Overlays and churn in WDM interconnected-ring metro networks

In WDM networks, multiple fibers are used to provide the needed capacity in highly congested routes. Such fiber overlays can also serve to limit the wavelength blocking experienced in transparent optical networks. In this paper we investigate the use of fiber overlays to manage connection blocking in transparent interconnected-ring networks. We show that fiber overlays help reduce wavelength blocking significantly. We derive the optimum number of ring overlays and show that churn has negligible impact on blocking