Mạng và viễn thông P11

Intelligent Networks and ServicesBy storing a massive ‘memory’ of customer and service information ina network, andreferring to it while setting up calls, and as a historical record of network use, a phenomenal new range of services becomes possible. The effect is almost as if the network had some degree of ‘intelligent’ power of thought
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Mạng và viễn thông P11 Networks and Telecommunications: Design and Operation, Second Edition. Martin P. Clark Copyright © 1991, 1997 John Wiley & Sons Ltd ISBNs: 0-471-97346-7 (Hardback); 0-470-84158-3 (Electronic) l1 Intelligent Networks and Services By storing a massive ‘memory’ of customer and service information ina network, andreferring to it while setting up calls, and as a historical record of network use, a phenomenal new range of services becomes possible. The effect is almost as if the network had some degree of ‘intelligent’ power of thought. This chapter commences by describing the ‘intelligent networks’ asa concept, and then goes on to give examples of the new services that we can expect from it.11.1 THE CONCEPT OF INTELLIGENT NETWORKS The concept development and of intelligent networks (INS) originated in North America. The forerunner was AT&T’s database 800 service, and AT&T continue to be a key driver of the technology. Subsequently much work has also originated from the RBOCs (the American RegionalBellOperatingCompanies, or local telephone com- panies), in conjunction with their jointly funded research arm, Bellcore. More recently, ETSI (the European Telecommunications Standards Institute) has been very active. Theconcept is based onthe premise that all services can be brokendowninto elemental capabilities called functionalcomponents or service-independentbuilding blocks (SIBs or SIBBs). For example, a simple service may include providing dial tone, collecting digits, performing number translation, switching the connection, and charg- ing at an appropriate rate.If we were now to examine a second service, then we would find that some of the functional components used in that service would overlap those already identified in the first. If a comprehensive set of these functional components (SIBs) could be implemented at every exchange (so-called service switchingpoint ( S S P ) ) and if a suitable means of controlling the exchanges, from new powerful and remote computers called service control points (or SCPs), could be found, then new and much more powerful services could be implementedsimply by writing software (a service script) for the SCP, enabling it to manipulate the SSP(s). 231232 NETWORKS INTELLIGENT AND SERVICES11.2 INTELLIGENT NETWORK ARCHITECTURE In the past, each exchange had at least a small amount of ‘intelligence’, comprising software programs and related data for call routing and service control of ‘basic’ tele- phone services. However, when we speak of an intelligent network we mean a network equipped with a much larger information reference store and with software capable of controlling more powerful services. The intelligence can be added to the network on either a distributed or a centralized basis, according to the circumstances of the established network, the equipment to be used and the service to be provided. Here we compare and contrast the two architec- tures as a means of illustrating the scope of possibilities. In anetwork employing distributed intelligence the informationrequiredfor advanced call routing and service control is spread over a large number of sites or exchanges. Each exchange stores a large store of information necessary for the set up and control of the wide range of services it is expected to offer. This will include a store of customer-specific data (the information pertinent to a given customer’s network), as well as some service logic to tell the exchange exactly how each sophisticated service works, and the procedure for setting up calls. This sort of intelligent network could be created by continual enhancement of today’s exchanges, progressively adding software and hardware to cope with new service needs. The advantage of such an approach (storinginformationat alargenumber of exchanges) is thatthe service becomes available at all existing exchanges and the call handling capacity is large. The disadvantages are that the exchange software becomes very complex and the job of keeping all the exchanges’ software up to dateis unmanageable. Not only that, but the software and data duplication increases the risk of inconsistencies and may affect the service creation environment offline development environment (say 2-8 per network) - Iive environment public telephone exchange (Say 25 per network) point (SSP) (ideally a function included most main ...