5G Session Support
The Session and Service Continuity (SSC) support in 5G system architecture addresses the continuous requirements of different applications and services for a User Equipment (UE). The 5G system supports the SSC modes such that the network maintains the connectivity service to the UE. The SMF manages the UE IP address and ID allocation for establishing sessions. The SMF also maintains session connectivity on interfaces, such as N40, N4, N7, and N10, to facilitate charging.
The SMF uses the Xn interface to handover a UE from a source NG-RAN to the target NG-RAN when the AMF is unchanged, and without relocating the UPF. The SMF includes the N3 tunnel profile configuration to enable the notifications on the Control Plane (CP) and enable buffering on the UPF. The SMF supports activation and deactivation of the User Plane (UP) connection of a PDU session. The SMF also includes the DNS proxy feature to configure proxy servers for resolving the host names and their IP addresses.
The following features are related to this use case: