Software-Developing Related To IMS

IMS (IP Multimedia Subsystem) is a subsystem which support to IP multimedia operation that is brought forward by 3GPP. Its marked characteristic is that it adopt SIP system, correspondence is not related to connecting mode, it has multimedia operation controlling function is separated from carrying capacity, calling is separated from conversation, application is separated from service, operation is separated from network, mobile network is syncretized with internet, etc.With the development of technology in the network and multimedia area, the business of multimedia communication, especially the Voice IP technology has become a leading element in the Internet applications. The key technology of the development of Voice IP technology is Signaling Technology. At the present time, the most widely used protocols are H.323 and SIP. The Session Initiation Protocol is very concise in the structure, easy to be extended and realized, especially more suitable to access the Internet. All these advantages show that SIP is better than H.323 for Voice IP technology and the future development of network. So, the design and realization of IP Voice Soft-terminal based on SIP will be meaningful practice usage.This paper introduces the key technologies of developing IP voice soft-terminal, the SIP network architecture and makes comparison between SIP and the H.323 standard. This paper emphasizes the structure design implementation of IP voice soft-terminal based on the Windows platform, including the capture and compression of audio steams, the working thread of IP voice soft-terminal, and so on. And it shows that this soft-terminal can create the connection by SIP Signaling and finish the real-time communication through IP network by a functional testing experiment in local area network. Also tested the function of the soft-terminal and the server.