5.2.3 GTP’ record transfer flows

32.2753GPPCharging managementMultiMedia Telephony (MMTel) chargingRelease 17Telecommunication managementTS

As in IMS offline charging, GTP’ is not used between CDF and CGF for MMTel offline charging, because CDF and CGF are combined into CCF (see clause 4.2).

NOTE: Vendors may nevertheless implement a separate CDF and CGF for MMTel offline charging.
In this case, it is recommended that the approach chosen conforms to the principles and protocol applications specified in TS 32.295 [54].