影響虛擬私人網路流量績效之研究

Abstract

最近幾年，網際網路在大小和應用範圍上有著相當大的程度上的成長，也因此一直有新的通訊協定和演算法則的發展以符合網際網路的需求。而企業建構『虛擬私人網路』(Virtual Private Network; VPN)來增進企業本身運作績效的趨勢就要使用網際網路。虛擬私人網路流量能夠分成二部分:企業內網路流量和網際網路流量。許多因素將會影響虛擬私人網路流量的績效。在現實生活中，要安裝一個虛擬私人網路和測量它的績效是困難的。在我們的研究，我們設置一個虛擬私人網路流量模擬器(NS-2)來模擬虛擬私人網路流量在指數分配和伯拉圖分配之下的操作。本研究調查因素包括排隊法則，封包大小，佇列長度，網際網路流量比率和網際網路鏈接頻寬。這五因素將對虛擬私人網路流量績效有不同的沖擊。模擬結果可以讓網路管理者彈性的規劃架設在網際網路上的虛擬私人網路使其更有效的支援企業的操作。再者，我們概述各主要的模擬參數對虛擬私人網路的敏感度。

In recent years, the Internet has grown significantly in size and scope, and as a result new protocols and algorithms are being developed to meet changing operational requirements in the Internet. The trend for a business to implement its VPN (Virtual Private Network) to enhance the efficiency of a business operations definitely will use the Internet. VPN traffic can be divided into two components: Intranet traffic and Internet traffic. Many factors will affect VPN traffic performance. It is difficult to install a VPN and measure its performance in a real life. In our research, we setup a VPN traffic simulator with NS-2 network simulator to simulate VPN traffic operations under Exponential and Pareto distribution. Factors under investigation in this research include queuing discipline, packet size, queue length, Internet traffic ratio and Internet link bandwidth. These five factors will have different degrees of impact on VPN traffic performance. Simulation results show some insight of deploying VPN over the Internet that may give IT manager ideas of planning their networking infrastructure in supporting its business operations. Moreover, we summarize the sensitivity of each major simulation parameters in VPN traffic performance.