近年來，點對點（P2P）即時串流系統獲得越來越多的重視。在各種不同的系統中，隨機閒聊（gossip-based）的方式具有相當大的潛力，並且已經應用於真實網路世界。在這樣無固定架構的點對點串流系統中，不同節點群聚在一起互相交換影音串流資料，這種架構稱之為蜂群機制。為了維護群聚的正確以及節點間有效率的交換資料，可能會造成過多不必要的負擔（overhead）。在這篇論文中，我們提出了使用合作式蜂群機制的即時串流系統，稱為CSLive，能夠讓蜂群內的節點彼此之間形成合作關係。也就是說，CSLive將系統中相近的節點集合起來形成群組（cluster），而相同群組中的節點各自負責不同的串流部分；群組中的節點各自就其所負責的部份和群組之外的節點發出要求（request）以取得資料，並且在收到之後主動傳送給相同群組的其他節點。透過這種合作方式，CSLive可以降低傳統無固定架構的點對點即時串流系統中，每個節點為了取得資料所必須維護的夥伴（partner）數量，因此能更減少系統中大量交換訊息產生的負擔。更進一步而言，因為這種合作方式，系統中的節點可以預期大部分的串流都是由和自己相同群組的節點所提供，而我們知道相同群組中的節點彼此間的傳輸品質（communication quality）較佳。透過模擬我們證實這種合作機制能夠提升系統的效能。

Peer-to-peer (P2P) live streaming systems gain a lot of attention recently. Among the various architectures, the gossip-based approach holds great potential and has been used in real systems. In a gossip-based P2P streaming system, peer nodes are grouped together to exchange pieces of the live stream with each other. Maintaining the group, called a swarm, and pulling the streaming data from other peers incur nontrivial overhead. This thesis proposes to put the nodes in a swarm into a cooperative relationship. The idea is to gather nodes that are physically close into clusters, and let nodes in the same cluster cooperatively pull streaming data from outside of the cluster and actively push collected data to other nodes in the cluster. By cooperating with cluster members, the proposed CSLive system can reduce the number of partners with which a node needs to maintain, whereby cutting down the control overhead in gossip-based live streaming systems. Furthermore, with the cooperative operations, a node can expect to receive most streaming data from nodes in the same cluster, which have good communication quality, and only need to pull the responsible data from nodes outside of the cluster. The performance of the whole system may be improved. The proposed system is evaluated with simulation.

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