Design And Simulated Implementation Of Double-Link Failures Protection Algorithms In Traffic Grooming WDM Mesh Networks

With the appearance and development of Wavelength-Division Multiplexing (WDM) technology, network bandwidth resources are fully utilized. The WDM optical network carries a lot of traffic and the consequence is that any breakdown may lead to huge loss. Therefore, survivability of WDM optical network becomes extremely important. Most of current studies in optical networks are for single-link failure, and fewer studies are for double-link failures that mean the simultaneous failures of two fiber links. With the network size increasing, the probability of occurring double-link failures greatly increases. On the other hand, many new businesses, such as the settlement among banks, will not satify the single-link failure protection, but need a very reliable transmission and also pay more cost for this service. Therefore, it is nessesary to study the protection design for double-link failures.This thesis studies the protection algorithm of double-link failures in optical WDM mesh network with the capacity of traffic grooming. In this thesis, Chapter 2 describes the auxiliary graphs inlucing Virtual Topology Graph, Layered Graph and Integrated Graph for supporting traffic grooming, and also introduces the traffic grooming algorithm named Integrated Graph Algorithm in WDM mesh networks. Based on the integrated graph and traffic grooming algorithm, Chapter 3 designs the dedicated protection algorithm and shared protection algorithm for double-link failures, and further designs a modified shared protection algorithm to overcome the disadvantage in convetional shared protection algorithm. Because not every demand needs the complete and reliable protection for double-link failures, Chapter 4 designs a shared protection based on the demand's priority to provide the different-level protection for different-priority demand for saving network resources and recuding blocking probability.Finally, Chapter 5 develops the simulation software based on VC++ and makes the simulation and analysis for these designed algorithms on the performances of resource overbuild, mean blocking probability, algorithm running time, and quality of protection. Compared to traditional algorithms, these designed algorithms have better performances.