Question: In a 5GS supporting EPS interworking scenario for VAL services, what enables direct handling of PDU sessions (in 5GS) and PDN connections (in EPS) during inter-system mobility of a VAL UE?
Option 1: Dedicated user plane anchor point, i.e., UPF + PGW-U function
Option 2: NRM server's interaction with PCF
Option 3: VAL server's direct communication with MME in EPC
Option 4: Seamless session continuity via N26 interface alone
Explanation: A dedicated user plane anchor point, specifically the combination of UPF (User Plane Function) and PGW-U (PDN Gateway - User plane) function, is crucial for enabling the network to directly manage both PDU sessions in the 5G System (5GS) and PDN connections in the Evolved Packet System (EPS) during the inter-system mobility of a VAL (Vertical Application Layer) User Equipment (UE). This setup ensures efficient handling of data plane traffic across different system architectures, facilitating smoother interworking between 5GS and EPS.