| Summary: | 碩士 === 國立臺灣大學 === 電機工程學研究所 === 90 === While the rapidly growing Internet (IP networks basically) is driving the demands for higher transmission capacity and high-speed network equipments, dense wavelength-division multiplexing (DWDM) has emerged as an important physical layer technology where optical transmission provides a physical layer capable of carrying bits at the speed of the order of a gigabit per second. Therefore, DWDM optical network technology is expected to form the base infrastructure of the for the next-generation data-centric Internet. Several different technologies have been developed so far for the transfer of data over WDM where optical burst switching provides a good solution for metropolitan area which supports bursty traffic. It also provides an easy solution for IP over DWDM [1] networks which simplify the management and the overhead of ATM. Since current Internet only provides best effort service, supporting Quality of Service (QoS) has become a crucial issue.
This paper proposes a preemptive multi-class wavelength reservation protocol to provide differentiated service for Optical Burst Switched (OBS) networks [2] with DWDM technology. Unlike existing approaches, which may degrade to classless schemes or which may suffer from low wavelength utilization, our mechanism is robust, efficient, and supports an incremental deployment of QoS support. We maintain a usage profile for each class at the router, and implement a preemptive wavelength reservation mechanism to ensure QoS. We derive an analytical model and conduct simulations to evaluate the performance. The result shows that our approach performs the best in terms of lower blocking probability and higher resource utilization, making it an excellent QoS mechanism for OBS networks.
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