Cisco 3925 User Manual

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Cisco 3900 Series, Cisco 2900 Series, and Cisco 1900 Series Integrated Services Routers Generation 2 Software Configuration Guide
Chapter Configuring Radio Settings
Enabling Short Slot Time for 802.11g Radios
DETAILED STEPS
Use the no form of the fragment-threshold command to reset the setting to the default.
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 disabled by default.
In radio interface mode, enter the short-slot-time command to enable short slot time:
ap(config-if)# short-slot-time
Enter no short-slot-time command to disable short slot time.
Performing a Carrier Busy Test
You can perform a carrier busy test to check the radio activity on wireless channels. During the carrier
busy test, the wireless device drops all associations with wireless networking devices for 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 redisplay the carrier busy test results.
Command Purpose
Step 1
configure terminal Enters global configuration mode.
Step 2
interface dot11radio {0| 1} Enters interface configuration mode for the radio interface. The
802.11g/n 2.4-GHz and 5-GHz radios are radio 0.
The 802.11n 5-GHz radio is radio 1.
Step 3
fragment-threshold value Sets 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 Returns to privileged EXEC mode.
Step 5
copy running-config startup-config (Optional) Saves your entries in the configuration file.

Cisco 3925 Specifications

General

Brand	Cisco
Model	3925
Category	Network Router
Language	English