802.11 Wireless Networks (eBook)

Preface 7
Acknowledgments 8
Contents 9
Abbreviations 13
List of Figures 16
List of Tables 19
Introduction 20
IEEE 802 21
Wireless LANs 22
A Brief History of 802.11 26
The RF Environment 27
Book Outline 31
Summary 32
Radio Frequencies 34
The Electromagnetic Spectrum 34
Radio Waves 36
Direct Path 38
Absorption 41
Reflection 41
Diffraction 43
Refraction 44
Scattering 44
Multi-path 44
Radio Frequency Regulation 46
Spectrum Management 51
Summary 53
Medium Access Control 54
802.11 Services 55
MAC Frame Format 57
Distributed Coordination Function 58
Carrier Sensing 59
Transmission Methods 59
Inter-frame Spacing 60
Random Back-Off Algorithm 62
Fragmentation 62
Fairness 63
Point Coordination Function 64
Hybrid Coordination Function 64
Enhanced Distributed Channel Access 65
HCF Controlled Channel Access 67
Summary 69
Physical Layer 70
Frequency Hopping Spread Spectrum 70
Direct Sequence Spread Spectrum 73
High-Rate Direct Sequence Spread Spectrum 75
Orthogonal Frequency Division Multiplexing 77
Extended Rate PHY 79
MIMO-OFDM 81
Beamforming 85
Summary 90
Cryptography 92
Ciphers 92
Symmetric Key Cryptography 93
Asymmetric Key Cryptography 95
Encryption 97
RC4 98
DES and Triple-DES 99
AES 99
Message Digests 100
Digital Signatures 102
Digital Certificates 103
Generating Digital Certificates 105
Generating a Certificate Authority 106
Generating Certificates 109
Testing the Certificates 114
Summary 116
Wireless Security 118
Pre-RSNA 118
Authentication 119
Encryption and Integrity 120
RSNA 120
Authentication 121
Key Management 124
Encryption and Integrity 124
Summary 127
Configuring Wireless Networks 130
Ad-hoc Network 131
WEP 133
WPA with Pre-shared Key 134
Multiple SSIDs 138
Wireless Distribution System 140
Wireless Bridge 142
Build an Open Source Access-Point 145
Root Filesystem 145
Administration 146
Configuring the Access-Point 148
Installing Grub 149
Compile the Kernel 149
Install Root Directory Structure onto Compact Flash 151
Summary 153
Robust Security Network 154
Installing FreeRadius 155
Configuring FreeRadius 157
Configure FreeRadius to use MySQL 159
Testing 163
Configure EAP 165
Configure TLS 167
NAS Configuration 168
Wireless Client 169
Summary 173
MAC Layer Performance Analysis 174
Fragmentation 174
Analysis of Multiple Hops 175
Throughput 177
Summary 185
Link Rate Adaptation 186
Walffish-Ikegami Model 186
Berg Model 187
802.11b Link Rate Adaptation 190
Link Rate Adaptation in an Urban Area 195
802.11a Link Rate Adaptation 197
Link Rate Experiments 201
Summary 203
Appendix A Build a Xen Server 204
Install Xen 204
DomU Configuration 206
RADIUS Server 206
MySQL Server 207
DHCP Server 208
Test Client 209
Appendix B Initial Configuration of Access-Point Controllers 212
Alcalel-Lucent Omniaccess Controller 212
Meru Controller 213
References 220
Futher Reading 224
Index 226