Recently when working with Cisco wireless networks I have been really working to get Dynamic Channel Assignment tuned in and really understand much more about it. Some of the important things to make sure you are setting correctly include Anchor Time, DCA Interval (please don’t use the default, there is a blog post coming about that), etc.
One thing that became an option via CLI in the 7.3 code train was the ability to restart the RRM DCA process on the RF Group Leader. Why is this important I can hear some of you saying, or why would I want to do this? Here are a couple of examples of why.
If a controller enters or leaves an RF Group or if the RF Leader leaves and comes back online, as in a reboot, DCA will automatically enter startup mode to reconfigure DCA regardless fo the settings that have been changed on the controller, i.e. not using default of 10 minute intervals. But is there a need to do this manually? Yes.
As you add new APs into the network it is a good idea, and a Cisco recommendation, to initialize DCA startup mode. The reasoning behind this is as APs are added, DCA needs to rerun calculations and provide a more optimized channel plan based on the newly added APs and what the other APs are seeing over the air. When this command is run, it should be done from the RF Leader and will only affect the RF Leader.
The command should be run on both 2.4 GHz and 5 GHz radios:
2.4 GHz: config 802.11b channel global restart
5 GHz: config 802.11a Chanel global restart