Survivable Hierarchical Optical Path Network Design With Dedicated Wavelength Path Protection

In this paper, we propose a novel network design algorithm that yields the hierarchical optical path network with dedicated wavelength path protection. A hierarchical optical path network provides two granularities in implementing dedicated protection in the optical layer, namely waveband path protection and wavelength path protection. The characteristics of both protection mechanisms are investigated. We develop the concept of the source-destination Cartesian product space to aggregate closely located traffic demands, which leads to a significant reduction in network resources needed. The proposed wavelength path protection algorithm achieves lower network costs than that possible with waveband protection when traffic volume is relatively small. On the other hand, in the large traffic demand area, both schemes offer almost the same cost, which makes the waveband protection scheme attractive because of its operational simplicity. Numerical results clarify that survivable hierarchical optical path network is more cost effective than the single layer optical path network with optical layer protection, irrespective of which protection scheme is utilized.