Question: In an NR MBS (Multicast/Broadcast Service) session, what type of F1-U tunnel is used for PTM (Point-to-Multipoint) transmission between the gNB-CU (Central Unit) and gNB-DU (Distributed Unit)?
Option 1: Shared F1-U tunnel
Option 2: UE dedicated F1-U tunnels
Option 3: Both shared and dedicated F1-U tunnels based on PTM configuration
Option 4: No F1-U tunnel is established for PTM transmission
Explanation: According to the NR MBS architecture, a shared F1-U tunnel is specifically utilized between the gNB-CU and the gNB-DU for MRBs (Media Resource Blocks) with PTM transmission. This setup efficiently supports multicast/broadcast services by allowing multiple UEs to receive the same data stream over a single tunnel, reducing network resource utilization.