The Design And Implementation Of The VoIP Client Based On SIP

Along with the development of Internet technology, the services provided by Internet are getting more and more abundant. VoIP (Voice over Internet Protocol) which converge the traditional telecom technology and Internet technology has been a promising competitor in voice communication field. It can make the network more efficient, cut the cost and provide multiple value-added services. VoIP has a bright future even though there are some improvements need to be done in the service quality and security area.The Session Initiation Protocol (SIP) which was drafted by IETF is widely used for controlling multimedia communication sessions such as voice and video calls. The protocol can be used for creating, modifying and terminating sessions consisting of one or several media streams. SIP is one of the main protocols used to handle the VoIP signals. It is simple, flexible, easy to extended and implemented. Besides of these characters, SIP can support QoS perfectly, and meets all the demands of VoIP. It therefore gets more and more attention and progress. The research will make a great sense.First of all, this paper introduces the background and situation of VoIP. Next, we will describe the VoIP principle and the protocols used in it. We will especially give a detailed introduction to SIP, and the single process of it. Based on this, we will analyses the architecture and implementation of a VoIP client, and give the test report. Finally, we will make a brief summary of the research work and discusses the improvable areas of the implementation.