Question: When forwarding user plane data from the Control Plane (CP) function to the User Plane (UP) function towards a UE or PDN, what additional information must the GTP-U protocol encapsulation contain?
Option 1: Only the PDN Connection ID
Option 2: Only the Bearer ID
Option 3: Information to identify whether the UE or PDN is targeted
Option 4: Both the PDN Connection ID and Bearer ID, but not target identification
Explanation: This is correct because, as specified, for forwarding towards the UE or PDN from the CP function to the UP function, the UP encapsulation protocol (GTP-U) must contain information that allows the UP function to determine whether the User Equipment (UE) or the Packet Data Network (PDN) is the intended target. This ensures proper routing and handling of the user plane traffic.