臺灣博碩士論文加值系統

在這一篇論文中，我們評估一個使用波長維度 (Wavelength dimension) 來解決競爭問題的緩衝式波分多工 (Wavelength Division Multiplexing, WDM) 光數據封包交換機的架構。在這個架構的每個輸出端都裝有一個別的緩衝器和裝備可調式波長轉換器 (Tunable Wavelength Converters, TWCs) 來讓輸入端之間共同使用。結合波長維度的使用來解決競爭問題，這個方法縮小了每個輸出端緩衝器的尺寸和使用較少波長轉換器的數量；因此，它是有成本效益的。根據這個架構，一個較低的數據封包遺失機率 (Packet loss probability) 能夠達成。我們也可看到緩衝式光交換機比無緩衝式光交換機使用較少的波長轉換器數目。此外，我們將利用數值模擬來評估殘存函數 (survivor function)。

此外，我們分析輸出端競爭過程的平均競爭時間 (Mean contention time) 和輸出端緩衝器的平均數據封包延遲 (Mean packet delay)。我們的研究指出輸出端競爭過程能被塑造成一個BI/D/B/N的排隊過程和輸出端緩衝器能被塑造成一個G[x]/D/1/B的排隊過程。利用數值模擬來評估具備共用波長轉換器之緩衝式波分多工光交換機的平均合計延遲 (Mean total delay)。

In this thesis, a buffering WDM optical packet switch scheme employing the wavelength converters for contention resolution is evaluated. The architecture is dedicated to an individual buffer for each output and is equipped with tunable wavelength converters (TWCs) shared among the input lines. Combined with the wavelength dimension for contention resolution, this reduces the size of each output buffer and employs a lesser number of wavelength converters; therefore, it is cost-effective. Based on the architecture, lower packet loss probability can be achieved. We also observe that buffering optical switch allows reductions on the employed number of converters compared with the bufferless architecture. Besides, we will evaluate survivor function by means of numerical simulations.

Furthermore, we analyze mean contention time in output contention process and mean packet delay in output buffer. Our studies indicate that the output contention process can be modeled by a BI/D/B/N queueing process and the output buffer can be modeled by a G[x]/D/1/B queueing process. Mean total delay in buffering packet switch equipped with shared TWCs is evaluated by means of numerical simulations.

Chapter 1. Introduction ……………………………………………………………1
1.1. SCM Header and Packet Format……………………………………………2
1.2. Contention solution…………………………5
1.2.1. Wavelength Dimension Technique………………5
1.2.2. Buffering Technique…………………………7
1.2.3. Deflection Routing Technique………………9
1.3. The Motivation of our Research………12
Chapter 2. Previous Architectures of WDM Packet Switch………14
2.1. Wavelength Conversion Technique………………14
2.2. Bufferless WDM Switch with Shared TWCs……17
2.3. Partially Shared Buffering for WDM Packet Switch………………………19
2.4. Comparisons of Bufferless and Shared Buffer Schemes……………………22
Chapter 3. Shared TWCs for Buffering WDM Packet Switch…………25
3.1. WDM Optical Packet Switch…………………25
3.2. Dimensioning the Number of TWCs…………28
3.3. Evaluation of packet loss probability…36
3.3.1. Evaluation of Ploss in Full-Conversion Configuration (r = NM)………36
3.3.2. Evaluation of Ploss in No-Conversion Configuration (r = 0)………………37
3.3.3. Evaluation of Ploss when r TWCs are utilized (0 < r < NM)………………39
3.4. Numerical Results of Packet Loss Probability……………………………………41
Chapter 4. Evaluation of mean total delay and survivor function ………45
4.1. Numerical Results of Mean Total Delay…………………………………45
4.1.1. Output Contention Process (BI/D/B/N queue)……………………46
4.1.2. Output Buffer Process (G[x]/D/1/B queue)………………………………47
4.2. Numerical Results of Survivor Function……52
Chapter 5. Concluding Remarks…………………55

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