Link-disjoint routing algorithms with link-disjoint degree and resource utilization concern in translucent WDM optical networks

Link-disjoint routing strategy can offer a set of reliable alternate paths when the active best path fails. However, simply employing a set of fully disjointed paths may not necessarily result in the efficient network resource utilization in some circumstances, which degrades the performance of the network system under a highly loaded traffic condition. In this study, we propose two heuristic link-disjoint routing algorithms to recruit a set of link-disjoint paths considering network resource optimization. Resource balance-based link-disjoint routing (RBR), as the first proposed scheme, selects a set of link-disjoint paths under a balanced condition between resource consumption and the link-disjoint degree (the percentage of the disjointed level between links of the selected paths and the links of the new path to be selected). The second scheme, resource optimization-based with customized link-disjoint degree routing (ROR), computes a set of link-disjoint paths which prioritize the minimum resource consumption and a required link-disjoint degree. The simulation results show that RBR and ROR significantly outperform the traditional shortest path in term of blocking probability. RBR works relatively at the same level as ROR. ROR's effectiveness is rather various depending on the given link-disjoint degree and the network size. We also find out that the link-disjoint degree of approximately 90% enables ROR to produce its best blocking performance in USANet backbone network topology while a lower degree suits a smaller network size.