Research And Realization Of Value Added Services' Providing In SoftSwitch

Accelerated by the development of the SoftSwitch technology, the IP network and the legacy telecom network is inosculating and evolving into NGN based on packets switching step by step. As the core equipment of call controlling, the SoftSwitch is an opening platform for value-added services providing, it integrates the service capability of existing network and opens core capability and resource to the 3rd party application which locates at the edge of network. It makes it possible that providing rich VAS to merged network's user.This paper starts with illustration of development of the telecom network's service providing, then analyses the architeture of SoftSwitch and NGN and discusses 2 service providing ways of VAS in detail: 3rd party service utilizing opening APIs including Parlay/OSA,JAIN etc. other than inter-working with traditional Intelligent NetWork.This paper studys some key technique of VAS providing. A universal service control view which can provides multi-party, multi-media services using the mentioned 2 methods is constructed. It also does some research on the key problem of IP network interworking with traditional IN: different access networks' call control protocol mapping to IN-BCSM which is presented by SIP. And the message transforming between Parlay API and SIP protocol which is needed by the 3rd party application logic communicating with SoftSwitch is studied.Integrating with actual practice, the author gives module design of parts in SoftSwitch environment which have relation with VAS providing. The application module for general call control, the inter-working with IN interface module and media connection manage module are described with functional architecture and finite state machine, which assure the realization of multi-party&multi-media services in call control and media management. At the end, the inner module of a Parlay GateWay which can used as an application server at the same time is designed and a SDK module which used to simplify the Parlay client application is realized.