Designs of OTN-level shared mesh restoration in WDM networks

Switched optical transport networks (OTNs) and OTN-level shared mesh restoration (SMR) are promising technologies for improving the efficiency of the current OTN/WDM networks. In this paper, we present the evaluation results of OTN-level SMR in WDM networks. We focus on equipment cost, capacity utilization, and the value of sharing factor N in 1 : N protection. Evaluation results show that OTN-level SMR can simultaneously improve cost and capacity utilization as compared to 1+1 dedicated protection. We also investigate the cost impact of SMR operational restrictions: fixed tributary slot assignment for fast restoration, and the upper limit on the value of N for the sake of maintaining service quality. We find that both restrictions incur only marginal cost increases against unlimited sharing of protection resources. These findings motivate network designers to apply the new dimensioning presented in this paper, which improves the robustness of WDM networks with OTN-level SMR by adequately managing protection resources and controlling the value of N at a marginal cost increase.