無線區域網路虛擬接取點之建立、管理與移動

Creation, Management and Mobility of Virtual Access Points in Wireless Local Area Networks

林佑恩(You-En Lin) ； 蔡廷銘(Ting-Ming Tsai)

《電腦與通訊》 158期 (2014/08) Pp. 5-12

摘要

在目前無線區域網路建置中，接取點的管理通常是零散而獨立的，布建者必需以人工的方式登入接取點設定名稱、運作頻道及認證密碼。用戶端則必需先在各個頻道上掃描，以找到布建者預先設定好的名稱，並配合輸入認證密碼才能存取網路。由於頻道掃描加上認證流程可能花費數秒時間，對於經常往來不同接取點的用戶而言，冗長的網路接取程序大幅降低服務體驗。此外，將這些獨立運作缺乏管理的接取點堆疊成高密度無線網路時，網路總吞吐將不如預期成長。本篇論文將軟體定義網路（Software-Defined Network; SDN）的概念推展到無線接取網路上，將原本各自獨立運作的接取點，交由中央伺服器統一管理，以降底負載不均、同頻干擾、換手斷線等問題。用戶預先向伺服器註冊帳號和喜好配置後，直接使用該組配置來接取網路，伺服器將在鄰近的接取點創造其專屬的虛擬接取點，直接提供面向用戶端的服務。當用戶端移動時，虛擬接取點將隨用戶端搬移至別的實體接取點，對用戶端而言始終都與相同的接取點連結，無需查覺換手程序的存在。

關鍵字

無線區域網路（Wireless Local Area Network ； WLAN） ； 軟體定義網路 （Software-Defined Network ； SDN） ； 虛擬接取點（Virtual Access Points ； VAP）

並列摘要

Access points in current wireless local area network operate independently and are managed manually by logging into the terminal for configuration, such as service set identification and operating channel. To access network service, client stations have to scan possible channels, execute the processes of authentication and association. These processes may take several seconds and greatly degrade the Internet experience, especially for the user who frequently moves among different coverage of access points. Additionally, if users desire high throughput and ubiquitous network accessing by distributing high-density access points, the performance of whole network does not grow as expected due to ill management of independent access points. In this paper, we extend the software-defined network (SDN) into the access network such that access points are managed by a central controller to deal with the issues, such as load balance, interference of channel allocation and handover.