Research And Implementation Based On Mobile Voip SIP

With the rapid development of wireless network technology and the continually strong mobile device features, the traditional media businesses have been unable to meet people's needs. How to develop the mobile media with more value-added services in the existing heterogeneous network environment has become the most popular of current research. One of the most typical applications is VoIP technology. A key realization achieving VoIP technology is the signaling technology. There are two wildly used signaling systems:H.323 and SIP. H.323 is powerful but complex. It provides a complete framework with higher requirement and is achieved more difficultly. SIP protocol is a signaling control protocol which is simply expensing and achieving, based on text. More important is that it is unrelated to the low-level access. Above the reasons, the research based on the support and application of SIP for mobile VoIP has more important significance and value for developing access unrelated mobile multimedia applications.This thesis design enables network service components of SIP. Through this system, mobile VoIP users based on SIP are easily able to locate and establish multi-media session, then complete the voice interaction. Follows RFC3261 specification, this system redesigns the SIP protocol stack based on the MJSIP protocol stack and achieves transport layer, transaction layer and transaction user layer. It achieves SIP element location, including proxy servers, registration servers and redirect servers and builds a SIP-based platform for network convergence. Meanwhile, this paper has researched on emerging open-source Android mobile operating system which uses the SIP protocol stack on the Android platform to achieve a simulated end-to-server communication.While completing the above functions, this thesis focuses on the support of SIP for mobility and raises a dynamic hierarchical registration model, used to implement the switching delays within the domain for mobile device.Because the SIP protocol is lack of security mechanisms, in the SIP applications, security issues are valued to concern. This thesis also carried out the safety of SIP-related research and realized Http summary of certification program.This system carries out a number of tests to verify the correctness and stability of the SIP server in a simulated network environment. This article only provides the basic functions of SIP network and verifies feasibility and conveniences of SIP mobile multimedia. Next stage, we will focus on web development SIP-based multimedia applications, such as:multi-party conferencing systems.