Software Implementations Of VOD System In Community Broadband Network

With the phenomenal prevalence of the intelligent communities and the rapid development of broadband access technologies, a variety of broadband technology based applications are becoming familiar to people day by day. Video on demand system is the typical case among those applications.The key challenge in VOD domain is to provide interactive services for thousands of potential users at a reasonable cost. In order to address this problem, we carried out a deep study on VOD server performance aiming at maximizing the total amount of concurrent data streams the system can bear as well as maximizing the user number the system can serve simultaneously.Depending on the technology adopted, VOD system can be distinguished into two categories. The first one is based on unicasting and the second one uses multicasting. They all have their own advantages and disadvantages. Unicasting based systems can offer the user full control over the media stream, thus are much preferable by the user. But since each stream is exclusive occupied by a single user, the cost per user is very high. Therefore the price of the service may hinder the wide acceptance of the system. On the contrary, in the multicasting systems, all the users ordering the same program can share the resources while the intelligent network switching system is on duty of the transmitting and dispatching of the program data. Hence the system can theoretically support unlimited number of users at one time. On the other hand, since each stream is shared by numerous users, it's difficult to provide sufficient interaction to make the users much satisfied. As a result, we can see that these two kinds of systems are complementary to each other. In order to get the widest market coverage, we decided to provide these two kinds of systems at one time.This thesis mainly introduces and illustrates the Ethernet based intelligent community VOD system designed and developed in our lab, including the design and implementation of two independent and complementary subsystems: the unicasting VOD subsystem and the multicasting VOD subsystem. It consists of seven chapters.In the first chapter, I simply analyze VOD system in detail covering the constitution, the categorization, and the prospect. The second chapter introduces the intelligent community broadband access system as a whole. This system is designed and developed by our lab. It not only includes the VOD subsystem, but also encompasses several other subsystems: live digital TV program, video conference, IPphone,network management,accounting,etc. There is still some other supporting equipment: switches,residential gateways and so on. They coexist in the big system,supporting and supplementing each other. The third chapter described the processing and storage of the video program data. In the forth chapter,I give a deep and broad analysis about the critical elements which affect the performance of a VOD server greatly. Chapter five and six elaborate the concrete implementation of these two systems respectively. The last chapter is a general statement of the system and future work.