Appendix B Wireless LANs
NWA-3166 User’s Guide
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RTS/CTS
A hidden node occurs when two stations are within range of the same access
point, but are not within range of each other. The following figure illustrates a
hidden node. Both stations (STA) are within range of the access point (AP) or
wireless gateway, but out-of-range of each other, so they cannot "hear" each
other, that is they do not know if the channel is currently being used. Therefore,
they are considered hidden from each other.
Figure 167
RTS/CTS
When station A sends data to the AP, it might not know that the station B is
already using the channel. If these two stations send data at the same time,
collisions may occur when both sets of data arrive at the AP at the same time,
resulting in a loss of messages for both stations.
RTS/CTS is designed to prevent collisions due to hidden nodes. An RTS/CTS
defines the biggest size data frame you can send before an RTS (Request To
Send)/CTS (Clear to Send) handshake is invoked.
When a data frame exceeds the RTS/CTS value you set (between 0 to 2432
bytes), the station that wants to transmit this frame must first send an RTS
(Request To Send) message to the AP for permission to send it. The AP then
responds with a CTS (Clear to Send) message to all other stations within its range
to notify them to defer their transmission. It also reserves and confirms with the
requesting station the time frame for the requested transmission.
Stations can send frames smaller than the specified RTS/CTS directly to the AP
without the RTS (Request To Send)/CTS (Clear to Send) handshake.
You should only configure RTS/CTS if the possibility of hidden nodes exists on
your network and the "cost" of resending large frames is more than the extra
Summary of Contents for NWA-3166
Page 2: ......
Page 15: ...15 PART I Introduction Introduction 17 The Web Configurator 29 Tutorials 33 ...
Page 16: ...16 ...
Page 32: ...Chapter 2 The Web Configurator NWA 3166 User s Guide 32 ...
Page 64: ...Chapter 3 Tutorials NWA 3166 User s Guide 64 ...
Page 66: ...66 ...
Page 70: ...Chapter 4 Status Screen NWA 3166 User s Guide 70 ...
Page 122: ...Chapter 8 Wireless Screen NWA 3166 User s Guide 122 ...
Page 128: ...Chapter 9 SSID Screen NWA 3166 User s Guide 128 ...
Page 158: ...Chapter 14 IP Screen NWA 3166 User s Guide 158 ...
Page 166: ...Chapter 15 Rogue AP Detection NWA 3166 User s Guide 166 ...
Page 186: ...Chapter 17 Internal RADIUS Server NWA 3166 User s Guide 186 ...
Page 213: ...Chapter 19 Log Screens NWA 3166 User s Guide 213 ...
Page 214: ...Chapter 19 Log Screens NWA 3166 User s Guide 214 ...
Page 235: ...Chapter 20 VLAN NWA 3166 User s Guide 235 ...
Page 236: ...Chapter 20 VLAN NWA 3166 User s Guide 236 ...
Page 270: ...Appendix B Wireless LANs NWA 3166 User s Guide 270 ...
Page 300: ...Appendix D IP Addresses and Subnetting NWA 3166 User s Guide 300 ...
Page 308: ...Appendix E Text File Based Auto Configuration NWA 3166 User s Guide 308 ...
Page 314: ...Appendix F How to Access and Use the CLI NWA 3166 User s Guide 314 ...
Page 326: ...Appendix H Customer Support NWA 3166 User s Guide 326 ...
Page 332: ...Index NWA 3166 User s Guide 332 ...