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Cisco IOS Software Configuration Guide for Cisco Aironet Access Points
OL-30644-01
Chapter6 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:
ap# configure terminal
ap(config)# interface dot11radio 0
ap(config-if)# no speed basic-2.0 basic-5.5
ap(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 802.11n
radios, which define 32 symmetrical settings (8 per spatial stream):
MCS 0–7
MCS 8–15
MCS 16–23
MCS 24–31
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. 802.11 a, b, and g radios use 20-MHz
channel widths.
Tip For the latest information on the Data Rates based on MCS Index, Guard Interval (GI), and channel
width, for you access point, refer to its Cisco Aironet (AP series name) Series Access Points Data Sheet
on the Cisco.com site.
MCS rates are configured using the speed command. The following example shows a speed setting for
an 802.11n 5-GHz radio:
interface Dot11Radio0
no ip address
no ip route-cache
!
ssid 1250test
!
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.
speed (continued) On the 802.11n 2.4-GHz radio, the default option sets
rates 1.0, 2.0, 5.5, and 11.0 to enabled.
On the 802.11n 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 802.11n radios is
0–15.
Step4 end Return to privileged EXEC mode.
Step5 copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose