以複合式路徑選擇機制改善分波多工光網路波長路由演算法之研究

Abstract

分波多工技術是近年來在光通訊網路相當熱門的研究議題，其應用範圍相當廣泛，而在WDM網路中，因為波長連續限制或是兩節點間因為光路徑被阻斷(block)所造成連線阻塞問題。許多研究著手於波長轉換器(wavelength converter)的設置或是透過路徑及波長分配RWA(Routing& Wavelength assignment)方式來解決。本論文探討以複合式路徑選擇機制解決分波多工光網路的阻塞率問題。針對路徑選擇不夠靈活問題作一討論，考慮可能影響的因素，並在作路徑選擇時，同時把節點距離、可用波長、節點靈活程度、跳躍次等等複合因素考慮作為選擇路徑的基礎，尋找適合的路徑傳送資料，再利用權重計算，看出影響路徑選擇之節點靈活程度與其他單位成本之間的關係。並與其它路徑方法所產生的缺失作一比較。最後由模擬可得知，此方法在結果上不僅得到較好的效能，對於實際網路的連線阻塞率也能有效降低。In the recent years, the wavelength division multiplexing topology in optical networks is a very hot subject. The application of wavelength division multiplexing is popular in our daily life. However, in order to solve the wavelength continuity constraint and light path blocked between source and destination, a lot of methods were developed in this study. Like use wavelength converter or based on Routing and Wavelength assignment algorithm. This thesis focused on fixed alternate routing and also purposed the algorithm which discussed the composite elements on Routing and Wavelength assignment in optical networks. Therefore, we analyzing the effects of light path, like distance, available wavelength, node degrees, hop counts…etc. Then we assign route and wavelength by those composite elements, furthermore, consider weight function by simulation. Finally, we compare simulation results pertain to fixed alternate routing and our method. The results show that our method not only can got optimal performances on networks but also reduce blocking probability more than fixed alternate routing.