Research And Implementation Of A SIP-based Multimedia Service Access System

With the exploding development of the Internet, the requirements of multimedia telecommunication have increased from single audio or video service to the integration of audio, video, text, fax, E-mail and file transfer service etc. In this paper, we focus on the design and implementation of multimedia service access system.At first, we present a pattern-oriented, event-based and scalable model of multimedia service access system with three layers. We design the architecture of the access system of "Multimedia Session System with Mobile/Roaming Supported" under the guidance of this model. Then, we design a SIP state machine which supports authentication and external session management, formalize the signaling process and discover the state conflict through logical consequences. To improve the performance, we integrate sender-initiative, receiver-initiative and dynamic restriction with our load balancing algorithm.This paper also describes the implementation details including classes, data structures and function interfaces. Finally, we test the performance of this system using the 3^rd party testing instrument, and the results show that it meets the access requirement for large quantity of users.