博士 / 國立交通大學 / 資訊科學與工程研究所 / 98 / Future optical Metropolitan Area Networks (MANs) have been expected to exploit advanced Optical Packet Switching (OPS) technologies to cost-effectively satisfy a wide range of applications having time-varying and high bandwidth demands and stringent delay requirements. In this thesis, we present a high-performance real-time medium access control scheme for our experimental high-performance OPS metro WDM slotted-ring network (HOPSMAN). HOPSMAN has a scalable architecture in which the node number is unconstrained by the wavelength number. It encompasses a handful of nodes (called server nodes) that are additionally equipped with optical slot erasers capable of erasing optical slots resulting in an increase in bandwidth efficiency. In essence, HOPSMAN is governed by a novel medium access control (MAC) scheme, called Probabilistic Quota plus Credit (PQOC), which is further enhanced with QoS assurance, called Probabilistic Quota plus Credit with QoS Assurance (PQOC/QA). The proposed MAC scheme embodies a highly efficient and fair bandwidth allocation in accordance with a quota being exerted probabilistically. The probabilistic quota is then analytically derived taking the server-node number and destination-traffic distribution into account. Besides, the MAC scheme introduces a time-controlled credit for regulating a fair use of remaining bandwidth particularly in the metro environment with traffic of high burstiness. Moreover, PQOC/QA adopts slot-basis reservation through a simple and flexible marking mechanism to support QoS and to resolve the intrinsic access problem in WDM network. Instead of focusing on estimation of the bandwidth requirements, PQOC/QA sets up real-time connections by employing constant mean rate reservation on each cycle of the ring and effectively accommodates bursty real-time traffic (VBR). Furthermore, we develop a novel approximation to acquire the accurate results of the expected connection setup queueing delay by means of an M/G/m queueing analysis. In the analysis, the maximum admissible quota of real-time traffic is regarded as the number of servers and the service time has a duration that follows an exponential form with an added constant. In M/G/m queueing analysis, the accurate results have only been attained for a limited number of special service distributions, while most of the proposed approximation only maintained a less than 10% relative error for certain properties of service distributions. Our approximation results, which are derived under the particular general service distribution in our system, show that the mean setup queueing time is in profound agreement with the analytic result. Additionally, extensive simulation results show that HOPSMAN with the proposed MAC scheme achieves exceptional delay-throughput performance and remarkable real-time traffic performance (high statistical multiplexing gain for real-time traffic, exceedingly low VBR delay and jitter) under a wide range of traffic loads and burstiness.
| Identifer | oai:union.ndltd.org:TW/098NCTU5394059 |
| Date | January 2010 |
| Creators | Chao, I-Fen, 趙一芬 |
| Contributors | Yuang, Maria C., 楊啟瑞 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | en_US |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 92 |
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