Fair scheduling of dynamically provisioned WDM connections with differentiated signal quality

Abstract

Emerging, on-demand applications (e.g., Interactive video, ultra-high definition TV, backup storage and grid computing) are gaining momentum and are becoming increasingly important. Given the high bandwidth required by these applications, Wavelength Division Multiplexing (WDM) networks are seen as the natural choice for their transport technology. Among the various on-line strategies proposed to provision such services, the ones based on service level agreement (SLA) metrics such as setup delay tolerance and connection holding-time awareness showed a good potential in improving the overall network blocking performance. However, in a scenario where connection requests are grouped in different service classes, the provisioning success rate might be unbalanced towards those connection requests with less stringent requirements, i.e., not all the connection requests are treated in a fair way. This paper addresses the problem of how to guarantee the signal quality and the fair provisioning of different service classes, where each class corresponds to a specified target of quality of transmission (QoT). With this objective in mind three fair scheduling algorithms are proposed in a dynamic traffic scenario, each one combining in a different way the concept of both set-up delay tolerance and connection holding-time awareness. Proposed solutions are specifically taylored to facilitate the provisioning of the most stringent service class so as to balance the success rate among the different classes. Simulation results confirm that the proposed approaches are able to guarantee a fair treatment reaching up to 99% in terms of Jain's fairness index, considering the per-class success ratio, without compromising the improvements in terms of overall network blocking probability.