Section: 8.2.2.3 UE – SMF
Content: The NAS-SM supports the handling of Session Management between the UE and the SMF. The SM signalling message is handled, i.e. created and processed, in the NAS-SM layer of UE and the SMF. The content of the SM signalling message is not interpreted by the AMF. The NAS-MM layer handles the SM signalling is as follows: - For transmission of SM signalling: - The NAS-MM layer creates a NAS-MM message, including security header, indicating NAS transport of SM signalling, additional information for the receiving NAS-MM to derive how and where to forward the SM signalling message. - For reception of SM signalling: - The receiving NAS-MM processes the NAS-MM part of the message, i.e. performs integrity check, and interprets the additional information to derive how and where to derive the SM signalling message. The SM message part shall include the PDU Session ID. Legend: - NAS-SM: The NAS protocol for SM functionality supports user plane PDU Session Establishment, modification and release. It is transferred via the AMF, and transparent to the AMF. 5G NAS protocol is defined in TS 24.501[ Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3 ]  [47] Figure 8.2.2.3-1: Control Plane protocol stack between the UE and the SMF