User's Manual

mechanism, the transmitting station sends out an RTS packet to the receiving

station, and waits for the receiving station to send back a CTS (Clear to Send)

packet before sending the actual packet data. This setting is useful for

networks with many clients. With many clients, and a high network load, there

will be many more collisions. By lowering the RTS threshold, there may be

fewer collisions, and performance should improve. Basically, with a faster RTS

threshold, the system can recover from problems faster. RTS packets

consume valuable bandwidth, however, so setting this value too low will limit

performance.

Beacon Interval

In addition to data frames that carry information from higher layers, 802.11

includes management and control frames that support data transfer. The

beacon frame, which is a type of management frame, provides the "heartbeat"

of a wireless LAN, enabling stations to establish and maintain communications

in an orderly fashion. Beacon Interval represents the amount of time between

beacon transmissions. Before a station enters power save mode, the station

needs the beacon interval to know when to wake up to receive the beacon

(and learn whether there are buffered frames at the access point).

Preamble Type

There are two preamble types defined in IEEE 802.11 specification. A long

preamble basically gives the decoder more time to process the preamble. All

802.11 devices support a long preamble. The short preamble is designed to

improve efficiency (for example, for VoIP systems). The difference between the

two is in the Synchronization field. The long preamble is 128 bits, and theshort

is 56 bits.

WPA2

It is the second generation of WPA. WPA2 is based on the final IEEE 802.11i

amendment to the 802.11 standard.

Temporal Key Integrity Protocol (TKIP)

The Temporal Key Integrity Protocol, pronounced tee-kip, is part of the IEEE

802.11i encryption standard for wireless LANs. TKIP is the next generation of

WEP, the Wired Equivalency Protocol, which is used to secure 802.11 wireless

LANs. TKIP provides per-packet key mixing, a message integrity check and a

re-keying mechanism, thus fixing the flaws of WEP.