Question: In a 5G System (5GS) supporting Wireless and Wireline Convergence Access, what is the specific Reporting Trigger value in an Usage Reporting Rule (URR) for IPTV services using IGMP, as indicated to the Session Management Function (SMF) by the User Plane Function (UPF)?
Option 1: Session Establishment
Option 2: IGMP Snooping
Option 3: Multicast Group Join
Option 4: IGMP reporting
Explanation: In the context of IPTV services utilizing IGMP within a 5G System, the UPF notifies the SMF about changes in multicast flow associations using a specific Reporting Trigger in the URR. For IGMP, this trigger is set to "IGMP reporting" when adding or removing a PDU session from a DL replication tree associated with an IP Multicast flow, facilitating the SMF's awareness and potential reporting to the Policy Control Function (PCF) and/or Charging Function (CHF). This precise trigger value ensures efficient management of multicast resources in converged access networks.