Question: What is the purpose of the UDM invoking Nausf_UPUProtection service operation message, and what does it include?
Option 1: To request UE Parameters Update Data from the AUSF, including the parameters protected by secured packet.
Option 2: To send UE Parameters Update Data to the AMF for further processing.
Option 3: To authenticate the UE using primary authentication procedure.
Option 4: To update the UDM's stored parameters with new values.
Explanation: The UDM invokes Nausf_UPUProtection service operation message to get UPU-MAC-IAUSF and CounterUPU from the AUSF. This message includes the UE Parameters Update Data (UPU Data), which contains parameters protected by secured packet, if any, as well as any UE parameters for which the final consumer is the ME. The purpose of this step is to allow the UDM to verify that the UE has not been tampered with and to ensure the integrity of the UE Parameters Update Data.