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Chapter 10      Configuring Radio Settings
Configuring the Role in the Radio Network
You can also configure a fallback role for root access points. The wireless device automatically assumes 
the fallback role when its Ethernet port is disabled or disconnected from the wired LAN. The default 
fallback role for Cisco ISR wireless devices is:
Shutdown—the wireless device shuts down its radio and disassociates all client devices.
To set the wireless device’s radio network role and fallback role, follow these steps, beginning in 
privileged EXEC mode:
NoteWhen you enable the role of a device in the radio network as a bridge/workgroup bridge and enable the 
interface using the no shut command, the physical status and the software status of the interface will be 
up, only if the device on the other end (access point or bridge) is up. Otherwise, only the physical status 
of the device will be up. The software status will be up (ready) when the device on the other end is 
configured and ready.
CommandPurpose
Step 1configure terminalEnters global configuration mode.
Step 2interface dot11radio { 0 }Enters interface configuration mode for the radio interface:
The 2.4-GHz and the 802.11g/n 2.4-GHz radios are radio 0.
Step 3station-role 
 
non-root {bridge | wireless-clients} 
 
 
root {access-point | ap-only | 
[bridge  | wireless-clients] | 
[fallback | repeater | shutdown]}
 
 
workgroup-bridge {multicast | 
mode | 
universal }
Sets the wireless device role.
 Set the role to non-root bridge with or without wireless 
clients, root access point or bridge, or workgroup bridge.
NoteThe bridge mode radio supports point-to-point 
configuration only.
NoteThe repeater and wireless-clients commands are not 
supported on Cisco 860 and Cisco 880 series 
embedded-wireless devices.
NoteScanner is not supported on Cisco 860 and Cisco 880 
series embedded-wireless devices.
 The Ethernet port is shut down when any one of the radios 
is configured as a repeater. Only one radio per access point 
may be configured as a workgroup bridge or repeater.
Step 4endReturns to privileged EXEC mode.
Step 5copy running-config startup-config(Optional) Saves your entries in the configuration file. 
						

							 
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Chapter 10      Configuring Radio Settings
Configuring Radio Data Rates
Radio Tracking
You can configure the access point to track or monitor the status of one of its radios. If the tracked radio 
goes down or is disabled, the access point shuts down the other radio. If the tracked radio comes up, the 
access point enables the other radio.
 To track radio 0, enter the following command:
# station-role root access-point fallback track d0 shutdown
 To track radio 1, enter the following command:
# station-role root access-point fallback track d1 shutdown
Fast Ethernet Tracking
You can configure the access point for fallback when its Ethernet port is disabled or disconnected from 
the wired LAN. You configure the access point for Fast Ethernet tracking as described in the 
“Configuring the Role in the Radio Network” section on page 10-2. 
NoteFast Ethernet tracking does not support the repeater mode.
 To configure the access point for Fast Ethernet tracking, enter the following command:
# station-role root access-point fallback track fa 0
MAC-Address Tracking
You can configure the radio whose role is root access point to go up or down by tracking a client access 
point, using its MAC address, on another radio. If the client disassociates from the access point, the root 
access point radio goes down. If the client reassociates to the access point, the root access point radio 
comes back up.
MAC-address tracking is most useful when the client is a non-root bridge access point connected to an 
upstream wired network.
For example, to track a client whose MAC address is 12:12:12:12:12:12, enter the following command:
# station-role root access-point fallback track mac-address 12:12:12:12:12:12 shutdown
Configuring Radio Data Rates
You use the data rate settings to choose the data rates that the wireless device uses for data transmission. 
The rates are expressed in megabits per second. The wireless device always attempts to transmit at the 
highest data rate set to basic, also called required on the browser-based interface. If there are obstacles 
or interference, the wireless device steps down to the highest rate that allows data transmission. You can 
set each data rate to one of three states: 
 Basic (the GUI labels Basic rates as Required)—Allows transmission at this rate for all packets, both 
unicast and multicast. At least one of the wireless device’s data rates must be set to Basic. 
 Enabled—The wireless device transmits only unicast packets at this rate; multicast packets are sent 
at one of the data rates set to Basic.  
						

							 
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Chapter 10      Configuring Radio Settings
Configuring Radio Data Rates
 Disabled—The wireless device does not transmit data at this rate. 
NoteAt least one data rate must be set to basic.
You can use the Data Rate settings to set an access point to serve client devices operating at specific data 
rates. For example, to set the 2.4-GHz radio for 11 megabits per second (Mbps) service only, set the 
11-Mbps rate to basic and set the other data rates to disabled. To set the wireless device to serve only 
client devices operating at 1 and 2 Mbps, set 1 and 2 to basic and set the rest of the data rates to disabled. 
To set the 2.4-GHz, 802.11g radio to serve only 802.11g client devices, set any Orthogonal Frequency 
Division Multiplexing (OFDM) data rate (6, 9, 12, 18, 24, 36, 48, 54) to basic. To set the 5-GHz radio 
for 54-Mbps service only, set the 54-Mbps rate to basic and set the other data rates to disabled.
You can configure the wireless device to set the data rates automatically to optimize either the range or 
the throughput. When you enter range for the data rate setting, the wireless device sets the 1-Mbps rate 
to basic, and the other rates to enabled. The range setting allows the access point to extend the coverage 
area by compromising on the data rate. Therefore, if you have a client that cannot connect to the access 
point while other clients can, the client may not be within the coverage area of the access point. In such 
a case, using the range option will help extend the coverage area, and the client may be able to connect 
to the access point. Typically the trade-off is between throughput and range. When the signal degrades 
(possibly due to distance from the access point), the rates renegotiate in order to maintain the link (but 
at a lower data rate). Contrast that against a link configured for a higher throughput that simply drops 
when the signal degrades enough to no longer sustain a configured high data rate, or roams to another 
access point with sufficient coverage, if one is available. The balance between the two (throughput vs. 
range) is a design decision that must be made based on resources available to the wireless project, type 
of traffic the users will be passing, service level desired, and as always, the quality of the RF 
environment.When you enter throughput for the data rate setting, the wireless device sets all four data 
rates to basic. 
NoteWhen a wireless network has a mixed environment of 802.11b clients and 802.11g clients, make sure 
that data rates 1, 2, 5.5, and 11 Mbps are set to required (basic) and that all other data rates are set to 
enable. The 802.11b adapters do not recognize the 54-Mbps data rate and do not operate if data rates 
higher than 11-Mbps are set to required on the connecting access point.
To configure the radio data rates, follow these steps, beginning in privileged EXEC mode:
CommandPurpose
Step 1configure terminalEnters global configuration mode.
Step 2interface dot11radio { 0 }Enters interface configuration mode for the radio interface.The 
2.4-GHz and the 802.11g/n 2.4-GHz radios are radio 0. 
						

							 
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Configuring Radio Data Rates
Step 3speed
802.11b, 2.4-GHz radio:
{[1.0] [11.0] [2.0] [5.5] [basic-1.0] 
[basic-11.0] [basic-2.0] [basic-5.5] | 
range | throughput}
802.11g, 2.4-GHz radio:
{[1.0] [2.0] [5.5] [6.0] [9.0] [11.0] 
[12.0] [18.0] [24.0] [36.0] [48.0] 
[54.0] [basic-1.0] [basic-2.0] 
[basic-5.5] [basic-6.0] [basic-9.0] 
[basic-11.0] [basic-12.0] 
[basic-18.0] [basic-24.0] 
[basic-36.0] [basic-48.0] 
[basic-54.0] | range | 
 
throughput [ofdm] | default }
802.11a 5-GHz radio:
{[6.0] [9.0] [12.0] [18.0] [24.0] 
[36.0] [48.0] [54.0] [basic-6.0] 
[basic-9.0] [basic-12.0] [basic-18.0] 
[basic-24.0] [basic-36.0] 
[basic-48.0] [basic-54.0] |
 
range | throughput | 
ofdm-throughput | default }
802.11n 2.4-GHz radio on Cisco 860 
and Cisco 880 ISR:
{[1.0] [11.0] [12.0] [18.0] [2.0] 
[24.0] [36.0] [48.0] [5.5] [54.0] [6.0] 
[9.0] [basic-1.0] [basic-11.0] 
[basic-12.0] [basic-18.0] 
[basic-24.0] [basic-36.0] 
[basic-48.0] [basic-5.5] [basic-54.0] 
[basic-6.0] [basic-9.0] [default] 
[m0-7] [m0.] [m1.] [m10.] [m11.] 
[m12.] [m13.] [m14.] [m15.] [m2.] 
[m3.] [m4.] [m5.] [m6.] [m7.] 
[m8-15] [m8.] [m9.] [ofdm] 
[only-ofdm] | range
 | throughput }
Sets each data rate to basic or enabled, or enters range to 
optimize range or throughput to optimize throughput. 
 (Optional) Enter 1.0, 2.0, 5.5, and 11.0 to set these data 
rates to enabled on the 802.11b, 2.4-GHz radio. 
Enter 1.0, 2.0, 5.5, 6.0, 9.0, 11.0, 12.0, 18.0, 24.0, 36.0, 
48.0, and 54.0 to set these data rates to enabled on the 
802.11g, 2.4-GHz radio. 
Enter 6.0, 9.0, 12.0, 18.0, 24.0, 36.0, 48.0, and 54.0 to set 
these data rates to enabled on the 5-GHz radio.
 (Optional) Enter basic-1.0, basic-2.0, basic-5.5, and 
basic-11.0 to set these data rates to basic on the 802.11b, 
2.4-GHz radio.
Enter basic-1.0, basic-2.0, basic-5.5, basic-6.0, basic-9.0, 
basic-11.0, basic-12.0, basic-18.0, basic-24.0, basic-36.0, 
basic-48.0, and basic-54.0 to set these data rates to basic 
on the 802.11g, 2.4-GHz radio. 
NoteThe client must support the basic rate that you select or 
it cannot associate to the wireless device. If you select 
12-Mbps or higher for the basic data rate on the 
802.11g radio, 802.11b client devices cannot associate 
to the wireless device 802.11g radio.
Enter basic-6.0, basic-9.0, basic-12.0, basic-18.0, 
basic-24.0, basic-36.0, basic-48.0, and basic-54.0 to set 
these data rates to basic on the 5-GHz radio.
 (Optional) Enter range or throughput or 
ofdm-throughput (no ERP protection) to automatically 
optimize radio range or throughput. When you enter 
range, the wireless device sets the lowest data rate to basic 
and the other rates to enabled. When you enter 
throughput, the wireless device sets all data rates to basic. 
(Optional) On the 802.11g radio, enter speed throughput 
ofdm to set all OFDM rates (6, 9, 12, 18, 24, 36, and 48) 
to basic (required) and set all the CCK rates (1, 2, 5.5, and 
11) to disabled. This setting disables 802.11b protection 
mechanisms and provides maximum throughput for 
802.11g clients. However, it prevents 802.11b clients from 
associating to the access point.
 (Optional) Enter default to set the data rates to factory 
default settings (not supported on 802.11b radios).
On the 802.11g radio, the default option sets rates 1, 2, 5.5, 
and 11 to basic, and rates 6, 9, 12, 18, 24, 36, 48, and 54 to 
enabled. These rate settings allow both 802.11b and 
802.11g client devices to associate to the wireless device 
802.11g radio.
Command Purpose 
						

							 
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Chapter 10      Configuring Radio Settings
Configuring MCS Rates
Use the no form of the speed command to remove one or more data rates from the configuration. This 
example shows how to remove data rates basic-2.0 and basic-5.5 from the configuration:
ap1200# configure terminalap1200(config)# interface dot11radio 0
ap1200(config-if)# no speed basic-2.0 basic-5.5
ap1200(config-if)# end
Configuring MCS Rates
Modulation Coding Scheme (MCS) is a specification of PHY parameters consisting of modulation order 
(BPSK, QPSK, 16-QAM, 64-QAM) and FEC code rate (1/2, 2/3, 3/4, 5/6). MCS is used in the wireless 
device 802.11n radios, which define 32 symmetrical settings (8 per spatial stream):
 MCS 0–7
 MCS 8–15
 MCS 16–23
 MCS 24–31
The wireless device supports MCS 0–15. High-throughput clients support at least MCS 0–7. 
MCS is an important setting because it provides for potentially greater throughput. High-throughput data 
rates are a function of MCS, bandwidth, and guard interval. The 802.11 a, b, and g radios use 20-MHz 
channel widths. 
Ta b l e 10-2 shows potential data rated based on MCS, guard interval, and channel width.
speed (continued)On the 5-GHz radio, the default option sets rates 6.0, 12.0, 
and 24.0 to basic, and rates 9.0, 18.0, 36.0, 48.0, and 54.0 
to enabled.
On the 802.11g/n 2.4-GHz radio, the default option sets 
rates 1.0, 2.0, 5.5, and 11.0 to enabled. 
On the 802.11g/n 5-GHz radio, the default option sets 
rates to 6.0, 12.0, and 24.0 to enabled.
The default MCS rate setting for both 802.11g/n radios is 
0–15.
Step 4endReturns to privileged EXEC mode.
Step 5copy running-config startup-config(Optional) Saves your entries in the configuration file.
Command Purpose
Ta b l e 10-2 Data Rates Based on MCS Settings, Guard Interval, and Channel Width  
MCS IndexGuard Interval = 800 nsGuard Interval = 400 ns
20-MHz Channel 
Width Data Rate 
(Mbps)40-MHz Channel 
Width Data Rate 
(Mbps)20-MHz Channel 
Width Data Rate 
(Mbps)40-MHz Channel 
Width Data Rate 
(Mbps)
06.513.57 2/915
1132714 4/930
219.540.521 2/345 
						

							 
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Chapter 10      Configuring Radio Settings
Configuring MCS Rates
MCS rates are configured using the speed command. The following example shows a speed setting for 
an 802.11g/n 2.4-GHz radio:
interface Dot11Radio0no ip address
no ip route-cache
!ssid 800test
!
speed basic-1.0 2.0 5.5 11.0 6.0 9.0 12.0 18.0 24.0 36.0 48.0 54.0 m0. m1. m2. m3. m4. 
m8. m9. m10. m11. m12. m13. m14. m15.
3265428 8/960
4398143 1/390
20-MHz Channel 
Width Data Rate 
(Mbps)40-MHz Channel 
Width Data Rate 
(Mbps)20-MHz Channel 
Width Data Rate 
(Mbps)40-MHz Channel 
Width Data Rate 
(Mbps)
55210957 5/9120
658.5121.565135
76513572 2/9152.5
8132714 4/930
9265428 8/960
10398143 1/390
115210857 7/9120
127816286 2/3180
13104216115 5/9240
14117243130270
15130270144 4/9300
The legacy rates are:
5-GHz: 6, 9, 12, 18, 24, 36, 48, and 54 Mbps
2.4-GHz: 1, 2, 5.5, 6, 9, 11, 12, 18, 24, 36, 48, and 54 Mbps
Table 10-2 Data Rates Based on MCS Settings, Guard Interval, and Channel Width  (continued)
MCS Index Guard Interval = 800 ns Guard Interval = 400 ns 
						

							 
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Chapter 10      Configuring Radio Settings
Configuring Radio Transmit Power
Configuring Radio Transmit Power
Radio transmit power is based on the type of radio or radios installed in your access point and the 
regulatory domain in which it operates. 
To set the transmit power on access point radios, follow these steps, beginning in privileged EXEC mode:
Use the no form of the power command to return the power setting to maximum, the default setting. 
Limiting the Power Level for Associated Client Devices
You can also limit the power level on client devices that associate to the wireless device. When a client 
device associates to the wireless device, the wireless device sends the maximum power level setting to 
the client.
NoteCisco AVVID documentation uses the term Dynamic Power Control (DPC) to refer to limiting the power 
level on associated client devices.
To specify a maximum allowed power setting on all client devices that associate to the wireless device, 
follow these steps, beginning in privileged EXEC mode:
CommandPurpose
Step 1configure terminalEnters global configuration mode.
Step 2interface dot11radio { 0 }Enters interface configuration mode for the radio interface.
The 2.4-GHz and the 802.11g/n 2.4-GHz radios are radio 0.
Step 3power local 
These options are available for the 
2.4-GHz 802.11n radio (in dBm):
{8 | 9| 11 | 14 | 15 | 17 | maximum }
Sets the transmit power for the radio so the power level is 
allowed in your regulatory domain. 
Step 4endReturns to privileged EXEC mode.
Step 5copy running-config startup-config(Optional) Saves your entries in the configuration file.
CommandPurpose
Step 1configure terminalEnters global configuration mode.
Step 2interface dot11radio { 0 }Enters interface configuration mode for the radio interface. The 
2.4-GHz and the 802.11g/n 2.4-GHz radios are radio 0. 
						

							 
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Chapter 10      Configuring Radio Settings
Configuring Radio Channel Settings
Use the no form of the client power command to disable the maximum power level for associated clients. 
NoteAironet extensions must be enabled to limit the power level on associated client devices. Aironet 
extensions are enabled by default.
Configuring Radio Channel Settings
The default channel setting for the wireless device radios is least congested; at startup, the wireless 
device scans for and selects the least-congested channel. For the most consistent performance after a site 
survey, however, we recommend that you assign a static channel setting for each access point. The 
channel settings on the wireless device correspond to the frequencies available in your regulatory 
domain. See the access point’s hardware installation guide for the frequencies allowed in your domain.
Each 2.4-GHz channel covers 22 MHz. The bands for channels 1, 6, and 11 do not overlap, so you can 
set up multiple access points in the same vicinity without causing interference. Both 802.11b and 
802.11g 2.4-GHz radios use the same channels and frequencies.
The 5-GHz radio operates on 8 channels from 5180 to 5320 MHz, up to 27 channels from 5170 to 5850 
MHz depending on regulatory domain. Each channel covers 20 MHz, and the bands for the channels 
overlap slightly. For best performance, use channels that are not adjacent (44 and 46, for example) for 
radios that are close to each other.
NoteToo many access points in the same vicinity can create radio congestion that can reduce throughput. A 
careful site survey can determine the best placement of access points for maximum radio coverage and 
throughput. 
802.11n Channel Widths
802.11n allows both 20-MHz and 40-Mhz channel widths consisting of 2 contiguous non-overlapping 
channels (for example, 2.4-GHz channels 1 and 6) 
Step 3power client
These options are available for 
802.11n 2.4-GHz clients (in dBm):
{local | 8 | 9 | 11 | 14 | 15 | 17 | 
maximum}
Sets the maximum power level allowed on client devices that 
associate to the wireless device.
Setting the power level to local sets the client power level to 
that of the access point.
Setting the power level to maximum sets the client power to 
the allowed maximum.
NoteThe settings allowed in your regulatory domain might 
differ from the settings listed here.
Step 4endReturns to privileged EXEC mode.
Step 5copy running-config startup-config(Optional) Saves your entries in the configuration file.
Command Purpose 
						

							 
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Chapter 10      Configuring Radio Settings
Enabling and Disabling World Mode
One of the 20-MHz channels is called the control channel. Legacy clients and 20-MHz high-throughput 
clients use the control channel. Only beacons can be sent on this channel. The second 20-MHz channel 
is called the extension channel. The 40-MHz stations may use this channel and the control channel 
simultaneously. 
A 40-MHz channel is specified as a channel and extension, such as 1,1. In this example, the control 
channel is channel 1 and the extension channel is above it. 
To set the wireless device channel width, follow these steps, beginning in privileged EXEC mode:
Enabling and Disabling World Mode
You can configure the wireless device to support 802.11d world mode, Cisco legacy world mode, or 
world mode roaming. When you enable world mode, the wireless device adds channel carrier set 
information to its beacon. Client devices with world mode enabled receive the carrier set information 
and adjust their settings automatically. For example, a client device used primarily in Japan could rely 
on world mode to adjust its channel and power settings automatically when it travels to Italy and joins a 
network there. Cisco client devices detect whether the wireless device is using 802.11d or Cisco legacy 
world mode and automatically use world mode that matches the mode used by the wireless device. 
CommandPurpose
Step 1configure terminalEnters global configuration mode.
Step 2interface dot11radio {0 }Enters interface configuration mode for the radio interface. The 
802.11g/n 2.4-GHz radio is radio 0.
Step 3channel 
{frequency | least-congested | 
width [20 | 40-above | 40-below] 
| dfs }
Sets the default channel for the wireless device radio.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 Cisco 800 series ISR wireless devices and consists 
of three available settings: 20, 40-above, and 40-below. 
 
- Choosing 20 sets the channel width to 20 MHz.  
- Choosing 40-above sets the channel width to 40 Mhz with the 
extension channel above the control channel. 
 
- Choosing 40-below sets the channel width to 40 MHz with the 
extension channel below the control channel.
NoteThe channel command is disabled for 5-GHz radios that 
comply with European Union regulations on dynamic 
frequency selection (DFS). See the 
“Enabling and 
Disabling World Mode” section on page 10-11 for more 
information.
Step 4endReturns to privileged EXEC mode.
Step 5copy running-config 
startup-config(Optional) Saves your entries in the configuration file. 
						

							 
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Chapter 10      Configuring Radio Settings
Disabling and Enabling Short Radio Preambles
You can also configure world mode to be always on. In this configuration, the access point essentially 
roams between countries, changing its settings as required. 
World mode is disabled by default.
To enable world mode, follow these steps, beginning in privileged EXEC mode:
Use the no form of the command to disable world mode. 
Disabling and Enabling Short Radio Preambles
The radio preamble (sometimes called a header) is a section of data at the head of a packet that contains 
information that the wireless device and client devices need when sending and receiving packets. You 
can set the radio preamble to long or short:
 Short—A short preamble improves throughput performance.
 Long—A long preamble ensures compatibility between the wireless device and all early models of 
Cisco Aironet Wireless LAN Adapters. If these client devices do not associate to the wireless 
devices, you should use short preambles.
You cannot configure short or long radio preambles on the 5-GHz radio. 
CommandPurpose
Step 1configure terminalEnters global configuration mode.
Step 2interface dot11radio { 0 }Enters interface configuration mode for the radio interface. 
Step 3world-mode  
dot11d country_code code  
{ both | indoor | outdoor } 
world-mode roaming
 
| legacy 
Enables world mode.
 Enter the dot11d option to enable 802.11d world mode. 
 –When you enter the dot11d option, you must enter a 
2-character ISO country code (for example, the ISO 
country code for the United States is US). You can find 
a list of ISO country codes at the ISO website. 
 –After the country code, you must enter indoor, 
outdoor, or both to indicate the placement of the 
wireless device.
 Enter the legacy option to enable Cisco legacy world 
mode.
 Enter the world-mode roaming to place the access point 
in a continuous world mode configuration.
NoteAironet extensions must be enabled for legacy world 
mode operation, but Aironet extensions are not 
required for 802.11d world mode. Aironet extensions 
are enabled by default.
Step 4endReturns to privileged EXEC mode.
Step 5copy running-config startup-config(Optional) Saves your entries in the configuration file.