The Reserch And Implement On The Media Forwarding Fuction Based On IMS

IP Multimedia Subsystem is a new form for multimedia services,which can provide more innovative and anddiversified multimedia services, and is regarded as the core technology for next generation network. With the rapid development of network applications, VoIP technology has been widely applied on IMS. SBC(Session Border Controller) is a effective way for the session border control.So it has the highlighted significance of the high-performance,versatile Media Forwarding Function's research and implementation based on the SBC.This paper,on the basis of the distributed SBC, proposes the universal media transmission structure on IMS,defines a lightweight media control protocol, researches and implements the a high-performance media forwarding server, supporting heterogeneous network media adaptation and meet a wide range of reliable applications of VoIP on IMS.IMS network is still at an experimental and a small business stage, so there is no unified architecture for the kinds of media transmission model on IMS and the main difficulties of the network interconnection is FW/NAT traversal and media adaptation.So a universal media transmission model under a variety of network conditions on the media communications is particularly necessary. This paper uses the distributed SBC equipment and a self-defined media control protocol to achieve the correct media transmission. This self-defined control protocol is proved to be universal, manageability, compatibility and experiments proves the proper control for media.After the analysis of MFF's requirement, this paper proposes the Media Forwarding Function's model based on IMS. It compares a variety of traditional I/O multiplexing mechanism,selects the most high-performance of the current mechanism—epoll to implement the forwarding functions, achieving higher efficiency, lower delay and more users; then contrasts the current distinction service model, in accordance with the actual needs of specific,defines the multiports multithreading implementation mechanism of the equipment classification and the inter-equipment classification,which is a more simple, flexible mechanism to meet the requirements of clients.Through specific performance testing, client session numbers,media forwarding delay and the distinction service all achieve the target.IMS supports multiple media encoding format, so it has facilitate achievement on the media transcoding. After the analysis of a variety of solutions to media transcoding,it uses simulation test taking a efficient and flexible programme to the transcoding, protecting the equipment to maintain a high state of efficiency of the treatment. In the entire forwarding comprehensive management, it takes more use of load balancing and the principle of optimal allocation of resources to achieve the overall harmonization to ensure that a large-scale clients effectively process.