Question: In a 5G network, when a voice call is changed to a CS (Circuit Switched) multimedia call using SCUDIF (Service Change Usage Data Indication Framework), which of the following pieces of information MUST be collected on both sides of the call, in addition to the nature of the service change (User or network-initiated)?
Option 1: Only the Initiator of the service change (A side or B side)
Option 2: Type of the service change (To speech or to multimedia) and Call Duration
Option 3: Initiator of the service change (A side or B side) and Type of the service change (To speech or to multimedia)
Option 4: Location Information of both A and B sides, and Call Quality Metrics
Explanation: According to telecom standards for flexible charging in service changes, collecting information on who initiated the change (A side or B side) and the direction of the service change (to speech or to multimedia) is crucial. This allows operators to apply maximum flexibility in billing scenarios, especially when converting between voice and multimedia services within a call session.