RLDP: A novel risk-level disjoint protection routing algorithm with shared backup resources for survivable backbone optical transport networks

In this paper, we investigate the problem of survivable routing in backbone optical transport networks with Shared-Risk Link Groups (SRLG) constraints. We present a new idea that considers the different risk-level protection for difference service level requirements of connection requests. Based on the presented idea, we propose an effective Risk-Level Disjoint Protection (RLDP) routing algorithm for provide different service level for connection requests. In RLDP, the backup path can be partial SRLG-disjoint with the primary path, and the backup wavelengths also can be shared by different backup paths if their corresponding primary paths are risk-level disjoint. Compared with the conventional SRLG-Disjoint Protection (SDP) routing algorithm that provide full SRLG-disjoint survivable routing for each connection request, RLDP can perform better resource utilization ratio and blocking probability. Simulation results are shown to be promising.