The AP will attempt to resolve the DNS name CISCO-CAPWAP-CONTROLLER.localdomain. When the AP is able to resolve this name to one or more IP addresses, the AP sends a unicast CAPWAP Discovery Message to the resolved IP address(es). Each WLC that receives the CAPWAP Discovery Request Message replies with a unicast CAPWAP Discovery Response to the AP.

A 401 error response indicates that the client tried to operate on a protected resource without
providing the proper authorization. It may have provided the wrong credentials or none at all.
Note: answer 'HTTP Status Code 200' 4xx code indicates a "client error" while a 5xx code indicates
a "server error".

Type of service, when we talk about PACKET, means layer 3