一個基於軟體定義網路的環狀網路架構與實作

Abstract

對於多點分佈的網路環境而言，將各點串聯成一個具有備援效果的環狀網路架構是較為簡易的設計。現今環狀網路架構是基於IP(Internet Protocol)協定的動態路由機制所構成，其可以藉由線路頻寬計算出路徑成本而選擇較佳路徑進行傳輸。若遇傳輸障礙情勢導致目的端無法連線的情況，可自動轉換至另一路徑繼續傳輸。然而在這樣的設計下，固定的來源端和目的端之間的傳輸路徑便存在單一方向性，無法有效運用另一路徑進行傳輸。本論文基於軟體定義網路(Software Defined Network, SDN)的技術，讓環狀網路架構的路由不再有單一方向性，能夠運用所有可用的路徑。與傳統環狀網路架構實驗環境相比較，軟體定義網路技術實驗環境的每秒平均傳輸量是傳統網路技術實驗環境的2.265倍。因此，軟體定義網路技術適合應用於既有之環狀網路架構當中，提升現有技術的傳輸瓶頸。

For multi-point distribution network environment, it's a simple design to connect every single node by ring architecture as an auto recovery network system. Nowadays, ring network architecture is based on the IP (Internet Protocol) dynamic routing technology and the data transmission route is selected by path cost which is calculated by bandwidth. In case of abnormal transmission situation, the packet destination can not be reachable. It can automatically switch to an alternative path for continuing transmission. However, in this design, it just choose the same route if source and destination do not change, so it means the transmission path exists single direction, we can not use other paths for transmission. In this thesis, the use of SDN(Software Defined Network) technology in virtual ring topology environment, it centralizes all the logical computing on the controller, like: route calculation, packet transfer action and so on. Network devices follow the actions from controller instruction, so network devices only perform packet delivery. In the ring network architecture, SDN technology allows routing is no longer a single direction, we can use all available paths. Compare with ring network architecture based on SDN and ring network architecture based on dynamic routing protocol, SDN technology improves 2.265 times than dynamic technology of data transmission per second. Therefore, using SDN technology can eliminate ring network architecture transfer bottleneck which is constructed by dynamic routing technology.