Active restoration (AR) is a novel lightpath restoration scheme proposed recently for guaranteeing a certain degree of survivability in WDM optical networks with a reasonable tradeoff between capacity requirement and restoration time. An analytical model has been proposed to understand the restoration probability behavior of a connection request in optical networks employing AR based on the assumption that all the backup routes of the connection are independent. In a real AR-based optical network, however, the backup paths of a connection are likely correlated since they may share some common links along their routes. As the first step toward the restoration probability analysis incorporating the correlation among backup paths of a connection in AR-based networks, we propose in this paper an analytical approach to modeling the restoration probability of the connection by considering all the possible correlation between any two of its successive backup paths. Compared to the old restoration models without considering the correlation among backup paths, the proposed new model can significantly improve the accuracy in estimating the restoration probability for AR-based networks, as verified by extensive simulation results based on two typical backbone network topologies.
['Mohamed Mostafa A. Azim', 'Xiaohong Jiang', 'Susumu Horiguchi']
Performance Analysis for Active Restoration-Based Optical Networks Incorporating the Correlation Among Backup Routes