Embodiments of the present invention provide a communication method, an access network device, a core network device, and user equipment. One example method includes: sending, by a core network device, a handover request to an access network device, wherein the handover request comprises first information, and the first information comprises an identifier of allowed network slice selection assistance information (NSSAI); and sending, by the access network device, a handover request acknowledgement to the core network device.