Feedback-based offset time selection for end-to-end proportional QoS provisioning in WDM optical burst switching networks

摘要

Wavelength division multiplexing (WDM) optical burst switching (OBS) is a promising technology for the next generation Terabit networks. The capability of this technology to support service differentiation has become a key research issue due to the increasing need for traffic differentiation in Internet backbone networks. We develop a feedback-based offset time selection method to provide proportional service differentiation in terms of burst dropping probability. Compared to other relative Quality-of-Service (QoS) methods, proportional QoS allows a service provider to adjust the performance spacing of a class of traffic relative to others. Unlike other proportional QoS methods which guarantee only per-hop proportional QoS, our proposed method is able to achieve end-to-end proportional QoS. By making use of link states collected by probe packets, we dynamically adjust the offset times needed to achieve the predefined proportional QoS among different classes of traffic for various ingress-egress node pairs. As the offset time selection is done for the node pairs, fairness among node pairs with various hop lengths in terms of achieving the proportional QoS is maintained. The effectiveness of the proposed method is evaluated through simulation experiments.