ZyWALL 5 User’s Guide
Appendix F
575
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 26
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 ZyXEL ZyWALL 5
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Страница 86: ...ZyWALL 5 User s Guide 84 Chapter 3 Wizard Setup ...
Страница 96: ...ZyWALL 5 User s Guide 94 Chapter 4 LAN Screens ...
Страница 102: ...ZyWALL 5 User s Guide 100 Chapter 5 Bridge Screens ...
Страница 130: ...ZyWALL 5 User s Guide 128 Chapter 7 WAN Screens Figure 45 WAN PPPoE Encapsulation ...
Страница 138: ...ZyWALL 5 User s Guide 136 Chapter 7 WAN Screens Figure 50 Dial Backup Setup ...
Страница 144: ...ZyWALL 5 User s Guide 142 Chapter 7 WAN Screens ...
Страница 152: ...ZyWALL 5 User s Guide 150 Chapter 8 DMZ Screens ...
Страница 174: ...ZyWALL 5 User s Guide 172 Chapter 10 Firewall Screens Figure 68 Creating Editing A Firewall Rule ...
Страница 179: ...ZyWALL 5 User s Guide Chapter 10 Firewall Screens 177 Figure 73 My Service Rule Configuration ...
Страница 220: ...ZyWALL 5 User s Guide 218 Chapter 13 Introduction to IPSec ...
Страница 238: ...ZyWALL 5 User s Guide 236 Chapter 14 VPN Screens Figure 110 VPN Rules IKE Network Policy Edit ...
Страница 261: ...ZyWALL 5 User s Guide Chapter 15 Certificates 259 Figure 122 My Certificate Details ...
Страница 280: ...ZyWALL 5 User s Guide 278 Chapter 16 Authentication Server Figure 133 Local User Database ...
Страница 317: ...ZyWALL 5 User s Guide Chapter 19 Bandwidth Management 315 ...
Страница 318: ...ZyWALL 5 User s Guide 316 Chapter 19 Bandwidth Management ...
Страница 352: ...ZyWALL 5 User s Guide 350 Chapter 21 Remote Management ...
Страница 366: ...ZyWALL 5 User s Guide 364 Chapter 23 Logs Screens Figure 188 Log Settings ...
Страница 389: ...ZyWALL 5 User s Guide Chapter 24 Maintenance 387 Figure 210 Restart Screen ...
Страница 390: ...ZyWALL 5 User s Guide 388 Chapter 24 Maintenance ...
Страница 416: ...ZyWALL 5 User s Guide 414 Chapter 27 WAN and Dial Backup Setup ...
Страница 432: ...ZyWALL 5 User s Guide 430 Chapter 30 DMZ Setup ...
Страница 492: ...ZyWALL 5 User s Guide 490 Chapter 37 System Information Diagnosis ...
Страница 508: ...ZyWALL 5 User s Guide 506 Chapter 38 Firmware and Configuration File Maintenance ...
Страница 520: ...ZyWALL 5 User s Guide 518 Chapter 40 Remote Management ...
Страница 536: ...ZyWALL 5 User s Guide 534 Chapter 42 Troubleshooting Figure 343 Java Sun ...
Страница 564: ...ZyWALL 5 User s Guide 562 Appendix C IP Subnetting ...
Страница 570: ...ZyWALL 5 User s Guide 568 Appendix E PPTP ...
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Страница 620: ...ZyWALL 5 User s Guide 618 Appendix J Importing Certificates ...
Страница 622: ...ZyWALL 5 User s Guide 620 Appendix K Command Interpreter ...
Страница 628: ...ZyWALL 5 User s Guide 626 Appendix L Firewall Commands ...
Страница 632: ...ZyWALL 5 User s Guide 630 Appendix M NetBIOS Filter Commands ...
Страница 638: ...ZyWALL 5 User s Guide 636 Appendix O Brute Force Password Guessing Protection ...
Страница 660: ...ZyWALL 5 User s Guide 658 Appendix Q Log Descriptions ...