在同儕式群播技術裡，會話參與者作為節點並組織起來去建構覆蓋於實體網路上的一層網路拓撲。基於這樣的形式，同儕們執行群播程式而能夠容易地彼此散佈並取得資料。同儕式串流系統是把串流程式實施在同儕式群播之上的系統。在這種系統裡，使用的覆蓋式網路之拓撲與其維持法則挑選了參與者的串流資料支援者。然而，其拓撲與不被保證的通訊效率、被限制的上傳量、提供者的變動等等這些負面影響有關，因而直接影響了串流資料送達效率與(使用者)感受的串流資料品質等這些常見的效能評估準則。因此，如何形成能適當地調和這些負面影響的覆蓋式網路是個具有挑戰性的問題。這形成了動機使我們在這篇論文裡提出了一個具有彈性及地域感知性的覆蓋式網路用以建構同儕式串流系統。在我們的系統中，一個節點能不靠特定串流伺服器而容易地扮演串流資料來源去建立串流的會話。我們提出的群組概念以及數個法則建構並維持了我們的覆蓋式網路成為一個雙層的結構，使之相稱於被覆蓋的實體網路拓撲因而形成了整體上縮短的送達路徑。在一個地域群組裡，會話參與者因為做為一個節點而能在鄰接的同儕中有效率地獲得足夠的串流支援者。此外，加諸於地域群組大小的限制有助於均勻的利用同儕們的資源。在所做的模擬裡，我們把模擬結果與基於非結構式同儕網路的競爭者做比較。從支援者節點的通訊效率、串流來源至終端的送達效率及串流資料送達路徑的可靠性等觀點，這些比較顯示出我們的系統相較於競爭者具有某些程度的效能優勢，因而表露其具有可擴展性、效率及穩定性，並能持續地滿足串流效能的評估準則。

In the peer-to-peer multicast, session participants as peers are organized to construct an overlaying topology over physical infrastructures. In this manner, peers can easily disseminate data to and gather data from others by running multicast application. The peer-to-peer streaming system is constructed by applying streaming applications over peer-to-peer multicast, in which the streaming suppliers is chosen by the topology and maintenance schemes of employed overlay. However, the negative impacts such as non-guaranteed communication efficiency, limited upload capacity, dynamic of suppliers, etc. which are related to the topology of employed overlay and directly affect the common performance metrics, data stream delivery efficiency and perceived quality. Thus, how to form an overlay to properly accommodate those impacts is a challenging issue. In this thesis, we are motivated to propose a flexible locality-aware overlay network for the construction of a peer-to-peer streaming system. In our system, a peer can simply establish a streaming session and as a streaming source without the help of dedicated streaming servers. Based on the group concept and proposed schemes, our overlay is constructed and organized as a 2-layered structure to match the underlying network topology, making the totally short delivery paths. In a locality group, a session participant as a peer can efficiently obtain sufficient streaming suppliers as neighboring peers. Moreover, the bounded size of locality groups helps utilize of the resources of peers evenly. In our simulation the results are compared with the competitor built on unstructured peer-to-peer overlay network and show a degree of performance in terms of communication efficiency on supplying peer, source-to-end streaming delivery efficiency, and reliability on streaming delivery path. Our system can thus be demonstrated having scalability, efficiency and stability, with the constant satisfaction of streaming performance metrics.

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