Research On The Support Of OS To QoS Of Stream Media

With the rapid development of Internet and Intranet, Video On Demand is imperative to satisfy the requirement of entertainment on network and remote multimedia education. Recently, VOD, which transfers and processes the stream-media information on demand, has become a widely used-method of passing information. VOD is one kind of cross-link products of multiple technologies, such as computer science technology, communication technology, multimedia technology and compressing -storage technology.Linux is the product of Internet. As a network based OS, many companies, enterprises, institution of scientific research and computer fans are fond of it. They provide a variety kinds of services, suchas WWW, FTP and VOD etc., to consummate Linux operating system. But VOD with high quality based on Linux is a research scope that still remains to be solved fully.This paper is proposed out of the situations we mentioned above. However, we do not mean to study the whole VOD system, and we only focus on the underlying system of VOD梩he technique used to support Multimedia Stream by OS.With the development of the information technology, the home-networking technology has made an important breakthrough. As the only interface between home networking and Internet, the Home GateWay play an important role in the integration of information appliance. According to this, we take the Home GateWay as the extensive client of VOD, and use the Home GateWay to transmit, code and decode the Multimedia Stream.The author improves the existing QoS architecture of Linux OS, and implement the QoS API by-System-call. By using QoS API, the QoS request decided by user is passed into kernel. Based the concept of Differentiate Service, the DCLASS object is constructed by using DSCP, and is added to RSVP message. The DCLASS object is used to aggregate the RSVP's flows, which can improve the shortcoming of RSVP. The extension of RSVP桝RSVP(Aggregative RSVP) is proposed, and implemented in Linux. ARSVP is used to implement control of the video streams, and improve the processing ability of the Multimedia Stream in Linux.In this paper, the general work is to construct the Home GateWay and Video Server based on Linux OS. We mainly discuss how to improve the quality of VOD service in the VOD system architecture, and how to efficaciously transmit the independent video streams between server and client.As far as the Linux kernel is concerned, we get two shortcomings of the underlying support system of the Multimedia Stream in this paper:1) the protocol stack of networking is too simple to guarantee the quality of service of the Multimedia Stream's transmission;2)Lack of the independent QoS configuring interface, and unable to implement the applications for which QoS would request. And so, we extend the existing QoS architecture of the Linux OS, and provide newresolution to Multimedia Stream. These are the main work in the research. The main contribution in this paper are described as below:Extend the Linux kernel, implement the QoS API, and take QoS API as the base of the implementing QoS application;Integration with characteristic of the Linux kernel, improve on RSVP; At last, we describe a new accounting system based on QoS.In the future work, We may use the network system supporting QoS implemented in this paper as the underlying of VOD. Thereby, it is possible to implement VOD with software-based means.During the research, author accomplished the project "the research of the Pervasive Computing and Home GateWay" supported by SVA and published a piece of papers in domestic core magazine.