隨著網路的快速發展，近年來像是檔案分享、Web 瀏覽、網路遊戲、網路電視以及即時轉播等網路應用程式如雨後春筍般出現。在這些應用程式之中，即時影音串流受到使用者有越來越多的機會使用網路以及消費者等級個人電腦的運算能力越來越好的影響在最近幾年愈趨流行。然而隨著使用者的增加，傳統客戶端－伺服器架構的已經無法滿足同時間大量使用者收看即時影音串流。除此之外，傳統的架構必須消耗大量資金在頻寬的取得以及服務設施（如編碼伺服器、影音串流伺服器及網路伺服器）的佈建。有鑑於此，一個稱之為點對點（Peer-to-
Peer）傳輸架構的新技術被用於即時影音串流系統以達到更高的使用者人數同時降低網路頻寬以及服務設備的成本。這種點對點的即時影音串流利用使用者的網路頻寬以及運算能力來分擔串流服務系統骨幹的負擔，在這樣的點對點網路中，每位使用者既是伺服器端也是客戶端。但是這樣的網路存在動態的特性，使用者可以隨意的加入以及離開點對點的網路，此外使用者的硬體以及網路可能不如伺服器般強大，因此對串流系統帶來了穩定性以及效能上的隱憂。
在本篇論文中，我們提出了針對點對點串流系統的即時監控系統來觀測點對點網路中使用者的網路狀況、收看品質以及系統狀態來評估系統的效能；來自使用者的即時數據經過統整之後透過網頁以列表及圖表的方式呈現。這些觀測的資料也會妥善的保存在後端的資料庫中並且可以在事後用來研判系統的缺陷。
除此之外，我們也做了一系列的量測來評估所提出的即時監控系統的效能。另外我們也藉由模擬的實驗來驗證監控資訊的正確性；與實際運作的點對點即時影音串流系統結合來驗證我們所提出的即時監控架構的可行性。

As the fast development of network, there are many emerging Internet applications such as file-sharing, web browsing, gaming, Internet television and live video streaming. Among these applications, live video streaming becomes popular in recent years with the growing access to network and the higher computational power of consumer-grade personal computers. As the increasing of the user number, traditional client-server architecture which costs greatly in both infrastructure and bandwidth becomes insufficient to serve great amount of user simultaneously. As a consequence, the peer-to-peer (P2P) architecture is proposed to achieve greater amount of user the streaming system is able to serve as well as save the cost of hardware and bandwidth at the same time. P2P live streaming takes advantage of the bandwidth and computational power of the users to share the loading of the backbone. However, this brings reliability and performance problem into the system due to the dynamic nature of peer-to-peer network.
In this thesis we proposed a real-time monitoring system for peer-to-peer live streaming applications which provides traffic, user receiving quality and system information in tables and charts of the streaming system through web-based output. The information is useful helping service providers to assess the system performance as well as the quality of the streaming service. The monitored information is also stored in backend database and will be valuable to diagnose the streaming system afterwards.
In addition, a series of experiments are conducted to evaluation the performance of our system. And we validate the correctness of the monitoring information through simulated experiment and verify the feasibility of our system by combining our real-time monitoring system with a real-world peer-to-peer live streaming system.

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[14] RFC1157 - Simple Network Management Protocol (SNMP)
[15] RFC1757 - Remote Network Monitoring Management Information Base
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