Question: Upon receiving a PWS Failure Indication from an NG-RAN node, what action does the AMF take regarding the FAILURE-INDICATION-NG-RAN message when interfacing with multiple CBCFs?
Option 1: The AMF sends a unique FAILURE-INDICATION-NG-RAN message to each CBCF, detailing specific failed cells.
Option 2: The AMF only sends the FAILURE-INDICATION-NG-RAN message to the primary CBCF, which then distributes the information as needed.
Option 3: The AMF forwards the same FAILURE-INDICATION-NG-RAN message to all CBCFs it interfaces with.
Option 4: The AMF does not send the FAILURE-INDICATION-NG-RAN message if it interfaces with multiple CBCFs, to avoid redundancy.
Explanation: This is correct because when the AMF receives a PWS Failure Indication from an NG-RAN node, indicating a failure in one or more cells served by that node, it must inform all relevant CBCFs to ensure timely and widespread awareness of the service disruption. Since the AMF may interface with multiple CBCFs for comprehensive coverage or redundancy, forwarding the same message to all ensures consistency and completeness of information across the network, facilitating coordinated response and management of the cell broadcast service failure.