Specifications

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Cisco IOS Software Configuration Guide for Cisco Aironet Access Points
OL-5260-01
Chapter 6 Configuring Radio Settings
Enabling Short Slot Time for 802.11g Radios
The default setting is 2338 bytes. Beginning in privileged EXEC mode, follow these steps to configure
the fragmentation threshold:
Use the no form of the command to reset the setting to defaults.
Enabling Short Slot Time for 802.11g Radios
You can increase throughput on the 802.11g, 2.4-GHz radio by enabling short slot time. Reducing the
slot time from the standard 20 microseconds to the 9-microsecond short slot time decreases the overall
backoff, which increases throughput. Backoff, which is a multiple of the slot time, is the random length
of time that a station waits before sending a packet on the LAN.
Many 802.11g radios support short slot time, but some do not. When you enable short slot time, the
access point uses the short slot time only when all clients associated to the 802.11g, 2.4-GHz radio
support short slot time.
Short slot time is supported only on the 802.11g, 2.4-GHz radio. Short slot time is disabled by default.
In radio interface mode, enter this command to enable short slot time:
ap(config-if)# slot-time-short
Enter no slot-time-short to disable short slot time.
Performing a Carrier Busy Test
You can perform a carrier busy test to check the radio activity on access point channels. During the
carrier busy test, the access point drops all associations with wireless networking devices for around 4
seconds while it conducts the carrier test and then displays the test results.
In privileged EXEC mode, enter this command to perform a carrier busy test:
dot11 interface-number carrier busy
For interface-number, enter dot11radio 0 to run the test on the 2.4-GHz radio, or enter dot11radio 1 to
run the test on the 5-GHz radio.
Use the show dot11 carrier busy command to re-display the carrier busy test results.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
interface dot11radio { 0 | 1 } Enter interface configuration mode for the radio interface. The
2.4-GHz radio is radio 0, and the 5-GHz radio is radio 1.
Step 3
fragment-threshold value Set the fragmentation threshold. Enter a setting from 256 to
2346 bytes for the 2.4-GHz radio. Enter a setting from 256 to
2346 bytes for the 5-GHz radio.
Step 4
end Return to privileged EXEC mode.
Step 5
copy running-config startup-config (Optional) Save your entries in the configuration file.