Black Box LW0050A, Руководство пользователя

Страница: 11 / 146

9
CONTENTS
Chapter Page
Appendix B. Specifications ......................................................................................107
B.1 Specifications for LW0050A–LW0053A and LW0055A–LW0058A ..........107
B.2 Specifications for LW0054A and LW0059A ................................................109
Appendix C. Wireless LAN Concepts ......................................................................112
C.1 Topology........................................................................................................112
C.1.1 Wired LAN Topology ..........................................................................112
C.1.2 Wireless LAN Topology ......................................................................113
C.2 Roaming ........................................................................................................115
C.3 Load Balancing ............................................................................................115
C.4 Dynamic Rate Switching ..............................................................................116
C.5 Media Access ................................................................................................116
C.6 Fragmentation ..............................................................................................117
C.7 Collision Avoidance ......................................................................................117
C.8 Channelization..............................................................................................117
Appendix D. Radio Signal Propagation ..................................................................118
D.1 Introduction ..................................................................................................118
D.2 RF Terms and Definitions ............................................................................119
Appendix E. IEEE 802.11 Technical Tutorial ........................................................125
E.1 Architecture Components............................................................................125
E.2 IEEE 802.11 Layers Description ..................................................................126
E.3 The MAC Layer ............................................................................................127
E.3.1 The Basic Access Method: CSMA/CD ..............................................127
E.3.2 Virtual Carrier Sense ..........................................................................128
E.3.3 MAC-Level Acknowledgments ............................................................129
E.3.4 Fragmentation and Reassembly..........................................................129
E.3.5 Inter Frame Spaces ..............................................................................131
E.3.6 Exponential Backoff Algorithm..........................................................131
E.4 How Does a Station Join an Existing Cell (BSS)? ......................................132
E.4.1 The Authentication Process................................................................133
E.4.2 The Association Process ......................................................................133
E.5 Roaming ........................................................................................................133
E.6 Keeping Synchronization ............................................................................134
E.7 Security ..........................................................................................................134
E.7.1 Preventing Access to Network Resources ..........................................134
E.7.2 Eavesdropping ....................................................................................134
E.8 Power Saving ................................................................................................135
E.9 Frame Types ..................................................................................................136
E.10 Frame Formats ..............................................................................................136