24.3013GPPNon-Access-Stratum (NAS) protocol for Evolved Packet System (EPS)Release 18Stage 3TS
The present document specifies the procedures used by the protocols for mobility management and session management between User Equipment (UE) and Mobility Management Entity (MME) in the Evolved Packet System (EPS). These protocols belong to the non-access stratum (NAS).
The EPS Mobility Management (EMM) protocol defined in the present document provides procedures for the control of mobility when the User Equipment (UE) is using the Evolved UMTS Terrestrial Radio Access Network (E-UTRAN). The EMM protocol also provides control of security for the NAS protocols.
The EPS Session Management (ESM) protocol defined in the present document provides procedures for the handling of EPS bearer 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 E‑UTRAN and other 3GPP or non-3GPP access networks:
– For inter-system mobility between E-UTRAN and GERAN, UTRAN or NG-RAN, this includes rules for a mapping between parameters and procedures used by the NAS protocols defined in the present document and the NAS protocols specified in 3GPP TS 24.008  for GERAN and UTRAN, and 3GPP TS 24.501  for NG-RAN.
– For inter-system mobility between E-UTRAN and generic non-3GPP access networks, this includes specific NAS procedures to maintain IP connectivity to the PDN Gateway and to provide parameters needed by the UE when using mobility management based on Dual-Stack Mobile IPv6 (see 3GPP TS 24.303 ) or MIPv4 (see 3GPP TS 24.304 ).
The present document is applicable to the UE and to the Mobility Management Entity (MME) in the EPS.
The present document is also applicable to the relay node in the EPS (see 3GPP TS 23.401 ).
The present document also specifies NAS signalling enhancement for the support of efficient transport of IP, non-IP, Ethernet and SMS data of CIoT capable devices.