Dynamic Frequency Selection - Cisco M10-RM Software Manual

Configuring Radio Channel Settings
Beginning in privileged EXEC mode, follow these steps to set the wireless device's channel width:
Command
Step 1
configure terminal
Step 2
interface dot11radio {0 |
1slot/port }
Step 3 channel
{frequency | least-congested |
width [20 | 40-above | 40-below]
| dfs }
Step 4 end
Step 5
copy running-config
startup-config

Dynamic Frequency Selection

Access points with 5-GHz radios configured at the factory for use in the United States, Europe,
Singapore, Korea, Japan, Israel, and Taiwan now comply with regulations that require radio devices to
use Dynamic Frequency Selection (DFS) to detect radar signals and avoid interfering with them. When
an access points detects a radar on a certain channel, it avoids using that channel for 30 minutes. Radios
configured for use in other regulatory domains do not use DFS.
When a DFS-enabled 5-GHz radio operates on one of the 15 channels listed in
automatically uses DFS to set the operating frequency. When DFS is enabled, the access point monitors
its operating frequency for radar signals. If it detects radar signals on the channel, the access point takes
these steps:
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Cisco IOS Software Configuration Guide for Cisco Aironet Access Points
6-16
Blocks new transmissions on the channel.
Flushes the power-save client queues.
Broadcasts an 802.11h channel-switch announcement.
Disassociates remaining client devices.
If participating in WDS, sends a DFS notification to the active WDS device that it is leaving the
frequency.
Randomly selects a different 5-GHz channel.
Purpose
Enter global configuration mode.
Enter interface configuration mode for the radio interface.
The 2.4-GHz radioand the 802.11n 2.4-GHz is radio 0.
The 5-GHz radio and the 802.11n 5-GHz is radio 1.
Set the default channel for the wireless device radio.
shows the channels and frequencies. To search for the
least-congested channel on startup, enter least-congested.
Use the width option to specify a bandwidth to use. This option is
available for the 1250 series access point and consists of three
available settings: 20, 40-above, and 40-below. chosing 20 sets the
channel width to 20 MHz. Chosing 40-above sets the channel width
to 40 Mhz with the extension channel above the control channel.
Chosing 40-below sets the channel width to 40 MHz with the
extension channel below the control channel.
The channel command is disabled for 5-GHz radios that
Note
comply with European Union regulations on dynamic
frequency selection (DFS). See the
Guard Interval" section on page 6-20
Return to privileged EXEC mode.
(Optional) Save your entries in the configuration file.
Chapter 6 Configuring Radio Settings
Table 6-4
"Setting the 802.11n
for more information.
Table 6-4, the access point
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