With release 4.1.185 you can now modifiy the DCA behavior to lessen the impact of a rolling Channel change.
first limit the available channels to 1,6,11
second through the command line you can determine when DCA starts and how ofter it runs. the folling is from the release document.
New DCA CLI Commands
These new CLI commands have been added to configure the dynamic channel allocation (DCA)
algorithm:
• To control the DCA sensitivity with respect to changes in the environment, enter this command:
config advanced {802.11a | 802.11b} channel dca sensitivity {low | medium | high}
The DCA algorithm determines whether to make a channel change based on how much better a new
channel would be for the radio with the worst DCA metric in the radio band. The DCA metric is
comprised of noise, interference, channel load, and overlapping neighbors (other radios on the same
channel). Previously, a channel change would occur if another channel was 5 dBm better than the
current channel of the radio with the worst DCA metric. This new command allows you to control
how sensitive the DCA algorithm is to environmental changes, such as signal, load, noise, and
interference, when determining whether to change channels. Table 2 shows the three available DCA
sensitivity levels.
For example, if the radio with the worst DCA metric in the 2.4-GHz band has a metric of -60 dBm
on its current channel and the DCA algorithm finds that the metric would be -80 dBm on another
channel (which is an improvement of 20 dBm), the DCA algorithm would change the channel if the
DCA sensitivity is set to high or medium. It would not change the channel if the sensitivity is set to
low.
• To define the time when DCA starts, enter this command:
config advanced {802.11a | 802.11b} channel dca anchor-time hour
where hour is an hour in the day from 0 to 23 (12:00 a.m. to 11:00 p.m.).
• 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.
Note 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.
Table 2 DCA Sensitivity Levels
DCA Sensitivity
Level Description
2.4-GHz DCA Sensitivity
Threshold (dB)
5-GHz DCA Sensitivity
Threshold (dB)
High High sensitivity to
environmental changes
5 5
Medium (default) Moderate sensitivity to
environmental changes
15 20
Low Low sensitivity to
environmental changes
30 35
Apparently RRM will still run on its own schedule.
There is light
Bill
