Motorola AP-6511 Reference Manual page 218

Motorola Solutions AP-6511 Access Point System Reference Guide
RTS Threshold
Short Preamble
Guard Interval
Probe Response Rate
Probe Response Retry
9. Select the
7-20
Specify a Request To Send (RTS) threshold (between 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 checkbox 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.
Use the drop down menu to specify a Long or Any guard interval. The guard
interval is the space between symbols (characters) being transmitted. The
guard interval is there to eliminate inter-symbol interference (ISI). ISI occurs
when echoes or reflections from one symbol interfere with another symbol.
Adding time between transmissions allows echo's and reflections to settle
before the next symbol is transmitted. A shorter guard interval reduces
overhead and increases data rates by up to 10%.The default value is Long.
Use the drop-down menu to specify the data transmission rate used for the
transmission of probe responses. Options include, highest-basic, lowest-basic
and follow-probe-request (default setting).
Select the radio button to retry probe responses if they are not acknowledged
by the target wireless client. The default value is enabled.
WLAN Mapping tab.