Question: Who initiates the initial and subsequent Session Transfer procedures when a User Equipment (UE) is active in an IMS (IP Multimedia Subsystem) session?
Option 1: The Serving Call Continuity Application Server (SCC AS) initiates the procedures based on UE's location updates.
Option 2: The User Equipment (UE) initiates the procedures, with execution and control handled by the SCC AS.
Option 3: The operator's network automatically triggers the Session Transfer when detecting a need for access network change.
Option 4: A separate entity, dedicated to session management, initiates these procedures upon request from the UE or SCC AS.
Explanation: This is correct because the User Equipment (UE) takes the first step in initiating both the initial and subsequent Session Transfer procedures. However, the actual execution and control of these procedures are managed by the Serving Call Continuity Application Server (SCC AS), ensuring seamless service continuity across different access networks or between UEs under the same operator.