Improvement Of Service Execution Environment For IMS Service

The basic idea of intelligent network (IN) is to separate traditional switching function of the traditional switches and service control function, which makes new telecom service produced much faster, flexible and convenient. The extensive application of intelligent network, especially mobile intelligent network technology, greatly promote the development of telecommunication services. Telecom technology changing rapidly, after years' development, IMS (IP Multimedia Subsystem) technology is generally matured. The important feature of IMS, which includes access independence and complete separation of service and control has gained much attention. IMS technology is generally accepted as a full-service operation network solution. In order to save construction cost and efficiently use the existing intelligent network system, upgrading the original IN system to provide IMS service is the definite trend.Features of IMS service function and SIP (Session Initiation Protocol) protocol are very different from those of IN service and CAP (CAMEL Application Part) protocol. If IMS service is developed under the execution environment of IN service, a lot of problems will be brought out. This paper designs and implements the improvement of service execution environment of SCP (Service Control Point), which uses C++ program language and multithread technology. This solution supports IMS service development and execution, without affecting the original IN service execution environment.Chapter one introduces the relative concepts of IN, CMIN02 system that has been in large-scaled used and the architecture of CMIN02-SCP software. Subsequently it introduces the appearance and specification of IMS service. To support IMS services, this chapter explains the overall reforming plan of SCP. The last part of this chapter is a general introduction of the key technology used in design—multithread technology.Chapter two introduces the structure of SCF process, deeply elaborating the intelligent network service logic implementation mechanism and flows in SCF process. The current operating mechanisms of service logic program perfectly fit the development and operation of SIB (Service Independent Building Block) mode.In chapter three, it first provides an example of a user making phone calls and hearing busy tones. It compares IN service signaling flow with IMS service signaling flow by flow charts, which show the different specifications of IMS service and IN service. Focus on the features of IMS service, this chapter points 6 main problems of providing IMS service in the existing service execution environment. For these reasons, the existing service execution environment must be improved, in order to support the IMS services.Chapter four starts with the reasons of introducing C++ service execution environment. Thereafter it introduces improvement methods for service execution environment, which includes message dealing process, C++ service dealing process and C++ service loading methods. It analyzes the reasons of using multithread technology and semi-synchronous/asynchronous multithread mode. To ensure the service message is serially processed, the improving plan of multithread working mode is addressed. It emphasizes the structure and data flow of C++ service execution environment.In chapter five, it mainly describes the two key parts of improved service execution environment mechanisms. Firstly it introduces detail design and implementation of multithread module. Then, this chapter explains the design and implementation of the key module of C++ service execution environment—development and system interface module. Finally, using UML sequence diagram, it illustrates sending and receiving messages flows of C++ service execution environment, showing the relationships between main modules. Chapter six describes the advantages of improved service execution environment. It introduces the current application of the environment, explains the shortcomings which is also the direction of next stage's work. At last, the author forecasts the future of C++ service execution environment.