Network-initiated PDU session connection update method between terminal and network

A method performed by a terminal in a communication system, the method comprising:

• transmitting, to an access and mobility management function (AMF) entity of a visited public land mobile network (VPLMN), a registration request message including information on at least one requested network slice selection assistance information (NSSAI) associated with a home public land mobile network (HPLMN);
• and
• receiving, from the AMF entity, a registration accept message as a response to the registration request message, the registration accept message including information on at least one allowed NSSAI associated with the VPLMN based on the at least one requested NSSAI associated with the HPLMN,
• wherein the at least one allowed NSSAI associated with the VPLMN is determined by the AMF entity based on information for slice selection.

An access and mobility management function (AMF) entity of a visited public land mobile network (VPLMN) in a communication system, the AMF entity comprising:

• a transceiver;
• and
• a controller configured to:
• receive, from a terminal, a registration request message including information on at least one requested network slice selection assistance information (NSSAI) associated with a home public land mobile network (HPLMN),
• transmit, to a user data management (UDM) entity, a request message for requesting subscription data based on the registration request message,
• receive, from the UDM entity, a response message as a response to the request message, the response message including information for slice selection,
• determine at least one allowed NSSAI associated with the VPLMN based on the information for the slice selection, and
• transmit, to the terminal, a registration accept message as a response to the registration request message, the registration accept message including information on the at least one allowed NSSAI associated with the VPLMN.

A terminal in a communication system, the terminal comprising:

• a transceiver;
• and
• a controller configured to:
• transmit, to an access and mobility management function (AMF) entity of a visited public land mobile network (VPLMN), a registration request message including information on at least one requested network slice selection assistance information (NSSAI) associated with a home public land mobile network (HPLMN), and
• receive, from the AMF entity, a registration accept message as a response to the registration request message, the registration accept message including information on at least one allowed NSSAI associated with the VPLMN based on the at least one requested NSSAI associated with the HPLMN,
• wherein the at least one allowed NSSAI associated with the VPLMN is determined by the AMF entity based on information for slice selection.