Research On Some Key Technologies For NGN Core Service Platform And IMS Stateful Proxy

How to provide an open and standard service development method by integrating each kind of network resources in NGN (Next Generation Network) and to meet the performance demand of each kind of service by efficiently utilizing limited system resources in NGN multi service environment are important problem for NGN's success which is driven by services. NGN core service platform is based on Parlay/OSA technology, and helps service providers develop services conveniently and quickly through using network capabilities.In the IMS (IP Multimedia Subsystem), the CSCF (call session control function) servers, as stateful proxies, perform session management, based on the SIP (Session Initiation Protocol). To have highly reliable SIP sessions, a CSCF need to support fault tolerance to improve the reliability of services.The main contributions of this thesis are as following:(l)The structure of NGN core service platform, the peripheral subsystems adapted to core service execution platform, and an internal protocol between peripheral subsystems of current core service platform and other entites are proposed. This thesis also presents the design of these subsystems, analyzes key technologies of WEB servers and the ControlServlet module. This design can implement functions of user management, system management, self-management and statistics/analysis function.(2)The thesis describes the current mechanisms of Parlay/OSA and points out current lacks of Parlay/OSA APIs. These lacks mostly appear in the dymanic management of service sessions, the protocol mapping from CC SCF (Call Control Service Capability Features) to SIP, QoS (Quality of Service) assurance, the architecture of Parlay/OSA APIs, authentication mechanisms between Client Application and Framework, and charging process. This thesis proposes corresponding ideas of improving those lacks. It also presents technologies of authentication mechanism and digital signature. On the basis of analysis, we also point out the shortcoming of CHAP (Challenge Handshake Authentication Protocol), analyze...