| In 1995 the first IP(Internet protocol)phone came out.Until today, IP phone has been applied in telecommunication level system and more and more be a part of people's usual life.As Internet's rapid development, a great deal of communication go along with it. So it become a new problem that how to amalgamate various services into traditional telecommunication network and IP Phone is the answer.SIP is an application-layer control protocol for creating, modifying, and terminating sessions with one or more participants. It can amalgamate traditional telecommunication network application into Internet application and break the traditional telecommunication service model,it provides muti-media service based of IP with Internet rules, so IP Phone which use SIP as signaling protocol become a choice by more and more developers. This thesis discusses the IP phone terminal software base on SIP protocol over Intemet(SIP phone).The thesis studies the method of software development of IP soft terminal based on SIP, does total design and integrant design, resolves some actual development problems.The thesis reserches the SIP calling process, RTP and other interrelated protocols. Accomplish the design and software development of phone system for audio and video in detail, including the design and realization of network interface, the design and realization of SIP stack and the design and realization of SIP UA, and reserch the collection of AV(audio and video) data, the realization of compress/decompress and the realization of the mutil media real-time transport via RTP. At last, we give the disadvantages of the VoIP system, and present some ideas to improve it and make it prefer. |
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