Dependency-Based Analytical Model for Computing Connection-Blocking Rates and Its Applications in the Sparse Placement of Optical Converters

Dependency-Based Analytical Model for Computing Connection-Blocking Rates and Its Applications in the Sparse Placement of Optical Converters In this paper, we present a new analytical model that captures link dependencies in optical wavelength-division multiplexing (WDM) networks under uniform traffic, and enables the estimation of connection-blocking probabilities more accurately than previously possible. The basic formula of the dependency between two links in this model reflects their degree of adjacency, the degree of connectivity of the nodes composing them, and their carried traffic. Our validation tests have shown that the analytical dependency model gives accurate results, and successfully captures the main dependency characteristics observed in the simulation measurements. The usefulness of the model is illustrated by showing how to use it in enhancing a simulation-based algorithm that we recently proposed for the sparse placement of full wavelength converters in WDM networks. To analytically handle the presence of wavelength converters, a lightpath containing converters is divided into smaller subpaths, such as a wavelength-continuous path, and the nodes shared between these subpaths are full wavelength-conversion capable. The blocking probability of the entire path is obtained by computing the probabilities in the individual subpaths. We validate the analytical-based sparse-placement algorithm by comparing it with its simulation-based counterpart using a number of network apologies.