在All-IP核心網路上的品質預算之配置及路徑規劃


QoS Budget Allocation and Path Planning in ALL-IP Core Network


林岳生

現有大多數的QoS 繞徑演算法,均假設鏈結上的參數是固定的, 而依據固定鏈結參數的條件,尋求最佳的繞徑。 實際上鏈結上能保證的服務品質與鏈結實際的負載有關。 如果鏈結的所承諾提供的服務品質及所承諾之負載, 在最大容量維持不變的條件下,可以由繞徑程式自由選擇的話, 繞徑程式可能可以做更好的路徑規劃。 現有大多數的QoS 繞徑演算法,均假設鏈結上的參數是固定的,而依據固定鏈結參數的條 件,尋求最佳的繞徑。實際上鏈結上能保證的服務品質與鏈結實際的負載有關。 如果鏈結的所承諾提供的服務品質及所承諾之負載,在最大容量維持不變的 條件下,可以由繞徑程式自由選擇的話,繞徑程式可能可以做更好的路徑規劃。

本研究在BBQ(Budget-Based QoS)的架構下,期望藉由事先規劃鏈結上的參數設定,以提 供較具彈性的路由規劃,提升整體網路的效能,幫助營運者靈活可擴展的 管理網路,以到達營運者的營運目標。由於加入參數的調變, 使得繞徑問題變的更為複雜,在本文中,我 們設計了兩套不同的爬山式搜尋演算法,經反覆的模擬測試, 發現本研究的方式的確能提供較佳的網路規劃。

  Most of current QoS routing algorithms assume fixed network parameters, such as guaranteed service quality and bandwidth capacity. In fact, guaranteed quality of links is load dependent. Assuming that the maximum capacity of each link is limited, if the guaranteed quality and bandwidth capacity can be chosen by a routing algorithm, then the routing algorithm may find better paths. For example, guaranteed quality could be improved by using lower capacity on the link or by using the maximum capacity with poor guarantee quality.   Our research is based on BBQ (Budget-Based QoS) management architecture. We preplan the parameters on each link before routing. This method provides flexible routing options thereby increasing the total profit. We tested two different approaches of allocating parameters on each link. After several simulations, we found that these approaches that we developed could result in better network resource utilization and increase profit for the operator.