Question: Which reference point is utilized by IM-PC5 for interactions related to identity management functions between different VAL UEs, and what is its origin?
Option 1: PMIP (Proxy Mobile IPv6) reference point, originating from mobility management protocols.
Option 2: S1-U reference point, originating from LTE's User Plane protocol stack.
Option 3: F1 reference point, related to the interface for NG-RAN's functional split.
Option 4: PC5 reference point, as described in the context of Proximity-based Services (ProSe) specifications.
Explanation: The correct answer is Option 4 because IM-PC5 leverages the PC5 reference point for identity management interactions between VAL UEs. This is rooted in the Proximity-based Services (ProSe) framework, which enables direct communication between nearby devices, hence the relevance of PC5 (a reference point associated with ProSe) for managing identities in proximity-based scenarios. This highlights the integration of identity management with proximity services in telecom networks, showcasing how different functional areas converge to enable advanced use cases.