Question: What action can a User Equipment (UE) take if it receives a partially allowed Network Slice Selection Assistance Information (NSSAI) containing a Single-NSSAI (S-NSSAI) and the current Tracking Area Identity (TAI) is not in the list of TAs for which the S-NSSAI is allowed?
Option 1: The UE can initiate the UE-requested PDU session establishment procedure for the S-NSSAI.
Option 2: The UE shall not initiate the UE-requested PDU session establishment procedure for the S-NSSAI.
Option 3: The UE can send control plane user data to the Session Management Function (SMF).
Option 4: The UE can re-establish the user plane resources for an existing PDU session.
Explanation: According to the 3GPP specification, if the current TAI is not in the list of TAs for which the S-NSSAI is allowed, the UE shall not initiate the UE-requested PDU session establishment procedure for the S-NSSAI. This ensures that the UE only attempts to establish a PDU session when it is authorized to do so based on its current location and network slice configuration.