Study On Link Failure Protection Strategy Of Optical Transport Network For High-speed Railway

The optical transport network of high-speed railway has taken a very heavy job,including train status monitoring,operation scheduling,emergency operation of trains and so on.For complex and diverse transmission services,the focus of current research is ensuring the safe operation of the optical transport network for high-speed railway.In order to avoid the huge damage caused by the network failure,this paper does research on P-Cycles protection technology based on single-link failure and network failure protection scheme based on service flow in mesh network.1.In view of the single-link failure,a new heuristic algorithm(FREA)is proposed in this paper.FREA uses the SLA algorithm to construct the basic P-Cycles,takes the redundancy and normalized variance of unprotected working capacity as the evaluation indexes,limits the length of the P-Cycles with the unprotected link ratio,and compares the performance of the algorithm by setting different values of the parameters a,b,and M.Simulation results show that the algorithm has the best performance.When the network working capacity is determined,FREA is superior to POCA in terms of performance such as the number of P-Cycles,the running time of the algorithm,the overall protection efficiency and the network resource utilization ratio.By comparing the performance of free resource allocation between the two algorithms under five groups of random services,it can be concluded that the FREA can protect all working capacity in the network completely with less free resources.2.In view of the transmission services of the optical transport network,a new algorithm of P-Cycles protection(SM-FRREA)based on service flow mapping is proposed in this paper.SM-FREA constructs a virtual working capacity matrix to provide prioritized protection for links that have high-level,high-reliability and real-time services by using method of service mappings.Simulation results show that SM-FREA can effectively complete the mapping process from the service flow to the P-Cycles protection circle and completely protect the entire network services by increasing the complexity of the algorithm appropriately.