tailieunhanh - Signaling System No.7 Protocol Architecture And Sevices part 42

The Advanced Intelligent Network (AIN , IN CS-X) The term "Advanced Intelligent Network" can be misleading. People often consider AIN a separate entity from the IN. | The Advanced Intelligent Network AIN IN CS-X The term Advanced Intelligent Network can be misleading. People often consider AIN a separate entity from the IN. It is simply part of the evolution of the original IN concept. AIN is a term that is primarily used in North America to describe the evolution of the IN beyond the IN 1 phase. The AIN specifications introduced by Bellcore solidified and extended the concepts introduced by the early IN standards. AIN 0 was the first version released. However it is only given a brief introduction here because AIN and AIN have made it obsolete. Both AIN and are incremental releases toward the IN concept documented in AIN 1. As explained earlier beginning with AIN the ITU IN and Bellcore AIN standards align fairly well although ITU uses the term IN and Bellcore uses the term AIN they both describe the same general architecture and call model. The following sections discuss IN CS-1 and AIN as well as IN CS-2 and AIN together. Message encodings remain incompatible because of the differences between ITU TCAP and ANSI TCAP. The examples use AIN messages with ANSI TCAP encodings. Basic Call State Models BCSM One of the key differences between IN 1 and the succeeding AIN IN CS phases is the introduction of a formal call model. A call model is a definition of the call processing steps that are involved in making a call. During call processing in a switch a call progresses through various stages such as Digit Collection Translations and Routing. These stages existed before the introduction of the IN however there was no agreement between vendors on exactly what constituted each phase and what transitional events marked the entry and exit of each stage. Even within a vendor s implementation the delineation of stages could be ambiguous. IN defines a Basic Call State Model BCSM which identifies the various states of call processing and the points at which IN processing can occur known as Points In Call PIC .