Initial operation method for roaming terminal accessing network in mobile communication environment

A terminal attaching to a network in a mobile communication system, the terminal comprising:

• a transceiver configured to transmit and receive signals;
• and
• a controller connected to the transceiver and configured to control the transceiver to transmit an attach request message to a visited network (PLMN), the attach request message including roaming level information mapped to at least one service type that the terminal can receive and receive, if the visited network receives first service type information determined based on a service level agreement made for providing subscribers of the visited network and a home network (PLMN) with a roaming service and the roaming level information from the home network, an attach response message including second service type information corresponding to the first service type information from the visited network.

A visited network (PLMN) for controlling a network attachment in a mobile communication system, the visited network comprising:

• a transceiver configured to transmit and receive signals;
• and
• a controller connected to the transceiver and configured to control the transceiver to receive an attach request message including roaming level information mapped to at least one service type that a terminal can receive from the terminal, receive first service type information determined based on a service level agreement made for providing subscribers of the visited network and a home network (PLMN) with a roaming service and the roaming level information from the home network, and transmit an attach response message including second service type information corresponding to the first service type information to the terminal.

A home network (PLMN) for controlling a network attachment in a mobile communication system, the home network comprising:

• a transceiver configured to transmit and receive signals;
• and
• a controller connected to the transceiver and configured to control the transceiver to receive a service request message from a visited network (PLMN), the service request message including roaming level information mapped to at least one service type that a terminal can receive and a terminal identifier of the terminal, determine first service type information based on a service level agreement made for providing subscribers of the visited network and a home network (PLMN) with a roaming service and the roaming level information, and control the transceiver to transmit a service response message including the first service type information to the visited network.