Cisco Cisco 2106 Wireless LAN Controller

Previously, the DCA algorithm ran every 10 minutes. To now define how often DCA runs, enter this 
command:

config advanced {802.11a | 802.11b} channel dca interval value

where value is 0, 1, 2, 3, 4, 6, 8, 12, or 24. 0 equals 10 minutes and is the default value. The rest of 
the values represent hours. So if you specify a value of 8, DCA would run every 8 hours.

For example, if you specify an anchor time of 0 and a DCA interval of 12, the DCA algorithm would 
run at 12:00 a.m. and 12:00 p.m. every day.

You can view the configured DCA sensitivity, anchor-time, and interval on the 802.11a (or 
802.11b/g) Global Parameters > Auto RF page on the controller GUI. However, you can 
configure these values only from the controller CLI.

When the controller reboots, the DCA algorithm runs every 10 minutes for the first 100 minutes, 
regardless of the anchor-time and interval parameter configuration. This initial startup phase 
(which is identified in the controller CLI) enables the DCA algorithm to converge to a reliable 
channel before the scheduled operation occurs. After the first 100 minutes, the DCA algorithm 
runs at only the scheduled times.

To enable debugging for the DCA algorithm’s channel change, enter this command:

This command provides the previous channel, the 802.11 interference energy (both the previous and 
current values in dBm), the noise energy (both the previous and current values in dBm), and the 
reason why the channel was changed. Possible reasons include:

0 = Other (could occur as a result of a manual channel change)

1 = Signal (could occur if the RSSI at which the neighbor access points are seen has changed 
recently, possibly due to a channel change)

2 = Noise

4 = 802.11 interference

6 = Noise and 802.11 interference

You can see the reason why the DCA algorithm changed channels by clicking Monitor and 
then View All under Most Recent Traps on the controller GUI. The trap provides the MAC 
address of the radio that changed channels, the previous channel and the new channel, the 
reason why the change occurred, the energy before and after the change, the noise before 
and after the change, and the interference before and after the change.