Section: 4.4.1.3 Ga
Content: The Ga reference point supports interaction between a CDF and a CGF. The following information may flow across this reference point: - CDRs are sent from the CDF to the CGF; - Acknowledgements for these CDRs are returned from the CGF to the CDF. The protocol(s) crossing this reference point shall support the following capabilities: - Near real-time transactions; - Send one or more CDRs in a single request message; - Changeover to secondary destinations (alternate CGFs) in case of the primary CGF not being reachable; - Provide its own reliability mechanisms, e.g. retransmission of charging events, to run also on unreliable transport. This interface application is defined in TS 32.295[ Telecommunication management; Charging management; Charging Data Record (CDR) transfer ]  [54]. The content of the CDRs, and the CDR trigger conditions, are specific to the domain / subsystem / service and are detailed in the middle tier TSs.