互联网目前已经发展为一个由实时视频和视频点播等内容分发服务主导的网络.传统IP网络对于视频分发类任务的支持存在组播的部署复杂且开销大,不能有效利用多路径获取内容、对移动性的支持差和难以同时满足可靠性以及低延时需求等问题....互联网目前已经发展为一个由实时视频和视频点播等内容分发服务主导的网络.传统IP网络对于视频分发类任务的支持存在组播的部署复杂且开销大,不能有效利用多路径获取内容、对移动性的支持差和难以同时满足可靠性以及低延时需求等问题.命名数据网络(named data networking,NDN)作为新型的下一代互联网体系结构,支持网络内缓存和多路径传输,而且由消费者驱动的传输模式使其天然地支持消费者端移动性.以上特点使NDN具有高效传输视频内容的潜力.首先介绍了视频传输和NDN的基础背景,然后阐述了一些利用NDN中优势实现视频传输的设计方案.通过对已有方案的总结与比较,最后指出了在NDN中传输视频所面临的挑战.展开更多
为满足车载社交网络(Vehicular Social Network,VSN)中用户对视频等多媒体内容的需求,基于内容中心网络(Information-Centric Networking,ICN)架构,提出一种内容中心型VSN路由机制(Content-centric routing scheme in VSN,CVSN)。在CVSN...为满足车载社交网络(Vehicular Social Network,VSN)中用户对视频等多媒体内容的需求,基于内容中心网络(Information-Centric Networking,ICN)架构,提出一种内容中心型VSN路由机制(Content-centric routing scheme in VSN,CVSN)。在CVSN中,兴趣路由根据车辆节点的相似内容存储选择兴趣包转发节点;数据路由根据车辆节点间的同行率选择数据包转发节点。同时,基于VSN用户的兴趣偏好进行内容的网络内缓存管理,在缓存达到上限时,首先丢弃用户兴趣偏好低的内容。基于公交车应用场景对所提出的路由机制进行了仿真实验,通过与现有机制在包交付率、平均延迟、平均跳数和网络开销方面的性能对比表明了文中提出的机制是可行且有效的。展开更多
Information-Centric Networking(ICN), an alternative architecture to the current Internet infrastructure, focuses on the distribution and retrieval of content by employing caches in a network to reduce network traffic....Information-Centric Networking(ICN), an alternative architecture to the current Internet infrastructure, focuses on the distribution and retrieval of content by employing caches in a network to reduce network traffic. The employment of caches may be accomplished using graph-based and content-based criteria such as the position of a node in a network and content popularity. The contribution of this paper lies on the characterization of content popularity for on-path in-network caching. To this end, four dynamic approaches for identifying content popularity are evaluated via simulations. Content popularity may be determined per chunk or per object, calculated by the number of requests for a content against the sum of requests or the maximum number of requests. Based on the results, chunk-based approaches provide 23% more accurate content popularity calculations than object-based approaches. In addition, approaches that are based on the comparison of a content against the maximum number of requests have been shown to be more accurate than the alternatives.展开更多
In-network caching and Interest packets aggregation are two important features of Content-Centric Networking(CCN).CCN routers can directly respond to the Interest request by Content Store(CS)and aggregate the same Int...In-network caching and Interest packets aggregation are two important features of Content-Centric Networking(CCN).CCN routers can directly respond to the Interest request by Content Store(CS)and aggregate the same Interest packets by Pending Interest Table(PIT).In this way,most popular content requests will not reach the origin content server.Thus,content providers will be unaware of the actual usages of their contents in network.This new network paradigm presents content providers with unprecedented challenge.It will bring a great impact on existing mature business model of content providers,such as advertising revenue model based on hits amount.To leverage the advantages of CCN and the realistic business needs of content providers,we explore the hits-based content provisioning mechanism in CCN.The proposed approaches can avoid the unprecedented impact on content providers' existing business model and promote content providers to embrace the real deployment of CCN network.展开更多
Due to large size and different popularity for different part of the video, most proxy caches for streaming medias cache only a part of the video. Thus, an accurate understanding on the internal popularity distributio...Due to large size and different popularity for different part of the video, most proxy caches for streaming medias cache only a part of the video. Thus, an accurate understanding on the internal popularity distribution of media objects in streaming applications is very important for the development of efficient cache mechanisms. This letter shows that the internal popularity of popular streaming media obeys a k-transformed Zipf-like distribution through analyzing two 6-month long traces recorded at different streaming video servers of an entertainment video-on-demand provider. This empirical model can be used to design an efficient cach- ing algorithm.展开更多
Some unsafe languages,like C and C++,let programmers maximize performance but are vulnerable to memory errors which can lead to program crashes and unpredictable behavior.Aiming to solve the problem,traditional memory...Some unsafe languages,like C and C++,let programmers maximize performance but are vulnerable to memory errors which can lead to program crashes and unpredictable behavior.Aiming to solve the problem,traditional memory allocating strategy is improved and a new probabilistic memory allocation technology is presented.By combining random memory allocating algorithm and virtual memory,memory errors are avoided in all probability during software executing.By replacing default memory allocator to manage allocation of heap memory,buffer overflows and dangling pointers are prevented.Experiments show it is better than Diehard of the following aspects:memory errors prevention,performance in memory allocation set and ability of controlling working set.So probabilistic memory allocation is a valid memory errors prevention technology and it can tolerate memory errors and provide probabilistic memory safety effectively.展开更多
文摘互联网目前已经发展为一个由实时视频和视频点播等内容分发服务主导的网络.传统IP网络对于视频分发类任务的支持存在组播的部署复杂且开销大,不能有效利用多路径获取内容、对移动性的支持差和难以同时满足可靠性以及低延时需求等问题.命名数据网络(named data networking,NDN)作为新型的下一代互联网体系结构,支持网络内缓存和多路径传输,而且由消费者驱动的传输模式使其天然地支持消费者端移动性.以上特点使NDN具有高效传输视频内容的潜力.首先介绍了视频传输和NDN的基础背景,然后阐述了一些利用NDN中优势实现视频传输的设计方案.通过对已有方案的总结与比较,最后指出了在NDN中传输视频所面临的挑战.
文摘为满足车载社交网络(Vehicular Social Network,VSN)中用户对视频等多媒体内容的需求,基于内容中心网络(Information-Centric Networking,ICN)架构,提出一种内容中心型VSN路由机制(Content-centric routing scheme in VSN,CVSN)。在CVSN中,兴趣路由根据车辆节点的相似内容存储选择兴趣包转发节点;数据路由根据车辆节点间的同行率选择数据包转发节点。同时,基于VSN用户的兴趣偏好进行内容的网络内缓存管理,在缓存达到上限时,首先丢弃用户兴趣偏好低的内容。基于公交车应用场景对所提出的路由机制进行了仿真实验,通过与现有机制在包交付率、平均延迟、平均跳数和网络开销方面的性能对比表明了文中提出的机制是可行且有效的。
基金funded by the Higher Education Authority (HEA)co-funded under the European Regional Development Fund (ERDF)
文摘Information-Centric Networking(ICN), an alternative architecture to the current Internet infrastructure, focuses on the distribution and retrieval of content by employing caches in a network to reduce network traffic. The employment of caches may be accomplished using graph-based and content-based criteria such as the position of a node in a network and content popularity. The contribution of this paper lies on the characterization of content popularity for on-path in-network caching. To this end, four dynamic approaches for identifying content popularity are evaluated via simulations. Content popularity may be determined per chunk or per object, calculated by the number of requests for a content against the sum of requests or the maximum number of requests. Based on the results, chunk-based approaches provide 23% more accurate content popularity calculations than object-based approaches. In addition, approaches that are based on the comparison of a content against the maximum number of requests have been shown to be more accurate than the alternatives.
基金This work was supported by National Key Basic Research Program of China （973 Program） under Grant No. 2012CB315802 National Natural Science Foundation of China under Grant No. 61171102 and No. 61132001 Prospective Research on Future Networks of Jiangsu Future Networks Innovation institute under Grant No. BY2013095-4-01. Beijing Nova Program under Grant No.2008B50 and Beijing Higher Education Young Elite Teacher Project under Grant No.YETP0478.
文摘In-network caching and Interest packets aggregation are two important features of Content-Centric Networking(CCN).CCN routers can directly respond to the Interest request by Content Store(CS)and aggregate the same Interest packets by Pending Interest Table(PIT).In this way,most popular content requests will not reach the origin content server.Thus,content providers will be unaware of the actual usages of their contents in network.This new network paradigm presents content providers with unprecedented challenge.It will bring a great impact on existing mature business model of content providers,such as advertising revenue model based on hits amount.To leverage the advantages of CCN and the realistic business needs of content providers,we explore the hits-based content provisioning mechanism in CCN.The proposed approaches can avoid the unprecedented impact on content providers' existing business model and promote content providers to embrace the real deployment of CCN network.
基金Supported by the National Natural Science Foundation of China (No.60302004), the Australian Research Council (Grant LX0240468) and Natural Science Foun-dation of Hubei, China (No.2005ABA264).
文摘Due to large size and different popularity for different part of the video, most proxy caches for streaming medias cache only a part of the video. Thus, an accurate understanding on the internal popularity distribution of media objects in streaming applications is very important for the development of efficient cache mechanisms. This letter shows that the internal popularity of popular streaming media obeys a k-transformed Zipf-like distribution through analyzing two 6-month long traces recorded at different streaming video servers of an entertainment video-on-demand provider. This empirical model can be used to design an efficient cach- ing algorithm.
基金supported by the Natural Science Foundation of China under Grant No.61100205the National High-Tech Research and Development Plan of China under Grant No.2009AA01Z433the Project of the Fundamental Research Funds of Beijing Institute of Technology
文摘Some unsafe languages,like C and C++,let programmers maximize performance but are vulnerable to memory errors which can lead to program crashes and unpredictable behavior.Aiming to solve the problem,traditional memory allocating strategy is improved and a new probabilistic memory allocation technology is presented.By combining random memory allocating algorithm and virtual memory,memory errors are avoided in all probability during software executing.By replacing default memory allocator to manage allocation of heap memory,buffer overflows and dangling pointers are prevented.Experiments show it is better than Diehard of the following aspects:memory errors prevention,performance in memory allocation set and ability of controlling working set.So probabilistic memory allocation is a valid memory errors prevention technology and it can tolerate memory errors and provide probabilistic memory safety effectively.
