种基于Sever和Proxy流媒体流行性的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 proving to be major limiting factors. Aiming at the characteristic of broadband network in a residential area, we propose a popularitybased on server-proxy caching strategy for streaming media. According to a streaming media popularity on streaming server and proxy, this strategy caches the content of this streaming media partially or completely, and plays an important role in decreasing server load, reducing the traffic from streaming server to proxy, and improving the startup latency of the client.     

QoS Negotiation and Renegotiation Based on Mobile Agents

As the Quality of Service （QoS） becomes increasingly important in the Internet development, there are more and more researches focusing on the issues of QoS negotiation. Mobile software agents represent a valid alternative to the implementation of strategies for the negotiation. In this paper, a QoS negotiation and renegotiation system architecture based on mobile agents is proposed. These agents perform the task in the whole process and therefore reduce the network load, overcome latency, and avoid frequent exchange information between clients and server. The simulation results show that it can improve the network resource utility about 10%.     

Towards Automated Provisioning and Emergency Handling in Renewable Energy Powered Datacenters

Designing eco-friendly system has been at the forefront of computing research. Faced with a growing concern about the server energy expenditure and the climate change, both industry and academia start to show high interest in computing systems powered by renewable energy sources. Existing proposals on this issue mainly focus on optimizing resource utilization or workload performance. The key supporting hardware structures for cross-layer power management and emergency handling mechanisms are often left unexplored. This paper presents GreenPod, a research framework for exploring scalable and dependable renewable power management in datacenters. An important feature of GreenPod is that it enables joint management of server power supplies and virtualized server workloads. Its interactive communication portal between servers and power supplies allows dataeenter operators to perform real-time renewable energy driven load migration and power emergency handling. Based on our system prototype, we discuss an important topic： virtual machine （VM） workloads survival when facing extended utility outage and insufficient onsite renewable power budget. We show that whether a VM can survive depends on the operating frequencies and workload characteristics. The proposed framework can greatly encourage and facilitate innovative research in dependable green computing.     

基于Internet的视频代理缓存服务器设计的若干关键问题

With the boom of the network technology, all kinds of services based on the Internet come into being. A-mong them, the most promising one is the video service. All of this kind of service has been paid much attention,such as videoconference and video-on-demand. Because of the instability of the Internet environment, the traditional Client/Server mode in the LAN, which is used to support the data transmission, is not suitable any longer. And the newly designed Server/Proxy/Client one is more effective. This paper describes this architecture and its service pat-tern, does some deep research on the key issues of the design of the proxy cache server, such as the caching and re-olacernent nlr the viden data, the management and coordination of multi-proxy-servers.     

System Architectural Design for DeliveringVideo Mail over the World-Wide-Web

This paper examines the feasibility of providing multimedia mail,in particular video mail,on the existing World-Wide-Web platform.In this instance, the Web browser will act as the user agent of the mailing system.With this,users will be able to compose,send and read video mail directly on the Web, This paper examines a number of different system architectures which can be employed for the development of Video Mail.Based on the following key issues:portability of system,flexibility of system,Internet standard support,security and authentication,and message compression and storage,a final architecture was chosen to build Video Mail.The approach taken is that the system will be interfaced to the Web using a standard Hyper Text Transfer Protocol(HTTP) server and a standard Web brower.This is achieved through the use of Common Gateway Interface(CGI) programs and forms which reside in a standard HTTP server to provide the functionality of video mail,and a separaete mail server for the storage and management of messages.This will cause the HTTp server to behave as if it is an electronic mail system.The paper also addresses implementation issues pertaining to the use of CGI programs,mail server development,and video and auidio composition and playback.     

An end-to-end robust approach for scalable video over the internet

With the growth of the Internet and abundant network resources, video streaming is becoming one of the increasingly important Internet applications. However, the current IP-based network provides only a single class best effort service. Video packet can be regarded as a packet loss by the video decoder either due to network congestion or due to exceeding the maximum delay threshold. It remains an open challenging task as to how to cope with the packet loss in the video streaming over the Int…     

多播在数字监控系统中的应用

This paper discusses problems of muhicasting and its application. Two ways are proposed to overcome theproblems of muhicasting according to the architectures of current networks and the functional requirements of asurveillance System. One is that Winsock API is directly used to implement muhicasting on a network supporting multicasting. The other adopts the technology of proxy server and tunneling on a network not supporting multicast-ing. In addition,this paper discusses some techniques of muhicasting,such as sending,resending,auto-adjusting with the change of the transmission aualitv of networks .and the management of multicast group and multicast addresses.     

Dynamical Immune Intrusion Detection System for IPv6

We have set up a project aiming at developing a dynamical immune intrusion detection system for IPv6 and protecting the next generation Internet from intrusion. We focus on investigating immunological principles in designing a dynamic multi-agent system for intrusion detection in IPv6 environment, instead of attempting to describe all that is intrusion in the network try and describe what is normal used and defined ＇non-selr as intrusion. The proposed abnormal detection model is designed as flexible, extendible and adaptable in order to meet the needs and preferences of network administrators for IPv6 environment.     

Proactive planning of bandwidth resource using simulation-based what-if predictions forWeb services in the cloud

Resource planning is becoming an increasingly important and timely problem for cloud users.As more Web services are moved to the cloud,minimizing network usage is often a key driver of cost control.Most existing approaches focus on resources such as CPU,memory,and disk I/O.In particular,CPU receives the most attention from researchers,but the bandwidth is somehow neglected.It is challenging to predict the network throughput of modem Web services,due to the factors of diverse and complex response,evolving Web services,and complex network transportation.In this paper,we propose a methodology of what-if analysis,named Log2Sim,to plan the bandwidth resource of Web services.Log2Sim uses a lightweight workload model to describe user behavior,an automated mining approach to obtain characteristics of workloads and responses from massive Web logs,and traffic-aware simulations to predict the impact on the bandwidth consumption and the response time in changing contexts.We use a real-life Web system and a classic benchmark to evaluate Log2Sim in multiple scenarios.The evaluation result shows that Log2Sim has good performance in the prediction of bandwidth consumption.The average relative error is 2%for the benchmark and 8% for the real-life system.As for the response time,Log2Sim cannot produce accurate predictions for every single service request,but the simulation results always show similar trends on average response time with the increase of workloads in different changing contexts.It can provide sufficient information for the system administrator in proactive bandwidth planning.     

Web SCADA System Architecture Design

When constructing SCADA （Supervisory Control and Data Acquisition） system, the main problems that need to be solved are the system＇s easy-extension, the system＇s easy-maintain and the unifying of the management information system, The effective way to solve these problems is designing SCADA system based on B/S architecture by Web technology. This paper provides a kind of SCADA system frame based on Web technology and mainly describes the structure of the software in the Web server in this frame.     

一种基于Sever和Proxy流媒体流行性的Caching策略

1 概述经过了2000、2001两年的社区宽带网建设的高速发展后,摆在中国ISP们面前的任务是如何在已建成的宽带网上开展增值服务,许多ISP尝试在宽带网上开展流媒体(Streaming Media)服务,如视频点播VOD(Video On-Demand)系统。然而,流媒体对网络带宽和实时性的要求使得流服务器必须能够进行端对端(End-to-End)的拥塞控制和质量调整,由于     

流媒体对象的缓存管理策略

基于流媒体服务的代理技术是流媒体研究领域中的重要课题.随着流媒体技术在Internet和无线网络环境中的高速发展,对流媒体代理服务器的研究也正在逐步深入.本文主要讨论通过代理技术改善媒体的服务质量,降低媒体的传输延迟以及减轻网络负载.在Internet环境下,对流媒体代理服务器的研究集中于流媒体的访问特性、缓存替换算法,构建和实现一个流媒体代理服务器是对流媒体代理技术研究的基础.     

基于CDN的流媒体分发技术研究综述

随着网络技术的高速发展,Internet用户飞速增长,网络拥塞、服务器负载过重、访问延迟过大等问题一直困扰着用户。CDN(ContentDistributionNetwork———内容分发网络)的出现极大改善了Internet的访问速度和服务质量。但是,流媒体内容的日益流行又对CDN技术提出了新的挑战。文章详细阐述了在CDN条件下,基于代理缓存机制,对流媒体进行智能分发技术的研究现状,详细描述了流媒体在主干网中的分发传输和它们之间的协作过程。     

Optimized streaming media proxy and its applications

Multimedia streaming is one of the most popular services on the current Internet. However, the major problem hinders streaming media applications is the network bandwidth. In this paper, we put forward a optimized streaming proxy system and think of utilizing it in peer-to-peer (P2P) applications. The main contribution of our proxy system is RTP segments splicing, prefix caching size determination and prefetching techniques, which are detailed discussed in this paper. By validating our implementation, the experimental results show that the streaming proxy can effectively contribute to reduce the server and backbone network load, thus achieve improved media quality and scalability. In addition, P2P network is a fascinate way for Internet resource sharing, many of researchers are devoting to research on P2P-based client communications. In our project, we make use of our proxy prototype into the streaming sharing over P2P network, each peer node just like a lightweight proxy between the server and the target peers. The real-time video sharing (RVS) system efficiently utilizes network bandwidth between peer clients through combining with our proxy as expected.     

P-chaining: a practical VoD service scheme autonomically handling interactive operations

Providing scalable VoD streaming services has recently become a hot issue, and many approaches have been proposed. Because video streaming services through the Internet are widely used, the need to support VCR operations also increases. However, there are few approaches to supporting VCR operations on the Internet. We propose a service scheme based on chaining, in which clients as well as the server provide streaming services. In the proposed scheme, services are provided by unicast and managed locally using node lists. In addition, our scheme can support frequent VCR operations without incurring significant overhead in the server workload. We have evaluated our scheme through simulation with real traces from a content distribution network (CDN) company and with various parameters. The results show that the proposed scheme reduces server workload significantly. The results also verify that frequent VCR operations can be served smoothly without causing too much overhead.

基于流行度预测的流媒体代理缓存替换算法

针对流行度随时间变化的特性,利用回归分析技术给出了一种流媒体文件的流行度预测算法,并在增加少量存储空间及计算时间消耗的情况下,将该预测算法应用于流媒体代理缓存服务器的缓存替换算法之中,模拟实验表明,该方法能减少缓存的替换次数,提高缓存命中率,性能较优。     

PopCap: popularity oriented proxy caching for peer-assisted Internet video-on-demand streaming services

With the success of Internet video-on-demand (VoD) streaming services, the bandwidth required and the financial cost incurred by the host of the video server becoming extremely large. Peer-to-peer (P2P) networks and proxies are two common ways for reducing the server workload. In this paper, we consider a peer-assisted Internet VoD system with proxies deployed at domain gateways. We formally present the video caching problem with the objectives of reducing the video server workload and avoiding inter-domain traffic, and we obtain its optimal solution. Inspired by theoretical analysis, we develop a practical protocol named PopCap for Internet VoD services. Compared with previous work, PopCap does not require additional infrastructure support, is inexpensive, and able to cope well with the characteristic workloads of Internet VoD services. From simulation-based experiments driven by real-world data sets from YouTube, we find that PopCap can effectively reduce the video server workload, therefore provides a superior performance regarding the video server’s traffic reduction.     

开放型网络英语教学系统中流媒体QoS的研究

采用设置本地端缓冲服务器的方法提高流传榆质量．在开放型网络英语教学系统中应用流媒体提供QoS的管理功能,解决音视频流缓冲问题,并提供相应机制支持网络环境下的流媒体QoS。实验结果表明,流体系结构较好实现网络教学环境下的流媒体播放,保证音视频流的QoS。采用此流体系结构能较好地实现对流的管理和控制。从而保证多媒体课件的传输质量。     

开放型网络英语教学系统中流媒体QoS的研究

采用设置本地端缓冲服务器的方法提高流传输质量,在开放型网络英语教学系统中应用流媒体提供QoS的管理功能,解决音视频流缓冲问题,并提供相应机制支持网络环境下的流媒体QoS。实验结果表明,流体系结构较好实现网络教学环境下的流媒体播放,保证音视频流的QoS。采用此流体系结构能较好地实现对流的管理和控制,从而保证多媒体课件的传输质量。