Advanced Radio Configuration - Cisco WS-CE500 Administration Manual

Wireless Configuration for the SA520W
Configuring the Radio
STEP 1
STEP 2
Cisco SA500 Series Security Appliances Administration Guide

Advanced Radio Configuration

This page is used to specify advanced configuration settings for the radio.
Click Wireless > Radio Settings > Advanced Settings.
The Advanced Radio Settings window opens.
Enter the following information:
• Beacon Interval: Beacon frames are transmitted by an access point at
regular intervals to announce the existence of the wireless network. Set the
interval by entering a value in milliseconds. The default setting is 100, which
means that beacon frames are sent every 100 milliseconds (10 seconds).
• Dtim Interval: The Delivery Traffic Information Map (DTIM) message is an
element that is included in some beacon frames. It indicates the client
stations that are currently sleeping in low-power mode and have buffered
data on the access point awaiting pickup. Set the interval by entering a value
in beacon frames. The default setting is 2, which means that the DTIM
message is included in every second beacon frame.
• RTS Threshold: Determines the packet size that requires a Request To Send
(RTS)/Clear To Send (CTS) handshake before sending. A low threshold
setting can be useful in areas where many client devices are associating
with the wireless device, or in areas where the clients are far apart and can
detect only the access point but not other clients. Although a low threshold
value consumes more bandwidth and reduces the throughput of the packet,
frequent RTS packets can help the network to recover from interference or
collisions. Set the threshold by entering the packet size in bytes. The default
value is 2346, which effectively disables RTS.
• Fragmentation Threshold: Frame length that requires packets to be broken
up (fragmented) into two or more frames. Setting a lower value can reduce
collisions because collisions occur more often in the transmission of long
frames, which occupy the channel for a longer time. Use a low setting in
areas where communication is poor or where there is a great deal of radio
interference. Set the threshold by entering the frame length in bytes. The
default value is 2346, which effectively disables fragmentation.
• Preamble mode: 802. 1 1b requires that a preamble be appended to every
frame before it is transmitted through the air. The preamble can be either the
traditional long preamble, which requires 192 μs for transmission, or it can be
an optional short preamble that requires only 96 μs. The long preamble is
needed for compatibility with the legacy 802. 1 1 systems operating at 1 and
2 Mbps. The default is Long.
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