Design And Implementation Of Ip Telephony Systems

IP telephone is a very hot topic in IT field and can transmit real time voiceinformation in internet network. As a convenient, express and very low costcommunication instrumentality it transmits the voice signal real-time on the internet.With the establishment of large scale IP network and the extension of its applicationfield, how to elongate the skeletal IP network to enterprise user has becoming a keyfocus to puzzle the provider a lot. In order to build IP telephone network configurationthat meets the domestic practical situation and develop our own IP telephoneequipments, a IP telephone system based on the protocol of H. 323 is proposed in thisthesis.On the base of the detailed research on multimedia communication protocol H.323of packet switching network and full analysis of critical technology IP telephonesystem, the idiographic elongation application of IP network in user class isimplemented in this thesis by adopting IP Centrex system design. As a skeletalapplication of network elongation, the system provides basic voice communication forpersonal user and small, medium-sized enterprise and multi-appreciation-businessservice and QoS assurance.On the base of research on four critical technologies, the overall design of IPCentrex system and its six modules is represented in depth. Also, GateKeeper isdesigned amply in the thesis.