Design And Realization Of VoIP System Based On SIP

With the development of computer science and network technology, information network based on the multimedia communication has become the focus all over the world.VoIP technology is not asingle but a system integrated with several technologies constructing communication network,including Signaling Protocol, Voice Codec, Media Transport and Gateway Control. SIP Compared with another Signaling Protocol H.323, it has virtues such as more simple in call flow and text messages. And it is taken into use by more and more equipment provider.This research discusses standard and key technology of IP telephony,analyzes this IP telephony protocol,designs a set of telephone service system based on VoIP, includingsystem analysis,system design and system realization,and finally tests this software toachieve the expected goal.I finished the paper based on this research.The present paper has studiedthe VoIP technology as well as accounting the correlation standard and the protocol, On the base of research of VoIP protocol and SIP, a set of API functions was designed to implement SIP UA functions.Analyzes the infrastructure of VoIP system basedon SIP.With the study of SIP's functions,SIP protocol stack,networkinfrastructure,SIP message,call process,we get the idea of SIP andfigure out the advantages of it. disposing OpenSER.Integrate with Radius as the authorization server when the clients login.Testing the system with protocol tool and giving the testing result. The test indicated that,this RADIUS server can with the client termianl,the gatekeeper coordinates together works,completes the Authentication and Accounting function, simultaneously. This system can support many kinds of services,has quite wonderful voice, Finally ,proposed this system deficiency and waits forfurther the thorough tentative plan.