Based on the advantages of both Grid and peer-to-peer （P2.） networks, an overlay network in the Grid environment is constructed by P2. technologies by a modified version of the Chord protocol. In this mechanism, dif...
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Based on the advantages of both Grid and peer-to-peer （P2.） networks, an overlay network in the Grid environment is constructed by P2. technologies by a modified version of the Chord protocol. In this mechanism, different nodes＇ accesses to different resources are determined by their contribution. Therefore, the heterogeneous resources of virtual organizations in large-scale Grid can be effectively integrated, and the key node failure as well as system bottleneck in the traditional Grid environment is eliminated. The experimental results indicate that this management mechanism can achieve better average performance in the Grid environment and maintain the P2. characteristics as well.
The design and evaluation of accelerated transmission （AT） systems in peer-to-peer networks for data transmission are introduced. Based on transfer control protocol （TCP） and peer-to-peer （P2.） substrate network...
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The design and evaluation of accelerated transmission （AT） systems in peer-to-peer networks for data transmission are introduced. Based on transfer control protocol （TCP） and peer-to-peer （P2.） substrate networks, AT can select peers of high performance quality, monitor the transfer status of each peer, dynamically adjust the transmission velocity and react to connection degradation with high accuracy and low overhead. The system performance is evaluated by simulations, and the interrelationship between network flow, bandwidth utilities and network throughput is analyzed. Owing to the collaborative operation of neighboring peers, AT accelerates the process of data transmission and the collective network performance is much more satisfactory.
P2.(peer to peer)网络中,节点的自私行为极大地降低了系统的可用性.基于债务关系的文件交换网络,构建了一种促进合作的激励机制.同时,该机制保证了文件交换的公平性.激励机制的关键在于DHT(distributed hash table)网络邻居有限的固有...
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P2.(peer to peer)网络中,节点的自私行为极大地降低了系统的可用性.基于债务关系的文件交换网络,构建了一种促进合作的激励机制.同时,该机制保证了文件交换的公平性.激励机制的关键在于DHT(distributed hash table)网络邻居有限的固有特征,因而节点间的交互易于形成重复博弈.DFFE(debt relationship based fair file exchange in DHT network)协议只需维护很少的本地节点交互信息,协议开销小、网络扩展性好.网络路由采用基于一跳信息的贪婪算法.理性节点间的博弈存在纳什均衡,其策略选择的近似算法具有渐进收敛性.仿真实验表明了激励机制的有效性和在动态网络中性能的稳定性.
P2.流媒体cache是一种有效减少带宽开销、提高对象利用率的技术,通常采用FIFO,LRU等算法置换内容.然而,流媒体不同于Web对象,P2.网络也有别于客户/服务器模式.在分布式应用中这些算法可能影响系统的性能,为此,分析了FIFO和LRU置换算法,提出了基于供求关系的SD算法,以及基于分片副本数量的REP算法,并对其进行评估和比较.针对不同的节点到达间隔,将SD和REP同FIFO,LRU进行比较,发现在启动延迟、媒体副本数量和根节点依赖度方面SD和REP几乎均优于FIFO和LRU.同LSB(least sent bytes)算法相比,某些场景中SD的启动延迟减少了约40%,而REP在副本数量方面远远超过LSB的结果,说明在P2.网络流媒体服务中使用SD和REP缓存置换算法有助于提高系统性能.
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