以 flow 為基礎之網際網路流量量測分析

Abstract

目前在Internet 的環境中，對於網路流量資訊仍舊存在許多未知。面臨 頻寬不足的問題，永遠是以增加線路的方式解決。由於廣域網路的流量量 測不易，連帶使得相關資訊缺乏，除了對於傳輸流量的內容茫然外，更無 法評估目前網路運作效能。傳統的網路量測分析，大多是以封包為基礎單 位，由於各種應用程式的特性不一，單純以封包數量並無法解釋真正的使 用型態。本研究將提出 Flow 的概念，並且利用 Flow 為量測單位，評估 網路效能，並且與傳統的封包量測互相比較。為了解決廣域網路量測的問 題，我們提出了一套適合於區域網路與廣域網路的系統架構，並且實作之 。最後，利用真實世界的網路環境，做為我們的量測分析個案，並且加以 討論。 Internet traffic style remains unknown in current environment. This is the reason why more circuit deployment is the only solution to bandwidth insufficency. Lack of wide area network traffic measurement and analysis always leads to the embarrassment of performance assessment. Further, even the bandwidth usage efficiency can not be evaluated.Traditional network measurement and analysis always base on the metric of packet. Since different applications behave differently, it is not feasible to explain the attribute of applications totally on the basis of packet volume.This research is going to introduce the concept of "Flow". We are going to use the flow model as new metrics for traffic measurement and analysis. Comparisions to the legacy packet based methods will be given.To solve the difficulty of wide area network measurement and analysis, we propose a system suitable for not only wide area networks but also local area networks. Design and implementation issues are described in the thesis.