Sip Protocol For The Research And Application

The Session Initiation Protocol (SIP) is an application-layer control (signaling) protocol distributed by IETF for creating, modifying, and terminating sessions with one or more participants. These sessions include Internet telephone calls, multimedia conferences, and multimedia distribution.SIP invitations used to create sessions carry session descriptions that allow participants to agree on a set of compatible media types. SIP makes use of elements called proxy servers to help route requests to the user's current location, authenticate and authorize users for services, implement provider call-routing policies. SIP also provides a registration function that allows users to upload their current locations for use by proxy servers. SIP runs on top of several different transport protocols.As one of the two standards for constructing VoIP (Voice over IP) system, SIP is becoming a focus because of being a simple, agile, and high effective tool. SIP provides a new application space to VoIP with the nicer expansibility and compatibility.The purpose of this thesis is to explore the designing idea, content, and realization mechanism of SIP. On the basis of exploring, a transaction managing module and a syntax parsing module are designed to be used to solve the key problems (transaction managing and syntax parsing) in the SIP applications. This thesis also introduce the designing idea and realization method for the two modules. In addition, the testing results to the function of the modules are presented.