This might be caused by interference. Check the cables and antennas to make sure they are in good working condition. Check to see if there is anything obstructing the antennas. You could try changing the channel on the root bridge to anything besides auto detect. The default channel it listens to is channel 6. The only way to actually see if there is radio interference is to do a spectrum analysis.
Transferring Crash file from standby: Login to the Active WLC in HA.
From CLI: (Cisco Controller) >transfer upload datatype crash (Cisco
Controller) >transfer upload filename (Cisco
Controller) >transfer upload mode tftp (Cisco Controller) >transfer
This is the start of a display filter cross reference between Wireshark
and OmniPeek. The 1st installment is a table of advanced filters. More
filters will be added as time allows. It is a living doc, so check back
for changes every so often Please feel f...