可回復式網路中存活度准許控制機制與備援頻寬保留之研究

Abstract

以備援路徑為基礎的網路回復機制可用以提供高速網路中傳輸服務的存活度保障；本研究針對網狀高速網路提出一個二階的備援路徑保留機制。在准許控制階段，本機制從預先搜尋的工作路徑與備援路徑集合中，為每一個傳輸需求選擇適當的工作路徑與備援路徑組合；而在調整階段中，當備援頻寬的使用量超過事先設定的界線時，本機制將重新調整網路中的備援路徑配置，以增進備援頻寬的使用效率。本研究同時提出對應的數學最佳化模式，用已驗證備援路徑調整機制之效能。從實驗結果得知，本研究所提出的機制能夠明顯降低備援頻寬的消耗量，同時維持網路具有較高的存活度；從多個網路的實驗案例中，本機制的備援頻寬配置與數學模式最佳解的平均差距約在最佳解的3.6%以內。

For high-speed networks, restoration mechanism based on backup path provides a means for assuring their survivability. In this research, we propose a two-phase backup path (BP) reservation mechanism for high-speed mesh networks. In the admission phase, a pair of working path (WP) and backup path is selected from the provisioned sets of WP’s and BP’s. In the adjustment phase, if the backup capacity utilization has exceeded the pre-set threshold, BP assignments are rearranged to optimize the usage of backup capacity. A mathematical model is formulated to verify the quality of the optimized solutions. Computational experiments indicate that the proposed mechanism significantly reduces the consumption of backup capacity while still maintaining a high degree of survivability. Moreover, experiments show that the optimized solutions obtained are shown on average to be within 3.6 percent of optimal.