無線區域網路行動監控與管理平台

Abstract

在無線網路逐漸成熟與普及的今天，無線基地台的設置越來越多，無線網路的架設與管理也就顯得重要。對於無線網路的架設而言，應儘量避免無線基地臺彼此之間的干擾，並提高無線基地臺的涵蓋效率以減少無線基地臺的數目；對於無線網路的管理來說，當一個管理者面對許多可能具有不同設定無線基地臺時，一個方便、快速、自動的管理介面能夠讓管理者很容易的檢查或修改大量的無線基地臺的設定，以減少管理者的操作步驟與所需的時間。 本論文的目的即是提供一個無線網路的管理系統。此一管理系統包含兩個概念：分散式自動化的資料收集與集中式的管理機制。我們透過APMU、Wireless Sniff和Station Association Log三個模組來達成我們的管理概念。APMU位於主要伺服器，提供集中式的設定與管理無線基地台的介面；Wireless Sniff採用Client-Server的架構，Sniff Client具有三個無線網路介面，可同時間收集3個不同無線網路頻道的封包，設置於無線基地臺附近，並將收集的封包傳輸到主要伺服器的Sniff Server；Station Association Log位於主要伺服器負責定期從各個基地台收集資料，建立log。 管理者可以交互利用此系統的三個模組之來進行管理的工作，例如先由「Wireless Sniff」收集各個無線頻道上的資料給主伺服器，管理者在分析收集的資料之後，再利用伺服器中的APMU來更改基地台的設定值；當無線網路出現問題時，可以透過「Station Association Log」所建立基地臺log檢查出可能發生的問題，而透過其他管理方式或是APMU來更改設定解決問題。所以這三個模組的結合可以提供一個更方便、快速、自動的管理介面，進而讓無線網路可以更穩定與更有效率。

IEEE 802.11 Wireless LAN (WLAN) access points (APs) have been widely deployed as the enterprise or hotspot access networks to Internet. As the number of APs deployed in a network grows, an effective AP management system is becoming a necessity for the administration of a network with a large number of WLAN APs. In this thesis, we present the design and implementation of an effective WLAN AP management system. With the presented WLAN AP management system, a WLAN AP administrator can easily collect wireless packets, re-configure APs, and monitor mobile stations (MSs) associated with a particular AP. The design of our WLAN AP management system is based on distributed snooping of WLAN packets and centralized AP management. It consists of three software components, an Access Point Management Utility (APMU), a Wireless Sniffer System, and a Station Association Log. APMU is situated at the administration server. It provides centralized management interfaces for the administrator to query APs status and configure APs. The Wireless Sniffer System is composed of a wireless Sniffer client and a Sniffer server. The wireless Sniffer client can sniff three WLAN channels simultaneously. It collects WLAN packets sniffed from all WLAN radio channels and sends them to the Sniffer server situated at the administration server. The Sniffer server then filters packets in accordance with the instruction given by the administrator. The Station Association Logging module resides on (or nearby) the administration server and collect MS association log form all APs periodically. The association log can help the administrator to find out or trace malicious MSs or be used to provide location based services. With the aforementioned three components, a WLAN administrator can manage a WLAN with a large number of APs more effectively.