Patent ID: 8811985

Claim:
A network registration method in which a mobile station performs a registration procedure to a communication network including a switching apparatus and a subscriber information management server, the network registration method comprising the steps of: (A) transmitting, from the mobile station to the communication network, an attach request for starting the registration procedure; (B) notifying, at the subscriber information management server, the switching apparatus of external network identification information which is identification information of an external network associated with the mobile station having transmitted the attach request, wherein the attach request does not include any information for identifying an external network; (C) setting up, at the switching apparatus, a bearer between a gateway apparatus connected to the external network and the mobile station on the basis of a gateway apparatus identity corresponding to a default APN in the notified external network identification information; (D) allocating, at the gateway apparatus, address information with which the mobile station connects to the external network, to the mobile station; and (E) notifying, at the switching apparatus, the external network identification information and the address information, to the mobile station, wherein in the step (E), the switching apparatus notifies the mobile station of the external network identification information and the address information through an attach response to the attach request.