Research And Implementation Of IP Telephony Gatekeeper

Since 1990s, the rapid development of Internet has great influence in telecommunication field. The research of multi-media communication system on exchanging network is gradually becoming the focus of people. The technique maturity of Audio and video frequency compression, real-time data transfer and network have make it reality to realize the multi-media correspondence on the IP network.This paper begins with the history development of IP telephone, introduction of Next Generation Network. And then concludes that IP telephone is the inevitable direction of the development of voice correspondence development of Next Generation Network in chapter 1. Given the advantage of IP phone system and significance of research it. In chapter 2 we first study several kinds of international standards for IP telephony and mainly study IP telephony based on H.323 standards that have been our country standards for IP telephony field. The key technique towards IP telephony is studied too. The long-termed and near-period project of the system of IP network telephone was designed in Chapter 3 under H.323 standards and considering the IP telephony developing hotspot. Long-term project is a complete solution, but the period of its development is longer. However near-period project Xy-Com IP telephone is suitable for now to go to develop. Whole system of near-period project includes Gatekeeper, auto answer machine server, four or one port IP network telephone HUB, USB interface terminal of an IP telephone, standard H.323 terminal etc. Whole system constitute an IP PBX system, which not only have the basic function of an IP network telephone, but also have part of the supplementary service, such as call transfer, and have part of the ability of UMS. These all have the most advanced ideas. Gatekeeper is designed and implemented That is the main work of this paper. Gatekeeper that not only completes the basic function but also realizes call transfer function is designed and implemented at length in chapter 4 according to the project of near period in chapter 3. In chapter 5, auto answer machine and other equipments in our system were designed and implemented. In this chapter our whole system were tested and acquired a good test result.