S5 Interface (The EPC Interface)

The S5 interface connects the SGW to a PGW. The interface is based on the GTPv2 protocol. Basicly the interface transports user data packet and also handles signaling (control plane). The S5 interface is used if configure SGW and PGW in different node (hardware). It's possible to configure SGW and PGW in same node (hardware), so the S5 interface isn't needed, S5 will configure internally.

Please refer to The EPS Interface.