隨著近年來基礎設施即服務（IaaS，Infrastructure as a Service）的快速增長，虛擬機器（Virtual Machine）在即時移轉（Live Migration）時網路服務的可靠性也成為大家越發關心的話題。
本篇論文提出了一種在廣域網路下進行即時移轉時保持網路服務連線的機制，稱作ArcticTern。利用ArcticTern，可在虛擬機器跨子網域即時移轉至不同網域的宿主機（Host）時持續保持網路服務與使用者的連線。
本篇論文的研究未來將整合至一個分散式阻斷服務攻擊（DDoS，Distributed Denial of Service）防禦系統中，搭配未來將完成的其他機制，我們預期能在分散式阻斷服務攻擊發生時將虛擬機器移轉至遠方網路上的其他位置，並且過濾新建連線以阻擋惡意使用者，透過大量佈署此系統達到防止分散式阻斷服務攻擊的目的。

Nowaday, Infrastructure as a Service (IaaS) becomes more and more popular in the age of cloud computing. As a result, availability of network services in live Virtual Machine (VM) migration becomes an important issue. In this research, we propose a new mechanism to keep network services connection alive during live virtual machine migration over Wide Area Networks (WANs), called ArcticTern. Moreover, we provide a way to migrate virtual machines into another subnet while keeping the client connection alive. ArcticTern will integrate into a Distributed Denial of Service (DDoS) Defense System. With other part of DDoS Defense System, we expect VM will migrate to another host that is not in the same subnet automatically. DDoS Defense System will also filter future connection to blocking malicious connections. By mass deploying the DDoS Defense System with ArcticTern functionality, we expect it will avoid DDoS Attack.

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