A QoS-aware wavelength assignment scheme for optical networks

Dispersion in fiber optic is wavelength dependent and it degrades the quality of service (QoS) in an optical network. Although use of dispersion compensating fiber reduces the effects of dispersion but it is very costly. In this paper, we propose a QoS-aware wavelength assignment (QWA) scheme to improve the quality of service in an optical network by reducing the overall dispersion in the network. In this scheme, the connection requests with longer lightpath are assigned the wavelengths having lesser dispersion and the wavelengths having higher dispersion are assigned to the lightpaths with shorter distance. The lightpaths are computed using alternate path routing to achieve the lower blocking probability. The performance analysis of QWA scheme is done in terms of total dispersion using step-index fiber (SIF). Results of our experiments show that QWA scheme outperforms conventional wavelength assignment scheme based on First-Fit method (WAFF).