隨著網路技術的進步，網路頻寬逐漸的成長，同儕網路技術 ( Peer-to-Peer network technology )也開始發展起來， 跟傳統的主從式( Client-Server )架構相比較，同儕網路就是每個終端使用者貢獻自己的能力，如運算能力、網路頻寬、磁碟空間和自己擁有的檔案，形成層疊網路( Overlay Network )，每個使用者都可直接分享他們擁有的資源。
而其中Bitorrent是現在同儕網路中使用率較高的分散式檔案傳輸軟體，在Bitorrent 中使用者程式無法得知所有的下載者，且彼此依對方上傳速度頻寬決定是否同意允許下載，導致使用者程式可能不知道區域網路中有其他同儕程式擁有相同的檔案，使的通過路由器之間的傳送造成了重複的流量，降低了頻寬的使用效率。本論文主要分析，如何減少頻寬的浪費，使用者也能得到快速下載的的服務品質。
本文提出一個機制與訊息引導算法，藉由通透的代理伺服器來攔截並修改使用者程式至網站伺服器上所下載BitTorrent的metainfo檔案，將使用者程式與原Tracker的連線導向至我們在區域網路中設置的內部Tracker Agent，再由我們所設定的 Bittorrent 客戶端代理程式( Peer agent )引導不同的使用者程式抓取不同的檔案片斷，並且透過我們所設定的客戶端代理程式與訊息引導算法來增加區域化的流量。

With the improvement of New network technologies and network bandwidth. Compare with the traditional Client-Server framework, the Peer-to-Peer network (P2P) technology allows users to share their computing power, disk spaces, bandwidth, and file that own on the overlay network.Then every user can share their resource directly.
Bitorrent is a very popular distributed file transfer system. But in Bitorrent Peer can not know all of the other Peers, and does not know which LAN user have the same file. Partial Peer list and tit-for-tat make redundant traffic flow seriously.This thesis analysis how to reduce redundant traffic flow and increase quality of downloading.
To alleviate the problem, we use a transparent proxy to hijack a metainfo file downloaded by a user from a Web server. Then, the original tracker of the metainfo is replaced by a new tracker agent. The Peer therefore connects to the local BitTorrent tracker, then our Bittorrent Peer agent will guide Peer to get different piece first. By providing guide information to local Peers, this approach will increase local file sharing with local exchange by our Bittorrent Peer agent.

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