MANET中QoS路径可靠性的分析构架

文章研究了MANET中多径特性对QoS路径可靠性的影响,针对多跳路径的可靠性计算问题,提出了一种分析构架。几个考虑的主要参数有平均链路簇,多径数目,路径复杂度和跳数差别因子。方案具有一定的普遍适用性,在给定的源和目的节点中,对于单路径和多径的情况都能较好运用。     

QoS体系中流量工程与网络规划的功能框架

概述了Internet网络的发展趋势,分析了QoS提供体系的研究现状,指出了现有研究的不足,然后,将网络规划引入QoS提供体系架,把网络规划和流量工程结合起来,拓展了原有的QoS提供体系框架,最后,提出了网络规划和流量工程综合框架的系统流程,并且严区分了网络规划,流量工程和网络优化的作用范围。     

Not All Packets Are Equal, Part 2: The Impact of Network Packet Loss on Video Quality

In this second part of a two-part article, the authors highlight the impact that different durations of IP packet loss have on the quality of experience for IP-based video streaming services. They describe the visual impairments that result from such packet losses and present the results of testing and analysis to compare impairments for different loss durations for both MPEG-2-encoded standard and high-definition services.     

校园网视频点播业务QoS指标测量技术研究

随着教育信息化的不断深入,将视听教学延伸到计算机多媒体教学和网络教学成为研究热点。针对当前校园网视频点播业务存在的延时、抖动、丢包和声画不同步等QoS问题,研究了QoS的测量方法、视频点播业务主要参数、主要QoS指标和测量工具。此外,搭建了测量环境,测量了不同比特率、不同并发用户数下的时延、抖动、丢包率,并分析了测量结果,提出了改善业务QoS的策略。     

无线传感器网络中视频质量评估方法

视频在无线传感器网络传输,由于网络的不稳定,可能使视频质量受到一定的影响。在人类视觉模型的基础上,提出一个改进的无参考质量评估算法,直接通过收到的图像,判断视频质量的好坏。较之当前广泛使用的视频评估算法一媒体延迟指标而言,大大提高在网络丢包时,对于视频质量评估的准确性。评估结果接近人眼观察的效果,并且可以大规模投入使用,具有较强现实意义和商业使用价值。     

Analysis and Provision of QoS for Distributed Grid Applications

Grid computing provides the infrastructure necessary to access and use distributed resources as part of virtual organizations. When used in this way, Grid computing makes it possible for users to participate in collaborative and distributed applications such as tele-immersion, visualization, and computational simulation. Some of these applications operate in a collaborative mode, requiring data to be stored and delivered in a timely manner. This class of applications must adhere to stringent real-time constraints and Quality-of-Service (QoS) requirements. A QoS management approach is therefore required to orchestrate and guarantee the timely interaction between such applications and services. We discuss the design and a prototype implementation of a QoS system, and demonstrate how we enable Grid applications to become QoS compliant. We validate this approach through a case study of an image processing task derived from a nanoscale structures application.     

基于主动网络的QoS策略研究

在对传统网络的QoS策略进行分析的基础上,结合主动网络的体系结构、工作原理及特点,提出了基于主动网络技术的综合服务（IntServ）、区分服务（Diff3erv）和多协议标记交换（MPLS）模型。     

Distributed Video Production: Tasks,Architecture and QoS Provisioning

In this paper, we apply a top-down approach to describe the architecture components of Distributed video production (DVP) systems. We first introduce the concept of a Distributed video production environment and describe typical DVP tasks involved. We then propose a generic layered functional model that captures the characteristics of the DVP architecture. Subsequently, we identify system and network performance parameters and discuss possible network protocol stack realizations for the transport of DVP traffic. Finally, we propose a quality of service-sensitive model for resource allocation and optimization.     

QoSPlan: A Measurement Based Quality of Service aware Network Planning Framework

In this article we present QoSPlan—a measurement based framework for preparing information relevant to Quality of Service (QoS)-aware IP network planning, which aims at reducing a core operational expenditure for the network operator. QoSPlan is designed to reduce the cost of deployment and maintenance of network monitoring systems. The process involves analysis of pre-existing accounting data to estimate a network-wide traffic matrix. Part of this estimation process relates to the generalization of QoS-related effective bandwidth coefficients taken from traffic analyzed on the network. We offer recommendations on how to appropriately realize QoSPlan to maximize its accuracy and effectiveness when applied to different network traffic scenarios. This is achieved through a thorough sensitivity analysis of the methods proposed using real traffic scenarios and indicative network topologies. We also provide an economic analysis of the deployment and maintenance costs associated with QoSPlan in comparison to a direct measurement approach, demonstrating cost savings of up to 60 % given different topology sizes.     

An Integrated Framework for Implementing Quality of Network Concepts

This paper presents an integrated framework for describing and implementing quality of network (QoN) concepts. It focuses on identifying a systems engineering framework for better understanding how to specify and implement QoN concepts. We demonstrate, by means of several examples, that the quality of service interfaces between the end user and the underlying network are very important. Finally, we provide insights as to future development efforts needed to realize the goal of high quality networks.     

视频流媒体的QoS特征分析及质量保证

网络数据传输的质量保证一般可分为空间域保证和时间域保证。空间域保证是传输数据的量的保证,取决于网络的带宽和丢失率特征;时间域的保证是对传输数据的时效性保证,取决于网络的延时和延时抖动特征。传统的数据媒体对网络传输的空间域保证有严格的要求,而没有严格的时间域保证要求。它不允许有数据丢失,但能够容忍一定的时间延时和延时抖动;而视频流媒体与此相反,它能够容忍一定的数据丢失,但要求较为严格的延时和延时抖动保证。这篇文章主要对视频流媒体数据传输的空间域特征和时间域特征进行讨论,分析其对视频流媒体的质量影响,为流媒体的网络传输QoS保证策略提供有价值的参考。     

网络视频录像系统中视频采集的研究与实现

介绍了一种在网络录像系统（NVR）中实现高清流媒体采集的方案。基于RTSP/RTP协议,实现了对视频数据的封装与传输,结合多线程编程技术,可以满足同时采集多路视频数据的需求,节省了系统资源,提高了用户体验。     

自相似网络流量中QoS问题的研究

针对自相似网络流量中QOS问题,应用仿真实验方法,对优先队列的QOS问题进行研究,实验结果表明,网络自相似流量需要较长队列和较大缓冲区容量。     

校园网VOD系统服务质量研究

近年来,随着我国教育信息化的高速发展,校园网上VOD多媒体教学视频流的传输面临着越来越多的服务质量(Quality of Service,QoS)需求。当今的基于Ipv4的网络在流量、延迟和网络带宽管理上功能很弱,不可能给这些流媒体应用提供真正的QoS控制和保证。构建新的Ipv6校园网,在流媒体技术的基础上,结合Ipv6技术与组播技术,才能更好的解决校园网上流媒体传输的QoS问题。     

QoS在网络处理器上的设计与实现

本文主要介绍了 Qo S的几个基本的功能模块 ,并结合网络处理器的结构特点提出了一套具体的实现方案 ,最后简要的分析该方案的性能。     

基于IPv6视频点播QoS测量系统设计与实现

论文根据IPv6视频点播中对服务质量的需求,对视频点播服务过程的分析,提出了迟到数据包率和缓冲时间的计算方法,算法简化了QoS参数计算的复杂性。经测试基于IPv6视频点播系统QoS测量模块的数据能够正确反映视频点播的QoS参数,该模块已用于系统实际测量。     

基于控制理论的数据流QoS自适应框架及卸载技术的研究

数据流管理系统中的查询处理需要满足各种服务质量(QoS)要求,其中延迟是用户非常关注的QoS参数.如何在系统资源有限、数据输入速度及特征可变,且单个元组的CPU处理代价动态变化的情况下,使系统具有自适应的能力以确保高质量的QoS,是迫切需要解决的问题.为此,提出了一种全面考虑CPU处理能力及内存容量的QoS自适应框架,并运用基于控制理论的PID控制器管理内存负载,超载时进行卸载处理;同时提出有效的清洗策略和队列调度策略,保证系统在动态环境中具有良好的自适应性.实验结果表明,该框架具有稳定性好、健壮性强的优点,在错失率相同的情况下,卸载率、系统资源利用率等几方面性能均优于其他现有方法.     

数据流QoS自适应框架调度算法的研究与实现

在数据流QoS自适应框架中,针对如何为具有截止期和重要性两个特征参数的流数据分派优先级,在讨论了了当前调度算法优缺点的基础上,提出了称为截止期-重要性优先DIF（deadline-importance first）的实时调度算法,并利用链表给出了算法的实现.实验结果表明,在所有负载条件下DIF算法相对于EDF（earliest deadline first）算法、HVF（highest value first）算法和CDF（criticalness-deadline first）算法,在性能方面具有明显改善,特别在系统过载的情况下,能够优雅地降级.     

Impact of QoS operations on an experimental testbed network

By making the best use of limited bandwidth, quality of service (QoS) provisioning over internet is essential for satisfying various types of internet-application requirements. The traffic classification and scheduling are the key functions to provide various kinds of class of service (CoS) under an overload condition. This paper investigates QoS performance in a network equipment testbed when implementing these main functions. We examine the major CoS functions provided by the Juniper T320 router, and measure their performance. In addition to fundamental analysis of the QoS behavior, we show the impact of QoS operations on a parallel system distributed in multi-domain networks as a practical case study of grid environments.     

端到端QoS的解决方案DiffServ分析研究及其实现

简要介绍了解决端到端QoS的IntServ(IntegratedService)方案及TOS/IPPrecedence方案 ,通过对这两种方案的局限性的分析 ,提出利用DiffServ(DifferentiatedServices)方案解决端到端QoS ,并且给出具体实现的方法 ,重点讨论了实现中的若干问题和策略 ,在此基础上对DiffServ与多协议标签交换MPLS的结合进行了研究 ;最后阐述了DiffServ的未来发展。