Research And Implementation Of The SIP Server In IPPBX

This topic research the IP private exchange (IPPBX) software realization based on SIP, through add the SIP signaling gateway, the media gateway, registers server, proxy server and so on to the NGL04 foundation hardware platform, develops a comprehensive media communications system with VoIP, data, immediate message.The VoIP system based on SIP should be composed by the proxy server, the registration server, the media gateway and other parts.This article will describe the realization method in detail to implement the call flow, the calling condition proxy server,the registration server of VoIP system based on SIP.SIP has defined the proxy server to the calling condition proxy and non-condition proxy. Under the non-condition pattern, the proxy server receives the call request, after the execution corresponding operation transmit the request, does not retain the calling condition. The calling condition proxy server has recorded the all condition information, may control the call completely, may realize some complex service logic to provide the rich service. The paper will describe the method to implement the calling condition proxy server based on the limited state machine.The SIP user should register to the registration server before initiates the conversation. The registration server usually preserve the user's registration address information in the location server, so the proxy server or the Redirection server knew which addresses may arrive.The registration information is renovatesed (default cycle is 1h), therefore the user should register initiative forwardly as a cycle.The registration service generally follows other functions, like provides the authorization function and so on.The paper described a realization method of the registration server with authorization function.The quantity of immediate message is huge, in under the entire proxy pattern, the immediate message and the response are transmitted by the proxy server, to bring the huge pressure to the proxy server. The paper propose a method to implement the immediate message on the embedded lightweight server.In addition.