面向高清视频点播的P2P传输技术研究
摘要
电视节目的高清化进一步加剧了视频点播的网络带宽和服务器性能压力,导致IPTV和IP-QAM等在线视频点播的并发服务用户数成倍降低。特别是因为IP网缺乏有效QoS能力使其承载的IPTV很难真正开展高清视频点播服务。可以采用先下载后播放的离线视频点播方式分散网络带宽压力,而P2P服务模式能够进一步降低服务器性能要求。因此提出了城域网上基于P2P技术的高清视频点播方法,因为没有版权风险设计了基于集中式资源管理的P2P系统,提高了检索效率,降低了节点软件的复杂度。为了解决有线电视数字化造成的家庭第二台电视闲置问题,基于NAS平台构建了家庭服务器作为P2P节点,使家庭中多台机顶盒可以并发点播P2P下载的节目。
常规的P2P在高清视频点播中的随机传输会导致城域网骨干拥塞。因此通过仿真分析了流量分布特性,提出了利用城域网具有稳定拓扑的特点寻找最近邻资源接点的方法,把P2P流量推向网络边缘,消除骨干网堵塞。为此定义了描述节点拓扑位置的向量,设计了节点间距离向量的生成算法和距离向量的紧邻比较算法。在此基础上实现了用于最近邻接点选择的拓扑服务器。为了实现节目尽快在城域网上快速分布,提出了资源节点的广度优先服务策略和稀有片优先策略。
为了解决中心资源索引的P2P系统存在的单点故障和服务性能不足问题,利用微软的网络负载均衡技术实现了节目检索在多台服务器上的并发服务。负载均衡采用共享虚拟IP地址和MAC地址,造成交换机向所有成员服务器广播网络通信。因此开发了服务端口不在网络负载均衡管理之下的节点资源分布侦听服务,同步接收节点的资源分布变动通告,保证所维护的资源分布信息的一致性。
最后,选择OMNET++对面向城域网优化的P2P点播系统进行仿真,结果表明系统具有可行性,并且在扩展性、优化效果和稳定性方面具有一定的优良性。
High-definition (HD) television channels are increasing rapidly, which need much more bandwidth of the networks and the higher performance of the servers. Thus the quantity of the concurrent users is reduced in several times for the online VOD (video on demand) technologies of IPTV and IP-QAM. Especially, IPTV cannot carry the real HD-VOD for the lack of QoS. So it's appropriate to play the programs after downloading for moving the downloading traffic from the peak time. Then P2P technology can be employed to decreasing the demand for the server's performance. The HD-VOD method based on P2P is put forward in MAN, which uses the central resource indexing method due to no piracy. The home server is built on NAS as the P2P node, and serves the several STBs as the VOD server.
The jam would happen in the backbone of MAN due to the random transmission of the traditional P2P. MAN is a structured network in the small scale, and the distribution characteristics of the P2P flow is analyzed by simulating. A tree structured network model of MAN is built, and then an algorithm is proposed to select the nearest neighbors. Multi-dimensional vector is applied to descript peer node's location. The topology of MAN and peer node vectors were saved in the topology server. To avoid the negative effects of rare piece, the seed node's operating mechanism was optimized; which can balance the amount of rare pieces by giving priority to the nodes requesting the rare pieces. To distribute the resources to cover MAN rapidly, a scope-first algorithm is proposed to give priority to the remote neighbors.
In order to solve the shortage of center serving mode, Microsoft network load balancing technology is adopted to achieve concurrent index service. By all the servers in the NLB cluster share the same virtual IP address and the same MAC address, the service for the peers' resources information updating is built with the port out of NLB for receiving the messages' broadcasting from the peers, which ensures the provision of continuous and reliable service.
At last, the paper emulates scenarios of this system, executes and gives a performance test. The results of tests indicate that the system is feasible and the overall performance is good in reliability and scalability.
常规的P2P在高清视频点播中的随机传输会导致城域网骨干拥塞。因此通过仿真分析了流量分布特性,提出了利用城域网具有稳定拓扑的特点寻找最近邻资源接点的方法,把P2P流量推向网络边缘,消除骨干网堵塞。为此定义了描述节点拓扑位置的向量,设计了节点间距离向量的生成算法和距离向量的紧邻比较算法。在此基础上实现了用于最近邻接点选择的拓扑服务器。为了实现节目尽快在城域网上快速分布,提出了资源节点的广度优先服务策略和稀有片优先策略。
为了解决中心资源索引的P2P系统存在的单点故障和服务性能不足问题,利用微软的网络负载均衡技术实现了节目检索在多台服务器上的并发服务。负载均衡采用共享虚拟IP地址和MAC地址,造成交换机向所有成员服务器广播网络通信。因此开发了服务端口不在网络负载均衡管理之下的节点资源分布侦听服务,同步接收节点的资源分布变动通告,保证所维护的资源分布信息的一致性。
最后,选择OMNET++对面向城域网优化的P2P点播系统进行仿真,结果表明系统具有可行性,并且在扩展性、优化效果和稳定性方面具有一定的优良性。
High-definition (HD) television channels are increasing rapidly, which need much more bandwidth of the networks and the higher performance of the servers. Thus the quantity of the concurrent users is reduced in several times for the online VOD (video on demand) technologies of IPTV and IP-QAM. Especially, IPTV cannot carry the real HD-VOD for the lack of QoS. So it's appropriate to play the programs after downloading for moving the downloading traffic from the peak time. Then P2P technology can be employed to decreasing the demand for the server's performance. The HD-VOD method based on P2P is put forward in MAN, which uses the central resource indexing method due to no piracy. The home server is built on NAS as the P2P node, and serves the several STBs as the VOD server.
The jam would happen in the backbone of MAN due to the random transmission of the traditional P2P. MAN is a structured network in the small scale, and the distribution characteristics of the P2P flow is analyzed by simulating. A tree structured network model of MAN is built, and then an algorithm is proposed to select the nearest neighbors. Multi-dimensional vector is applied to descript peer node's location. The topology of MAN and peer node vectors were saved in the topology server. To avoid the negative effects of rare piece, the seed node's operating mechanism was optimized; which can balance the amount of rare pieces by giving priority to the nodes requesting the rare pieces. To distribute the resources to cover MAN rapidly, a scope-first algorithm is proposed to give priority to the remote neighbors.
In order to solve the shortage of center serving mode, Microsoft network load balancing technology is adopted to achieve concurrent index service. By all the servers in the NLB cluster share the same virtual IP address and the same MAC address, the service for the peers' resources information updating is built with the port out of NLB for receiving the messages' broadcasting from the peers, which ensures the provision of continuous and reliable service.
At last, the paper emulates scenarios of this system, executes and gives a performance test. The results of tests indicate that the system is feasible and the overall performance is good in reliability and scalability.
引文
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[30]Yunhao Liu, Xiaomei Liu, Li Xiao, Lionel M.Ni Xiaodong Zhang.2004.Location-aware Topology Matching In P2P Systems.INFOCOM'04,2220-2230
[31]Jing Wang, Shoubao Yang:Content-based Clustered P2P Search Model Deponding on Set Distance.in the 2006 IEEE/WIC/ACM International Workshop on P2P Computing and Autonomous Agent.IEEE Computer Society,2006,pp,471-476.
[32]Petar Maymounkov,David Mazieres.Kademlia:A Peer-To_Peer Information System Based on the XOR Metric.http://kademlia.scs.cs.nyu.edu
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[34]Wu C J,Li C Y,Hou J M.Improving the Download Time of BitTorrent-like Systems.Communications,2007,28(3):1125-1129
[35]Leibowitzn, Ripeanu M, Wierzbicki A. Deconstructing the Kazaa network. In:Proc of 3rd IEEE Workshop on Internet Applications. CA, USA,2003,112-120
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[37]钟玉琢等编著.数字电视机顶盒和多媒体家庭网关[M].北京：清华大学出版社,2008.11
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[42]张选波. 搭建Windows Server 2008基于Web服务的网络负载平衡.http://xuanbo.blog.51cto.com/499334/158843
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[2]李晓峰,崔卫,赵靖波,刘尊利,谢树民.绥芬河互动电视系统.电视技术,Vo1.33,No.9,2009.6-8
[3]夏卉,陈宁.基于IP-QAM的交互数字电视系统关键技术研究[J].有线电视技术,2007,(4)：33-38
[4]钟玉琢,向哲,沈洪.流媒体和视频服务器[M].北京：清华大学出版社,2003,183-191
[5]张文,赵子铭等.P2P网络技术原理与C++开发案例[M].北京：人民邮电出版社,2008,8：8-10,12-35
[6]Y.Guo,K.Suh,J.Kurose,D.Towsley, A Peer-to-Peer On-Demand Streaming Service and Its Performance Evaluation,in IEEE ICME 2003
[7]Ralf Steinmetz,Klaus Wehrle等著.P2P系统及其应用[M].北京：机械工业出版社,2008,5：50-80
[8]郭奕,唐继勇.NVOD系统结构分析以及关键技术研究[J].中国有线电视,2006,(16)：1576-1579
[9]刘超,吴国斌,倪宏,潘梁.有线数字电视推播业务系统的设计和实现[J].电视技术,2006,(7)：66-68
[10]李晓峰,庄文君,崔卫,刘永辉,刘剑.在单向电视网上实现大规模数字电视视频点播的方法
[P].中国专利200510104536.9,2005-11-18
[11]季伟,葛振斌.IPTV关键技术及应用[M].北京：机械工业出版社,2007,8：1-10
[12]Wu-Chi Feng, Jahanian, E.Sechrest. Providing VCR Functionality in a Constant Quality Video-On-Demand Transportation Service. Multimedia Computing and Systems,1996. Proceedings of theThird IEEE International Conference. PP.127-135
[13]Xiaofeng Li, Peng Zhao, Yonghui Liu, Jian Liu. The Method of Mobile Networks as the Return Channel for IP-QAM. Proceeding of WRI International Conference on Communications and Mobile Computing, 2010.224-226
[14]Xiaofeng Li, Liguo Xie, Gang Liu. Study of VOD Server Architecture with the Array of the Balanced Nodes in Storage and Networks. Proceedings of The 5th International Conference on Frontier of Computer Science and Technology,2010.214-218
[15]钟玉琢,王琪等.MPEG-2运动图像压缩编码国际标准及MPEG的新进展[M].北京：清华大学出版社,2002：56-60
[16]冼伟铨,向哲,钟玉琢.视频点播系统用户行为仿真平台[J].系统仿真学报.2001,13(2)：221-223
[17]Shih-Chiang Chien, Yung-Wei Kao and Shyan-Ming Yuan, "A Generic Publish/Subscribe Framework for Peer-to-Peer Environment" 2009 International Conference on New Trends in Information and Service Science (ICNTISS 09),IEEE Press,2009, pp.114-119
[18]杨祝林,陈浩,孙建华等.基于BitTorrent种子的内容分发算法[J].计算机工程.2009,35(3)：133-135
[19]程学旗等.P2P技术与信息安全[EB/OL].http:\\www.lmtw.com
[20]Ripeanu M.Peer-to-Peer architecture case study:Gnutella network. In:Proc of Peer-to-Peer Computing. CA, USA,2001:99-100
[21]Pouwelse J A, Garbacki P, Epema D H J. The bittorrent P2P file-sharing system:measurements and analysis. In:Proc of the 4th International Workshop on Peer. to. Peer Systems. NY, USA,Berlin, Germany,2005:205-216
[22]LVQ, Cao P, Cohen E. Search and replication in unstructured peer-to-peer networks. In:Proc of 16th ACM International Desent. New York, USA,2002:84-95
[23]王学.基于P2P的网络拓扑发现算法研究[D].大连理工大学.2007
[24]Bridge Q.Zhao,John C.S. Lui,Dah-Ming Chui.Analysis of Adaptive Incentive Protocols for P2P Networks.IEEE INFOCOM,2009:325-333
[25]Tina W, Randy K, Steven M C. An Evaluation of Preference Clustering in Large,Scale Multicast Applications. In:Proc of IEEE INFOCOM 2000, Tel AViV, Israel,2000,1-18
[26]BitTorrent protocol Specification.htttp://www.bittorrent.org
[27]中国电子视像行业协会.解读数字电视[M].北京：人民邮电出版社.2008.1：10-15
[28]李晓峰,庄文君,崔卫,刘永辉,刘剑,赵亚伟.一种优化城域网内P2P传输的方法[P].中国专利200710013549.4,2007-02-09
[29]T.O. Qiu,G.Chen,M Ye,Edward Chan and Ben Zhao, Towards Location-aware Topology in Both Unstructured and Structured P2P Systems.Intternational Conference on Parallel Processing (ICPP2007), Xi'an, China,Sseptember 10-14,2007
[30]Yunhao Liu, Xiaomei Liu, Li Xiao, Lionel M.Ni Xiaodong Zhang.2004.Location-aware Topology Matching In P2P Systems.INFOCOM'04,2220-2230
[31]Jing Wang, Shoubao Yang:Content-based Clustered P2P Search Model Deponding on Set Distance.in the 2006 IEEE/WIC/ACM International Workshop on P2P Computing and Autonomous Agent.IEEE Computer Society,2006,pp,471-476.
[32]Petar Maymounkov,David Mazieres.Kademlia:A Peer-To_Peer Information System Based on the XOR Metric.http://kademlia.scs.cs.nyu.edu
[33]Xiaofeng Li, Jinxing Che, Peng Zhao, Jian Liu. The Optimization of the P2P network Based on Topology within MAN.2010 INTERNATIONAL CONFERENCE ON NETWORKING AND DIGITAL SOCIETY/3,228-231
[34]Wu C J,Li C Y,Hou J M.Improving the Download Time of BitTorrent-like Systems.Communications,2007,28(3):1125-1129
[35]Leibowitzn, Ripeanu M, Wierzbicki A. Deconstructing the Kazaa network. In:Proc of 3rd IEEE Workshop on Internet Applications. CA, USA,2003,112-120
[36]何波,彭泽.P2P流媒体网络电视发展趋势及内容监管模式[EB/OL]. http://media.people.com.cn/GB/137684/8843283.html
[37]钟玉琢等编著.数字电视机顶盒和多媒体家庭网关[M].北京：清华大学出版社,2008.11
[38]杨春玲,张建伟,刘锦锦,王勇超,鲁东明.基于BitTorrent的VOD系统分析与评估[J].计算机时代,2010,(03)
[39]Rongmei Zhang, and Y. Charlie Hu, "Assisted Peer-to-Peer Search with Partial Indexing", IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS, Vol.18,2007, pp.1146-1158, Auguest 2007
[40]郑伟平,齐德昱,徐克付.BitTorrent类型P2P流媒体系统研究[J].计算机科学,2010,(02)
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