G.5.4.1 The flowchart

33.1283GPPProtocol and procedures for Lawful Interception (LI)Release 18SecurityStage 3TS

Figures G.5-3, G.5-4, G.5-5 and G.5-6 show the LIPF logic for the service type of Voice when the target is not a non-local ID.

Figure G.5-3: Top level LIPF logic for service type of Voice when target is not a non-local ID

For the delivery type of IRI + CC, the IRI-POIs and the CC-TFs are provisioned. For the delivery type of IRI, the IRI-POIs are provisioned. For the delivery type of CC, the CC-TFs are provisioned.

Figure G.5-4 shows the LIPF logic for the provisioning of IRI-POIs and figure G.5-5 shows the LIPF logic for the provisioning of CC-TFs.

Figure G.5-4: LIPF logic for delivery type of IRI for service type of Voice when target is not a non-local ID

The S-CSCF, E-CSCF, P-CSCF, IBCF, MGCF and AS (in figure G.5-4) provide IRI-POI functions under certain conditions as noted within the illustration. To prevent those IRI-POIs from providing the LI functions when not supposed to, the LIPF may have to include a parameter during the provisioning. If STIR/SHAKEN is required to be intercepted in the network, then the provisioning of IRI-POIs in IBCF and AS include the parameter ReportDiversionPASSporTInfo if the target identity is IMPU. Additional STIR/SHAKEN related provisioning is illustrated in figure G.5-6A.

Figure G.5-5: LIPF logic for delivery type of CC for service type of Voice when target is not a non-local ID

The IBCF, MGCF and AS (in figure G.5-5) provide CC-TF functions under certain conditions as noted within the illustration. To prevent those CC-TFs from triggering the CC-POIs when not supposed to, the LIPF may have to include a parameter during the provisioning.

Figure G.5-6 illustrates the LIPF logic for LALS triggering.

Figure G.5-6: LIPF logic for LALS triggering for the service type of Voice

In LALS triggering option 1, the host NF that provides the LTF is same as the NF that provides the IRI-POI functions. And therefore, the host NFs that provide the LTF can be different based on the IMS deployment options.

The P-CSCF, IBCF and LMISF-IRI (in figure G.5-6) provide LTF under certain conditions as noted within the illustration. Under special scenario, the S-CSCF may provide the IRI-POI for emergency services (instead of E-CSCF) as specified in TS 33.127 [5]. To prevent those LTFs from providing the LI functions when not supposed to, the LIPF may have to include a parameter during the provisioning.

Figure G.5-6A illustrates the LIPF logic for additional STIR/SHAKEN related provisioning.

Figure G.5-6A: LIPF logic for additional STIR/SHAKEN related provisioning

For STIR/SHAKEN related reporting, IBCF, AS, P-CSCF (VPLMN with LBO), LMISF-IRI (VPLMN with HR) provide the IRI-POI functions. The LIPF logic shown in figure G.5-6A is additional logic required to support the LI for STIR/SHAKEN.

As illustrated in figure G.5-4, the IRI-POIs in P-CSCF, LMISF-IRI and AS are provisioned as part IMS-based voice LI. Likewise, the IRI-POI in IBCF is also provisioned for IMS-based voice LI when the alternate option is used.

When the STIR/SHAKEN is required to be intercepted in the network, the IRI-POIs in IBCF and AS are to be provisioned with ReportDiversionPASSporTInfo value when the target identity is IMPU.