應用於隨選視訊媒體串流之適應性複合同儕系統

使用同儕架構來設計串流系統是個熱門的研究題目，並且也已經有一些商業的同儕串流系統在運轉。這些被提出的做法，有的採用樹狀疊蓋式網路，而有的採用網狀疊蓋式網路。前者適合連續收看一段影音的時間相對久之使用者，而後者則適合相對短之使用者。然而在一系統中，這兩種使用者的數目都不算少，所以只採用單獨的一個疊蓋式網路並不能滿足使用者不同的收看行為。而單純地要使用者同時加入樹狀和網狀疊蓋式網路，立會同時承繼兩者的缺點。因此，我們提出一個應用於隨選視訊媒體串流之適應性複合同儕系統，『複合』的意思是本系統包含了一個樹狀疊蓋式網路和一個網狀疊蓋式網路。在本系統中，大部分的使用者設備都會週期性地檢查自己狀態是比較適合哪個疊蓋式網路，然後切換到該疊蓋式網路去。部分未來可能閒置的樹狀疊蓋式網路之葉節點，會被挑選來下載較少人暫存的影音片段，以服務網狀疊蓋式網路中的使用者。該挑選之葉節點的數目會依據兩個疊蓋式網路的資源需求而適切調整。

關鍵字

同儕架構；串流；樹狀疊蓋式網路；網狀疊蓋式網路；複合；適應性

並列摘要

Peer-to-peer on-demand media streaming with VCR Interactions has received more and more attention recently. Many studies proposed tree-based overlays for efficient delivery. Because the tree topology is vulnerable to node dynamics, it is not suitable for peers which continuously play a video for a relatively short time. In contrast, mesh-based overlay, though robust, suffers from high control overhead or unacceptable latency. Thus, mesh-based solutions can not satisfy the peers continuously playing a video for a relatively long time. Since a practical system will be neither pure stable nor pure dynamic, a single tree overlay or mesh overlay can not meet the real requirements. Some researchers simply combine the above two solutions, in which peers join both the two overlays. However, those architectures still have the respective problems inherent in the tree and mesh overlays. In this paper, we propose an adaptive hybrid peer-to-peer system that leverage both tree and mesh structures. In the proposed system, most peers join only one suitable overlay based on their viewing behavior. A portion of idle leaf nodes of the tree overlay are further selected to download the rarest video chunks to serve the peers in the mesh one. We also present a policy to adapt the number of selected leaf nodes to meet the resource demand of both the two overlays.

並列關鍵字

Peer-to-peer Architecture ； P2P Architecture ； Streaming ； Tree-based Overlay ； Mesh based Overlay ； Hybird ； Adaptation

國際替代計量

應用於隨選視訊媒體串流之適應性複合同儕系統

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