The Itu H.323-based Voip Network

The combination of theories of large scale system and information industrial is the new phase of the development of information industrial. And the method of hierarchical control is becoming more and more important in network technology. This research is based on the IP telephone project of Xi'an Datang Telephone Corp, the famous Chinese telecom equipment manufacturer. After applying method the hierarchical control to the VoIP system, writer designs and develops the central controller of VoIP system based on ITU-TH.323-- Gatekeeper. Basic structure and signaling of H.323 protocol is introduced, as well as the primary functions of Gatekeeper. A hierarchical VoIP network model based on Gatekeeper is put forward through analyzing the shortage of gatekeepers?currently working way and applying the thought of hierarchical control. Some problems in the implementation of gatekeeper such as routing, billing, authentication function, call signal flow and quality of service are analyzed. Solutions and strategies based on the main frame and signaling - characteristics of H.323 protocol are put forward accordingly. The design. scheme and realization of gatekeeper are described. The project puts up good performance in simulating environment. The total VoIP system of Xi抋n Datang Telephone, gatekeeper included, has been passed the authentication of Ministry of Information Industrial, and been granted the right to access telecom net.