Theoretical analysis of preconfigured k-edge-connected structures in flexible bandwidth optical networks

We propose a protection scheme based on preconfigured k -edge-connected structures (p-kecs) and study the spectrum resource redundancy of flexible bandwidth optical networks under single-link-failure and multiple-link-failure environments. The lower bound of redundancy and the upper bound on efficiency of preconfigured protection structures in flexible bandwidth optical networks are provided. With sufficient capacity, the analysis shows that p-cycle is the optimal structure against single-link failure and p-kecs are the optimal structures to address multiple-link failures. Straddling links reduce the network redundancy while requiring little or no increase in spare spectrum capacity relative to the total spectrum capacity consumed in the protection process. We theoretically prove that the spectrum resource redundancy of the p-kecs has the same lower bound as that of flexible bandwidth optical networks under multiple-link failures. Numerical results show that p-kecs can achieve or approximate the lower bound on redundancy and support protection against multiple-link failures in static and dynamic networks. These results support the theoretical underpinning for the efficiency of p-kecs in providing protection against multiple-link failures in flexible bandwidth optical networks.