Feasibility Research Of JAIN SIP Within IMS System

In the recent several years, mobile communication gains a rapid development with the evolution of the telecommunication and computer technologies. At the same time people call for more and more requirements for many kinds of mobile IP services.In order to realize these requirements of the growing thirst among communications providers, their partners and subscribers for a new generation of IP based services, a new technology: IMS is introduced into the existing mobile telecommunications by 3GPP, especially for SIP (Session Initiation Protocol) as IP signal which can support flexible mobile and fixed IP services. Using SIP, mobile communications service providers and their partners can customize and deliver a portfolio of SIP-based services that let subscribers use conferencing, Web controls, Presence, IM and more within a single communications session.As the session controlling protocol of application layer, SIP has the features of simple, expansibility. At the basis of simple introduction of SIP protocol, the JAIN SIP exploring construction for the fulfillment of SIP communication of SUN Co. is discussed in detail. To use Java language and take JAIN SIP as the core, all kinds of communication entity basic method in the fulfillment of SIP communication are described and simple model for SIP communication is built.First, this paper depicts the overview of IMS system, including these different kinds of network elements within IMS system. From the view of the current mobile telecommunication system, the paper briefly presents these different mobile IP services within IMS system.Second, this paper has a deep research on the SIP protocol with the related application and implementation in the second chapter.Since the mobile application within IMS system developed based on SIP protocol, the analysis and design pattern of JAIN SIP specifications are presented in the third chapter.As a key technology within mobile communications, SIP has been defined from several points by some specifications and drafts which are not the detailed standard for the generality and inter-working of mobile application. Based on Java language, JAIN SIP provides the modular architecture with a series of standard interface to solve this problem. In this chapter, the implementation of SIP server and client based on JAIN SIP is introduced into SIEMENS IMS system, also presents some shortcomings of JAIN SIP with the further enhanced points at the end.