Question: In a 5G Core (5GC) network, what is the primary purpose of monitoring the data volume and number of GTP data packets on the N9 interface between PSA UPF and I-UPF?
Option 1: To detect security threats and anomalies in user plane traffic
Option 2: To evaluate and optimize the bandwidth of the N9 interface and understand 5GC traffic distribution
Option 3: To manage Quality of Service (QoS) for voice services only
Option 4: To support resource allocation and optimization on the N9 interface specifically for network slicing based on individual S-NSSAI
Explanation: Monitoring GTP data packets and volume on the N9 interface is crucial not just for general bandwidth optimization but, more specifically, when considering network slicing, it's vital to allocate resources efficiently based on unique Slice/Service Numbers (S-NSSAI). This ensures each slice receives appropriate resources, making Option 4 the most comprehensive and correct answer in the context of advanced 5G network management.