The CAMEL Application Part (CAP) is a signalling protocol used in the Intelligent Network (IN)

Intelligent network

The Intelligent Network , is the standard network architecture specified in the . It is intended for fixed as well as mobile telecom networks...

 architecture. CAP is a Remote Operations Service Element (ROSE)

Remote operations service element protocol

The Remote Operations Service Element is the OSI service interface, specified in , that provides remote operation capabilities, allows interaction between entities in a distributed application, and upon receiving a remote operations service request, allows the receiving entity to attempt the...

 user protocol, and as such is layered on top of the Transaction Capabilities Application Part

Transaction Capabilities Application Part

Transaction Capabilities Application Part, from ITU-T recommendations Q.771-Q.775 or ANSI T1.114 is a protocol for Signalling System 7 networks. Its primary purpose is to facilitate multiple concurrent dialogs between the same sub-systems on the same machines, using Transaction IDs to differentiate...

 (TCAP) of the SS#7 protocol suite. CAP is based on a subset of the ETSI

European Telecommunications Standards Institute

The European Telecommunications Standards Institute is an independent, non-profit, standardization organization in the telecommunications industry in Europe, with worldwide projection...

 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 (rather than fixed) networks. It builds upon established practices in the fixed line telephony business that are generally classed under the heading of (Intelligent Network Application Part) or INAP

INAP

The Intelligent Network Application Part is a signalling protocol used in the intelligent network architecture. It is part of the SS7 protocol suite, typically layered on top of TCAP.It can also be termed as logic for controlling telecommunication services migrated from traditional switching...

 CS-2 protocol.

Protocol specification

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 (e.g., 123 for voicemail that works everywhere) and closed user groups (e.g., office extension numbers that work everywhere).

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 3GPP TS 22.078 (service aspects) and 3GPP TS 23.078 (technical realization).

The definition of the protocol may be considered to be split into three sections:

• the definition of the Single Association Control Function (SACF)/Multiple Association Control Function (MACF) rules for the protocol, defined within the prose of the specification;
• the definition of the operations transferred between entities, defined using Abstract Syntax Notation One
  Abstract Syntax Notation One
  Data generated at various sources of observation need to be transmitted to one or more locations that process it to generate useful results. For example, voluminous signal data collected by a radio telescope from outer space. The system recording the data and the system processing it later may be...
  
  (ASN.1);
• the definition of the actions taken at each entity, defined by means of state transition diagrams.