Intelligent Networks (IN)

The Intelligent Network (IN) is an architecture that redistributes a portion of the call processing, that is traditionally performed by telephony switches, to other network nodes. This chapter explores how the IN moves service logic and service data out of the SSP, and the rationale behind it.

The complete set of IN capabilities has not been fully realized, but it continues to evolve and be implemented over time. It is a radical shift in architecture that requires coordinated changes by both vendors and service providers on a number of levels. Over approximately the last 20 years or so, standards have been published that define a common framework to enable its adoption. A variety of terms are used to describe the various stages of this evolution: IN, IN/1, AIN 0, AIN 1, AIN 0.1, AIN 0.2, IN CS-1, and IN CS-2. The list is only partially complete, and yet it represents a number of views of the Intelligent Network (IN) concept and its progression.

The Advanced Intelligent Network (AIN) is a term that Telcordia (formerly Bellcore) uses for North American IN standards that were released in the 1990s. This chapter presents the general concepts of the Intelligent Network (IN) and briefly examines the progression towards IN CS-2/AIN 0.2. The Intelligent Network Capability Set 2 (IN CS-2) is the set of standards published by ITU, while the Advanced Intelligent Network 0.2 (AIN 0.2) is the North American equivalent. Because it is the most recent specification that has a considerable amount of implementation at the time of this writing, the AIN 0.2 version of the IN is the primary focus of this chapter.

NOTE

The Telcordia AIN specifications dropped the use of the "0.2" version number from the specifications. These documents are simply referred to as the AIN specifications. Throughout this chapter, the term AIN 0.2 is retained. There are still AIN implementations that are only 0.1 compliant and the version number is useful to discriminate the functionality implemented by each version.

Because the terminology can become confusing, the term IN is used generically throughout this chapter to represent all versions of the Intelligent Network. The term AIN is used for the North American releases beyond IN/1. When a specific version is being referenced, the version number (such as AIN 0.2) is included. The call models within this chapter are based on the ITU IN standards, while most of the message examples are based on the North American AIN standards. This chapter includes an INAP section, which provides an example of how the European region uses INAP to provide IN capabilities.