Motorola WiNG 5.5 Reference Manual page 313

12. Set or override the following profile WLAN Properties for the selected access point radio.
Beacon Interval
DTIM Interval
RTS Threshold
Short Preamble
Set the interval between radio beacons in milliseconds (either 50, 100 or 200). A beacon
is a packet broadcast by adopted radios to keep the network synchronized. Included in a
beacon is information such as the WLAN service area, the radio address, the broadcast
destination addresses, a time stamp, and indicators about traffic and delivery such as a
DTIM. Increase the DTIM/beacon settings (lengthening the time) to let nodes sleep longer
and preserve battery life. Decrease these settings (shortening the time) to support
streaming-multicast audio and video applications that are jitter-sensitive.The default
value is 100 milliseconds.
Set a DTIM Interval to specify a period for Delivery Traffic Indication Messages (DTIM). A
DTIM is periodically included in a beacon frame transmitted from adopted radios. The
DTIM indicates broadcast and multicast frames (buffered at the access point) are soon to
arrive. These are simple data frames that require no acknowledgement, so nodes
sometimes miss them. Increase the DTIM/ beacon settings (lengthening the time) to let
nodes sleep longer and preserve their battery life. Decrease these settings (shortening
the time) to support streaming multicast audio and video applications that are jitter-
sensitive.
Specify a Request To Send (RTS) threshold (from 1 - 2,347 bytes) for use by the WLAN's
adopted access point radios. RTS is a transmitting station's signal that requests a Clear
To Send (CTS) response from a receiving client. This RTS/CTS procedure clears the air
where clients are contending for transmission time. Benefits include fewer data collisions
and better communication with nodes that are hard to find (or hidden) because of other
active nodes in the transmission path.
Control RTS/CTS by setting an RTS threshold. This setting initiates an RTS/CTS exchange
for data frames larger than the threshold, and sends (without RTS/CTS) any data frames
smaller than the threshold.
Consider the trade-offs when setting an appropriate RTS threshold for the WLAN's access
point radios. A lower RTS threshold causes more frequent RTS/CTS exchanges. This
consumes more bandwidth because of additional latency (RTS/CTS exchanges) before
transmissions can commence. A disadvantage is the reduction in data-frame throughput.
An advantage is quicker system recovery from electromagnetic interference and data
collisions. Environments with more wireless traffic and contention for transmission make
the best use of a lower RTS threshold.
A higher RTS threshold minimizes RTS/CTS exchanges, consuming less bandwidth for
data transmissions. A disadvantage is less help to nodes that encounter interference and
collisions. An advantage is faster data-frame throughput. Environments with less
wireless traffic and contention for transmission make the best use of a higher RTS
threshold.
If using an 802.11bg radio, select this option for the radio to transmit using a short
preamble. Short preambles improve throughput. However, some devices (SpectraLink
phones) require long preambles. The default value is disabled.
Device Configuration 5 - 227