雙向環形光網路中具最大使用效率及最少停留點的機制

Abstract

近幾年來，由於分波多工(WDM)技術的出現，在廣區域網路(WAN)中能獲得的傳輸頻寬也大量的增加(如: 2.5, 10, 40Gps)。隨著時間經過，光纖網路的發展不但有了很大的進步，而且訊務的流量也大幅激增。一個訊務可能被分配使用一整條波長的頻寬去傳輸，然而，相對一個波長的頻寬，一個訊務的流量然是相當的小。為了有效的利用資源，利用訊務彙集的技術，把許多需求頻寬小的訊務彙集到頻寬大的波長上是很重要的研究議題。 在本篇論文中，我們討論了多重傳播動態訊務路徑選擇及彙集的問題，我們的目標是要讓波長頻寬的使用效率達到最高且同時降低連線呼叫的拒絕率，我們把這個問題公式化成整數線性規劃(ILP)。為了解決這個問題，我們提出了具最大利用效率及最少停留點(MUMO)的機制。在MUMO的機制中有兩個主要的步驟 :決定多重傳播訊務的最少停留點路徑以及讓使用度最大的多重傳播訊務彙集。從模擬結果我們可以知道不論在何種環境，MUMO機制的表現都比其他機制的表現好很多，我們也驗證了MUMO機制能很有效的安排多重傳播訊務，因此MUMO機制是一個具可行性且十分吸引人的方法。

In recent years, the emergency of wavelength division multiplexer (WDM) has led to a tremendous increase in the available transmission capacity (e.g. 2.5, 10 and 40Gbps) for wide area networks (WAN). The progress of optical network evolves with time; meanwhile, the carried traffic streams surge. The required bandwidth of the traffic stream is usually much smaller than the capacity of a wavelength. Thus, many lower-speed traffic streams should be multiplexed onto a high-speed wavelength channel by traffic-grooming techniques In the thesis, a traffic routing and grooming problem, which the traffic is dynamic, multicast and nonuniform in bi-directional optical ring networks, is studied. We propose a maximum utilization and minimum hops (MUMO) scheme with an objective to reduce the new call blocking probability and to maximize the utilization of used wavelength. There are two main operations in the MUMO scheme: multicast traffic routing with minimum hops and multicast traffic grooming with maximum utilization. The main purpose of the operations is to achieve better system utilization without changing the lightpath topology. From the simulation results, the performance of the MUMO scheme is much better than the performance of the other conventional schemes no matter in which environment. Consequently, we can conclude that the MUMO scheme is a feasible and attractive scheme for optical bi-directional ring network.