| The audio, video and data three major networks overlapping investment are a large amount of wastes of communication resources. The countries all over the world are studying this question, the unification of three nets and Next Generation Network (NGN) are the hottest topic now. VoIP is one of a key technology. VoIP portfolio is increasing in high gear, that it will most likely exceed PSTN in the near future. So as the enterprises, it can also unify the data and telephone network together, to improve the working way and the efficiency of working in coordination. The key equipment which joins the telephone and data network is gateways.This article locates in the enterprise level VoIP network voice terminal gateway, has expounded the fact in detail how to design and realize voice terminal gateway equipment based on SIP protocol and ARM platform. First, this text has described the background and principle of VoIP, then research and analyse SIP protocol to apply to the feasibility and superiority of the communication in time, thus put forward a kind of design plan that embedded VoIP network based on SIP agreement closes. Then in detail elaborated this system design and the realization from two big aspects, One respect is the systematic platform that has adopted ARM7 as the central hardware platform and VxWorks RTOS as the operating system. It is completed that transplant the VxWorks operating system into this hardware platform , realizing a low price but high-efficient embedded hardware platform of 32Bit CPU. another respect is application program development which Use the outstandingly opened-source SIP protocol stack, eXosip/oSIP protocol stack, therefore, has carried on task design and program development on this. Finally I has complete the test and the simulation to the system both software and hardware.The fact proved, this article proposed the plan and the realization has the very strong practical significance, simultaneously has conducts the following research the value. |
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