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Cisco IOS Software Configuration Guide for Cisco Aironet Access Points
OL-30644-01
Chapter6 Configuring Radio Settings
Configuring the Fragmentation Threshold
Configuring the Fragmentation Threshold
The fragmentation threshold determines the size at which packets are fragmented (sent as several pieces
instead of as one block). Use a low setting in areas where communication is poor or where there is a great
deal of radio interference.
The default setting is 23382346 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
wireless device 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 not supported by
802.11b clients. If you enable short slot time, 802.11b clients will not be able to join or communicate
with the AP radio. Short slot time is disabled by default.
In radio interface mode, enter this command to enable short slot time:
ap(config-if)# short-slot-time
Enter no short-slot-time to disable short slot time.
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 interface dot11radio {0 | 1slot/port} Enter interface configuration mode for the radio interface.
The 2.4-GHz radio and the 2.4-GHz 802.11n radio is 0.
The 5-GHz radio and the 5-GHz 802.11n radio is 1.
Step3 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.
Step4 end Return to privileged EXEC mode.
Step5 copy running-config startup-config (Optional) Save your entries in the configuration file.