由於Content distribution和data center技術的進步，在都會網路(MAN) 間的資料傳輸越來越分散，而使得目前僅扮演著橋樑角色的都會網路架構，變的不堪負荷。因此需要一個新的能同時達到個有效率且又能符合經濟效益的都會網路架構來解決這個問題。
在這篇論文中，我們提出OBR作為一個次世代的都會網路架構的解決方案，OBR不僅同時擁有OBS的低傳輸延遲(end-to-end delay) 及RPR的低封包掉失率(loss-rate)的優點，且相對於許多以optical packet switching 為基礎的網路架構，OBR更便宜且更有可能性在不久的未來作發展。為了評估OBR的效能，我們採用的大量的參數做多方面的模擬測試，根據模擬的結果，OBR在傳輸延遲及封包流失率上都能到達預期的表現，更甚，在網路規模加大的情況下，OBR的延遲時間而會稍稍下降且封包丟失率並不會有顯著得上升，這二個優點使得OBR比OBS及RPR更有競爭力。
關鍵字－MAN、WDM、OBS、OBR、RPR、HORNET、LightRing、Diffserv、optical packet switching.

Due to the advances in content distribution and data center technologies, the traffic inside metropolitan area network (MAN) becomes more and more distributed. The current MAN architecture that only plays the role of bridge becomes insufficient to handle such new traffic patterns. Hence, the demand for a new MAN architecture is inevitable. It is expected to be both efficient and cost-effective.
In this thesis, we proposed Optical Buffer Ring (OBR) as the solution of next generation MAN. It combines both OBS's low end-to-end delay and RPR's low loss rate. And compared to more advanced network architectures based on optical packet switching, OBR is of lower cost and thus more feasible in the near future. To evaluate the performance of OBR, we conducted simulation study over large set of parameters. According to the results, the performance of OBR indeed coincides with our expectation. Furthermore, OBR scales better than both OBS and RPR in that the end-to-end delay of OBR decreases as network size increases while the loss rate increases little with network size.
Index Terms－MAN, WDM, OBS, OBR, RPR, HORNET, LightRing, Diffserv, optical packet switching.

致 謝 i
中文摘要 ii
Abstract iii
Contents iv
List of Figures vi
List of Tables vii
Chapter 1 Introduction 1
Chapter 2 Background and Related Works 5
2.1 Barriers of Optical Networks 5
2.2 Resilient Packet Ring (RPR) 6
2.3 Optical Burst Switching (OBS) 7
2.4 Optical Packet Switching 11
Chapter 3 Optical Buffer Ring Network 14
3.1 Network Operations 14
3.2 Node Structure 15
3.3 Control Header Processing 17
3.4 Bandwidth Guarantee 20
Chapter 4 Simulation Study 21
4.1 Simulation Model 21
4.2 Result of Simulations 23
Chapter 5 Conclusions and Future Research 29
Reference 31

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