Which of the following is correct for the roles of Portal authentication system?
A . The client is Any Office software.
B . The role of portal server is to receive the client authentication request, provide free portal service and authentication interface and interact with the access device to authenticate the client.
C . The role of RADIUS server is to redirect all HTTP requests from users in the authentication network segment to the Portal server.
D . The role of the admission control device is to complete the user’s authentication, authorization and accounting.