摘要: | 光纖網路由於有許多技術仍處於發展初期,設備成本無法正確估計,而且對流量訊需求及新的應用發展具不確定性,導致無法正確量化網路頻寬的大小,加上網路設計規劃時,必須考量到之前發展的光纖設備和技術造成的限制作用。因此,網路最佳化問題在分波多工器WDM 全光網路中已日益獲得重視,線性規劃Integer Linear programming (ILP)是可以精確執行此任務的一種方式。 本論文中提及Routing and wavelength assignment(RWA)動態規劃多光纖、無波長轉換器的WDM 網路。給予一個流量矩陣,如每一個連結的光纖數量、每一條光纖所能支援的波長數量和每一個通訊需求所需的連線數量及連線時間等數據,建立線性規劃算式,運用Branch & Bound 演算法找出網路中所能建立連線的最大數量,分析及設計使得網路獲得最佳化。由於Branch and Bound 運算數量隨著變數的增加而呈指數增長,為使演算法在可接受的運算時間內分析更大量的變數,經由適當的上限(upper bound)設定或適當的設計網路模型達成此目的為網路最佳化的重要議題。另一方面,由於訊號在全光網路中會經過許多沒有光電轉換的交換器,在交換器中會產生串音來傷害訊號的品質,為此我們提出加入由串音因子計算BER,並在接收端設一個BER 可接受下限值的QoS 限制。 Many optical technologies are relatively immature with respect to electronics, thus the cost of equipments can not be estimated correctly. The unknown of future traffic demand and new applications development,it can not scale well with the network size. And network optimization must take currently and immaturity equipments functional constraints into account in the design. So, optimization problem of the WDM all-optical network is an important issue today. Integer Linear Programming is the most used exact method to perform this task. In this thesis, we present dynamic routing and wavelength assignment in multifiber WDM networks without wavelength conversion. Give a traffic matrix with parameters fiber amount, wavelength amount,connect lightpath request amount and connect period, to propose an ILP formulation. By using Branch and bound algorithm to find out the maximum lightpath that can be connected in the network, analysis and design to get network optimized. The computation of Branch and bound algorithm is polynomially increase with variant amount. The appropriate upper bound or appropriate network modeling can let the algorithm computes more variants in the acceptablecomputation time. Moreover, because a signal in all optial network passes through many switches without O-E-O converter, the crosstalk in the occurs in switches will impair the signal quality, thus we propose the BER counts with crosstalk factors, and set the QoS constraint of acceptable BER in the receiver into the formulation. |