Question: In a scenario where a UE contacts a visited Network Application Function (NAF) outside its home network, what is a key requirement for the Zn-Proxy in the visited network when communicating with the subscriber's home Bootstrapping Server Function (BSF)?
Option 1: To prioritize traffic based on QoS parameters of the visited NAF.
Option 2: To encrypt all communications with the visited NAF but not necessarily with the home BSF.
Option 3: To authenticate subscribers directly without involving the home BSF.
Option 4: To validate the visited NAF's authorization for GBA and assert its DNS name to the subscriber's home BSF.
Explanation: This is correct because, according to security protocols (like GAA and GBA), a crucial function of the Zn-Proxy is to ensure security and authorization. Validating the visited NAF's participation in GBA and asserting its identity (via DNS name) to the home BSF are essential for maintaining the integrity of the bootstrapping process and protecting user profiles, impacting the security and trust model in telecom networks, especially in roaming scenarios.