Customized Applications for Mobile networks Enhanced Logic


Customized Applications for Mobile networks Enhanced Logic is a set of standards designed to work on either a GSM core network or the Universal Mobile Telecommunications System network. The framework provides tools for operators to define additional features for standard GSM services/UMTS services. The CAMEL architecture is based on the Intelligent Network standards, and uses the CAP protocol. The protocols are codified in a series of ETSI Technical Specifications.
Many services can be created using CAMEL, and it is particularly effective in allowing these services to be offered when a subscriber is roaming, like, for instance, No-prefix dialing or seamless MMS message access from abroad.

CAMEL entities

CAMEL specification were published in phases, with four phases having been established , each building on the previous. Phases 1 and 2 were defined before 3G networks existed, and as such support adding IN services to a GSM network, although they are equally applicable to 2.5G and 3G networks. Phase 3 was defined for 3GPP Releases 99 and 4, and hence is a GSM and UMTS common specification, while Phase 4 was defined as part of 3GPP Release 5.
In line with other GSM specifications, later phases should be fully backwards compatible with earlier phases; this is achieved by means of the Transaction Capabilities Application Part Application Context negotiation procedure, with each CAMEL phase is allocated its own AC version.

Phase 1

CAMEL Phase 1 defined only very basic call control services, but introduced the concept of a CAMEL Basic call state model to the Intelligent Network. Phase 1 gave the gsmSCF the ability to bar calls, allow a call to continue unchanged, or to modify a limited number of call parameters before allowing it to continue. The gsmSCF could also monitor the status of a call for certain events, and take appropriate action on being informed of the event.
Phase 1 was defined as part of Release 96 in 1997.

Phase 2

CAMEL Phase 2 enhanced the capabilities defined in Phase 1. In addition to supporting the facilities of Phase 1, Phase 2 included the following:
Phase 2 was defined as part of 3GPP Releases 97 and 98, in 1998, although it is referenced in the stage 1 specification of Release 96.

Phase 3

The third phase of CAMEL enhanced the capabilities of phase 2. The following capabilities were added:
Phase 3 was released as part of 3GPP Releases 99 and 4 in 1999.

Phase 4

The fourth phase of CAMEL built on the capabilities of phase 3. The following features were defined:
With CAMEL Phase 4, it is possible that only a limited subset of the new functionalities is supported, in addition to the complete support of CAMEL Phase 3.
Phase 4 was released as part of 3GPP Release 5 in 2002.