Question: How can a network operator generate Call Detail Records (CDRs) for online charged subscribers?
Option 1: By using only offline charging functions.
Option 2: By performing online charging and offline charging simultaneously, or by employing specific offline charging functions within the Online Charging System (OCS).
Option 3: By generating CDRs directly from the subscriber's account on the OCS.
Option 4: By forwarding network resource usage to the Billing Domain (BD) for further processing.
Explanation: In online charging, CDR generation is not mandatory but can be achieved by either performing both online and offline charging simultaneously or by utilizing specific offline charging functions within the OCS. This allows for flexibility in managing subscriber billing and network resource usage tracking.