ZyXEL Communications VMG8825-B Series, Руководство пользователя, Страница: 324 / 360

Appendix B Wireless LANs
VMG8825-B Series User’s Guide
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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.
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:
Wireless Security Overview
Wireless security is vital to your network to protect wireless communication between wireless clients,
access points and the wired network.
Wireless security methods available on the VMG are data encryption, wireless client authentication,
restricting access by device MAC address and hiding the VMG identity.
The following figure shows the relative effectiveness of these wireless security methods available on your
VMG.
Note: You must enable the same wireless security settings on the VMG and on all wireless
clients that you want to associate with it.
IEEE 802.1x
In June 2001, the IEEE 802.1x standard was designed to extend the features of IEEE 802.11 to support
extended authentication as well as providing additional accounting and control features. It is
supported by Windows XP and a number of network devices. Some advantages of IEEE 802.1x are:
Table 149 IEEE 802.11g
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)
Table 150 Wireless Security Levels
SECURITY
LEVEL
SECURITY TYPE
Least Secure
Most Secure
Unique SSID (Default)
Unique SSID with Hide SSID Enabled
MAC Address Filtering
WEP Encryption
IEEE802.1x EAP with RADIUS Server Authentication
Wi-Fi Protected Access (WPA)
WPA2