Summary: | 碩士 === 元智大學 === 資訊工程學系 === 90 === As network bandwidth increases, multimedia applications such as multimedia conferencing and distant learning will get popular over Internet. But all multi-unicast packets transport over Internet face several similar difficulties. The greatest difficulty we may face is large network delay jitter. The temporal relationships among the media streams may be disturbed owing to network delay jitter, which is called asynchronous problem. This thesis proposes a proxy-based group synchronization architecture for large-scale multicast communications in unreliable wide-area networks such as Internet. Our architecture uses a dynamic clustering scheme, in which users in close proximity are clustered into a group. A member in a group is selected as a group leader who serves as a transmission proxy for the group, which we call synchronization node. We propose a buffer level control on the synchronization node to eliminate the variation of the end-to-end delay. We also propose a traffic control scheme to reduce backbone traffic. Simulation results show that by using clusters and the proposed traffic control scehme, we can efficiently reduce the control messages and backbone traffic between the multi-unicast server and end nodes and make end nodes easier to be synchronized.
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