The Design And Implementation Of IP Phone Based On SIP

With the progress of Computer technology, packet switching technology and voice compressing technology, the two networks that are the voice network and the data network tend to become amalgamation, so there came into being VoIP(Voice over IP)network phone to satisfy people's needs for real-time communication.Nowadays there are two directions for VoIP: H.323 and SIP. H.323 is mature, but it is relatively too sophisticated. SIP(Session Initiation Protocol) is a IP phone signaling protocol. It is simple, but it is a rising protocol and it has come into being only for a short time, so it is immature.Since SIP is a rising protocol, most related applications are archetypal. In addition because SIP is on the application layer, it's relatively easy to project based on it. So with the other members of the team the author designs and implements an IP phone software on Linux system, making use of a relatively mature SIP protocol stack named oSIP.The main contributes of this thesis is all the SIP related parts in the project, including the theoretic research on the SIP protocol, the analyzing of how to apply oSIP protocol stack and the design and implementation of an oSIP based SIP user agent. In addition this thesis also introduces the design and implementation of the user interface of the project, using GTK+, a high layer graphics storage. In the end this thesis summarizes the key technologies used in the project.