An administrator has multiple AAA servers, some Microsoft RADIUS and some ClearPass. When 802.1X users authenticate, the administrator wants to ensure that the authentication requests are handled by…

An administrator has multiple AAA servers, some Microsoft RADIUS and some ClearPass. When 802.1X users authenticate, the administrator wants to ensure that the authentication requests are handled by the appropriate AAA server. Users enter their username in this format:

username@domain_name. What must the administrator implement to ensure the correct AAA server processes the authentication request?