PDF of this tutorialInternational standards work for IN began in 1989 within the ITU and the ETSI. These standards bodies have been developing IN capability sets that will be upwardly compatible in parallel. The ITU builds its "Q.1200 Recommendation Series for IN Architecture," and ETSI takes these recommendations and modifies them for use by European operators.
Capability sets refers to a set of services and service features that can be built using SIBs. All capability sets use the IN conceptual model. Each capability set is associated with a planned phase in the standards process. The first capability set, CS–1, was defined by the ITU in 1992 but was found to be too extensive and incomplete by ETSI. ETSI defined the Core INAP standard in 1994 as a subset of the original CS–1. The ITU adopted this work and reissued the standard in 1995. This 1995 release of the CS–1 recommendations is generally referred to as "CS–1R," for "refined."
For CS–1 IN services to be implemented, Core INAP supports the interactions among the functional entities defined earlier: SSF, SCF, SRF, and SDF. Application service elements (ASEs) are available in the Core INAP specification to provide a definition of specific application interactions between functional entities. In general information flows/operations within ASEs are defined within Core INAP using the abstract syntax notation 1 (ASN.1) nomenclature. Examples of basic CS–1 information flows include the following:
- connect
- prompt and collect user information
- analyze information
- play announcement
- release call
Using a common IN service, the premium rate service, the interrelationship of services, service features, and the SIBs is provided below. The premium-rate service provides a business owner with a special premium-rate number. Customers that call this special number are charged at a special rate for both the call as well as for information and/or services obtained through the call. The network operator collects the revenue associated with the call and distributes a share to the business owner of the premium-rate number. Examples of premium rate include weather, stock, sports, and other information services.
A premium rate service has two core service features:
- The one number service feature permits the business owner (subscriber) to have two or more terminating lines in a number of locations, using a single premium-rate number.
- The premium charging service feature permits the subscriber to receive some of the revenue associated with each premium-rate call.
There are other optional service features associated with the premium-rate service, such as call distribution, time and origin-dependent routing, recorded announcements, and many others.
Within the premium-charging service feature there are three associated SIBs: the charge SIB, the call log information SIB, and the service data management SIB.
Within the charge SIB, there are a number of information flows/operations at work. For example, the SCF can issue a FurnishChargingInformation information flow that carries charging characteristics for a particular call to the SSF. Once the SSF receives these characteristics, the SSF generates a billing record. Within the same SIB, the SCF may also issue the SendChargingInformation information flow that sends charging characteristics to an SSF that controls the way that the SSF charges for a call. Other information flows are associated with this SIB, such as EventNotificationCharging and ApplyCharging that perform related charging functions.
In summary, the INCM is used to first describe a service without reference to the distribution of functionality within the network. The service is then decomposed into service features, and all service features must be mapped onto corresponding SIBs. Each capability set defines the catalog of services, service features, and SIBs. Service designers can create new services within the boundaries of the capability sets, usually building SIB chains or service scripts.
