【作者】 左强翔；

【导师】 吴洁；

【作者基本信息】 南京航空航天大学 ， 计算机应用技术， 2008， 硕士

【摘要】 音视频通信系统在当前的应用极为广泛,也日益重要。目前大部分采用C/S模式,在这种模式中,服务器要承担所有的重担,这给服务器造成了极大的压力,服务器无疑是系统最大的瓶颈,对等(P2P)技术的出现给这个问题带来了可行的解决途径。根据P2P的技术特征,主要的研究与应用问题集中在所形成的覆盖网络层。从而本文最终的问题就是如何设计一个优秀的P2P覆盖网络模型,这也是P2P技术研究与应用的关键。因此,本文设计了一个层次化的拓扑感知网络模型――PPAVCS网络模型,并设计了相应的算法。模型是在Kademlia网络模型基础上的改进,主要针对逻辑网络与物理网络不匹配和节点异构性这两个结构化网络普遍存在的问题做了尝试性的解决。在模型中引入了超级节点和域的概念,超级节点是由综合性能强的节点担当,一个域是由一个超级节点和与它物理距离相近的普通节点组成,从而达到与物理网络匹配和节点异构性的目的。普通节点只能在域内查询资源,当它查询失败时,由超级节点帮助在域间进行查询。最后在模拟环境中通过P2PSim模拟器对模型性能进行了模拟分析,仿真结果表明改进的模型性能优于Kademlia网络模型,同时设计实现了一个具备基本功能的音视频通信系统,以验证模型的现实可行性。更多还原

【Abstract】 At the present time, Audio & Video Communication (AVC) systems are widely used and become more important in people’s life. But most systems are designed based on C/S model, in which the Server should perform all the tasks, they cause the Server a heavy burden, and server became the main bottle-neck of systems. The emergence of P2P brings a feasible solution to the problem. According to the technical features of P2P, problems of the research on P2P and application of it mainly concentrate on the Overlay network. So how to design an outstanding P2P Overlay network model is the last problem of the thesis.So the thesis designs a hierarchical & topology-aware network model and relevant algorithm based on the Kademlia network. The improvement mainly focuses on the two prevalent issues about the current structural P2P network: logical network mismatch with the physical one and node’s heterogeneity.The thesis introduces SuperNode and zone concept in the model. The SuperNode is acted by the node which has strong integrated performance; the zone has one SuperNode and some NormalNodes which have similar distance from the SuperNode of the zone, so to achieve the purpose of the match with physical network and node’s heterogeneity. When the NormalNode query resources, it queries them in the zone firstly, if if failed, then it queries them in other zones through the SuperNode of the zone. In the end, the thesis not only simulate and analysis its performance through P2PSim simulator, the simulative results demonstrate that the performance of improved model is better than the Kademlia network model, but also design and realize an AVC system to validate its practical feasibility, which has some basic functions.更多还原