Research On Key Technology Of Content Delivery Based On Service Grid Architecture

The rapid development of the network technology and application, especially broadband network and multimedia technology, makes it possible for the application like distance learning, visual telephone, video on demand, and video conference to become a part of daily life with everybody. In particular, the use of multimedia formats has become common for delivery of rich media content to the public - both residential and business. To overcome this challenge of massive multimedia consuming, only installing more high-speed main pipes will not be enough; service providers need a more intelligent and powerful middleware infrastructure to control and manage content service. Among all kinds of middleware solutions, Content Delivery Networks (CDN) becomes a mainstream. CDN is based on a large-scale distributed application layer network of servers located closer to the edges of the Internet for efficient delivery of digital content including various forms of multimedia content. The main goal of the CDN architecture is to push content as close to the user as possible to minimize content latency and jitter and to maximize available bandwidth speed.Although CDN is an effective means of content access and delivery, there are several barriers to make CDN a more common service: delivery architecture, resource model, delivery mechanism, resource allocation, performance evaluation, cost and so on. Furthermore, in order to more effectively address the requirements to access multimedia services from everywhere at anytime, recent research has focused on the development of new scalable, efficient, and flexible "next generation" middleware platforms. These middleware platforms are intended to support the deployment of mainstream broadband applications including CDN technology. One such next-generation middleware platform is the grid technology.This thesis is a part of research output of National Natural Science Foundation of China Program (60373018) -Named as "Research on Grid-based Rich Media Content Delivery Network". From the analysis of some hard problems in content delivery technology today and an arriving grid delivery technology, we present content delivery service grid as a new multimedia delivery architecture based on service grid architecture. Furthermore, we carry out a series of key technology research including system architecture and service model, resource model and service locating, resource reservation and co-allocation, QoS control and SLA negotiation, andperformance evaluation model and so on.Firstly, we propose a new content delivery infrastructure based on service grid, and describe the Intergrid-intragrid system architecture, hierarchical Intergrid virtual organization relationship architecture. Furthermore, we provide a new service model and describe the main components and key services in this model.Secondly, based on the analysis of hard problems of resource model in the CDN and computational grid, the thesis gives a novel resource model, VO-Assistant Hierarchical Resource Tree Model - VAHRTM model, to organize resource and manage all kinds of resources in the content delivery environment. VAHRTM organizes resource to form hierarchical architecture in lengthways according to native communication relationship among resources. At the same time, the resource hosts in the same depth can dynamically form Virtual Organization in widthways to cooperate for providing of content service and efficient locating of service. The algorithm and experiment have verified the advantages of this model.Thirdly, we analyze all kinds of resource allocation schemes such as GARA and propose a novel content delivery service resource allocation scheme - On Demand Queuing. This thesis proposes the function architecture of the scheme, and researches the hierarchical scheduling mechanism, monitoring and adapt mechanism, including the main algorithms.Fourthly, we propose a new performance evaluation model as a branch of the service model. We construct the novel evaluation parameter system by extending Queuing Network evaluation...