Congestion Control and Quality-of-Service (QoS) on Jumpstart Optical Burst Switched Environment

Abstract

This thesis studies the congestion control and Quality-of-Service (QoS) problems in Optical Burst Switched (OBS) networks. It consists of three parts. In the first part, we consider path switching as a congestion control mechanism at the edge of the network. We study a suite of path-switching strategies, each of which gives a different method to estimate the path congestion online. We also develop a framework for combining several path switching strategies into hybrid strategies whose results are based on the decisions of multiple individual methods. We demonstrate the effectiveness and benefits of adaptive path selection via simulation.

In the second part of the thesis, we develop a general framework for absolute service guarantees for an OBS network in terms of the end-to-end burst loss. We first present a parameterized model for wavelength sharing. Then, we develop a heuristic for optimizing the policy parameters to support per-link absolute QoS guarantees. Finally, we present a methodology for acquiring the per-link parameters from the end-to-end QoS requirements so as to provide network-wide guarantees. We present numerical results to validate our approach.

In the third part, we present a per-link wavelength provisioning scheme based on Constrained Markov Decision Processes (CMDP) theory to provide service differentiation. Service differentiation is evaluated with two objectives on OBS networks: to maximize the constrained throughput; and to minimize the loss of the best effort traffic subject to the constraints on the priority traffics. The randomized threshold policies we obtain are simple to implement and operate, and make effective use of statistical multiplexing.