POSTER: A New Approach to Impairment-Aware Static RWA in Optical WDM Networks
In order to set up a number of lightpaths to satisfy user requirements for data communication, the static (also called offline) Route and Wavelength Assignment (RWA) problem must be solved. The quality of transmission (QoT) of an optical signal propagating through an optical network degrades, due to physical layer considerations such as optical noise, chromatic and polarization mode dispersion, four wave mixing, cross-phase modulation and cross-talk . This leads to an increase in the Bit Error Rate (BER) of the optical signal and the corresponding lightpath becomes infeasible for communication if the BER value crosses a certain threshold limit. We have used an analytical model proposed by Pereira et al  to estimate the BER. The interdependence between the physical and the network layers makes the RWA problem in the presence of impairments a cross-layer optimization problem . To address this problem, a number of approaches are emerging, usually referred to as impairment-aware-RWA (or IARWA) algorithms that take into account the interaction between the network and the physical layers. Our objective is to design a transparent network, where the IA-RWA algorithm must provision lightpaths so that the BER value of each lightpath never exceeds a given threshold.
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