Question: What is the primary characteristic of the user plane PDUs delivery over the Xn-U interface, as represented by a specific IOC in the 5G Network Resource Model (NRM)?
Option 1: Guaranteed delivery with prioritized Quality of Service (QoS)
Option 2: Best-effort delivery without guaranteed latency
Option 3: Synchronous transmission requiring simultaneous data link layer setup
Option 4: Non-guaranteed delivery, typically using GTP-U/UDP/IP stack for transport
Explanation: The correct answer highlights the key aspect of the Xn-U interface's behavior in transporting user plane PDUs between NG-RAN nodes. Non-guaranteed delivery implies that the network does not ensure the arrival of all packets, which is a characteristic of connectionless protocols like UDP, often used in conjunction with GTP-U for efficient, best-effort transport of user plane data in telecom networks. This understanding is crucial for managing expectations around service reliability and throughput in 5G networks.