Tracking area selection method, device, and system

A tracking area selection method, wherein the method comprising:

• obtaining, by a mobility management network element, from identification information of a network slice requested by a terminal, identification information of a network slice on which authentication and authorization are to be performed;
• initiating, by the mobility management network element, an authentication and authorization procedure for the network slice on which authentication and authorization are to be performed;
• determining, by the mobility management network element, based on a result of the authentication and authorization procedure for the network slice, identification information of a network slice that the terminal is allowed to access;
• obtaining, by the mobility management network element, second information based on first information and the identification information of the network slice that the terminal is allowed to access,
• wherein the first information comprises identification information of a network slice that the terminal is rejected to access or the identification information of the network slice requested by the terminal,
• the network slice that the terminal is rejected to access is a network slice that is not supported by a tracking area in which an access network device is located and that is in the network slice requested by the terminal, and
• the second information comprises identification information of a target network slice and radio resource information corresponding to the target network slice;
• and
• sending, by the mobility management network element, the second information to the access network device.