The Design And Implement Of VOIP System

To date, in order to provide a worldwide IP network transmission framework through adopting new generation network is perceived. User is able to use different services by accessing the network as well as communicate with other agents anytime anywhere. Such multimedia communication will not be restricted in a pair of telephone conversation. The ability of multi-communication may be anticipate to provide the service. Under this kind of multimedia communication service environment that an integrated, efficient, and extensibility of multi-point conference control function requirement is predictable. In this paper, a COD Agent is adopted to integrate three kinds of VoIP protocol as the method to accomplish online multi users and making communication with each other. The COD Agent have the multi-point conference of great ability. First, COD Agent VoIP(Code-On-Demand Agent VoIP) that implement a session initiation protocol (SIP) as the base for control mechanism. The SIP can efficiently accomplish multi-point conferencing at this control function. Nevertheless, it need only to load dynamic program for SIP terminal without adding new server node into the core network. But it maintains a simple core network and simplicity for SIP and compatibility within other SIP UA. In fact, using the same method of the end user agent that is able dynamic loading its program into MGCP terminal. In addition, there is no need to make any change in all MGCP servers. The research have two main achievement: 1. The user can adapt different VoIP protocal, for a mechanism based on the Code-On-Demand agent mechanism. 2. Designed and Implementation the Agent Code dispatch mechanism, It may defer to the request to inform various users automatically to download the demand VoIP Agent. The development of VOIP technology and services has made a deep affcction to the traditional telephony service, especially to the International or National Direct Call service. How to setup one set of VOIP network architecture and to develop the VOIP devices suitable for our country have been the value question. IP-Phone, A new technology which transmits voice over internet . This is a economical, easy, efficacious communication means. In China, Four companies provide this service. But, there some problems in IP-Phone, such as transfer delay, delay variation and common communication interruption. The goals of this topic,Firstly,developing a simple IP-Phone system. Secondly, providing some technologies to improve the voice quality over internet. This paper introduces voice technology and IP-Phone systems and standard used in IP-Phone , the developing of a simple IP-Phone system. Then, the more possible ways to improve voice quality over internet. The naissance and development of IP telephony offers a new way to shorten the distance among the people and foresshows the progress of the new generation information network.