Session Management Function Functional Description

Below are the Functionalities supported by Session Management Function (SMF), a single Instance of SMF may implement some are all Functionalities.

Session Management Functions like Session Establishment, modify and release, and tunnel maintain between UPF and AN node.

UE IP address allocation & management optionally Authorization.

ARP proxying or IPv6 Neighbour Solicitation Proxying functionality for the Ethernet PDUs. SMF responds to the ARP and / or the IPv6 Neighbour Solicitation Request by providing the MAC address corresponding to the IP address sent in the request.

Selection and control of UP function, including controlling the UPF to proxy ARP or IPv6 Neighbour Discovery, or to forward all ARP/IPv6 Neighbour Solicitation traffic to the SMF, for Ethernet PDU Sessions.

Configures traffic steering at UPF to route traffic to proper destination.

Termination of interfaces towards Policy control functions.

Lawful intercept for SM events and interface to LI System.

Charging data collection and support of charging interfaces.

Control and coordination of charging data collection at UPF.

Termination of SM parts of NAS messages.

Downlink Data Notification.

Initiator of AN specific SM information, sent via AMF over N2 to AN.

Determine SSC mode of a session.

Roaming functionality

Handle local enforcement to apply QoS SLAs (VPLMN)

Charging data collection and charging interface (VPLMN)

Lawful intercept (in VPLMN for SM events and interface to LI System).

Support for interaction with external DN for transport of signalling for PDU Session authorization/authentication by external DN.

In addition to the functionalities of the SMF described above, the SMF may include policy related functionalities.