ZyWALL 70 User’s Guide
612
Appendix G Wireless LANs
Figure 386
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.
Fragmentation Threshold
A
Fragmentation Threshold
is the maximum data fragment size (between 256 and 2432
bytes) that can be sent in the wireless network before the AP will fragment the packet into
smaller data frames.
Summary of Contents for ZyWALL 70
Page 1: ...ZyWALL 70 Internet Security Appliance User s Guide Version 3 64 3 2005 ...
Page 2: ......
Page 38: ...ZyWALL 70 User s Guide 38 List of Figures ...
Page 46: ...ZyWALL 70 User s Guide 46 List of Tables ...
Page 74: ...ZyWALL 70 User s Guide 74 Chapter 2 Introducing the Web Configurator ...
Page 92: ...ZyWALL 70 User s Guide 92 Chapter 3 Wizard Setup ...
Page 102: ...ZyWALL 70 User s Guide 102 Chapter 4 LAN Screens ...
Page 108: ...ZyWALL 70 User s Guide 108 Chapter 5 Bridge Screens ...
Page 130: ...ZyWALL 70 User s Guide 130 Chapter 6 Wireless LAN ...
Page 136: ...ZyWALL 70 User s Guide 136 Chapter 7 WAN Screens Figure 45 WAN General ...
Page 155: ...ZyWALL 70 User s Guide Chapter 7 WAN Screens 155 Figure 55 Dial Backup Setup ...
Page 234: ...ZyWALL 70 User s Guide 234 Chapter 13 Introduction to IPSec ...
Page 275: ...ZyWALL 70 User s Guide Chapter 15 Certificates 275 Figure 125 My Certificate Details ...
Page 294: ...ZyWALL 70 User s Guide 294 Chapter 16 Authentication Server Figure 136 Local User Database ...
Page 314: ...ZyWALL 70 User s Guide 314 Chapter 17 Network Address Translation NAT ...
Page 318: ...ZyWALL 70 User s Guide 318 Chapter 18 Static Route ...
Page 324: ...ZyWALL 70 User s Guide 324 Chapter 19 Policy Route ...
Page 340: ...ZyWALL 70 User s Guide 340 Chapter 20 Bandwidth Management ...
Page 376: ...ZyWALL 70 User s Guide 376 Chapter 22 Remote Management ...
Page 390: ...ZyWALL 70 User s Guide 390 Chapter 24 Logs Screens Figure 194 Log Settings ...
Page 413: ...ZyWALL 70 User s Guide Chapter 25 Maintenance 413 Figure 216 Restart Screen ...
Page 414: ...ZyWALL 70 User s Guide 414 Chapter 25 Maintenance ...
Page 440: ...ZyWALL 70 User s Guide 440 Chapter 28 WAN and Dial Backup Setup ...
Page 456: ...ZyWALL 70 User s Guide 456 Chapter 31 DMZ Setup ...
Page 460: ...ZyWALL 70 User s Guide 460 Chapter 32 Route Setup ...
Page 470: ...ZyWALL 70 User s Guide 470 Chapter 33 Remote Node Setup ...
Page 522: ...ZyWALL 70 User s Guide 522 Chapter 39 System Information Diagnosis ...
Page 538: ...ZyWALL 70 User s Guide 538 Chapter 40 Firmware and Configuration File Maintenance ...
Page 550: ...ZyWALL 70 User s Guide 550 Chapter 42 Remote Management ...
Page 558: ...ZyWALL 70 User s Guide 558 Chapter 43 IP Policy Routing ...
Page 573: ...ZyWALL 70 User s Guide Chapter 45 Troubleshooting 573 Figure 360 Java Sun ...
Page 574: ...ZyWALL 70 User s Guide 574 Chapter 45 Troubleshooting ...
Page 582: ...ZyWALL 70 User s Guide 582 Appendix B Removing and Installing a Fuse ...
Page 602: ...ZyWALL 70 User s Guide 602 Appendix D IP Subnetting ...
Page 608: ...ZyWALL 70 User s Guide 608 Appendix F PPTP ...
Page 626: ...ZyWALL 70 User s Guide 626 Appendix H Triangle Route ...
Page 656: ...ZyWALL 70 User s Guide 656 Appendix K Importing Certificates ...
Page 658: ...ZyWALL 70 User s Guide 658 Appendix L Command Interpreter ...
Page 664: ...ZyWALL 70 User s Guide 664 Appendix M Firewall Commands ...
Page 668: ...ZyWALL 70 User s Guide 668 Appendix N NetBIOS Filter Commands ...
Page 674: ...ZyWALL 70 User s Guide 674 Appendix P Brute Force Password Guessing Protection ...
Page 696: ...ZyWALL 70 User s Guide 696 Appendix R Log Descriptions ...