Main functions of the protocols that are part of the NAS are:
- the support of mobility of the user equipment (UE).
- the support of session management procedures to establish and maintain IP connectivity between the UE and a packet data network gateway (PDN GW).
For the support of the above functions, the following procedures are supplied within 3GPP 24301 specification:
- elementary procedures for EPS mobility management
- elementary procedures for EPS session management.