Handling messages related to an application function session bound to a protocol data unit session

A method performed by a first network function (NF), the method comprising:

• receiving from a second NF a service request to create an Application Function (AF) session context,
• after receiving the service request, determining whether a time sensitive communication and time synchronization function (TSCTSF) is a NF type required for the service request;
• determining whether to accept or reject the service request when determining that the TSCTSF is the NF type required for the service request;
• and
• transmitting towards the second NF a first response to reject the service request and the first response indicates that a signalling path for the service request is invalid when determining rejecting the service request and the TSCTSF is the NF type required for the service request.

A method performed by a second network function (NF), the method comprising:

• transmitting towards a first NF a service request to create an AF session context;
• and
• after transmitting the service request, receiving from the first NF a first response indicating that the service request is rejected, wherein
• the first response indicates that a time sensitive communication and time synchronization function (TSCTSF) is required for the service request.

A first network function (NF), the first NF comprising:

• memory;
• and
• processing circuitry, wherein the first NF is configured to perform a method comprising:
• receiving from a second NF a service request to create an Application Function (AF) session context,
• after receiving the service request, determining whether a time sensitive communication and time synchronization function (TSCTSF) is a NF type required for the service request;
• determining whether to accept or reject the service request when determining that the TSCTSF is the NF type required for the service request;
• and
• transmitting towards the second NF a first response to reject the service request and the first response indicates that a signalling path for the service request is invalid when determining rejecting the service request and the TSCTSF is the NF type required for the service request.

A second network function (NF), the second NF comprising:

• memory;
• and
• processing circuitry, wherein the first NF is configured to perform a method comprising:
• transmitting towards a first NF a service request to create an AF session context;
• and
• after transmitting the service request, receiving from the first NF a first response indicating that the service request is rejected, wherein
• the first response indicates that a time sensitive communication and time synchronization function (TSCTSF) is required for the service request.