CAMEL Application Part


The CAMEL Application Part is a signalling protocol used in the Intelligent Network architecture. CAP is a Remote Operations Service Element user protocol, and as such is layered on top of the Transaction Capabilities Application Part of the SS#7 protocol suite. CAP is based on a subset of the ETSI Core and allows for the implementation of carrier-grade, value added services such as unified messaging, prepaid, fraud control and Freephone in both the GSM voice and GPRS data networks. CAMEL is a means of adding intelligent applications to mobile networks. It builds upon established practices in the fixed line telephony business that are generally classed under the heading of or INAP CS-2 protocol.

Protocol specification

The CAMEL Application Part portable, software provides mechanisms to support operator services beyond the standard GSM services for subscribers roaming within or outside the Home PLMN. The CAP product extends the IN framework to GSM/3G networks for implementing IN-based services within GSM/3G networks.
CAMEL is used when the subscriber is roaming between networks, allowing the home network to monitor and control calls made by the subscriber. CAMEL provides services such as prepaid roaming services, fraud control, special numbers and closed user groups.
As with CAMEL, CAP has been defined in four phases, each of which has an accompanying specification that builds upon the previous phase. Each CAP phase provides the message set and procedures needed to support the corresponding CAMEL phase requirements, as defined in and .
The definition of the protocol may be considered to be split into three sections: