Method for determining SSC mode and apparatus

An apparatus, comprising:

• a memory configured to store instructions;
• and
• one or more processors coupled to the memory and configured to execute the instructions to cause the apparatus to:
• determine a requested service and session continuity (SSC) mode;
• send a first request message to a first core network element, wherein the first request message is a request for establishing a first protocol data unit (PDU) session with a first session type by using the requested SSC mode, and wherein the first session type is any one of an Internet Protocol (IP) session type, an Ethernet session type, or an unstructured session type;
• receive, in response to sending the first request message, a first response message from the first core network element, wherein the first response message indicates that the request for establishing the first PDU session is rejected, wherein the first response message comprises a cause code and an allowed SSC mode that is allowed for the first session type, wherein the allowed SSC mode is different than the requested SSC mode, and wherein the cause code indicates that the requested SSC mode is not supported;
• and
• reattempt, in response to the cause code, to establish the first PDU session with the first session type by using the allowed SSC mode that is allowed for the first session type.

A computer program product comprising instructions stored on a non-transitory computer-readable medium that, when executed by one or more processors of an apparatus, cause the apparatus to:

• determine a requested service and session continuity (SSC) mode;
• send a first request message to a first core network element, wherein the first request message is a request for establishing a first protocol data unit (PDU) session with a first session type by using the requested SSC mode, and wherein the first session type is any one of an Internet Protocol (IP) session type, an Ethernet session type, or an unstructured session type;
• receive, in response to sending the first request message, a first response message from the first core network element, wherein the first response message indicates that the request for establishing the first PDU session is rejected, wherein the first response message comprises a cause code and an allowed SSC mode that is allowed for the first session type, wherein the allowed SSC mode is different than the requested SSC mode, and wherein the cause code indicates that the requested SSC mode is not supported;
• and
• reattempt, in response to the cause code, to establish the first PDU session with the first session type by using the allowed SSC mode that is allowed for the first session type.