隨著個人電腦能力與網路頻寬的提升，使得網路影音多媒體串流的需求也隨之增加。在主從架構中 (Client-server Architecture)，視訊服務是由伺服器單獨提供影片頻寬給需要服務的使使用者，但是隨著使用者的增加，則會造成網路頻寬需求的暴增與伺服器的負載過大。 針對使用者增加所帶來的問題，許多研究則提出群播 (Multicast) 技術來因應。然而群播技術是建構在有支援IP層群播 (IP Multicast) 的網路架構下，因此當面對使用者以非同步 (asynchronous) 方式要求視訊服務，同時又面臨在真實網路上IP層群播並沒有完善佈置之窘境時，應用層群播 (Application-Layer Multicast)則被提出來解決在非同步情形下佈置群播的問題。 本篇論文主要考量使用者或同儕 (peer) 進入系統要求服務的先後順序，來建構應用層群播，以支援在同儕式網路 (Peer-to-Peer Network) 上進行多媒體串流服務。雖然先前研究中亦有類似的因素考量，然而卻未能真正考慮在真實網路上每個同儕皆擁有不同網路頻寬之事實，而我們的研究則確實考量同儕的頻寬及其頻寬分配問題，並提出有效的方法來合成頻寬，使得要求服務的同儕得以平順地連續播放影片。為驗證本論文所提之研究方法的效能，我們進行一系列在各種環境下的模擬分析，而結果則充分顯示本論文之方法能有效地降低網路頻寬的需求以及伺服器的負載。 As the growth of bandwidth of Internet, the delivery of multimedia stream increases too. In the popular client-server architecture ,users requested for the multimedia service are all served by the server. As the growth of the users , the bandwidth of the server will be a serious problem. This is so called the bursty problem. Many previous multicast researches are proposed to handle the bursty problem. They are built on the assumption of IP-multicast. They use single stream to serve many synchronous requested user. But now the deployment of multicast faces a serious problem about the absence of IP-multicast. So the application-level multicast (or overlay multicast) are used as the alternative way to deploy the multicast service. In this paper, we want to use the arrival time of the user to construct the application-level multicast. We use this application-level multicast to deploy the P2P streaming and to handle the asynchronous user requests. Different from the previous work not to limit peer bandwidth, we consider the allocation of the peer bandwidth to let users view multimedia smoothly and let our network link cost be low. We use simulation to analyze our method under several conditions.
