Study On The Survivability For IP Over WDM Optical Networks

As the rapid development of internet and telecommunications, and the sharp increment of the network users, the requirement of the users to networks has also changed markedly. Under this background, IP over WDM optical networks appears. At the same time, people require more about network survivability. So, study on the survivability of IP over WDM network has become a hot issue.In this thesis, the evolution of network hierarchy, the service models of IP over WDM networks and the MPLS/GMPLS are discussed firstly. Then, the recovery mechanisms on IP layer and WDM layer are introduced individually. Thirdly, an optical network simulation platform based on NS2 is built. The NS2 network components are extended in this simulation platform so as to simulate the optical networks in NS2. Finally, a coordination recovery strategy for multi-layer optical networks based on monitoring system is presented. The new strategy is simulated on NS2 simulation platform, and the advantage on restoration efficiency of this strategy is verified.The restoration in multi-layer optical network can be implemented well by the new strategy, and the structure and the protocol of the networks needn't to be changed. At the same time, the real-time monitoring provides the rapid recovery in network layer, which is achieved by setting backup static routing before network congestion appeared. It is shown by simulation that the application of monitoring system solves the problem of the coordination restoration of the multi-layer optical networks, and also greatly reduces the recovery time in the network layer by establishing a static routing in advanced, so the network survivability is enhanced. In addition, the implementation of this strategy needn't to change the existing network architecture, so the strategy has a high reference value for existing network survivability research.