Appendix E Wireless LANs
ZyWALL USG 300 User’s Guide
1048
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 670
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.
Содержание USG-300 - V2.20 ED 2
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Страница 30: ...Table of Contents ZyWALL USG 300 User s Guide 30 ...
Страница 31: ...31 PART I User s Guide ...
Страница 32: ...32 ...
Страница 38: ...Chapter 1 Introducing the ZyWALL ZyWALL USG 300 User s Guide 38 ...
Страница 46: ...Chapter 2 Features and Applications ZyWALL USG 300 User s Guide 46 ...
Страница 64: ...Chapter 3 Web Configurator ZyWALL USG 300 User s Guide 64 ...
Страница 74: ...Chapter 4 Installation Setup Wizard ZyWALL USG 300 User s Guide 74 ...
Страница 116: ...Chapter 6 Configuration Basics ZyWALL USG 300 User s Guide 116 ...
Страница 128: ...Chapter 7 Tutorials ZyWALL USG 300 User s Guide 128 Figure 73 Configuration Network Interface WLAN Add ...
Страница 184: ...Chapter 7 Tutorials ZyWALL USG 300 User s Guide 184 ...
Страница 221: ...Chapter 8 L2TP VPN Example ZyWALL USG 300 User s Guide 221 ...
Страница 222: ...Chapter 8 L2TP VPN Example ZyWALL USG 300 User s Guide 222 ...
Страница 223: ...223 PART II Technical Reference ...
Страница 224: ...224 ...
Страница 238: ...Chapter 9 Dashboard ZyWALL USG 300 User s Guide 238 ...
Страница 282: ...Chapter 10 Monitor ZyWALL USG 300 User s Guide 282 ...
Страница 303: ...Chapter 13 Interfaces ZyWALL USG 300 User s Guide 303 Figure 269 Configuration Network Interface Ethernet Edit ...
Страница 320: ...Chapter 13 Interfaces ZyWALL USG 300 User s Guide 320 Figure 275 Configuration Network Interface Cellular Add ...
Страница 330: ...Chapter 13 Interfaces ZyWALL USG 300 User s Guide 330 Figure 278 Configuration Network Interface WLAN Add No Security ...
Страница 345: ...Chapter 13 Interfaces ZyWALL USG 300 User s Guide 345 Figure 286 Configuration Network Interface VLAN Edit ...
Страница 355: ...Chapter 13 Interfaces ZyWALL USG 300 User s Guide 355 Figure 288 Configuration Network Interface Bridge Add ...
Страница 378: ...Chapter 14 Trunks ZyWALL USG 300 User s Guide 378 ...
Страница 394: ...Chapter 15 Policy and Static Routes ZyWALL USG 300 User s Guide 394 ...
Страница 408: ...Chapter 16 Routing Protocols ZyWALL USG 300 User s Guide 408 ...
Страница 428: ...Chapter 19 NAT ZyWALL USG 300 User s Guide 428 ...
Страница 433: ...Chapter 20 HTTP Redirect ZyWALL USG 300 User s Guide 433 ...
Страница 434: ...Chapter 20 HTTP Redirect ZyWALL USG 300 User s Guide 434 ...
Страница 456: ...Chapter 23 Authentication Policy ZyWALL USG 300 User s Guide 456 ...
Страница 474: ...Chapter 24 Firewall ZyWALL USG 300 User s Guide 474 ...
Страница 481: ...Chapter 25 IPSec VPN ZyWALL USG 300 User s Guide 481 Figure 355 Configuration VPN IPSec VPN VPN Connection Edit IKE ...
Страница 492: ...Chapter 25 IPSec VPN ZyWALL USG 300 User s Guide 492 Figure 358 Configuration VPN IPSec VPN VPN Gateway Edit ...
Страница 515: ...Chapter 25 IPSec VPN ZyWALL USG 300 User s Guide 515 ...
Страница 516: ...Chapter 25 IPSec VPN ZyWALL USG 300 User s Guide 516 ...
Страница 529: ...Chapter 26 SSL VPN ZyWALL USG 300 User s Guide 529 ...
Страница 530: ...Chapter 26 SSL VPN ZyWALL USG 300 User s Guide 530 ...
Страница 540: ...Chapter 27 SSL User Screens ZyWALL USG 300 User s Guide 540 ...
Страница 542: ...Chapter 28 SSL User Application Screens ZyWALL USG 300 User s Guide 542 ...
Страница 550: ...Chapter 29 SSL User File Sharing ZyWALL USG 300 User s Guide 550 ...
Страница 635: ...Chapter 34 IDP ZyWALL USG 300 User s Guide 635 ...
Страница 636: ...Chapter 34 IDP ZyWALL USG 300 User s Guide 636 ...
Страница 646: ...Chapter 35 ADP ZyWALL USG 300 User s Guide 646 Figure 448 Profiles Protocol Anomaly ...
Страница 657: ...Chapter 35 ADP ZyWALL USG 300 User s Guide 657 ...
Страница 658: ...Chapter 35 ADP ZyWALL USG 300 User s Guide 658 ...
Страница 690: ...Chapter 37 Content Filter Reports ZyWALL USG 300 User s Guide 690 ...
Страница 708: ...Chapter 38 Anti Spam ZyWALL USG 300 User s Guide 708 ...
Страница 730: ...Chapter 39 Device HA ZyWALL USG 300 User s Guide 730 ...
Страница 746: ...Chapter 40 User Group ZyWALL USG 300 User s Guide 746 ...
Страница 752: ...Chapter 41 Addresses ZyWALL USG 300 User s Guide 752 ...
Страница 764: ...Chapter 43 Schedules ZyWALL USG 300 User s Guide 764 ...
Страница 780: ...Chapter 45 Authentication Method ZyWALL USG 300 User s Guide 780 ...
Страница 802: ...Chapter 46 Certificates ZyWALL USG 300 User s Guide 802 ...
Страница 814: ...Chapter 48 SSL Application ZyWALL USG 300 User s Guide 814 ...
Страница 820: ...Chapter 49 Endpoint Security ZyWALL USG 300 User s Guide 820 Figure 534 Configuration Object Endpoint Security Add ...
Страница 824: ...Chapter 49 Endpoint Security ZyWALL USG 300 User s Guide 824 ...
Страница 876: ...Chapter 50 System ZyWALL USG 300 User s Guide 876 ...
Страница 916: ...Chapter 54 Reboot ZyWALL USG 300 User s Guide 916 ...
Страница 918: ...Chapter 55 Shutdown ZyWALL USG 300 User s Guide 918 ...
Страница 938: ...Chapter 56 Troubleshooting ZyWALL USG 300 User s Guide 938 ...
Страница 946: ...Chapter 57 Product Specifications ZyWALL USG 300 User s Guide 946 ...
Страница 1118: ...Appendix F Open Software Announcements ZyWALL USG 300 User s Guide 1118 ...