Analysis of Blocking Probability for First-Fit RWA in Transmission Impaired Optical Networks

Wavelength routed optical networks can experience increased call blocking due to insufficient quality of transmission. The routing and wavelength assignment algorithm must verify the quality of the lightpath before accepting it. In this paper, analytical expressions for the total blocking probability are derived for first fit wavelength assignment for networks suffering from transmission impairments. Physical layer degradations considered include amplifier noise and crosstalk between WDM channels. The technique effectively predicts the performance for wavelength selection techniques that consider a single candidate channel or all channels for quality of transmission compliance. The analysis is also applicable to first-fit algorithms with different static channel orderings.