Research And Implement Of Communication Software Based SIP On Windows Platform

SIP is the key call control protocol used in packet-based voice and multimedia networks.With the development at full speed of VolP technologies, SIP protocol is being paid more attention day by day.At present, Electronic communications and the computer industry is becoming technically merged, PC introduced to the field of telecommunications brings enormous benefits for developers and end-users.The paper focuses on the SIP, and research the communication software(TAPI) based SIP on Windows platform,the main works contain:Firstly,the paper introduced VoIP concept,development, third-party interface briefly and gave a detailed description of today's fastest-growing VoIP protocol-SIP , including an overview of SIP , description of the message contents,the fields and so on. As the most common body of SIP, the paper described SDP's functions and fields. On this basis we achieved the right SIP entities-VPP stack for the talks, containing stack modules and functions, transaction FSM and the timer mechanism.Secondly, paper described the third-party interface TAPI's development, basic services,structure and composition. It also highlightly described the relationship between TAPI and TSPI. Then paper elaborated the third party connection software XETelephoneSP based on SIP basic overhead construction and the concrete realization methodAs message carrier of the software-SIP, the paper concentrated on how VPP SIP stack was applied on the software,the detailed content contained:initial process of VPP stack,interface matching to APP and the topper message's convert.Final the paper gave an account of one kind of the realization method how to make use of XETelephoneSP to make a call.The last, paper put some proposals for the amelioration of XETelephoneSP and prospected the third-party interface's further improvement.