Resource Criticality Analysis of Static Resource Allocations in WDM Networks

Various static resource allocation algorithms have been used in WDM networks to allocate resources such as wavelength channels, transmitters, receivers, and wavelength converters to a given set of static lightpath demands, based on certain design objectives. However, although optimized resource allocations can be obtained, it remains an open issue how to determine which resources are bottlenecks to achieve better performance. Existing static resource allocation algorithms do not explicitly measure the impact of a given resource on the design objective. In this paper, we propose such a measurement based on the Lagrangian relaxation (LR) framework We use the optimized values of Lagrange multipliers as a direct measurement of the criticality of resources. Such a quantitative measurement can be naturally acquired along with the optimization process to obtain the optimal solution (or a near optimal solution) to the static routing and wavelength assignment (RWA) problem. Such a measurement helps to identify critical resources, and thus to decide the best way to add or reallocate resources.