Higher Ed Campus deployment, ~950 APs. Not using DFS channels. Getting a lot of channel changes in 5GHz. Started crunching data from SNMP traps (since there isn't an easy way that I've found to report on *all* channel changes):
wlsxTrapAPARMChangeReason.0: armEmptyCh(12) | 112 |
wlsxTrapAPARMChangeReason.0: armErrorThresh(10) | 242 |
wlsxTrapAPARMChangeReason.0: armInterference(8) | 123 |
Looking for a little clarification on what ARM determines as cause.
armInterference - If memory serves me - this is 802.11 co/adjacent channel interference; and is cited as a cause when interference index thresholds are crossed. I believe my ability to "tweak" this setting is in the ARM profile in the "Free Channel Index", which is the delta between interference index between channels before it changes channels. Can someone confirm I've got this right?
armErrorThresh - My understanding here is We've met the configurable "Error Rate Threshold" (default 50%) for a configurable interval (default 30 seconds). So this is the heavy hitter in my environment - meaning relatively - lots of PHY errors over 30 seconds at a time. Is it fair to assume that these errors would be caused by both wifi AND non-wifi interference sources? I know there is another configurable channel change cause in armNoiseThreshold which I am not seeing.
armEmptyCh- I get why this happens.
Thanks for helping clear some of this up. I know I've got some non-wifi interferers out there, and student have rouge access points... I'm trying to narrow in on which is having a more signifigant impact on things.
Kevin