A Test-Bed for Comparing Impairment Aware Routing & Wavelength Assignment Algorithms in WDM Networks

When an optical signal propagates through optical fibers, the quality of the signal degrades due to a number of physical phenomena. Traditional Routing and Wavelength Assignment (RWA) approaches assume an ideal physical layer medium and ignore the effects of physical layer impairments on the lightpath feasibility. In the last few years investigators have started taking into account the fact that the quality of transmission (QoT) of an optical signal propagating through an optical network degrades, due to physical layer considerations. To measure the extent of this degradation due to physical layer impairments (PLI), metrics such as the Bit Error Rate (BER) used. In a translucent network, when the quality of a signal is reduced sufficiently, the signal has to be regenerated. In a transparent network, regenerators are not allowed so that lightpaths with high bit error rates are disallowed. A number of heuristic approaches for impairment aware RWA have been proposed for transparent and for translucent networks.;As a result of this investigation a test-bed ahs been developed for Impairment Aware Static Route and Wavelength Assignment (IA-RWA) in transparent networks. This includes a tool for computing BER values and allows the user to run a new heuristic for IA-RWA and study its performance against a number of existing heuristics for IA-RWA.