Method and apparatus for supporting roaming service traffic routing in mobile communication system

A method performed by a visited-network repository function (v-NRF) in a communication system, the method comprising:

• receiving, from an access and mobility management function (AMF), a first network function (NF) discovery request message for session management function (SMF) selection including an identifier (ID) of a target public land mobile network (PLMN) for traffic routing;
• transmitting, to a home-network repository function (h-NRF), a second NF discovery request message including the ID of the target PLMN;
• receiving, from h-NRF, a first NF discovery request response message including information on an SMF for traffic routing in the target PLMN;
• and
• transmitting, to the AMF, a second NF discovery request response message including information on the SMF for traffic routing in the target PLMN.

A method performed by a home-network repository function (h-NRF) in a communication system, the method comprising:

• receiving, from a visited-network repository function (v-NRF), a first network function (NF) discovery request message including an identifier (ID) of a target public land mobile network (PLMN) for traffic routing;
• identifying an SMF for traffic routing in the target PLMN based on the ID of the target PLMN;
• and
• transmitting, to the v-NRF, a first NF discovery request response message including information on the SMF for traffic routing in the target PLMN.

An access and mobility management function (AMF) in a communication system, the AMF comprising:

• a transceiver;
• and
• a controller coupled with the transceiver and configured to:
• receive, from a user equipment (UE), a registration request message,
• receive, from a unified data management (UDM), subscription information for session management function (SMF) selection including an identifier (ID) of a target public land mobile network (PLMN) for traffic routing, and
• select an SMF for traffic routing in the target PLMN based on the ID of the target PLMN included in the subscription information.

A visited-network repository function (v-NRF) in a communication system, the v-NRF comprising:

• a transceiver;
• and
• a controller coupled with the transceiver and configured to:
• receive, from an access and mobility management function (AMF), a first network function (NF) discovery request message for session management function (SMF) selection including an identifier (ID) of a target public land mobile network (PLMN) for traffic routing,
• transmit, to a home-network repository function (h-NRF), a second NF discovery request message including the ID of the target PLMN,
• receive, from h-NRF, a first NF discovery request response message including information on an SMF for traffic routing in the target PLMN, and
• transmit, to the AMF, a second NF discovery request response message including information on the SMF for traffic routing in the target PLMN.

A home-network repository function (h-NRF) in a communication system, the h-NRF comprising:

• a transceiver;
• and
• a controller coupled with the transceiver and configured to:
• receive, from a visited-network repository function (v-NRF), a first network function (NF) discovery request message including an identifier (ID) of a target public land mobile network (PLMN) for traffic routing,
• identify an SMF for traffic routing in the target PLMN based on the ID of the target PLMN, and
• transmit, to the v-NRF, a first NF discovery request response message including information on the SMF for traffic routing in the target PLMN.