User manual

MWGAR/MWGARB User Manual

Version: 2.0

faster. RTS packets consume valuable bandwidth, however, so setting this value

too low will limit performance.

4.12 What is 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).

4.13 What is 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 the short is

56 bits.

4.14 What is SSID Broadcast?

Broadcast of SSID is done in access points by the beacon. This announces your

access point (including various bits of information about it) to the wireless world

around it. By disabling that feature, the SSID configured in the client must match

the SSID of the access point.

Some wireless devices don't work properly if SSID isn't broadcast (for example

the D-link DWL-120 USB 802.11b adapter). Generally if your client hardware

supports operation with SSID disabled, it's not a bad idea to run that way to

enhance network security. However it's no replacement for WEP, MAC filtering or

other protections.

4.15 What is Wi-Fi Protected Access (WPA)?

Wi-Fi’s original security mechanism, Wired Equivalent Privacy (WEP), has been