Dynamic frequency selection – Rockwell Automation 1783-WAPxxx Stratix 5100 Wireless Access Point User Manual User Manual

Page 257

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Rockwell Automation Publication 1783-UM006A-EN-P - May 2014

257

Configuring Radio Settings

Chapter 7

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.

channel

{frequency | least-congested | width [20 | 40-above

| 40-below] | dfs}

4. Return to privileged EXEC mode.

end

5. (Optional) Save your entries in the configuration file.

copy running-config startup-config

Dynamic Frequency Selection

Access points with 5 GHz radios configured at the factory for use in the North
America, Europe, 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 don’t use DFS.

When a DFS-enabled 5 GHz radio operates on one of the 15 channels listed in

Table 84 on page 258

, the access point 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:

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.
If the channel selected is one of the channels in

Table 84 on page 258

,

scans

the new channel for radar signals for 60 seconds.

If there are no radar signals on the new channel, enables beacons and

accepts client associations.

TIP

The channel command is disabled for 5 GHz radios that comply with
European Union regulations on dynamic frequency selection (DFS).

See

Setting the 802.11n Guard Interval on page 262

for more

information.

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