Analysis And Implementation Of Abstract Signaling Switching In Softswitch System

Next Generation Network (NGN) is a kind of integrated and open network which can deliver diversified services such as voice, data and multimedia. NGN divides various devices into different layers according to their functions. It can also provide all kinds of access for users driven by services. In next generation network, all services, including real-time one and non real-time one, are beared by a wideband packet-based network.Softswitch is the call control core of the next generation network. As it is called, Softswitch is a kind of software based switching, which separates the control function of telephone call from transmission layer. The bore idea of Softswitch is the separation of call and bearing, and the separation of service and control. If the original Voice over IP devices, such as IP voice gateway, are to merge to Softswitch, the software need to be layered. That is to say, it should use internal APIs (Application Programming Interface) to realize the independence of call and bearing, and of service and control. Therefore, the definition of internal APIs is the key to implement Softswitch. The main part of the thesis is to discuss the implementation of one of the APIs - protocol access and adaptation. Through it, protocols/signalings of NGN access layer, such as H.323, SIP, No.1, No.7, can be accessed easily and conveniently.In the first chapter of the thesis, the basic concepts of NGN and softswitch, the demand on software architecture, the structure and contribution of the thesis are introduced. Several mainstream protocols/signalings of access layer are investigated in chapter 2. Through summarization and comparison between them, abstract signaling is defined based on some existing common used one. In the third part, the operation procedure of the abstract signaling is demonstrated in detail, including the interworking between abstract...