I suggest you perform a link test to see if there are any issues with the link. A link test uses a ping from parent-to-child or child-to-parent to test the link quality. The RF parameters of the ping reply packets received by the access point are polled by the controller to find the link quality. Because radio link quality can differ depending on the direction (client to access point versus access point to client), it is critical to have Cisco Compatible Extensions linktest support so that link quality is tested in both directions. It polls the controller every so many seconds until the row status indicates success or failure. During the link test, the table is populated. If the link test fails, the controller reverts to a ping test.