Towards an event-driven scheduling of the setup of optical connections. (c2011)

Abstract

Supporting the diverse Quality of Service (QoS) requirements of the everemerging Internet applications is one challenging task for optical networks' operators. To come to grips with this challenge, we propose a QoS-Aware Optical Connection Setup Management scheme that uses the Earliest Deadline First (EDF) queuing discipline to schedule the setup of the optical connections. The benefits of this EDF-based scheme are twofold: a) it reduces the blocking probability since blocked connection requests due to resource unavailability are queued for possible future setup opportunities and b) it realizes QoS differentiation by ranking the blocked requests in the EDF queue according to their connection setup time requirements, which are viewed as deadlines during connection provisioning. As such, pending less delay-tolerant requests are guaranteed to experience better QoS than the ones having longer setup time requirements. This work then takes one step further by proposing various alternatives to the EDF-based management scheme. More specifically, multiple scheduling strategies aiming at improving the fraction of successfully established high priority connections are proposed, such as: Greedy Scheduling (GS), Retrial Based Scheduling (RBS), Soft Scheduling (SS), Round Robin Scheduling (RRS), and QoS Neutral Scheduling (QNS). Finally, extensive simulations are performed to gauge the merits of the proposed strategies and to study their performance in the context of two network topologies, namely, the National Science Foundation Network (NSFNET) and the European Optical Network (EON).