For many years Cisco access-points have been equipped with the Congio RF inspector chip, better known by the more marketing friendly word CleanAir.
So what is CleanAir. Is it a chip that will suck in all the polluted air in a 25 meter radius of the access-point and filter it so the air will be cleaner? No! The CleanAir chipset doesn’t exactly clean anything. It simply reports a quality index of RF spectrum that it covers.
That said the CleanAir chip can support the Radio Reset Management engine in the Cisco Wireless LAN Controllers in selecting a channel. The CleanAir function can detect non-Wi-Fi interfering devices and if the interference is great enough it will try to change channel. This is called Event Driven Radio Ressource Management (EDRRM).
EDRRM is configured under the RRM-DCA part of each radio’s global options. It is a simple check box to enable it and then a drop down menu to select the sensitivity threshold. Low will be 35, Medium 50 and High 60.
“But does it work?” a customer asked me. The best way to prove that it works would be a demo.
On Ebay I found a 30USD Wireless camera with out receiver. It is not a super powerful transmitter, but it will transmit at close to a 100% duty cycles.
If I kept it within a few feet of the demo access-point it should do the trick.
My setup would be a simple Cisco 3602i AP running on a small Cisco WLC and using Metageek Chanalyzer with WiSpy to monitor the RF environment.
Today I run macOS and are cut off from using most of Metageek’s fantastic tools, but fortunately I saved the Chanalyzer .WSX file. Today I decided to make a video from the playback.
To run over the video my SSID “RostgaardOlsen” is running on the access-point AP3602 on Channel 11. At around 17 seconds into the video I fire up the wireless camera that will generate interference. This is centred just above channel 12. One minute into the video the EDRRM kicks in and moves the access-point to channel 1, away from the inference.
Disclaimer: As nothing is ever just black or white you should enable EDRRM with care. In some scenarios it is great that the network is self-healing. But on the other side what if the access-point moved to channel 1 and this channel already had a high load. This could be the straw that breaks the camel’s back. So instead of having one area with problems you might have two.