Slack time–based scheduling scheme for live video streaming in P2P network

Nowadays, peer‐to‐peer network plays a significant role in data transfer and communication. The past few years have witnessed considerable growth in this area because of its inherent advantages. Peer‐to‐peer live streaming has a significant impact on video transmission over the Internet. Major factors that influence the performance of P2P live streaming are overlay construction and scheduling strategies. Although, a large number of scheduling schemes are developed but none of them is comprehensive enough to provide solutions to live streaming issues. These suffer from substantial delay and low video quality at the receiver side. In this paper, a new start‐up–based selection procedure and slack time–based scheduling scheme is proposed. The start‐up selection procedure defines the start‐up buffer location for new peer, and the scheduling scheme selects both the chunk and peers. The proposed scheduling scheme uses both push and pull priority–based strategies. The simulation results of the proposed approach demonstrates significant improvement in both the network performance and video quality at the receiver side. It is observed that playback delay, startup delay, and end‐to‐end delay in the network are reduced and quality of the video at receiver side is improved as the distortion and frame loss ratio is decreased.     

GaMe‐PLive: a new game theoretic mechanism for P2P live video streaming

GaMe‐PLive is a game theoretical framework for peer‐to‐peer live video streaming. Prevention of free‐riding and minimization of loss rate in video data transmission are the important objectives of the proposed framework. GaMe‐PLive is also extremely evasive about overhead of extra control messages exchange. At first, a static game with complete information between peers is described, which models the peer's interactive decision process for acceptance/rejection of a video chunk request. All peers repeatedly play this game during video playback periodically. Afterwards, the proposed game is analyzed to obtain a Nash equilibrium, which determines a peer's best strategic response for participation in the video chunk distribution. It will be proved that by applying some simple and feasible conditions, the desired objectives can be reached. The experimental results reveal that the proposed system has been successful in detecting free‐riders with negligible false negative and false positive rate. Also, tolerable loss chunk percentage has been satisfied in all performed tests. Besides, an interesting social norm emerges in GaMe‐PLive: Less participation leads to more missing chunks. GaMe‐PLive will be proven to be quite resistant against cheating peers. The proposed framework displays high performance even if there is not a video server with high upload bandwidth. Copyright © 2015 John Wiley & Sons, Ltd.     

基于P2P流媒体直播系统的数据传输策略

针对P2P模式下视频流媒体直播系统的数据传输策略用改进的模拟退火算法进行了优化。以全局规划的思想建立了P2P视频流媒体的数据传输策略数学模型VMDTSA-P2P,模型充分考虑了可用出口带宽和可用性时间对播放连续性的影响,把它们作为获取最优解的目标函数因子,并用改进后的模拟退火算法进行解的寻优,相比于传统的数据传输策略,在具有大量用户的情况下加快了新节点从伙伴节点中选择数据块提供节点的速度,并且保证得到近似最优的数据块提供节点组合,减少了视频流媒体直播系统播放的延迟,从而提高了播放的连续性、流畅性,保证了视频播放的质量。通过该算法在模拟P2P系统中的实现,验证了该算法在P2P系统中对数据传输的准确性和高效性。     

Access control mechanism using flexible multi‐layer structure for mesh‐based P2P live streaming systems

When thousands of new peers seek to join the peer‐to‐peer (P2P) system within a very short time (i.e., the so‐called flash crowd event), most of the peers suffer a long startup delay as a result of peer over‐competition. Accordingly, recent studies have proposed a slot‐based user access control (UAC) mechanism, which periodically admits a certain number of new peers to the system, and a user batch join (UBJ) mechanism, which preconstructs the new peers into a fixed‐size tree structure before peer join process. However, in the UAC mechanism, it is difficult to determine the optimal time slot length; while in the UBJ mechanism, it is difficult to determine the optimal tree size. Accordingly, the present study proposes a structured access control (SAC) mechanism, in which the new‐arriving peers are preconstructed to a flexible multilayer structure to overcome the limitation of a fixed‐size tree structure, and the number of peers in each layer of the structure is determined based on a consideration of the remaining upload bandwidth of the P2P system. Based on the assumption of a heterogeneous upload bandwidth capability of the peers, an analytical model is derived to describe the growth behavior of a P2P system with access control. It is shown that the simulation results for the growth rate of a P2P system based on the SAC mechanism are in good agreement with those obtained from the analytical model. In addition, the simulation results show that the SAC mechanism outperforms the UAC and UBJ mechanisms in terms of a more rapid system growth and a shorter average startup delay. Copyright © 2016 John Wiley & Sons, Ltd.     

Adaptive video protection in large scale peer‐to‐peer video streaming over mobile wireless mesh networks

Because video streaming over mobile handheld devices has been of great interest, the necessity of introducing new methods with low implementation cost and scalable infrastructures is a strong demand of the service. In particular, these requirements are present in popular wireless networks such as wireless mesh networks (WMN). Peer‐to‐peer (P2P) networks promise an efficient scalable network infrastructure for video streaming over wired and wireless networks. Limited resources of the peers in P2P networks and high error rate in wireless channels make it more challenging to run P2P streaming applications over WMNs. Therefore, it is necessary to design efficient and improved error protection methods in P2P video streaming applications over WMNs. In this paper, we propose a new adaptive unequal video protection method specially intended for large scale P2P video streaming over mobile WMNs. Using this method, different frames have different priorities in receivers along the recovery process. Moreover, we precisely and completely evaluate different aspects related to frame protection in these networks using five important performance metrics including video distortion, late arrival distortion, end‐to‐end delay, overhead and initial start‐up delay. The results obtained from a precise simulation in OMNeT++ show that the proposed adaptive method significantly outperforms other solutions by providing better video quality on mobile wireless nodes. Copyright © 2015 John Wiley & Sons, Ltd.     

基于P2P网络流媒体直播系统研究与设计

主要讨论了一种基于P2P网络的流媒体直播的相关技术,研究设计了一个支持大量用户同时在线的直播系统方案,能够充分利用客户端资源,减轻服务器负载,并实现较好的视频直播效果,该系统采用了P2P传输技术,系统的可扩展性和稳定性都明显优于传统流媒体视频传输系统.     

P2P流媒体模型的资源传输机制

针对流媒体的点播和直播服务,提出了基于P2P的流媒体应用层多播和点播的解决方案,构建了基于超级节点和普通节点的两层体系结构的视频流媒体模型.描述了模型的总体结构,分析了资源传输机制.基于校园网对模型进行了测试,测试结果表明,模型能够实现基于流媒体应用的多点数据快速互传.     

P2PVOD系统中实时资源调度管理的实现

在P2P VOD系统中针对音视频等实时资源的调度管理进行研究,并对媒体资源的发布、查找功能进行实现.构建域内、域间二级架构,用于管理系统中所有客户端上的资源.对客户端发布的媒体资源按照点播的起始时间进行分类管理,以便对媒体资源进行准确快速定位.提出资源参考点的计算方法,增强域内和域间资源的搜索功能.实验平台基于普通局域...     

A reliable overlay video transport protocol for multicast agents in wireless mesh networks

A new video transport protocol for multicast agents in wireless mesh networks (WMNs) is proposed in this paper. The proposed protocol enables a significant reduction in the transmission overhead, while providing reliable communication for its use in multicast applications. This proposed reliable protocol provides a practical approach for an overlay peer‐to‐peer multicast facility supported within the application layer. This obviates the need to give upgraded routers capable of handling multicast broadcasting or modify the existing protocol stack. The protocol tolerates partial losses in multimedia transmissions, while supporting control of the delay sensitivity of such transmissions in WMNs. The key issue in this protocol is the ability to detect packet loss, anticipate retransmission requests, and use the anticipated retransmission requests to transmit the lost packets prior to requests from other receiving agents. The proposed protocol allows for the receiver to determine if retransmission of lost packets is required, ensuring the greatest flexibility needed for a reliable multicast protocol. Copyright © 2009 John Wiley & Sons, Ltd.     

Research on grouping strategy of SIP-based streaming media P2P live broadcast network

The rapid development of Internet has led to the explosion of information sharing, and how to supervise the sharing is a main research topic on current Internet. Aiming at the disadvantage that the current Peer-to-Peer （P2P） is hard to manage and control, this paper presents a Session Initial Protocol （SIP）-based P2P network of three-level architecture. SIP middleware is introduced to the middle level of the three-layer architecture. By the connection function of the SIP signaling, the P2P transmission on media-level can be controlled. Using SIP＇s register and authentication function, the manage layer can manage the whole P2P network. Based on the aforementioned architecture, this paper investigates the grouping strategy on a live broadcast application in P2P network. Combined with the function of SIP register, the paper works on several grouping strategies, sets up models to manage users by grouping them, presents a weight-based K-means IP address grouping algorithm, and realizes it. The experiment shows that the grouping strategy presented in this paper can solve the problem of group sharing of network resource, and can realize the efficient-sharing, reasonable-distributing of network resource     

基于可重构路由器上缓存的流媒体协作分发策略

提出一种新颖的基于可重构路由器上缓存的协作分发策略来加速流媒体。通过网络存储即多个边缘路由器节点对热点视频数据进行合作缓存,就近为用户提供服务,从而使得流媒体服务器的性能要求尤其是带宽需求得到巨大的降低,骨干网传输的流量也明显减少,同时用户响应延迟也得到明显的改善。此外,实现了一个原型系统来评价基于路由器上缓存的流媒体协作分发策略的性能,结果表明该方案相比于现有的方案在改善网络性能以及用户体验方面取得很大的提升。     

A location‐aware peer‐to‐peer overlay network

This work describes a novel location‐aware, self‐organizing, fault‐tolerant peer‐to‐peer (P2P) overlay network, referred to as Laptop. Network locality‐aware considerations are a very important metric for designing a P2P overlay network. Several network proximity schemes have been proposed to enhance the routing efficiency of existing DHT‐based overlay networks. However, these schemes have some drawbacks such as high overlay network and routing table maintenance overhead, or not being completely self‐organizing. As a result, they may result in poor scalability as the number of nodes in the system grows. Laptop constructs a location‐aware overlay network without pre‐determined landmarks and adopts a routing cache scheme to avoid maintaining the routing table periodically. In addition, Laptop significantly reduces the overlay maintenance overhead by making each node maintain only the connectivity between parent and itself. Mathematical analysis and simulations are conducted to evaluate the efficiency, scalability, and robustness of Laptop. Our mathematical analysis shows that the routing path length is bounded by log_d N, and the joining and leaving overhead is bounded by d log_d N, where N is the number of nodes in the system, and d is the maximum degree of each node on the overlay tree. Our simulation results show that the average latency stretch is 1.6 and the average routing path length is only about three in 10 000 Laptop nodes, and the maximum degree of a node is bounded by 32. Copyright © 2006 John Wiley & Sons, Ltd.     

移动P2P视频流媒体体系下的帧位分配算法

针对移动P2P流媒体系统中存在多视频源的特点,提出了多视频源串行和并行调度算法。串行调度算法,接收Peer通过实时侦测的QoS变化触发视频源的更换,并通过流序列时间模型来同步各个视频源。并行调度算法,多个视频源同时提供服务,并通过帧位分配算法分配各视频源的传输任务。帧位分配算法首先将视频序列分成包含固定帧数的块系列,然后进行块级位分配以充分考虑帧间效应。对于单个帧块位分配问题,算法将其建模成了非线性规划问题,通过引入分段线性R-D模型将该问题进一步转换成了普通的线性规划问题,并提出了一个贪婪实现策略。实验结果显示流分配算法能获得高效、平稳的视频质量,而且时间效率也非常高,能较好的满足移动P2P视频流媒体系统的实时性。     

CDNPatch: a cost‐effective failover mechanism for hybrid CDN‐P2P live streaming systems

Among the most well‐established live media distribution technologies is content delivery network (CDN), which improves user‐perceived quality of service by delivering content from proxy servers deployed at the Internet's edge. In recent years, CDN providers started to tap into their subscribers' peer‐to‐peer (P2P) capacity to alleviate their server costs. Under the inherent peer dynamics, a major challenge of these hybrid CDN‐P2P systems is to provide efficient failure recovery with good quality of service guarantees at a reduced server cost. In this work we propose a cost‐effective failover solution named CDNPatch to address the aforementioned problem. CDNPatch enables peers to periodically precompute a few backup content suppliers by efficient information exchange and maintenance algorithms, and leverages auxiliary CDN servers and an economic server provisioning algorithm to reduce the chance of playback interruption occurring to peers. Our simulation results show that CDNPatch can mask the impact of peer dynamics of 3 real P2P systems, namely, SOPCast, PPStream, and PPTV, with 100 % failure recovery success rate and a failure recovery time less than 1 second at a cost of small P2P communication overhead of less than 1 kilobits per second, while using only 10%, 21%, and 51%, respectively, of the pure CDN scheme's server consumption.     

流媒体分发系统关键技术综述

 流媒体将是未来通信中的杀手业务.本文讨论了流媒体分发系统的关键技术,阐述了基于CDN (Content Distributed Network)和基于P2P (Peer to Peer )的流媒体的研究现状,针对基于CDN的流媒体,研究了流媒体调度算法,代理服务器缓存算法,基于CDN的交互式操作.针对基于P2P的流媒体,研究了数据分配算法,激励机制,流媒体对象的放置,应用层组播,基于P2P的交互式操作.指出了流媒体的未来研究方向.     

A QoE centric distributed caching approach for vehicular video streaming in cellular networks

Distributed caching‐empowered wireless networks can greatly improve the efficiency of data storage and transmission and thereby the users' quality of experience (QoE). However, how this technology can alleviate the network access pressure while ensuring the consistency of content delivery is still an open question, especially in the case where the users are in fast motion. Therefore, in this paper, we investigate the caching issue emerging from a forthcoming scenario where vehicular video streaming is performed under cellular networks. Specifically, a QoE centric distributed caching approach is proposed to fulfill as many users' requests as possible, considering the limited caching space of base stations and basic user experience guarantee. Firstly, a QoE evaluation model is established using verified empirical data. Also, the mathematic relationship between the streaming bit rate and actual storage space is developed. Then, the distributed caching management for vehicular video streaming is formulated as a constrained optimization problem and solved with the generalized–reduced gradient method. Simulation results indicate that our approach can improve the users' satisfaction ratio by up to 40%. Copyright © 2015 John Wiley & Sons, Ltd.     

A consistent QoS routing strategy for video streaming services in SDN networks

The software‐defined networking (SDN) paradigm proposes to decouple the control plane (decision‐making process) and the data plane (packet forwarding) to overcome the limitations of traditional network infrastructures, which are known to be difficult to manage, especially at scale. Although there are previous works focusing on the problem of quality of service (QoS) routing in SDN networks, only few solutions have taken into consideration the network consistency, which reflects the adequacy between the decisions made and the decisions that should be taken. Therefore, we propose a network architecture that guarantees the consistency of the decisions to be taken in an SDN network. A consistent QoS routing strategy is then introduced in a way that avoids any quality degradation of prioritized traffic while optimizing resources usage. Thus, we proposed a traffic dispersion heuristic in order to achieve this goal. We compared our approach with several existing framework in terms of best‐effort flows average throughput, average video bitrate, and video quality of experience (QoE). The emulation results, which are performed using the Mininet environment, clearly demonstrate the effectiveness of the proposed approach that outperforms existing frameworks.     

城域数据网P2P流量优化方案

分析了P2P流量在城域数据网中的流向,并从运营商网络建设的角度,提出了P2P流量优化方案,包括BRAS节点的分布部署、IPv6地址的加速引入、分布式地址转换技术的应用和对P4P技术的关注,为运营商在智能管道时代在流量管理方面获得主动。