The CAMEL Application Part (CAP) portable software provides mechanisms to support operator services beyond the standard GSM services for subscribers roaming within or outside the Home PLMN (HPLMN). 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.