23.0313G Security3GPPFraud Information Gathering System (FIGS)Stage 2Technical realizationTS
FIGS provides the following information flows to the HPLMN, with respect to roaming subscribers monitored by FIGS Levels 2 and 3.
FIGS Level 2:
call start and end times (both MO, MT and forwarded calls). (At CAMEL Phase 1 the gsmSSF will not put a timestamp on messages. The arrival times of messages at the gsmSCF will be used for call start and end times.)
FIGS Level 3:
As for level 2 with the addition of:
partial call information (accumulated duration of call still in progress) (CAMEL Phase only);
notification of the invocation of ECT, CD and MPTY, CF and call hold (CAMEL Phase 2 only).
Further phases of CAMEL will provide the functionality to check the IMEI of the ME used by a CAMEL subscriber. Other information required by 3GPP TS 42.031, annex A, that is not provided by CAMEL Phase 1 and CAMEL Phase 2, may also be provided by further phases of CAMEL.
The architecture of the services provided by FIGS Levels 2 and 3 is given in the diagrams below. Thick lines indicate possible CAMEL monitoring/control relationships.
Figure 1: FIGS architecture for MO call
Figure 2: FIGS Architecture for MT/forwarded call
Early call forwarding can be performed if the subscriber has set Unconditional Call Forward or the HLR has determined, before the call is extended to VPLMN B, that the B subscriber is not reachable. In all other cases the call must be extended to the VMSC.
The information flows required by FIGS levels 2 and 3 can be provided by the information flows on the CAP interfaces between the gsmSCF and the gsmSSF in the interrogating and visiting networks.
The interface between the gsmSCF and the Fraud Detection System (FDS) is non-standard.