QoS control and performance improvement methods for optical burst switching networks QoS Control and Performance Improvement Methods for Optical Burst Switching Networks

博士論文

Optical Burst Switching (OBS) has been proposed as a promising switching <br />technology for the next generation of optical transport network. In this dissertation, <br />we address the issue how to provide QoS control and improve performance in OBS <br />networks . <br /> In order to provide proportional differentiated services without or with absolute <br />constraints in bufferless OBS networks, a Dynamic Wavelength Selection (DWS) <br />scheme is introduced to assign more and longer periods of wavelengths to higher <br />priority classes dynamically and efficiently due to wavelength-sharing. The inte- <br />gration of DWS scheme and another proposed Delayed Burst Assignment (DBA) <br />scheme improves the burst loss performance by giving the burst head packet (BHP) <br />two opportunities of scheduling its data burst (DB). <br /> Furthermore, we propose two novel burst assembly algorithms with traMc shap- <br />ing functions to reduce the variance of assembled traffc and improve the burst <br />loss performance, which are named advanced timer-based and sliding window-based <br />assembly algorithms. <br /> Finally, an edge buffering based OBS layer fast error recovery scheme is pro-- <br />posed to improve the TCP performance over OBS networks, in which lost bursts are <br />retransmitted at edge nodes without being reassembled. <br /> In general, all the proposed schemes solve many of the fundamental issues faced <br />by optical burst switching networks, thereby making OBS more practical and efii- <br />cient in the near future.<br />

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総研大甲第1049号