Abstract:

Two algorithms are proposed against single span failure in WDM networks. One is called link-based optimized shared-protection algorithm (LB-OSPM). The other is Hamiltonian preconfigured cycle （p-cycle） based protection algorithm (HPC). LB-OSPM introduces wavelength usage matrix and wavelength reservation matrix to record the detailed usage of wavelengths reserved in the past so as to allow different protection paths of working trees to share reserved wavelengths. HPC takes advantages of single Hamiltonian p-cycle to cover all working links in the network to attain source efficiency and fast protection. Study uses the topology of COST239 to calculate the network blocking probability of these two algorithms under various conditions of wavelength resources and network loads and compares them with an existing cost-effective algorithm, optimal path-pair-based shared disjoint paths algorithm（OPP-SDP）. The results demonstrate that our algorithms can gain lower blocking probability while assuring a 100% restorability rate in the case of single span failure.

Key words: wavelength division multiplexing, multicast, shared protection, preconfigured cycle