當網路中出現不只一個來源端要進行群播傳輸，以現行網路層群播路由協定來說各個來源端會依照自己所需提供服務群組的分佈位置及網路狀態，建立出來源基礎樹(Source based tree)或群組共享樹(Share based tree)將其所需提供服務之群組成員連接起來。然而每一個來源端皆是獨立運作的方式建立出屬於自己的傳輸樹狀結構，這些各個來源端在獨立運作下所建立出的傳輸路徑則很有可能互相造成重疊。在線路頻寬不足的情況下這些重疊路徑將會變成網路傳輸效能降低及傳輸時間增加的主要原因，鑑於這個原因我們嘗試重新設計目前現行網路層之群播路由協定並改良成適合於多個來源端的網路環境，減少原本群播協定在多個來源端下可能會產生重疊路徑對網路傳輸效能與傳輸時間所造成的影響。我們提出一個分散式群播路由協定，適合在多個來源端的網路中使用。此協定以目前網路層鏈路狀態路由(Link state routing)群播協定為基礎，將Network coding[1]的概念引入於多來源群播協定中建立一編碼群播(Coded multicast)機制，利用此機制來減少因路徑重疊所造成的效能降低。藉由Coded multicast的方式來提高在重疊路徑上可攜帶的資訊量，進而使得接收端不會因路徑重疊的問題造成接收率下降及接收時間的增加。

When multiple sources try to multicast simultaneously in a network today, each may employ existing multicast routing protocol in network layer and create its multicast transmission tree by its own topology of group members and link costs of the network. Source based tree or share based tree connects every member of group to each other. However, every source creates its own transmission tree independently and parts of these transmission trees in the network may overlap. Due to limited bandwidth of each link, these overlapping paths could decrease transmission performance of network and increase transmission time. In this dissertation, we try to enhance the existing multicast routing protocol by increasing the throughput of overlapping paths with network coding. We propose a distributed multicast routing protocol for multi-source multicasting. This mechanism is based on link state multicast routing protocol and the idea of network coding. And we derive a new multiple source multicast protocol from the idea of network coding. The protocol is called Coded multicast. Through simulations, the proposed protocol is shown to be able to provided much better performance than traditional multicasting.

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