本篇論文主要在探討在wavelength-division-multiplexing網路（all-optical WDM networks）中light-trail routing的問題。Light-trail在WDM optical network上已經成為一個很有吸引力的架構且被考慮成為下一世代網路的骨幹。在本篇論文裡我們研究如何在static的網路流量需求下進行light-trail的routing，尋找一組滿足所有網路流量需求且使用較少網路資源的light-trail集合。
尋找Light-trail集合的演算法可採用ILP(Integer Linear Programming) formulation的方式來找出一組最佳解，但由於ILP formulation的時間複雜度較高，因此在本篇論文中我們提出了一個heuristic演算法來解決此問題。在我們提出的heuristic演算法中我們依序對所有的候選light-trail進行網路流量需求的配置，之後根據selection rule從中選出一條網路流量需求配置較佳的候選light-trail來建立為light-trail，重複以上動作直到滿足所有的網路流量需求，而每次挑選出來的light-trail會收集形成light-trail集合。
在這篇論文裡，我們使用了四種不同的performance measures來比較不同方法得到的結果，包含了total transceiver個數、total bandwidth浪費、total wavelength數以及total wavelength link數。而本篇論文的模擬結果也顯示了我們所提出的演算法能使用較少的transceiver個數、bandwidth浪費、wavelength數以及wavelength link數。

This paper studies the light-trail routing problem in optical WDM networks. Light-trail has been an attractive architecture in optical WDM networks, and be considered as a backbone in the next generation network. We investigate how to find a light-trail set that contains minimum network resources to support the traffic requests in optical WDM networks.
The algorithm of finding a light-trail set can adopt ILP(Integer Linear Programming) formulation to find an optimal solution. We also propose a heuristic for solving this problem, because the complexity of ILP formulation is too high. In proposed heuristic, we assign the traffic request to all candidate light-trails, next we according to the selection rule to choose a best candidate light-trail that efficiently use network resources, at last add this candidate light-trail to the light-trail set. Repeat the above action until satisfy all traffic requests.
In this paper, a number of performance measures including total number of transceiver, total waste of bandwidth, total number of wavelength and total number of wavelength link are used to compare with other algorithms. Simulation results show proposed heuristic can use less number of transceiver, waste of bandwidth, number of wavelength and number of wavelength link.

第一章 簡介 1
第二章 Light-trail架構 5
2.1. 節點架構 5
2.2. 建立light-trail 6
2.3. ‘Tune-in’ light-trail (TILT) 7
第三章 Light-trail設計問題 8
3.1. 問題描述 10
3.2. 相關研究 – 1 [10] 10
3.2.1. Traffic matrix preprocessing 10
3.2.2. ILP formulation 12
3.2.3. 討論 12
3.3. 相關研究 – 2 [12] 14
3.3.1. Traffic matrix preprocessing 14
3.3.2. LT-RT演算法 14
3.3.3. 討論 15
第四章 ILP formulation 16
4.1. Request preprocessing 16
4.2. proposed ILP formulation 22
第五章 Heuristic演算法 33
5.1. Requests preprocessing 33
5.2. Request assignment 34
第六章 實驗結果 45
6.1. 網路流量需求的產生及相關參數的設定 45
6.2. ILP formulation[10]、ILP formulation與heuristic演算法的比較 48
6.3. Heuristic演算法與LT-RT[12]的比較 51
第七章 結論 53
參考文獻 54

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