Architecture

The following figure shows the network architecture for the EPS-5G Core and 4G interworking.

3GPP Non-Roaming Architecture for EPS-5GC Interworking

The following architecture diagram shows that SMF using Diameter interfaces for Policy and online charging and the Gz for the offline charging. It uses the N4 interface towards the UPF. In this architecture diagram, the grayed element are the 5G nodes that are not used for the 4G only UE.

SMF Interworking with Diameter and GTPP Interfaces