Mobility Study And Implementation Of SIP

The Session Initiation Protocol (SIP) is an application-layer control (signaling) protocol distributed by IETF. As one of the two standards for constructing VOIP (Voice over IP) system, SIP is becoming focus because being simple, flexible and open. It is one of the essential protocols to implement Next Generation Network (NGN). With the development of IP and mobility, people have got the idea of merging the two technologies. SIP can support mobility well at application layer. The purpose of this thesis is to study and explore the implementation of SIP mobility. On the basis of studying SIP and how SIP provides mobility support to real-time multimedia application, a SIP based mobile VOIP system is designed. Developing the whole system is difficult and needs too much effort. So open source code——oSIP is used in the implementation of the software. In this thesis, oSIP code structure is studied and is used to implement transaction management module and parser modual in the software. The differences of each logic elements and mobility support are implemented in transaction user logic modual. In this thesis, UA design idea and mobility implementation are focus.