在現今世界，網路已是人類不可或缺部分，不論任何資訊都可在網路中取得，隨著科技的進步，以及人類對於未來無止盡的探索，因此大量資訊在網路中已是不可避免的問題。
如何在目前的網路架構中，提升網路整體效能，一直是研究方向的重點，在近幾年的研究中，軟體定義網路(SDN)衝擊了傳統網路架構，利用其幾項特點(1)可編程(2)控制平面與數據平面的分隔(3)集中控制，使其達成更佳的網路架構，再搭配其負載平衡機制更能讓SDN架構更有優勢，負載平衡需搭配路由演算法進行應用，其目的讓相對已壅塞路徑得到緩解，將新的流量導入到相對負載較小路徑，使其整體網路效能提升。
在本研究中基於軟體定義網路(SDN)，透過Open Flow通訊協定，可在網路系統中觀察，例如路徑或交換機負載情況，利用路徑上使用頻寬，以及交換機中Flow Entry數量、針對須增加Hop路徑新增門檻，透過權重值，改善演算法計算出最有效率路徑，來提升整體網路效能。

Today, Network is an indispensable part of humanity. You can acquire the information that you need with the use of it, as technology develops and humans make a great effort for exploring the future. With that large amounts of information which are inevitably available whether it's public or private information.
To help increase the performance of the network in the current network architecture, as it has always been the focus of research in recent years. A Software-defined network (SDN) impact the traditional network architecture. Which has the features of：
(1)Programmable
(2)Separation of control plane and data plane
(3)Centralized control
Using SDN can achieve an improved network architecture than before. Load balancing needs to be used with routing algorithm. Its purpose is to ease the relative congestion in the network to accommodate new flow of relatively small load of path. It can improve overall network performance based on software-defined network (SDN) in this study, through the Open Flow protocol. It can be observed in the network system. For example: path or switch load conditions. It can be measure through the used amount of bandwidth on the path and the number of Flow Entry in the switches and to add Hop by considering threshold. Through the weight value that will improve the algorithm to calculate the best path.

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