Ip Network Based On Virtual Coordinate Positioning Theory And Technology Research

Many large-scale distributed network applications such as application layer multicast and nearest sever selection can benefit from obtaining network distances between hosts conveniently. Although the distance metrics such as latency, bandwidth and packet loss rate can be accurately measured on demand, the huge number of wide-area-spanning end-to-end paths makes performing on-demand network measurements impractical because it is too costly and time-consuming. To bridge the gap between the contradicting goals of performance optimization and scalability, the network positioning technology attempt to predict the network distance between hosts, and it has become an important research field. The network positioning technology based on virtual coordinates especially gains much more concerns because of its simplicity and efficiency.In this paper, we will introduce the technology of IP network positioning at first, including the purpose of network positioning and the current development. Then we concentrate on the IP network positioning technology based on virtual coordinates, study the key idea of the very technology and describe the design approach and challenges of the network coordinate system. And then a novel landmarks selection mechanism which could predict network distance, conserve resources effectively and ensure the stability for the system will be taken into discussion. If the number of the landmarks is numerous, it is better to choose the selection mechanism in a random form; but if the number of the landmarks is little, we should use a kind of selection mechanism based on clustering mechanism to ensure a good distribution of the landmarks and improve the performance of the system. The selection mechanism mentioned above to choose the landmarks will make use to minimize the number of landmarks and will also ensure a good distribution of the landmarks. Hereunder, the so called minimize landmarks selection mechanism improves the performance of the network coordinate system. After that, we concentrate on the accuracy on the network coordinates, in order to finger out the best judgment standard for the accuracy on the network coordinates with mathematical methods. As far as the characteristics of the IP network are concerned, a set of network geometries and methods has been proposed. Based on the acquired IP network positioning technology based on virtual coordinates, this article combines the results of embedding network distances in space, contrast the performance of the accuracy standard between the obtained network system and the optimized network system. At the end of the article, we summarize the whole contents and propose the further work in this field.To sum up, the main contributions of this paper are as follows: we research on two subjects on the network positioning technology based on virtual coordinates: one is accuracy study, other for stability analysis. Novel landmark selection mechanism is proposed. When using a larger number of landmarks, the random selection is effective; when using a small number of landmarks, the selection methods based on clustering can make the landmarks have a good distribution, and also improve the stability of the system. The network coordinate system of landmarks is proposed based on current work, which minimizes the number of landmarks to reduce the measurement overhead, and uses the landmark selection mechanism mentioned above. Landmarks minimizes the measurements of all the ordinary hosts, which can reduce the measurement overhead of the system; at the same time, the distribution of the selected landmarks can improve the accuracy of distance prediction, and also make the system have good stability performance.