網路服務可用性之偵測與回報系統

Detection and Reporting System for Availability of Network Services

黃立行(Li-Shing Huang)

指導教授 ： 包蒼龍

大同大學/電機資訊學院/資訊工程學系所/碩士(2009年)

摘要

網路設備與伺服器斷線偵測回報系統是一個全時監控網路設備與伺服器是否斷線的系統。當系統偵測到斷線的狀況時，會向管理者寄發警告訊息，使得管理者能夠盡快地處理問題。本文提出五種機制，能夠有效地改善在發展網路設備與伺服器斷線偵測回報系統時，可能遭遇的數種問題。為了能夠順利偵測種類繁多的網路服務和網路設備，我們利用發出ICMP回應請求和建立TCP連線的方式作為偵測的機制，因此不必實作各種客戶端程式，亦能有效地監控各種伺服器的狀態。當網路與伺服器暫時過載或不穩定時，斷線偵測回報系統可能為將正常的伺服器誤判為斷線，並向管理者寄發警告訊息，我們利用Two-way De-bouncing偵測機制，有效地降低了誤判的機會。將機器斷線的警告訊息透過行動電話簡訊發送給管理者，是一種有效率但會產生額外費用的方式，我們利用Message Pool機制，使系統先將警告訊息合併之後才送出，有效地減少了發出的簡訊總量。當被監控的機器或是沒有回應的機器數量過於龐大時，斷線偵測系統必須花費很長的時間才能完成一次對於所有機器的偵測作業，我們利用平行偵測機制，讓斷線偵測系統同時偵測多部機器，有效地縮短了每一輪偵測作業所花費的時間。斷線偵測系統本身及其所在機房的網路和電力環境也都有可能發生問題，我們利用遠端備援機制，使得斷線偵測系統在較極端的狀況發生時，例如：整個機房停電，仍然能夠發揮偵測以及示警的功能。

關鍵字

網路服務可用性

並列摘要

In this thesis, we propose five mechanisms to solve the problems that we encountered when we developed the network service availability detection system in Ming Chuan University. For effectively detecting various kinds of network services, we use ICMP echo request and TCP socket as the detection mechanism. For accurately determining the availability of network services, we use a two-way de-bouncing availability determination mechanism to improve the accuracy of the availability detection. To save the cost of sending alert messages through mobile phone systems, we use a message pool mechanism to reduce the amount of alert messages without affecting the function of notifying the administrator of unavailable network services. To improve the poor performance caused by a long list of monitored machines for unavailable network services, we use a parallel detection mechanism which loads multiple detection processes simultaneously. For enhancing the availability of the network service availability detection system itself, we use a cross campus failover configuration to keep the detection system available when extreme situations occur.

並列關鍵字

availability of network service

參考文獻

[5] K. McCloghrie and M. Rose, "Management Information Base for Network Management of TCP/IP-based internets: MIB-II," RFC 1213, Mar. 1991.

[10] J. Postel, "Internet Control Message Protocol," RFC 792, Sep. 1981.

[11] R. W. Stevens, TCP/IP Illustrated, Volume 1: The Protocols. Addison-Wesley, 1994.

[13] HTTP - Hypertext Transfer Protocol. [Online]. http://www.w3.org/Protocols/

[16] Computer Center of Ministry of Education. [Online]. http://www.edu.tw/MOECC/