The following figures contain the reference configuration for the lawful interception. The circuit-switched configuration is shown in Figure 1a. The packet-switched configuration is shown in Figure 1b. Intercept configurations for HLR and IMS are shown in figures 1c and 1d. The WLAN interworking configuration is shown in Figure 1e. The intercept configurations for IMS conferencing is shown in Figure 1f. The CC intercept configuration for IMS-based VoIP is shown in Figure 1g. Intercept configurations for LALS are shown in Figure 1h. The intercept configuration for Non-Local ID at IBCF and MGCF is shown in Figure 1i. The intercept configuration for S8HR VoLTE in the visited PLMN is shown in Figure 1j. The intercept configuration for Push to Talk over Cellular (PTC) is shown in Figure 1k and 1l. Within the present document PTC encompasses PoC as a service and Mission Critical Push-To-Talk (MCPTT) services. The CSP Cell Supplemental Information configuration is shown in Figure 1m. The various entities and interfaces are described in more detail in the succeeding clauses. The additional intercept configurations for Evolved 3GPP Packet Switching Domain are described in clause 12.
PS domain of the UMTS system (GSN and Multimedia Packet Data services), 3GPP-WLAN interworking network and Evolved Packet Switching Domain provide UMTS/GSM/EPS customer's mobile equipment (UE) with connectivity service to another end of the communication. Another end of the communication may be a network element (server) or another UE. Therefore, UMTS/EPS system provides IP layer TS 23.008 services. Hence, UMTS/EPS NO/AP is responsible only for IP layer interception of CC data. In addition to CC data, the LI solution for UMTS/EPS offers generation of IRI records from respective control plane (signalling) messages. The IP layer connectivity service is needed to support application layer TS 29.234 service provision to UMTS/GSM/EPS customers. For instance, the following are examples of application layer services: email service; web browsing service; FTP service; audio services (e.g. VoIP, PoC); other multimedia services (MBMS, video telephony); The majority of the application layer services require addition of respective server functionality to the network. Note that it is not necessary that such application layer SP should be the same commercial entity as the UMTS/EPS AP/NO in question.
When location information of the target is delivered by an ICE, the MF may need to add the civic address associated with the access network point as known by the CSP. The method used to obtain the civic address will depend on the CSP implementation. (e.g. by accessing a remote database). National regulations define whether the civic address needs to be provided.
The LALS provides LCS information of the target on-demand, independently of the target's activity/events. Additionally, LALS may be triggered by any IRI event detected by an ICE to provide LCS location information of the target correlated to the triggering event.
When IA is provisioned LCS may provide enhanced geographic capabilities
For all UE locations obtained, generated or reported to the MF/DF, the ICE shall report the time at which the location was established by the location source (e.g. MME or HSS) and provide this to the MF/DF along with the location information. If this information cannot be provided by the location source the ICE shall indicate that the time is not available. If the information in the MME received over S1 (TS 36.413) includes one or more cell IDs, then all cell IDs shall be reported to the LEMF whenever location reporting is triggered at the MME.
Figure 1m: CSP Cell Supplemental Information Database configuration
The LALS Triggering Function depicted in Figure 1h may be implemented as a part of either an ICE or a DF2.
See clause 20 for the definitions of LMISF and BBIFF. These functions are specifically defined for LI in reference to the interception voice services in the VPLMN when S8HR approach is used as the VoLTE roaming architecture.
The reference configuration is only a logical representation of the entities involved in lawful interception and does not mandate separate physical entities.
Regional Mediation Functions, which may be transparent or part of the administration and delivery functions, are used to convert information on the HI1, HI2 and HI3 interfaces in the format described in various national or regional specifications. For example, if ETSI ES 201 671  or ANSI J-STD-025  is used, then the adaptation to HI1, HI2 and HI3 will be as defined in those specifications.
There is one Administration Function (ADMF) in the network. Together with the delivery functions it is used to hide from the 3G ICEs that there might be multiple activations by different Law Enforcement Agencies (LEAs) on the same target. The administration function may be partitioned to ensure separation of the provisioning data from different agencies.
See the remaining clauses of this document for definitions of the X1_1, X1_2, X1_3, X2, X3, LALS_T, Xia and Xib interfaces. These interfaces are specifically defined for LI and are not related to other interfaces/reference points having the same name specified in other 3GPP specifications (such as e.g. X2 interface specified in the e-UTRAN architecture).
Interception at the Gateways is a national option. However, if 3G direct tunnel functionality with the GGSN is used in the network, as defined in TS 23.060, then the GGSN shall perform the interception of IRI and the content of communications.
In Figure 1a DF3 is responsible for two primary functions:
Call Control (Signalling) for the Content of Communication (CC); and
Bearer Transport for the CC.
HI3 is the interface towards the LEMF. It shall be able to handle the signalling and the bearer transport for CC.
In Figures 1a, 1b, 1e, 1f, 1g, 1h, 1i and 1j, the HI2 and HI3-interfaces represent the interfaces between the LEA and two delivery functions. The delivery functions are used:
to distribute the Intercept Related Information (IRI) to the relevant LEA(s) via HI2 (based on IAs, if defined);
to distribute the Content of Communication (CC) to the relevant LEA(s) via HI3 (based on IAs, if defined).
In Figures 1c, 1d and 1h the HI2 interface represents the interface between the LEA and the delivery function. The delivery function is used to distribute the Intercept Related Information (IRI) to the relevant LEA(s) via HI2.
Figure 1g shows the CC interception configuration for VoIP. The trigger for the CC interception is provided by a SIP signalling node and identified within the Figures as CC Interception Triggering Function.
Figure 1m shows the CSP Cell Supplemental Information configuration that has an optional interface (shown as LI_CELL_INFO) connecting the DF2 and the CSP maintained record(s). This interface is implementation specific to the operator. This is used to obtain cell supplemental information held by the CSP and provide it to the LEA. In particular it delivers geo-location or civic location of the cell site to the LEA. More detail is contained in clause 22.