隨著網際網路上的頻寬需求急遽增加，採用高密度光波分割多工技術的光網路便成為未來骨幹網路的最有希望的後補之一。雖然高密度光波分割多工技術可將一個光纖分割成數百個波長，傳統的光波交錯連結器卻也因此需要大量交換埠的支持。大量的交換埠會使傳統的光波交錯連結器變得更加複雜，因此控制和管理如此複雜的連結器是必需的。由多層次型交錯連結器所組成的光波段技術於最近被提出，而這些多層次型交錯連結器是透過光纖鏈結交互連接的。光波段技術的構想即為能同時以各種不同的層次來處理資料流的繞徑，其中包含光纖、光波段及波長三種層次，和傳統的高密度光波分割多工技術相比之下，光波段技術更能夠減少交換埠的數目。
不需網際網路基礎架構支援的疊蓋式群播於最近被提出，有別於傳統的群播，疊蓋式群播的群播機能是在應用層實行。在這篇論文中，我們提出一個被稱作疊蓋式群播之較少調整花費的啟發式演算法，目的在於解決光波段網路上疊蓋式群播的繞徑及波長配置問題。我們的方法是以替代繞徑為基礎，當建立疊蓋式群播樹時傾向於選擇消耗較少交換埠、有更多可用頻寬以及較短距離的繞徑。在模擬實驗中，我們比較疊蓋式群播之較少調整花費的啟發式演算法和另外兩個先前被提出來的演算法，在不同程度的資料流負載及不同光波段粒子情況下作五種度量的比較。藉由模擬實驗的結果顯示我們所提出來的方法可以大幅改善另外兩個方法的阻斷機率。而在其他度量上，我們的方法也只略少於該度量最佳的演算法。

With the explosive growth of the Internet bandwidth demand, optical networks with Dense Wavelength Division Multiplexing (DWDM) become a promising candidate for the future Internet backbone. Although the DWDM technology can divide a fiber into hundreds of wavelengths, it also need a great deal of switching ports at traditional optical cross-connects (OXCs). The traditional OXCs will become more complex due to having such many switching ports. Thus, it is necessary to control and manage such complex OXCs. A WBS technology has proposed recently which is composed of multi-granular OXCs (MG-OXCs) interconnected by fiber links. The concept of WBS is to switch traffic at multiple granularities, including wavelength, waveband, and fiber at the same time. WBS technology can reduce more number of switching ports than traditional WDM technology need.
Overlay multicast has been proposed recently which requires no infrastructure support in the Internet. Not alike traditional multicast, the multicast functionality in overlay multicast is implemented at the application layer. In this thesis, we proposed a heuristic algorithm named Overlay-Multicast with Less Configuration Cost (OMLCC) which aims to solve the waveband routing and wavelength assignment problem for overlay multicast session on WBS networks. Our algorithm is based on alternative routing and tends to find a route with less consumption of switching ports, more available bandwidth, and shorter distance at the time when constructing a overlay multicast tree. We compare five performance metrics by using OMLCC, BASE and HMTP under different traffic loads and different waveband granularities. The simulation results show that OMLCC has significantly improvement as compared with other two algorithms in the blocking probability. While consider other metrics, the performance of OMLCC is a little less than the algorithm with the best performance on associated metric.

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