The present document specifies the non-access stratum (NAS) procedures in the 5G system (5GS) used by the protocols for:
mobility management between the UE and the AMF for both 3GPP access and non-3GPP access; and
session management between the UE and the 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 UE is using the NG radio access network (NG-RAN) and/or non-3GPP access network. 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 session contexts. Together with the bearer control provided by the access stratum, this protocol is used for the control of user plane bearers.
For both NAS protocols the present document specifies procedures for the support of inter-system mobility between the NG-RAN and the E-UTRAN connected to the EPC and between the NG-RAN and the non-3GPP access network.