Re-Authorization
The CHF triggers Reauthorization of charging descriptors using Charging Notify request. Reauthorization is implemented at the session-level or at a RG-level for both online and offline charging.
The SMF processes the reauthorization details (which contain an array of RG, ServiceId, QuotaMgmtIndicator) received in CHF Notify and retrieves the charging descriptors associated with the current PDU session. Any unmatched reauthorization item is skipped.
For the charging descriptors identified for reauthorization, the SMF queries for usage reports from UPF and sends it to the CHF.
As part of the CHF response, the SMF detects any change in quota/threshold information and performs N4 Session Modification to update URRs.