Performance Evaluation of Phorizon and Pjet_Veot Reservation Schemes for Optical Burst Switching

There have been rapid changes in the networking field in the past decade or so, mainly due to an exponential growth in the number of users and traffic volumes, and emergence of new applications. This has caused a higher demand for bandwidth, with better quality of service and reduced blocking probability. Meeting this demand efficiently would be possible in high-speed optical networks with a proper switching paradigm employing dynamic reservation schemes. Optical burst switching (OBS) is a new switching concept, based on ideas developed for electronic burst switching almost two decades ago. Now the idea has evolved to become a paradigm, which combines the best of both switching techniques i.e. circuit switching and packet switching, thus overcoming the inherent setbacks in the respective switching techniques. OBS applies an out of band signaling technique, which enables the bandwidth reservations to be made in advance. In this thesis, two modified reservation schemes are proposed based on the prioritized just enough time (pJET) and Horizon reservation schemes, which are referred to as the prioritized just enough time with variable extra offset time (pJET_VEOT) and the prioritized Horizon (pHorizon), respectively. These reservation schemes are designed to reduce the blocking probabilities of both classes of traffic, i.e. real-time (RT) and non real-time traffic (NRT), while provisioning sufficient Quality of Service (QoS) for ensured and timely delivery of higher priority traffic. Performance evaluation is conducted in order to analyze the reduction in blocking probability, the effect on system delay and to display the service differentiation achieved. This is done by comparing the proposed schemes to its predecessor schemes respectively. The predecessor schemes used in the simulation are pJET, Just Enough Time (JET) and Horizon The proposed schemes, pHorizon and pJET_VEOT show a significant reduction in blocking probabilities and along with sufficient provisioning of QoS for both classes of traffic tested, i.e. the RT and NRT when compared to Horizon, JET and pJET respectively.

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