A VXLAN Tunnel End Point (VTEP) sends an authentication request packet to an authentication server upon receiving a user access request from a user terminal, so as to cause the authentication server to perform an authentication for a user. The VTEP receives authorization information of the user for which the authentication is passed. The authorization information is sent by the authentication server, and includes a Virtual Switch Instance (VSI) identifier or a Virtual eXtensible LAN (VXLAN) identifier. The VTEP creates an Attachment Circuit (AC) interface on a user port connecting the user terminal of the VTEP. The VTEP associates the AC interface with the authorization information.