随着P2P分布式存储的研究深入,处在不同网络的节点间建立连接受到网络地址转换(network address translator,NAT)限制.现有的UDP对NAT的简单穿越(simple traversal of UDP through NAT,STUN)方案,不能满足P2P分布式存储对数据传输质量...随着P2P分布式存储的研究深入,处在不同网络的节点间建立连接受到网络地址转换(network address translator,NAT)限制.现有的UDP对NAT的简单穿越(simple traversal of UDP through NAT,STUN)方案,不能满足P2P分布式存储对数据传输质量的要求,并且由于对称型NAT的广泛使用,节点间数据传输必须经过服务器中继转发,中继服务器成为系统瓶颈.提出采用基于UDP的数据传输(UDP-based data transfer,UDT)协议的改进STUN方案,可以保证数据传输可靠性,同时基于端口预测的NAT穿越策略,不需要服务器中继即可实现在对称型NAT后的节点间建立P2P直连.展开更多
Multimedia streaming served through peer-to-peer (P2P) networks is booming nowadays. However, the end-to-end streaming quality is generally unstable due to the variability of the state of serve-peers. On the other han...Multimedia streaming served through peer-to-peer (P2P) networks is booming nowadays. However, the end-to-end streaming quality is generally unstable due to the variability of the state of serve-peers. On the other hand, proxy caching is a bandwidth-efficient scheme for streaming over the Internet, whereas it is a substantially expensive method needing dedicated powerful proxy servers. In this paper, we present a P2P cooperative streaming architecture combined with the advantages of both P2P networks and multimedia proxy caching techniques to improve the streaming quality of participating clients. In this frame- work, a client will simultaneously retrieve contents from the server and other peers that have viewed and cached the same title before. In the meantime, the client will also selectively cache the aggregated video content so as to serve still future clients. The associate protocol to facilitate the multi-path streaming and a distributed utility-based partial caching scheme are detailedly dis- cussed. We demonstrate the effectiveness of this proposed architecture through extensive simulation experiments on large, Inter- net-like topologies.展开更多
With the great commercial success of several IPTV (internet protocal television) applications, PPLive has received more and more attention from both industry and academia. At present, PPLive system is one of the most ...With the great commercial success of several IPTV (internet protocal television) applications, PPLive has received more and more attention from both industry and academia. At present, PPLive system is one of the most popular instances of IPTV applications which attract a large number of users across the globe; however, the dramatic rise in popularity makes it more likely to become a vulnerable target. The main contribution of this work is twofold. Firstly, a dedicated distributed crawler system was proposed and its crawling performance was analyzed, which was used to evaluate the impact of pollution attack in P2P live streaming system. The measurement results reveal that the crawler system with distributed architecture could capture PPLive overlay snapshots with more efficient way than previous crawlers. To the best of our knowledge, our study work is the first to employ distributed architecture idea to design crawler system and discuss the crawling performance of capturing accurate overlay snapshots for P2P live streaming system. Secondly, a feasible and effective pollution architecture was proposed to deploy content pollution attack in a real-world P2P live streaming system called PPLive, and deeply evaluate the impact of pollution attack from following five aspects:dynamic evolution of participating users, user lifetime characteristics, user connectivity-performance, dynamic evolution of uploading polluted chunks and dynamic evolution of pollution ratio. Specifically, the experiment results show that a single polluter is capable of compromising all the system and its destructiveness is severe.展开更多
文摘随着P2P分布式存储的研究深入,处在不同网络的节点间建立连接受到网络地址转换(network address translator,NAT)限制.现有的UDP对NAT的简单穿越(simple traversal of UDP through NAT,STUN)方案,不能满足P2P分布式存储对数据传输质量的要求,并且由于对称型NAT的广泛使用,节点间数据传输必须经过服务器中继转发,中继服务器成为系统瓶颈.提出采用基于UDP的数据传输(UDP-based data transfer,UDT)协议的改进STUN方案,可以保证数据传输可靠性,同时基于端口预测的NAT穿越策略,不需要服务器中继即可实现在对称型NAT后的节点间建立P2P直连.
基金Project (Nos. 90412012 and 60673160) supported by the NationalNatural Science Foundation of China
文摘Multimedia streaming served through peer-to-peer (P2P) networks is booming nowadays. However, the end-to-end streaming quality is generally unstable due to the variability of the state of serve-peers. On the other hand, proxy caching is a bandwidth-efficient scheme for streaming over the Internet, whereas it is a substantially expensive method needing dedicated powerful proxy servers. In this paper, we present a P2P cooperative streaming architecture combined with the advantages of both P2P networks and multimedia proxy caching techniques to improve the streaming quality of participating clients. In this frame- work, a client will simultaneously retrieve contents from the server and other peers that have viewed and cached the same title before. In the meantime, the client will also selectively cache the aggregated video content so as to serve still future clients. The associate protocol to facilitate the multi-path streaming and a distributed utility-based partial caching scheme are detailedly dis- cussed. We demonstrate the effectiveness of this proposed architecture through extensive simulation experiments on large, Inter- net-like topologies.
基金Project(2007CB311106) supported by National Basic Research Program of ChinaProject(242-2009A82) supported by National Information Security Special Plan Program of China
文摘With the great commercial success of several IPTV (internet protocal television) applications, PPLive has received more and more attention from both industry and academia. At present, PPLive system is one of the most popular instances of IPTV applications which attract a large number of users across the globe; however, the dramatic rise in popularity makes it more likely to become a vulnerable target. The main contribution of this work is twofold. Firstly, a dedicated distributed crawler system was proposed and its crawling performance was analyzed, which was used to evaluate the impact of pollution attack in P2P live streaming system. The measurement results reveal that the crawler system with distributed architecture could capture PPLive overlay snapshots with more efficient way than previous crawlers. To the best of our knowledge, our study work is the first to employ distributed architecture idea to design crawler system and discuss the crawling performance of capturing accurate overlay snapshots for P2P live streaming system. Secondly, a feasible and effective pollution architecture was proposed to deploy content pollution attack in a real-world P2P live streaming system called PPLive, and deeply evaluate the impact of pollution attack from following five aspects:dynamic evolution of participating users, user lifetime characteristics, user connectivity-performance, dynamic evolution of uploading polluted chunks and dynamic evolution of pollution ratio. Specifically, the experiment results show that a single polluter is capable of compromising all the system and its destructiveness is severe.
