Motorola WiNG 5.7.1 System Reference Manual page 136

5 - 52 WiNG 5.7.1 Access Point System Reference Guide
NOTE: AP6522, AP6522M, AP6532, AP6562, AP71XX, AP75XX, AP81XX and AP82XX
can support up to 256 client connections per access point. AP6511 and AP6521 model
access points (both single radio models) can support up to 128 client connections per
access point.
9. Set the following profile
Beacon Interval
DTIM Interval BSSID
RTS Threshold
WLAN Properties for the selected access point radio:
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 period determines how often the beacon contains a DTIM, for example, 1 DTIM for
every 10 beacons. 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 - 65,536 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. The default value is 65,536 bytes.
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.