Abstract: The substrate link failures have made a great impact on the reliability of Reconfigurable Service Carrying Networks (RSCNs) over Reconfigurable Flexible Network (RFNet). In this paper, the reliability problem of delay-sensitive RSCNs is solved based on a path backup strategy, and a two-stage approach is presented to further reduce the backup resource cost. In the topology preprocessing stage, according to whether the path split is supported by RSCNs, the Splittable Minimum Backup Topology Generation (S-MBT-Gen) and Minimum Backup Spanning Tree Generation (MBST-Gen) algorithms are respectively proposed to reduce the total bandwidth constraints of backup topology. In the topology mapping stage, a Reconfigurable service carrying Network Mapping algorithm with coordinated Primary and Backup Topology (RNM-PBT) is proposed to make the best of the substrate network resource. The simulation experiments show that our proposed algorithms can reduce the average resource cost and execution time cost, while improving the request accepted ratio of RSCNs.