio Frequency Considerations 327

Frequency Band Selection 327

2.4-GHz Frequency Band 327

5-GHz Frequency Band 328

Transmission Channel Settings 328

Manual Channel Settings 328

Single-Level Facilities 329

Multilevel Facilities 330

Adaptive Channel Settings 332

Difficult-to-Cover Areas 333

Signal Coverage in Elevators 333

Signal Coverage in Stairwells 336

Signal Coverage in Parking Areas 336

Radio Signal Interference Reduction 337

Chapter 13 Security Considerations 339

Security Elements 339

Encryption 340

Authentication 342

EAP Methods 342

Authentication Servers 344

Guest Access 345

Rogue Access Point Detection 346

RF Shielding 347

Wireless Security Polices 349

Part IV Wireless Network Installation and Testing

Chapter 14 Test Tools 353

Tool Considerations 353

Spectrum Analyzers 354

Real-Time Fast Fourier Transform 354

FFT Duty Cycle 356

Swept Spectrogram 357

Active Devices 357

Recording Spectrum Data 358

Signal Coverage Testers 358

Heat Maps 358

Positioning 360

Passive Versus Active Modes 361

Simulation 361

Free Signal Coverage Tester: NetStumbler 361

Wireless Protocol Analyzers 362

Filtering Frames 363

Recording Traces 363

Free Protocol Analyzer: WireShark 364

Chapter 15 Performing a Wireless Site Survey 367

Wireless Site Survey Considerations 368

Reviewing Requirements 369

Selecting Site Survey Tools 370

Obtaining Floor Diagrams 371

Inspecting the Facility 372

Assessing the Existing Network Infrastructure 372

Communications Rooms 372

Switches and Power over Ethernet 373

WAN 373

Identifying Potential Radio Signal Interference 373

Defining Signal Values for Acceptable Signal Coverage 376

Minimum Received Signal Strength 376

Minimum SNR 376

Uplink Versus Downlink Signal Values 377

Identifying 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 384

Writing an RF Site Survey Report 385

Chapter 16 Installing and Configuring a Wireless LAN 387

Wireless LAN Installation Considerations 387

Planning 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 391

Staging the Components 392

Installing Ethernet Switches and Cabling 393

Installing 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 402

Testing the Installation 402

Documenting the Installation 403

Chapter 17 Testing a Wireless LAN 405

Wireless LAN Testing Considerations 405

Signal Coverage Testing 406

Wireless Site Survey Coverage Testing 406

As-Installed Coverage Testing 407

Consider Beacon Rates 407

Performance Testing 408

Association Tests 408

Registration Tests 409

Network Connection Tests 409

Authentication Tests 410

Application Connection Tests 410

Application Tests 410

Load Tests 411

In-Motion Testing 412

Security Vulnerability Testing 413

Security Settings Verification 413

Penetration Testing 414

Private-Side Testing 414

Public-Side Testing 414

Acceptance/Verification Testing 415

Simulation Testing 416

Prototype Testing 417

Pilot Testing 418

Test Documentation 419

Part V Operational Support Considerations

Chapter 18 Managing a Wireless LAN 421

Operational Support Considerations 421

Help Desk 422

Connection Problems 422

Poor Signal Coverage 423

Poor Performance 423

System Status 423

Additional Considerations 423

Network 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 426

Maintenance 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 428

Engineering 428

Advanced Problem Resolution 429

Coverage Expansion 429

Capacity Increases 429

Firmware Review 429

Technology Upgrades 430

Design Review 430

Configuration 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 434

Trouble Ticket Coordination 435

Help Desk Group 435

Desktop Support Group 436

Network Support Group 436

Preparing for the Transfer to Operational Mode 436

Chapter 19 Troubleshooting a Wireless LAN 439

Troubleshooting Methodology 439

Identify the Problem 439

Identify the Underlying Cause of the Problem 440

Fix the Problem 440

Connection 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 443

Performance 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 447

Chapter 20 Preparing Operational Support Staff 449

Support Staff Considerations 449

Availability of Existing Staff 450

Experience Requirements 450

Education and Training Requirements 451

Vendor-Neutral Training 451

Vendor-Specific Training 452

College Education 452

Certifications 452

Staffing Sources 453

Glossary 455

9781587058899, TOC, 5/7/10

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