一种基于P2P VOD的视频共享系统的研究与实现

【作者】 姜松；

【导师】 李毅；

【作者基本信息】 电子科技大学 ， 计算机系统结构， 2008， 硕士

【摘要】 流媒体应用是推动未来宽带应用的主动力,但流媒体对带宽的高占用特性使其在Internet上大规模应用面临诸多困难。传统的C/S、单源组播以及CDN(Content Delivery Network)模式面临着网络带宽、拥塞控制和费用等问题。为了更好的解决流媒体在互联网的分发问题,基于P2P的流媒体分发技术被提出来了。P2P,即端对端网络,又称为对等计算,就是通信的主机互相互为服务器,每一台主机都享受其它机器提供的服务,也为别的机器提供服务。这一模式将服务由中心推向了边缘,充分利用了网络边缘的主机的资源。P2P网络的应用很广泛,模型也很多,有各自的优缺点。本文介绍了一个P2P流媒体系统P2P VOD,实现了用P2P网络进行大规模流媒体共享同步播放。本文针对P2P流媒体系统需要解决的一些关键问题:单源传输与多源传输、媒体源定位机制、源节点选择机制、数据传送调度机制、激励机制这几个方面进行了讨论,介绍了P2P VOD的解决方法。P2P VOD采用有一个中心目录服务器的结构,数据传输通过P2P的方式进行。P2P VOD采用了多源传输的模式,基于AS值的源节点选择机制,播放顺序优先的数据调度的机制,基于“报答”的激励机制,保证了流媒体数据的传输和播放质量。P2P VOD视频共享系统主要是基于BT协议来进行扩充,并针对流媒体的播放特点:在片段选择算法上对实时性和顺序性进行了更高的要求;考虑了多种阻塞机制来鼓励系统内的Peer节点参与到文件共享中来;提出了一个简单快捷的路由算法来避免消息的泛滥以及保证播放控制协议的快速传递;利用了用户的ID编号来进行同一局域网节点协作以及防火墙穿透技术来保证更多的Peer节点参与到整个系统中来。此外,P2P VOD系统还在BT协议的基础上添加了文件播放控制扩展协议,除了能够保证系统中的所有Peer节点用户尽可能地同步观看影视资源;还能够兼容传统的BT协议,这样可以保证系统除了可以利用自己的网络外还可以同时利用现有的广泛运用的BT网络。更多还原

【Abstract】 Streaming Media will become the main driving force for future broadband network application. But the characteristics of high bandwidth of the streaming media on the Internet are faced with many difficulties. The traditional C/S, single-source multicast and CDN (Content Delivery Network) model are facing network bandwidth, congestion control and cost issues. To better solve the problems of the streaming media used in the Internet distribution, the streaming media over P2P network technology has been proposed. P2P, that is, peer-to-peer network, also known as end to end computing, means that the hosts provide service for each other as the server. Every host enjoy the services provided by the other host, but also provide services for the others. This model will push the service from center to the edge of the network and it can make full use of the resources provide by the host in the edge of the network. P2P network has a wide range of use, and has many models. Each model has its character.This paper discusses a P2P streaming media system named P2P VOD system. It can achieve a large-scale streaming media share and play the media synchronization in the P2P networks. This paper discussed the key problems of the P2P streaming media system: single-source or multi-source transmission, media sources positioning mechanism, the source node selection mechanism, data transmission scheduling mechanism, incentive mechanisms in these areas were discussed, and it also introduced the solution of the P2P VOD system. P2P VOD using a central server directory server, data transmission through P2P network. P2P VOD adopted the multi-source transmission model, choose the peers based on the value of the source node AS selection mechanism, picked the file index with the high priority of data sequence mechanism, the incentive mechanism based on the "play back" method. All of these methods are used to ensure the streaming data transmission and the play quality.P2P VOD video sharing system is mainly used the BT protocol to expand. It also makes some improvement after considering the features of the streaming media. It adopts a higher demand of the real-time and order in the fragment chosen algorithm. It encourages all peers in the networks to share their file by using a variety of blocking mechanism. It proposes a simple and efficient routing algorithm to the flood spread of the message and to ensure that the control protocol can be rapidly broadcast by the peers. It makes use of the user’s ID number for the better collaboration in the same local network and uses the technology of transmitting through the firewall to ensure more participation join in the whole system.In addition, the P2P VOD system add a player control expansion protocol based on the BT protocol. It not only let all users in the system watch movies synchronization, but also compatible with the traditional BT protocol. It can let the P2P VOD system run in both its own special networks and the traditional BT networks.更多还原