Camel Call Flows

Research Seminar on Nomadic Computing

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Customised Applications for Mobile Enhanced Logic (CAMEL)
Paulius Meskauskas ([e-mail]) Research Seminar on Nomadic Computing Department of Computer Science University of Helsinki

1. ABSTRACT Taking the increasing competition of GSM networks into account, a standard was needed to enable competition between operators based on the services offered. ETSI has started in 1994 with the specification of Intelligent Network functionality in GSM, named Customised Applications for Mobile Enhanced Logic (CAMEL). CAMEL will provide the GSM operator with the ability to offer operator specific services based on IN service logic to a GSM subscriber even when roaming outside the HPLMN.

The CAMEL is a network feature and not a supplementary service. It is a tool for the network operator to provide the subscribers with the operator specific services even when roaming in the another network.

CAMEL is divided into several phases to provide GSM operators with CAMEL functionality as soon as possible. The first phase of the standard has been approved in 1997 and is currently implemented by the major GSM vendors. The standardatisation of the second phase has been finalised in 1998 with products to come in 1999. Phase 3 is planned to be finalised in the end of 1999 with products in 2000.

CAMEL makes use of IN SSP-SCP interface. The CAMEL application protocol (CAP) Phase 1 and 2 are based on ETSI Core INAP CS-1R. Howover, limited fraction of the whole operation set is used in order to assure 100% vendor compatibility in face of more than 200 mobile networks looking for mutual roaming agreements.

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2. CAMEL PHASE 1 ARCHITECTURE CAMEL phase 1 architecture is illustrated in figure 1 [1].
Home Network

HLR

MAP

gsmSCF

MAP CAP MAP CAP

gsmSSF

VLR Roaming leg

gsmSSF

GMSC

VMSC

Interrogating Network

Visiting Network

Figure 1.

References: [1] ETSI GSM 02.78: Digital cellular telecommunications system (Phase 2+); Customised Applications for Mobile network Enhanced Logic (CAMEL); Service definition (stage 1); v.5.3.0 ETSI GSM 03.78: Digital cellular telecommunications system (Phase 2+); Customised Applications for Mobile network Enhanced Logic (CAMEL); v.5.3.0 ETSI GSM 09.78: Digital cellular telecommunications system (Phase 2+); CAMEL Application Part (CAP) specification; v.5.3.0 ETSI Final Draft EN 301 152-1. Intelligent Netowork (IN); IN Capability Set 1 (CS1) extensions; Intelligent Network Application Protocol (INAP); Customized Applications for Mobile network Enhanced Logic (CAMEL); Part 1: Protocol Specification, v1.2.1 (1998-07). [2] [3] [4] Research Seminar on Nomadic Computing 13 (13) ABBREVIATIONS BCSM CAMEL DP EDP GMSC gsmSCF gsmSRF gsmSSF HLR HPLMN IPLMN MSC O-BCSM O-CSI OSS PIC PLMN SMF SS-CSI T-BCSM T-CSI VLR VPLMN Basic Call State Model Customized Applications for Mobile network Enhanced Logic Detection Point Event Detection Point Gateway MSC GSM Service Control Function GSM Specialised Resource Function GSM Service Switching Function Home Location Register Home PLMN Interrogating PLMN Mobile service Switching Centre Originating Basic Call State Model Originating CAMEL Subscription Information Operator Specific Service Point In Call Public Land Mobile Network Service Management Function Supplementary Service Notification CAMEL Subscription Information Terminating Basic Call State Model Terminating CAMEL Subscription Information Visitor Location Register Visited PLMN