ZyWALL 70 User’s Guide
Appendix G Wireless LANs
613
A large
Fragmentation Threshold
is recommended for networks not prone to interference
while you should set a smaller threshold for busy networks or networks that are prone to
interference.
If the
Fragmentation Threshold
value is smaller than the
RTS/CTS
value (see previously)
you set 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.
Preamble Type
A preamble is used to synchronize the transmission timing in your wireless network. There are
two preamble modes:
Long
and
Short
.
Short preamble takes less time to process and minimizes overhead, so it should be used in a
good wireless network environment when all wireless stations support it.
Select
Long
if you have a ‘noisy’ network or are unsure of what preamble mode your wireless
stations support as all IEEE 802.11b compliant wireless adapters must support long preamble.
However, not all wireless adapters support short preamble. Use long preamble if you are
unsure what preamble mode the wireless adapters support, to ensure interpretability between
the AP and the wireless stations and to provide more reliable communication in ‘noisy’
networks.
Select
Dynamic
to have the AP automatically use short preamble when all wireless stations
support it, otherwise the AP uses long preamble.
Note:
The AP and the wireless stations MUST
use the same preamble mode in order
to communicate.
IEEE 802.11g Wireless LAN
IEEE 802.11g is fully compatible with the IEEE 802.11b standard. This means an IEEE
802.11b adapter can interface directly with an IEEE 802.11g access point (and vice versa) at
11 Mbps or lower depending on range. IEEE 802.11g has several intermediate rate steps
between the maximum and minimum data rates. The IEEE 802.11g data rate and modulation
are as follows:
Table 239
IEEE802.11g
DATA RATE (MBPS)
MODULATION
1
DBPSK (Differential Binary Phase Shift Keyed)
2
DQPSK (Differential Quadrature Phase Shift Keying)
5.5 / 11
CCK (Complementary Code Keying)
6/9/12/18/24/36/48/54
OFDM (Orthogonal Frequency Division Multiplexing)
Содержание ZyWALL 70
Страница 1: ...ZyWALL 70 Internet Security Appliance User s Guide Version 3 64 3 2005 ...
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Страница 38: ...ZyWALL 70 User s Guide 38 List of Figures ...
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Страница 74: ...ZyWALL 70 User s Guide 74 Chapter 2 Introducing the Web Configurator ...
Страница 92: ...ZyWALL 70 User s Guide 92 Chapter 3 Wizard Setup ...
Страница 102: ...ZyWALL 70 User s Guide 102 Chapter 4 LAN Screens ...
Страница 108: ...ZyWALL 70 User s Guide 108 Chapter 5 Bridge Screens ...
Страница 130: ...ZyWALL 70 User s Guide 130 Chapter 6 Wireless LAN ...
Страница 136: ...ZyWALL 70 User s Guide 136 Chapter 7 WAN Screens Figure 45 WAN General ...
Страница 155: ...ZyWALL 70 User s Guide Chapter 7 WAN Screens 155 Figure 55 Dial Backup Setup ...
Страница 188: ...ZyWALL 70 User s Guide 188 Chapter 10 Firewall Screens Figure 71 Creating Editing A Firewall Rule ...
Страница 193: ...ZyWALL 70 User s Guide Chapter 10 Firewall Screens 193 Figure 76 My Service Rule Configuration ...
Страница 234: ...ZyWALL 70 User s Guide 234 Chapter 13 Introduction to IPSec ...
Страница 246: ...ZyWALL 70 User s Guide 246 Chapter 14 VPN Screens Figure 112 VPN Rules IKE Gateway Policy Edit ...
Страница 252: ...ZyWALL 70 User s Guide 252 Chapter 14 VPN Screens Figure 113 VPN Rules IKE Network Policy Edit ...
Страница 275: ...ZyWALL 70 User s Guide Chapter 15 Certificates 275 Figure 125 My Certificate Details ...
Страница 294: ...ZyWALL 70 User s Guide 294 Chapter 16 Authentication Server Figure 136 Local User Database ...
Страница 314: ...ZyWALL 70 User s Guide 314 Chapter 17 Network Address Translation NAT ...
Страница 318: ...ZyWALL 70 User s Guide 318 Chapter 18 Static Route ...
Страница 324: ...ZyWALL 70 User s Guide 324 Chapter 19 Policy Route ...
Страница 340: ...ZyWALL 70 User s Guide 340 Chapter 20 Bandwidth Management ...
Страница 376: ...ZyWALL 70 User s Guide 376 Chapter 22 Remote Management ...
Страница 390: ...ZyWALL 70 User s Guide 390 Chapter 24 Logs Screens Figure 194 Log Settings ...
Страница 413: ...ZyWALL 70 User s Guide Chapter 25 Maintenance 413 Figure 216 Restart Screen ...
Страница 414: ...ZyWALL 70 User s Guide 414 Chapter 25 Maintenance ...
Страница 440: ...ZyWALL 70 User s Guide 440 Chapter 28 WAN and Dial Backup Setup ...
Страница 456: ...ZyWALL 70 User s Guide 456 Chapter 31 DMZ Setup ...
Страница 460: ...ZyWALL 70 User s Guide 460 Chapter 32 Route Setup ...
Страница 470: ...ZyWALL 70 User s Guide 470 Chapter 33 Remote Node Setup ...
Страница 522: ...ZyWALL 70 User s Guide 522 Chapter 39 System Information Diagnosis ...
Страница 538: ...ZyWALL 70 User s Guide 538 Chapter 40 Firmware and Configuration File Maintenance ...
Страница 550: ...ZyWALL 70 User s Guide 550 Chapter 42 Remote Management ...
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Страница 582: ...ZyWALL 70 User s Guide 582 Appendix B Removing and Installing a Fuse ...
Страница 602: ...ZyWALL 70 User s Guide 602 Appendix D IP Subnetting ...
Страница 608: ...ZyWALL 70 User s Guide 608 Appendix F PPTP ...
Страница 626: ...ZyWALL 70 User s Guide 626 Appendix H Triangle Route ...
Страница 656: ...ZyWALL 70 User s Guide 656 Appendix K Importing Certificates ...
Страница 658: ...ZyWALL 70 User s Guide 658 Appendix L Command Interpreter ...
Страница 664: ...ZyWALL 70 User s Guide 664 Appendix M Firewall Commands ...
Страница 668: ...ZyWALL 70 User s Guide 668 Appendix N NetBIOS Filter Commands ...
Страница 674: ...ZyWALL 70 User s Guide 674 Appendix P Brute Force Password Guessing Protection ...
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