Here's the support troubleshooting. I thought the commands were very useful, and wanted to share:
#show clock
Note down the exact time of the issue happened ( The client disconnected and unable to connect to the network)
#show ap remote debug mgmt-frames client-mac <wireless device's mac address> ap-name <name of the AP client associated>
This will list the 802.11 management packets (Association Request, Association Response, Disassociation, and Deauth) for the specified wireless device.
#show log system all | include “<wireless device's mac address>
This command will show if the problem client is attempting to associate. Look for the problem client MAC address. It will also show to which AP the client MAC is attempting to associate. Note the BSSID.
#show ap association client-mac “<wireless device's mac address>
Use the AP BSSID taken from the output of the previous command and user MAC. This command can be used to verify if there are other users currently associated to this same AP thus helping to rule out infrastructure issues vs a single-client issue.
#show log errorlog all | include “<wireless device's mac address>”
This command can be used to determine if the RADIUS server is responding to client requests. Look for excessive RADIUS timeouts or instances of the Aruba switch taking a RADIUS server out of service for the server hold-down timer. (This indicates possible RADIUS server connectivity or performance issues and should be investigated as needed.)
#Show ap debug client-table ap-name <AP name where the wireless device is associated to>
In part of this CLI output it will display the wireless device’s Last_Rx_SNR, Tx_Rate, and Rx_Rate. If the SNR is 10 or lower, then the wireless device is far away from the AP. If the Tx_Rate or Rx_Rate are 1, 2, or 6 then the device may be experiencing interference or is far away from the AP
#show ip mobile trail <wirelessMACaddress>
This command displays the mobility history of a given client. This can be used to check for the frequency of roaming especially if the user has been stationary. If the client PC has been bouncing between APs due to driver issues, this can result in dropped WLAN connections.
#show user ip <ipaddr>
Investigate the following: Channel Frame Retry Rate – 10-20% is normal, 30 is intermediate and 40% is critical. This means 40% of the frames put to the air have been retransmitted. This is a symptom of heavy interference or low signal strength. Channel Noise – If channel noise is at a value of 65 or below then this is a critical interference level.
#show ap debug radio-stats ap-name <name-of-ap client connected> radio <0>
#show ap debug radio-stats ap-name <name-of-ap client connected> radio <1>
From the above commands we can determine the current Noise Floor and the RSSI/SNR.
From these steps you can determine possible causes for disconnection such as roaming problems, low signal strength, roaming outside of the WLAN coverage area and most importantly, the presence or not of major sources of interference.