Dynamic Frequency Selection - Cisco OL-8335-02 Configuration Manual

Dynamic Frequency Selection

Dynamic Frequency Selection
The Cisco Wireless LAN solution complies with regulations in Europe and Singapore that require radio
devices to use Dynamic Frequency Selection (DFS) to detect radar signals and avoid interfering with
them.
When a lightweight access point with a 5-GHz radio operates on one of the 15 channels listed in
Table
operating frequency.
When you manually select a channel for DFS-enabled 5-GHz radios, the controller checks for radar
activity on the channel for 60 seconds. If there is no radar activity, the access point operates on the
channel you selected. If there is radar activity on the channel you selected the controller automatically
selects a different channel, and after 30 minutes, the access point re-tries the channel you selected.
The Rogue Location Detection Protocol (RLDP) is not supported on the channels listed in
Note
The maximum legal transmit power is greater for some 5-GHz channels than for others. When it
Note
randomly selects a 5-GHz channel on which power is restricted, the controller automatically reduces
transmit power to comply with power limits for that channel.
Table 7-1
52 (5260 MHz)
56 (5280 MHz)
60 (5300 MHz)
64 (5320 MHz)
100 (5500 MHz)
Using DFS, the controller monitors operating frequencies for radar signals. If it detects radar signals on
a channel, the controller takes these steps:
•
•
•
•
7-8
7-1, the controller to which the access point is associated automatically uses DFS to set the
5-GHz Channels on Which DFS is Automatically Enabled
104 (5520 MHz)
108 (5540 MHz)
112 (5560 MHz)
116 (5580 MHz)
120 (5600 MHz)
It changes the access point channel to a channel that has not shown radar activity. The controller
selects the channel at random.
If the channel selected is one of the channels in
for 60 seconds. If there are no radar signals on the new channel, the controller accepts client
associations.
It records the channel that showed radar activity as a radar channel and prevents activity on that
channel for 30 minutes.
It generates a trap to alert the network manager.
Chapter 7 Controlling Lightweight Access Points
124 (5620 MHz)
128 (5640 MHz)
132 (5660 MHz)
136 (5680 MHz)
140 (5700 MHz)
Table 7-1, it scans the new channel for radar signals
Cisco Wireless LAN Controller Configuration Guide
Table 7-1.
OL-8335-02