User plane functions contain the user plane path of PDU sessions.

UPF traffic detection

  • Traffic detection
  • Traffic reporting
  • QoS enforcement
  • Traffic routing

UE IP address management

The UE sets the requested PDU session type during the PDU session establishment procedure based on its IP stack capabilities. A UE shall support IPV4,IPV6 or IPv4v6. When the IP version abilities of the UE is unknown in the UE, the UE shall request for PDU session type IPv4v6.

The 5GC and UE support mechanisms

During PDU session initialization procedure, the SMF sends the IP address to the UE via SM NAS signalling. The IPv4 address allocation and IPv4 parameter configuration via DHCPv4 can also be used once a PDU session is established. When the 5GC network assists DHCPv4 and permits that, it does not give the IPv4 address for the UE as part of PDU session initialization procedure.

The IP address is liberated by the SMF upon liberate of the PDU session.


Each subscriber in the 5G system shall be allocated one 5G subscription permanent identifier for use within the 3GPP system .

Subscription permanent identifier

A globally unique 5G subscription permanent identifier ( SUPI) shall be allocated to each subscriber in the 5G system and provisioned in the UDM/UDR.

The SUPI may contain : an IMSI , a network specific identifier used for private networks.

Permanent equipment equipment

A PEI is defined for the 3GPP UE accessing the 5G system. If the UE assisted at least one 3GPP access technology, the UE must be allocated a PEI in the IMEI format. /


The AMF shall allocate a 5G-GUTI to the UE that is common to both 3GPP and non-3GPP access.

An AMF may re-assign a new 5G-GUTI to the UE at any time.

AMF name

An AMF is identified by an AMF name.

Data network name

A DNN is equivalent to an APN.

DNN may be used to : select a SMF & UPF for a PDU session , select N6 interface(s) for a PDU session , determine policies to apply to this PDU session.

Internal - group identifier

The subscription data for an UE in UDR may associate the subscriber with groups.

A group is identified by an internal group identifier.

Generic public subscription identifier

It is needed for addressing a 3GPP subscription in different data network outside the 3GPP system.

GPSI’s are public identifiers used both inside and outside of 3GPP system.


An AMF UE NGAP ID is an identifier used to identify the UE in AMF on N2 reference point.

AMF allocates the AMF UE NGAP ID and send it to the 5G-AN.