Appendix A Wireless LANs
WAP6906 User’s Guide
74
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
Preamble is used to signal that data is coming to the receiver. Short and long refer to the length of the
synchronization field in a packet.
Short preamble increases performance as less time sending preamble means more time for sending
data. All IEEE 802.11 compliant wireless adapters support long preamble, but not all support short
preamble.
Use long preamble if you are unsure what preamble mode other wireless devices on the network
support, and to provide more reliable communications in busy wireless networks.
Use short preamble if you are sure all wireless devices on the network support it, and to provide more
efficient communications.
Use the dynamic setting to automatically use short preamble when all wireless devices on the network
support it, otherwise the WAP6906 uses long preamble.
Note: The wireless devices 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:
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 WAP6906 are data encryption, wireless client authentication,
restricting access by device MAC address and hiding the WAP6906 identity.
Table 26 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)
