Research On IP PBX Based On NGN Framework

With the popularization of Internet and the development of global economy and technology, Enterprise's communication requirement tends to be diversified. It has been already hard for traditional PBX to meet the development mode and growth need of modern enterprises and IP PBX accords with the converging trend of NGN and can meet the communication requirements of modern enterprises. IP PBX is replacing traditional PBX and becoming the most important enterprise communication solution.Softswitch is the core technology of NGN, whose concept is just originated from IP PBX. The idea of Softswitch stems from the application of American corporate network first. Nowadays, the era of NGN has come formally with NGN technology sweeping across the whole world. The development of NGN and Softswitch technology and the drawing up of relative international standards has enormously improved IP PBX technology. If NGN is realizing the convergence of a whole IP network, then IP PBX is realizing the convergence of enterprise layer network.On foundation of research on NGN, Softswitch and IP PBX, an organization scheme of the network for IP PBX system based on NGN is proposed in this project. This is a solution of pure IP, but it gives consideration to both traditional PSTN and traditional PBX for that it adopts open framework systematically.Every function package and the realization program of their basic function of the IP PBX system is designed in detail in this project. The author had taken part in the design and implementation work for basic voice call and majored in realizing the function of voice service-dealing module in Call Controller. The basic voice call flows are designed on the basis of MGCP protocol and SIP protocol and includes local office flow and inter-office flow. Call Controller includes many function modules. Among these modules, outer interface module and voice service-dealing module are the modules that fulfill the basic voice call. And sub-modules are further divided in voice service-dealing module based on Q931 protocol: User Side and Call Center. The function of MGW module and the implementation of fax and multimedia technology are also introduced in brief.The design and implementation of the overall scheme, the function packages and the basic voice call function has been tested to be practical in practice.