03.333G security3GPPLawful InterceptionStage 2TS
The following picture shows the extract from the reference configuration which is relevant for activation, deactivation and interrogation of the lawful interception.
Figure 2: Functional model for Lawful Interception activation, deactivation and interrogation
In addition to the typical GSM functional entities, a new functional entity is introduced – the ADMF – the Lawful Interception administration function. The ADMF:
– interfaces with all the LEAs that may require interception in the PLMN;
– keeps the intercept activities of individual LEAs separate;
– interfaces to the PLMN.
NOTE: The X1_1, X1_2 and X1_3-interfaces together are functionally equivalent to the X1-interface represented in GSM 01.33.
Every physical MSC/VLR and GMSC is linked by an own X1_1-interface to the ADMF. Consequently, every single MSC/VLR and GMSC performs interception (activation, deactivation, interrogation as well as invocation) independently from other MSC/VLRs and GMSCs. The X0_1-interface represents the interface between the requester of the lawful interception and the Lawful administration function; it is included for completeness, but is beyond the scope of standardization.
In case of location dependent interception the following network/national options exist:
– target location versus Interception Areas (IAs) check in the MSC/VLR and Delivery Functions (DFs);
– target location versus IAs check in the DFs (physical collocation of the DFs to the MSC/VLR, GMSC is required).
NOTE: The IA is previously defined by a set of cells. From the location of the target this set of cells permits to find the relevant IA.