在分波多工網路上符合光功率預算的群播演算法之設計

Abstract

群播是目前網際網路上一項應用廣泛的服務型態，當考慮要在分波多工網路施行群播傳輸時，利用光分裂技術即可達成群播傳輸之目的，且可節省大量的網路頻寬，但光分裂將會造成光功率的嚴重衰減。目前雖有文獻提出減少光功率衰減的方法，但都只是針對提高光功率的平均值，並不注意變異數的大小，這種做法並不能符合WDM網路實務上之所需。\n因此，本文提出一個快速計算動態群播樹最小功率的方法及藉以修正既有群播演算法的策略，修正後的演算法可以確保傳送至各目的節點的光功率不小於最低的光功率臨界值，以符合WDM網路實務上之所需。

The multicasting is one of the important applications in recently Internet networks. Using the technology of light splitting can achieve the purpose of multicasting and save a large amount of the bandwidth of networks. However, light splitting will result in series power loss. Although several literatures of reducing the optical power loss have been proposed, which are always aimed to increase the average value of the optical power but not care about the variance. Such methods are not satisfying the requirement in WDM networks in practice.\nIn this paper, we propose an effective algorithm which not only can resolve the multicasting routing problem in Sparse WDM networks but also can ensure the minimum of optical power, which is transmitted to destination nodes, within the power budget and is satisfied the requirement in WDM networks in practice.