Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3
The present document specifies the non-access stratum (NAS) procedures in the 5G system (5GS) used by the protocols for:
- mobility management between the user equipment (UE) and the access and mobility management function (AMF) for both 3GPP access and non-3GPP access; and
- session management between the user equipment (UE) and the session management function (SMF) for both 3GPP access and non-3GPP access.
The 5GS mobility management (5GMM) protocol defined in the present document provides procedures for the control of mobility when the user equipment (UE) is using the NG radio access network (NG-RAN), non-3GPP access network, or both. The 5GMM protocol also provides control of security for the NAS protocols.
The 5GS session management (5GSM) protocol defined in the present document provides procedures for the handling of 5GS PDU sessions. Together with the bearer control provided by the access stratum, this protocol is used for the control of user-plane resources.
For both NAS protocols the present document specifies procedures for the support of inter-system mobility between the NG-RAN and the evolved universal terrestrial radio access (E-UTRAN), between the NG-RAN and the non-3GPP access network connected to the EPC, and between the non-3GPP access network connected to the 5G core network (5GCN) and the E-UTRAN.
For both NAS protocols the present document specifies procedures for the support of mobility between the NG-RAN and the non-3GPP access network connected to the 5GCN.
In addition, the present document specifies the procedures in the 5GS for UE policy delivery service between the UE and the policy control function (PCF) for both 3GPP access and non-3GPP access.
The present document is applicable to the UE, the access and mobility management function (AMF), the session management function (SMF), and the PCF in the 5GS.
The clauses and subclauses in the present document are common for both 3GPP access and non-3GPP access unless it is explicitly stated that they apply to 3GPP access only or non-3GPP access only.