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Cisco IOS Software Configuration Guide for Cisco Aironet Access Points
OL-11350-01
Chapter6 Configuring Radio Settings
Disabling and Enabling Short Radio Preambles
network there. Cisco client devices running firmware version 5.30.17 or later 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.
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.
Beginning in privileged EXEC mode, follow these steps to enable world 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. Cisco Aironet Wireless LAN Client
Adapters support short preambles. Early models of Cisco Aironet's Wireless LAN Adapter (PC4800
and PC4800A) require long preambles.
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 interface dot11radio { 0slot/port |
1}
Enter interface configuration mode for the radio interface.
Step3 world-mode
dot11d country_code code
{ both | indoor | outdoor }
world-mode roaming
| legacy
Enable world mode.
•Enter the dot11d option to enable 802.11d world mode.
–
When you enter the dot11d option, you must enter a
two-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.
Note Aironet 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.
Step4 end Return to privileged EXEC mode.
Step5 copy running-config startup-config (Optional) Save your entries in the configuration file.