Appendix B Wireless LANs
NWA-3500/NWA-3550 User’s Guide
322
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 227
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
network overhead involved in the RTS (Request To Send)/CTS (Clear to Send)
handshake.
If the
RTS/CTS
value is greater than the
Fragmentation Threshold
value (see
next), then the RTS (Request To Send)/CTS (Clear to Send) handshake will never
occur as data frames will be fragmented before they reach
RTS/CTS
size.
Note: Enabling the RTS Threshold causes redundant network overhead that could
negatively affect the throughput performance instead of providing a remedy.
Summary of Contents for 802.11a/g Wireless CardBus Card ZyXEL AG-120
Page 2: ......
Page 8: ...Safety Warnings NWA 3500 NWA 3550 User s Guide 8...
Page 10: ...Contents Overview NWA 3500 NWA 3550 User s Guide 10...
Page 20: ...Table of Contents NWA 3500 NWA 3550 User s Guide 20...
Page 22: ...22...
Page 34: ...Chapter 1 Introducing the NWA NWA 3500 NWA 3550 User s Guide 34...
Page 52: ...Chapter 4 Management Mode NWA 3500 NWA 3550 User s Guide 52...
Page 108: ...108...
Page 146: ...Chapter 9 SSID Screen NWA 3500 NWA 3550 User s Guide 146...
Page 160: ...Chapter 10 Wireless Security Screen NWA 3500 NWA 3550 User s Guide 160...
Page 178: ...Chapter 14 IP Screen NWA 3500 NWA 3550 User s Guide 178...
Page 186: ...Chapter 15 Rogue AP Detection NWA 3500 NWA 3550 User s Guide 186...
Page 198: ...Chapter 16 Remote Management Screens NWA 3500 NWA 3550 User s Guide 198...
Page 260: ...Chapter 21 Load Balancing NWA 3160 Series User s Guide 260...
Page 264: ...Chapter 22 Dynamic Channel Selection NWA 3160 Series User s Guide 264...
Page 276: ...Chapter 23 Maintenance NWA 3500 NWA 3550 User s Guide 276...
Page 277: ...277 PART III Troubleshooting and Specifications Troubleshooting 279 Product Specifications 285...
Page 278: ...278...
Page 284: ...Chapter 24 Troubleshooting NWA 3500 NWA 3550 User s Guide 284...
Page 292: ...292...
Page 368: ...Appendix D Importing Certificates NWA 3500 NWA 3550 User s Guide 368...
Page 386: ...Appendix F Text File Based Auto Configuration NWA 3500 NWA 3550 User s Guide 386...