The Research On Dynamic Large File Transfers In Optical Networks

With the fast development of information technology and the steady progress of informatization level, there are higher and higher demands on network bandwidth. Optical network has the characteristics of high bandwidth and low latency, therefore it has become a preferred choice that can meet the higher and higher demand on network bandwidth from people and become the research hotspot in both academia and industry. Among the applications in optical network, one important issue is the large file transfers on optical network. No matter for data aggregation and the high-performance computing in e-Science, or the data downloading services in digital entertainment applications, the issue of large file transfers in optical network always plays an critical role in these applications. Considering the fact that an optical network is usually shared among multiple users and the optical link resources are limited, the large data file transfers requests submitted dynamically from different users will cause the optical resources contentions in the network. Therefore, the issue of how to effective schedule and allocate network resources to the applications of large file transfers from different users become a key point to improve the performance of the applications of dynamic large file transfers in optical networks.In this thesis, we first investigate the problem of large file transfers on wavelength-routed WDM optical network. We carry on our research from two aspects: scheduling and routing, and several heuristic dynamic scheduling schemes and a new Max-flow based rerouting strategy are proposed to analyze the performance of large file transfers in dynamic optical network environment. We consider two metrics, namely the efficiency and fairness, to evaluate the performance of the scheduling schemes and the rerouting strategy we proposed in this thesis. Here, the efficiency aims at how to achieve the best overall quality of optical network service, and the fairness regards the service quality deviation among the users in optical network. And we also analyze the performance of large file transfers in packet transport network. Based on the previous qualitative analysis of packet transport network from domestic and foreign scholars, in this thesis we further compare and analyze the performance between traditional SDH transport network and packet transport network for the application of dynamic large file transfers.In this thesis, we use simulations to verify the performance of the heuristic scheduling schemes and rerouting strategy we proposed, as well as the performance difference of large file transfers between traditional SDH transport network and packet transport network. The results of our simulations show that different scheduling schemes have different performance characteristics, and the rerouting strategy we proposed has better performance than the tradition adaptive routing strategy based on shortest available path. Our simulations also show that compared with the traditional SDH transport network, packet transport network can achieve better performance for the application of large file transfers because of its statistical multiplexing characteristics.