A distributed control protocol for wavelength routing with fairness improvement in WDM networks

This paper considers the problem of distributed routing with fairness impro vement in wavelength-routed wavelength-division multiplexed (WDM) networks with dynamic traffic conditions. The wavelength continuity constraint impos ed by WDM networks causes increased blocking of connection requests. The pe rformance loss is more for connections with longer hop counts, when compare d to that for connections with shorter hop counts. This is further worsened when distributed routing is used due to the reservation conflicts. We prop ose a distributed control protocol to select a usable wavelength and route and to improve fairness among connections with different hop counts. The pr oposed dynamic priority based fairness improvement scheme(DPFS) improves fa irness among connections by enforcing dynamically varying priority based co ntrol to the connection requests over access to a subset of the available w avelengths, while allowing a free access to the remaining wavelengths. We s tudy the effectiveness of the proposed protocol through extensive simulatio n experiments. The results show that the proposed scheme improves fairness significantly with an acceptable level of degradation in the overall networ k performance.