一种流媒体Caching策略

It is expected that by 2003 continuous media will account for more than 50% of the data available on origin servers, this will provoke a significant change in Internet workload. Due to the high bandwidth requirements and the long-lived nature of digital video, streaming server loads and network bandwidths are proven to be major limiting factors. Aiming at the characteristics of broadband network in residential areas, this paper proposes a popularity-based server-proxy caching strategy for streaming media. According to a streaming media popularity on streaming server and proxy, this strategy caches the content of the streaming media partially or completely. The paper also proposes two formulas that calculate the popularity coefficient of a streaming media on server and proxy, and caching replacement policy. As expected, this strategy decreases the server load, reduces the traffic from streaming server to proxy, and improves client start-up latency.     

流媒体代理缓存中RTSP协议的应用研究

流媒体代理缓存是为克服现有网络不适应流媒体传输的缺陷而提出的网络缓存技术。本文在介绍流媒体代理缓存技术的基础上,讨论作为流媒体技术关键协议的RTSP协议在流媒体代理缓存技术中的应用,并针对代理缓存内容一致性等问题提出了基于RTSP协议的解决方案。     

基于P2P流媒体技术的远程教育系统的设计

随着网络及流媒体技术的发展,越来越多的远程教育系统开始采用流媒体作为主要的网络教学方式.它可以提高网络课堂的质量,增强网络课堂的交互性.而基于P2P的流媒体可以充分发挥众多客户机的作用,有效利用客户机闲置的计算和存储资源,使客户机完成部分服务器的功能,降低服务器的负载和对网络带宽的占用率.因此,基于P2P的流媒体技术在远程教育中的应用已成为一种必然的趋势.在传统流媒体技术的基础上提出混合式结构的P2P流媒体模式,以进一步优化远程教育系统.     

Hybrid ants-like search algorithms for P2P media streaming distribution in ad hoc networks

Media streaming delivery in wireless ad hoc networks is challenging due to the stringent resource restrictions,po-tential high loss rate and the decentralized architecture. To support long and high-quality streams,one viable approach is that a media stream is partitioned into segments,and then the segments are replicated in a network and served in a peer-to-peer(P2P) fashion. However,the searching strategy for segments is one key problem with the approach. This paper proposes a hybrid ants-like search algorithm(HASA) for P2P media streaming distribution in ad hoc networks. It takes the advantages of random walks and ants-like algorithms for searching in unstructured P2P networks,such as low transmitting latency,less jitter times,and low unnecessary traffic. We quantify the performance of our scheme in terms of response time,jitter times,and network messages for media streaming distribution. Simulation results showed that it can effectively improve the search efficiency for P2P media streaming distribution in ad hoc networks.     

基于Ad hoc网络的移动P2P协同缓存应用研究

协同缓存通过多个代理缓存的协同工作,以提高缓存命中率,均衡网络和服务器负载,提高访问速度。P2P的结构使得网络富有延展性,在分布式计算中也有巨大的潜力。3G网络的部署和更多WIFI手持设备的投放,Ad hoc网络技术将有更关阔的应用空间。本文对基于无线移动网络的协同缓存技术进行了归纳分析,并提出了在基于Ad hoc网络的移动P2P系统协同缓存应用技术面临的问题和解决预期。     

基于P2P的内容分发网络合作式缓存的研究

在分析基于集中式管理合作缓存系统(CRISP)和基于分布式管理缓存系统(ICPS)的基础上,提出了一种基于P2P的内容分发网络合作式缓存系统模型.该模型具有P2P特点,普通节点既是访问网络的用户节点,又是缓存管理和文件共事的服务节点从而提高了缓存系统的可用性.     

基于P2P流媒体系统的实现研究

传统流媒体系统,受带宽和服务器限制,难以支持大规模并发客户。针对该问题,介绍了当前用P2P技术实现流媒体系统的现状,探讨了P2P的流媒体系统的系统结构及关键技术,分析了存在的问题,最后指出了P2P流媒体系统发展的研究方向。     

Deadline-aware network coding for video on demand service over P2P networks

INTRODUCTION With the widespread deployment of broadband access, Video-on-Demand (VoD) streaming on the Internet has received increasing attention recently. In VoD service, video streams are delivered to asyn- chronous users with low delay and VCR-like opera- tion support (e.g., pause, fast-forward, and rewind). However, streaming to a large population of clients is very challenging due to the limited server capacity and little deployment of IP multicast in today’s Internet (Quinn a…     

P2P网络内容分发中心化的研究与实现

P2P作为一种与服务器/客户端对立的网络架构,其应用近些年来在互联网中发展十分迅速,新的P2P应用更是层出不穷.分析P2P网络内容分发中心化时流媒体服务器之间的数据传输,指出它们的优缺点,结合CDN和P2P关键技术在网络中的应用,提出了轻量级的P2P传输系统,对网络流量、资源分块和分段大小的控制,提高资源查找的效率,从而简化P2P资源的查找实现     

Adaptive progressive download based on the MPEG-4 file format

In this paper we describe how progressive download and adaptive streaming can be combined into a simple and efficient streaming framework. Based on the MPEG-4 file format (MP4) we use HTTP for transport and argue that these two components are sufficient for specifying an open streaming architecture. The client selects appropriate chunks from the MP4 file to be transferred based on (1) the header information (i.e. the "moov" box) in the first part of the file and (2) his observation of network throughput. The framework is completely client driven which allows for better server scalability and reduces signalling overhead. We discuss architecture and implementation issues such as complexity, interoperability and scalability and compare to 3GPP PSS Re1-6 adaptive streaming when appropriate. Measurements from a simple MP4/HTTP streaming client are presented showing that appropriate chunks are selected such that increased reliability is achieved.     

基于P2P的校园网流媒体平台的设计与实现

传统流媒体平台对服务器性能,网络带宽等条件要求较高,对校园网的视频应用服务有一定的局限性。为解决此问题,设计了一种基于P2P架构的流媒体视频教学平台,将流媒体技术的实时性和P2P网络的分布性完美地结合起来,实现了视频直播和点播功能。     

Adaptive progressive download based on the MPEG-4 file format

In this paper we describe how progressive download and adaptive streaming can be combined into a simple and efficient streaming framework. Based on the MPEG-4 file format (MP4) we use HTTP for transport and argue that these two components are sufficient for specifying an open streaming architecture. The client selects appropriate chunks from the MP4 file to be transferred based on (1) the header information (i.e. the “moov” box) in the first part of the file and (2) his observation of network throughput. The framework is completely client driven which allows for better server scalability and reduces signalling overhead. We discuss architecture and implementation issues such as complexity, interoperability and scalability and compare to 3GPP PSS Rel-6 adaptive streaming when appropriate. Measurements from a simple MP4/HTTP streaming client are presented showing that appropriate chunks are selected such that increased reliability is achieved.     

基于P2P技术的流量管理分析和研究

介绍了P2P技术的定义、结技术构和应用等特点,分析了流量检测技术、流量控制技术以及管理解决方案,从P2P缓存技术的原理入和体系结构的分析入手,提出了控制管理的总体策略和P2P流量本地化,分析了Peer选择优化,最后提出优化策略。     

An embedded packet train and adaptive FEC scheme for effective video adaptation over wireless broadband networks

INTRODUCTION With the emergence of wireless technology, various multimedia services, e.g., audio and/or video, are reaching us today through portable devices any- time, anywhere and even more increasingly accessi- ble in the near future. High quality video streaming over wireless IP is one of the most attractive applica- tions by ongoing deployment of wireless local area network (WLAN) hotspots and even powerful Wi- MAX mobile coverage. However, the present Internet is not providing a…     

P2P流媒体系统概述

P2P技术的出现,使低成本的分布式服务成为可能。参与的用户既是服务的消费者,又是服务的提供者,这种特性尤其适合流媒体系统。P2P技术将集中的流媒体服务分散化,从而消除了传统系统的瓶颈,拓展了网络视频业务的应用范围。     

浅谈P2P中的测量研究

P2P技术的发展引发了Internet应用模式的研究。为了寻求网络运营商、内容提供商和互联网用户三方共赢的解决方法,P2P文件共享的方便和耗费带宽一直成为人们关注的话题。从传统主动、被动测量方法入手进行了系统的比较研究,借用国外在两种测量的融合上提出优化P2P网络新的理论思想,并从小波分解的角度对这一理论进行量化分析,指出其中存在的问题。     

Error resilient concurrent video streaming over wireless mesh networks

INTRODUCTION Wireless mesh networks (WMNs) are ad-hoc networks with full or partial mesh topologies, where nodes can automatically establish and maintain mesh connectivity among themselves. Such a mesh topol- ogy provides each node multiple communication paths to reach its peers. In the presence of link failures caused by, for example, node failures or interference, information can be rerouted through alternative paths to the destination. WMNs have no fixed infrastructure and are easily…     

Rate-distortion optimized bitstream switching for peer-to-peer live streaming

Peer-to-peer （P2P） technology provides a cost-effective and scalable way to distribute video data. However, high heterogeneity of the P2P network, which rises not only from heterogeneous link capacity between peers but also from dynamic variation of available bandwidth, brings forward great challenge to video streaming. To attack this problem, an adaptive scheme based on rate-distortion optimization （RDO） is proposed in this paper. While low complexity RDO based frame dropping is exploited to shape bitrate into available bandwidth in peers, the streamed bitstream is dynamically switched among multiple available versions in an RDO way by the streaming server. Simulation results show that the proposed scheme based on RDO achieves great gain in overall perceived quality over simple heuristic schemes.     

Adaptive peer-to-peer streaming with MutualCast

INTRODUCTION Many applications, such as software distribution, Internet TV/video streaming, video conferencing, multiplayer gaming, personal media distribution and P2P web content duplication, distribute the same content from one source node to many destination nodes. For these applications, IP multicast is an ideal network layer solution. A distribution tree rooted at the source can be formed to reach an arbitrary number of receivers. During content distribution, every single piece of…     

Coping with the point of entry problem in evaluating projects

In this article the so-called point of entry problem in evaluation work has been discussed. A summary of how this problem has been treated in the theoretical literature of evaluation has been presented. Some illustrations of the problem have been given, and it has been considered from both client and evaluator perspectives. A general rule calling for studies that assist in improving client services has been offered. And a chart for determining, in accordance with this rule, when to do what type of study has been introduced.It is hoped that the advice will assist evaluators and their clients to do a better job of planning evaluations. In addition, it is hoped that other students of the evaluation field will examine and possibly build on the work begun here. Both further conceptual analysis and empirical study are needed. In addition, the field could use some good workshops aimed at helping evaluators and their clients to better appreciate and deal with their evaluation point of entry problem.