5.1.8A Charging support for roaming architecture for voice over IMS with home routed traffic

32.2603GPPCharging managementIP Multimedia Subsystem (IMS) chargingRelease 17Telecommunication managementTS

The charging principle of roaming architecture for voice over IMS with home routed traffic is described in TS 32.240 [1].

In LBO roaming model where P-CSCF is located in VPLMN, the home network determines the serving PLMN of the UE from the location of the P-CSCF during initial IMS Registration, using the P-CSCF network identifier.

In deployments without IMS-level roaming interfaces where P-CSCF is located in HPLMN, the home network determines the serving PLMN of the UE using procedure defined in TS 23.228 [201], where P-CSCF requests the PCRF/PCF to report the PLMN identifier where the UE is currently located. The received PLMN ID information is then forwarded in the SIP REGISTER request.Figure 5.1.8A.1 shows an example for possible signalling and media flows in a Roaming Architecture for Voice over IMS with home routed traffic.

Figure 5.1.8A.1: Signalling and media flows in a Roaming Architecture for Voice over IMS with home routed traffic (Example)