Tianjin Unicom's SIP Sofephone

Currently, with the rapid development of internet and Multimedia technology and the growing broadband access users, internet has more and more influence on communications industry. Among them, VOIP services on the market share the most obvious. In order to better support multimedia business, traditional telecommunications networks had the necessary network transformation.NGN is the ultimate goal of this transformation.NGN system is mainly include H.323 and Session Initiation Protocol(SIP).SIP is defined by Internet Engineering Task Force,which for establishing the conversation streaming media between two or many participants. H.323 is defined by International Telecommunications Union.The SIP protocols are simple, flexible and easily to expand. So it is accounted to the important signal technology in the NGN, and obtains widespread development.This thesis design and implement the Tianjin Unicom's telephone terminal based on Tianjin Unicom's network and Tianjin Unicom's requirement. Solved the Tianjin Unicom's AE(access equipment) only have hardware equipment but not have soft equipment. Firstly the thesis analysis the system structure of SIP protocol and the open protocol stack OSIP using C language. Secondly, this thesis brings out the whole structure of the system Project. It is designed by module project and based on the requirement of Tianjin Unicom's telephone terminal. The system includes five modules,media transact module including audio & video module,data transfer module,protocol module and main controlling module. The protocol module is based on OSIP protocol stack. Transfer module uses UDP protocol to implement the transfer of message and multimedia data. Media transact module adopts window's function and DirectShow for the system transacting audio and video data.This thesis is the realization of Tianjin Unicom telephone's registration and call, formulated the Tianjin Unicom's standard about SIP phones, and saving the cost of test.