6-19
Cisco IOS Software Configuration Guide for Cisco Aironet Access Points
OL-30644-01
Chapter6 Configuring Radio Settings
Configuring Radio Channel Settings
Note We recommend that you use the world-mode dot11d country-code configuration interface command to
configure a country code on DFS-enabled radios. The IEEE 802.11h protocol requires access points to
include the country information element (IE) in beacons and probe responses. By default, however, the
country code in the IE is blank. You use the world-mode command to populate the country code IE.

Radar Detection on a DFS Channel

When an access point detects a radar on a DFS channel, the access point creates a file in its flash memory.
The file is based on the 802.11a radio serial number and contains the channel numbers on which the radar
is detected. This is an expected behavior and you should not remove this file.
CLI Commands
The following sections describe CLI commands that apply to DFS.

Confirming that DFS is Enabled

Use the show controllers dot11radio1 command to confirm that DFS is enabled. The command also
includes indications that uniform spreading is required and channels that are in the non-occupancy
period due to radar detection.
This example shows a line from the output for the show controller command for a channel on which DFS
is enabled. The indications listed in the previous paragraph are shown in bold:
ap#sh controllers dot11Radio 1
!
interface Dot11Radio1
Radio ElliotNess 5, Base Address f4ea.6710.6590, BBlock version 0.00, Software version
4.10.1
Serial number: FOC16145K24
Unused dynamic SQRAM memory: 0x00007CB4 (31 KB)
Unused dynamic SDRAM memory: 0x0008E490 (569 KB)
Spectrum FW version: 1.14.2
Number of supported simultaneous BSSID on Dot11Radio1: 16
Carrier Set: Americas (OFDM) (US) (-A)
Uniform Spreading Required: Yes
Configured Frequency: 0 MHz Channel 0
Allowed Frequencies: * Dynamic Frequency Selection (DFS) only
5180( 36) 5200( 40) 5220( 44) 5240( 48) *5260( 52) *5280( 56) *5300( 60)
*5320( 64) *5500(100) *5520(104)
*5540(108) *5560(112) *5580(116) *5660(132) *5680(136) *5700(140) 5745(149)
5765(153) 5785(157) 5805(161)
5825(165)
Listen Frequencies:
5180( 36) 5200( 40) 5220( 44) 5240( 48) 5260( 52) 5280( 56) 5300( 60)
5320( 64) 5500(100) 5520(104)
5540(108) 5560(112) 5580(116) 5600(120) 5620(124) 5640(128) 5660(132)
5680(136) 5700(140) 5745(149)
5765(153) 5785(157) 5805(161) 5825(165)
DFS Blocked Frequencies: none
Beacon Flags: 0, Interface Flags 20109, Interface Events 0, Mode 9; Beacons are disabled;
Probes are disabled
Configured TxPower: 14 dBm
Allowed Power Levels: 14 11 8 5 2 dBm