4.1 Architecture

23.0783GPPCustomised Applications for Mobile network Enhanced Logic (CAMEL) Phase 4Release 17Stage 2TS

4.1.1 Functional Entities used for CAMEL

This subclause describes the functional architecture needed to support CAMEL. Also the additions needed to the basic functionality are described. Figure 4.1 shows the functional entities involved in calls requiring CAMEL support. The architecture is applicable to the forth phase of CAMEL.

Figure 4.1: Functional architecture for support of CAMEL

HLR: For subscribers requiring CAMEL support, the HLR stores the information relevant to the current subscription regarding O‑CSI, D‑CSI, T‑CSI, VT‑CSI and TIF‑CSI. The O‑CSI is sent to the VLR at Location Update, on data restoration or if the O‑CSI is updated by administrative action. The D‑CSI is sent to the VLR at Location Update, on data restoration or if the D‑CSI is updated by administrative action. The VT‑CSI is sent to the VLR at Location Update, on data restoration or if the VT‑CSI is updated by administrative action. The TIF‑CSI is sent to the VLR at Location Update, on data restoration or if the TIF‑CSI is updated by administrative action. The O/D/T‑CSI is sent to the GMSC when the HLR responds to a request for routeing information.

GMSC: When processing the calls for subscribers requiring CAMEL support, the GMSC receives an O/D/T‑CSI from the HLR, indicating the GMSC to request instructions from the gsmSSF. The GMSC monitors on request the call states (events) and informs the gsmSSF of these states during processing, enabling the gsmSSF to control the execution of the call in the GMSC.

MSC: When processing the calls for subscribers requiring CAMEL support, the MSC receives an O‑CSI and / or D‑CSI and / or VT‑CSI from the VLR indicating the MSC to request instructions from the gsmSSF. The MSC monitors on request the call states (events) and informs the gsmSSF of these states during processing, enabling the gsmSSF to control the execution of the call in the MSC.

VLR: The VLR stores the O‑CSI, D‑CSI, VT‑CSI and TIF‑CSI as a part of the subscriber data for subscribers roaming in the VLR area.

gsmSSF: see subclause 3.1.

gsmSCF: see subclause 3.1.

gsmSRF: see subclause 3.1.

4.1.2 Interfaces defined for CAMEL

This subclause describes the different interfaces applicable to CAMEL. It specifies on a high level the functions specific to CAMEL.

4.1.2.1 HLR – VLR interface

This interface is used to send the CAMEL related subscriber data to the visited PLMN and for provision of MSRN. The interface is also used to retrieve subscriber status and location information of the mobile subscriber or to indicate suppression of announcement for a CAMEL service.

4.1.2.2 GMSC – HLR interface

This interface is used at terminating calls to exchange routeing information, subscriber status, location information, subscription information and suppression of announcements. The CAMEL related subscriber data that is passed to the IPLMN is sent over this interface.

4.1.2.3 GMSC – gsmSSF interface

This is an internal interface. The interface is described in the present document to make it easier to understand the handling of DPs (arming/disarming of DPs, DP processing etc.).

4.1.2.4 gsmSSF – gsmSCF interface

This interface is used by the gsmSCF to control a call in a certain gsmSSF and to request the gsmSSF to establish a connection with a gsmSRF. Relationships on this interface are opened as a result of the gsmSSF sending a request for instructions to the gsmSCF or opened as a result of the gsmSCF sending a request to the gsmSSF to initiate a new call.

4.1.2.5 MSC – gsmSSF interface

This is an internal interface. The interface is described in the present document to make it easier to understand the handling of DPs (arming/disarming of DPs, DP processing etc.).

4.1.2.6 gsmSCF – HLR interface

This interface is used by the gsmSCF to request information from the HLR. As a network operator option the HLR may refuse to provide the information requested by the gsmSCF.

4.1.2.7 gsmSCF – gsmSRF interface

This interface is used by the gsmSCF to instruct the gsmSRF to play tones/announcements to the users.

4.1.2.8 GMSC – MSC interface

This interface is used to transfer control of a call from a VMSC back to a GMSC for optimal routeing.