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1.
实时多媒体服务端到端QoS解决方案 总被引:1,自引:0,他引:1
区分服务(Diif-Serv)模型其主要是通过实时多媒体通信数据包进行分类和策略控制来达到调节网络资源的目的,从而实现对实时多媒体服务端到端服务质量QoS。如何时多媒体网络系统中的不同的信息流进行正确的区分服务.然后对不同类别采取不同的服务策略和拥塞管理,从而对网络资源进行有效配置,是实现实时多媒体服务端到端服务质量QoS的关键步骤。文章重点对实时多媒体信息如何进行分类及相应的服务策略和拥塞管理进行时比研究,提出实现端到端QoS服务质量的具体措施和解决方案。并在Cisco思科路由器和交换机建立的DiffSeFV网络环境中进行验证,实验结果表明。对实时多媒体信息进行合理的分类及采用相应服务策略.能很好地实现实时多媒体信息流端到端的服务质量QoS。最后阐述了Diffsenr区分服务存在的问题和未来的发展趋势。 相似文献
2.
IPv6环境下的端到端QoS模型 总被引:1,自引:0,他引:1
IP网络将向着IPv6的方向发展,提供可靠的网络服务并保证服务质量是未来IPv6网络需要解决的关键问题.介绍了IPv6的QoS功能,在分析比较综合服务(integrated services,IntServ)、区分服务(differentiated services,DiffServ)和多协议标签交换(multiprotocol label switching,MPLS)等服务质量模型的基础上,提出了一个基于IPv6的端到端QoS模型,探讨了模型的功能组成和工作过程,指出了进一步研究的方向. 相似文献
3.
Valeria Cardellini Valerio Di Valerio Vincenzo Grassi Stefano Iannucci Francesco Lo Presti 《International Journal of Software and Informatics》2013,7(2):195-220
Service selection has been widely investigated by the SOA research community as an effective adaptation mechanism that allows a service broker, offering a composite service, to bind at runtime each task of the composite service to a corresponding concrete implementation, selecting it from a set of candidates which differ from one another in terms
of QoS parameters. In this paper we present a load-aware per-request approach to service selection which aims to combine the relative benefits of the well known per-request and perflow approaches. Our service selection policy represents the core methodology of the Plan phase of a self-adaptive service oriented system based on the MAPE-K reference loop. Since the service broker operates in a variable and uncertain environment where the QoS levels negotiated with the service providers can fluctuate, it requires some mechanism to enforce the QoS constraints with its users. To this end, we also propose an algorithm for the Analyze phase of MAPE-K which is based on the adaptive Cusum algorithm and allows to determine whether a change in the QoS level requires a service selection replanning. We
present experimental results obtained with a prototype implementation of a service broker. Our results show that the proposed load-aware approach is superior to the traditional perrequest one and combines the ability of sustaining large volume of service requests, as the perflow approach, while at the same time offering a finer customizable service selection, as the per-request approach. Furthermore, the results show that the adaptive Cusum algorithm
can quickly detect changes in the execution environment and trigger a new optimization plan
before the system performance degrades. 相似文献
4.
5.
QoS Requirement Generation and Algorithm Selection for Composite Service Based on Reference Vector 总被引:2,自引:0,他引:2
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Under SOA (Service-Oriented Architecture), composite service is formed by aggregating multiple component services together in a given workflow. One key criterion of this research topic is QoS composition. Most work on service composition mainly focuses on the algorithms about how to compose services according to assumed QoS, without considering where the required QoS comes from and the selection of user preferred composition algorithm among those with different computational cost and di?erent selection resu... 相似文献
6.
重叠网服务质量(OverQoS)是一个崭新的研究课题。该文从应用的角度出发,根据OverQoS的驱动者不同,将基于重叠网的QoS架构分为主机系统驱动型和Overlay ISP驱动型,并剖析了两种OverQoS模型的内在特点,最后提出了相应的技术实现方案。 相似文献
7.
基于QNX操作系统的高可用性应用软件框架 总被引:2,自引:0,他引:2
针对QNX操作系统高度模块化的应用软件体系可能因部分模块故障而导致应用程序失去响应的情况,提出了一种高可用性应用软件设计框架.该应用软件设计框架利用了资源管理器的名字空间技术,赋予了应用程序自主发现模块故障并进行自我恢复的能力. 相似文献
8.
Dynamic Reconfiguration of Event Driven Architecture Using Reflection and Higher-Order Functions
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Component-based modelling is used as the basis of a number of approaches including Enterprise Architecture and System Architecture Design. Service Oriented Architecture (SOA) is a popular component-based approach but it has been criticised as not being suficiently flexible. A more flexible alternative is Event Driven Architecture (EDA) that can support Complex Event Processing. Dynamic reconfiguration of component behaviour is attractive because it allows an architecture to be extended and modified in situ without being taken off-line, updated and redeployed. This article shows how higher-order functions and reflection can support dynamic reconfiguration and how this approach is integrated with EDA. The approach is defined as patterns expressed in a component modelling language called LEAP and validated through a case study. 相似文献
9.
Cloud can be defined as a new computing paradigm that provides scalable, on-demand, and virtualized resources for users. In this style of computing, users can access a shared pool of computing resources which are provisioned with minimal management efforts of users. Yet there are some obstacles and concerns about the use of clouds. Guaranteeing quality of service (QoS) by service providers can be regarded as one of the main concerns for companies tending to use it. Service provisioning in clouds is based on service level agreements representing a contract negotiated between users and providers. According to this contract, if a provider cannot satisfy its agreed application requirements, it should pay penalties as compensation. In this paper, we intend to carry out a comprehensive survey on the models proposed in literature with respect to the implementation principles to address the QoS guarantee issue. 相似文献
10.
全球信息栅格服务质量互通性研究 总被引:1,自引:1,他引:0
全球信息栅格(Global Information Grid,GIG)是一种大而复杂的网络系统,目的是把美军分布在全球的信息系统、服务和应用结合在一起,形成一种无缝隙、可靠的安全网络;首先,对GIG网络体系结构传输部分进行了概述;其次,描述了网络与网络链接接口、以及在GIG网络应用中,对不同服务质量解决方案进行了归类;最后,讨论了网络交互领域与不同服务质量解决方案之间所面临的挑战。 相似文献
11.
汇聚组播:新型MPLS服务质量组播体系结构 总被引:1,自引:0,他引:1
为支持新兴网络应用,IP组播(multicast)和MPLS(multi-protocol label switching)技术分别从不同方向扩展了当前的IP路由和交换模式.MPLS和IP组播的结合是当前研究的一个热点,MPLS网络中的服务质量组播面临着标签资源匮乏、组播路由状态的可扩展性以及具体实现上的困难.针对这些问题,提出了基于汇聚方法的新型MPLS服务质量组播体系结构,提出在现有的路由控制平面上叠加一层面向IP组播服务的控制平面,取代组播路由协议并支持组播聚集,形成2层控制平面结构.定义了两平面之间的协作和交互方式,并通过扩展RSVP-TE(resource reservation protocol-traffic engineering) P2MP(point to multi-point)协议,在新的体系结构中融合了服务质量控制能力.另外,还探讨了汇聚组播中基于距离约束选择汇聚路由器的算法,实现了基于Linux的MPLS组播路由器和IP组播服务控制系统,并组建了实验平台.实验和模拟结果表明,基于汇聚组播的双平面网络控制结构能够适应组播用户和网络拓扑的动态变化,能够有效节省MPLS标签资源,平衡网络中组播流量的分布. 相似文献
12.
Boutaba Raouf Ren Ned Ning Rasheed Yasser Leon-Garcia Alberto 《Multimedia Tools and Applications》2002,16(1-2):99-136
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. 相似文献
13.
Solange Rito Lima Paulo Carvalho Vasco Freitas 《Journal of Network and Systems Management》2004,12(3):397-426
This article proposes a distributed admission control (AC) model based on on-line monitoring to manage the quality of Internet services and Service Level Specifications (SLSs) in class-based networks. The AC strategy covers intra- and interdomain operation, without adding significant complexity to the network control plane and involving only edge nodes. While ingress nodes perform implicit or explicit AC resorting to service-oriented rules for SLS and QoS parameters control, egress nodes collect service metrics providing them as inputs for AC. The end-to-end operation is viewed as a cumulative and repetitive process of AC and available service computation. We discuss crucial key points of the model implementation and evaluate its two main components: the monitoring process and the AC criteria. The results show that, using proper AC rules and safety margins, service commitments can be efficiently satisfied, and the simplicity and flexibility of the model can be explored to manage successfully QoS requirements of multiple Internet services. 相似文献
14.
计算网格应用可用性的度量模型 总被引:7,自引:0,他引:7
计算网格是很容易变化的不可靠的计算环境,因此如何保证应用的可用性成为构建网格系统的关键问题之一,而首先要解决的问题是如何对计算网格的可用性进行度量,分析了计算网格可用性的特征,提出从应用的角度度量计算网格可用性的方法,并设计了一种度量计算网格中应用可用性的模型,在这一模型中,应用的可用性用一个串行RBD来描述,每个网格结点上运行的应用的任务的可用性用概率模型描述,以此模型为基础,首先分析了在计算网格中影响应用可用性的关键因素,之后讨论了该度量模型在构建计算网格高可用服务体系结构中的应用。 相似文献
15.
Karsten-Berier Nicole Karsten Martin Schmitt Jens Steinmetz Ralf 《Multimedia Tools and Applications》2004,22(2):117-135
In order to support mobile multimedia applications in next generation wireless IP-based networks, it is necessary to deliver seamless voice, video and data at high quality. Therefore, session mobility and Quality of Service (QoS) for mobile end systems are required. Within this article, the authors point out a new way to approach the problem. Instead of tightly coupling a modified QoS signaling mechanism with a certain mobility mechanism, a more generic and long-term solution is proposed and exemplified on the basis of existing IETF protocols. The connection-less IP network layer is enhanced by a lightweight and truly optional connection-oriented mobile network service, which offers the possibility to establish soft state unicast connections at the network layer. Hence, a connection-oriented network service is available within a radio access network (RAN) architecture to all end systems—mobile or fixed—independent of the application. Thereby, it is possible to integrate QoS and connectivity signaling for mobile end systems, as well as other connection-oriented services like explicit routing or load balancing. 相似文献
16.
基于前期工作——可信可控网络体系结构TCNA(trustworthy and controllable network architecture),提出了一种QoS资源控制模型(resource control model for QoS,简称RCMQ).该模型从网络可控角度将QoS控制分为4层:QoS决策层面、QoS观测层面、QoS接口层面和QoS资源层面,模型部署包括独立集中的域内控制和一致性分布式控制.RCMQ模型闭环控制结构保证了QoS控制的有效性,而独立集中的QoS决策层面使得模型具有可扩展性.最后,通过仿真实验验证了RCMQ资源控制模型与InterServ模型相比,能够提供更为稳定的QoS传输,并且极大地减少了QoS状态维护,同时也从侧面说明可信可控网络体系比传统TCP/IP网络具有更高的可控性. 相似文献
17.
面向服务的体系结构SOA已经逐渐成为应用软件系统集成的主流技术。服务总线在构建SOA基础架构中起着关键作用,如何根据服务QoS进行动态优化是服务总线中的重要研究课题之一。SOARBus是一个支持QoS动态优化的服务总线,SOARBus实现组合服务请求动态调度算法和QoS感知的组合服务动态调整算法,使其能够根据引擎负载按照负载均衡原则对组合服务请求进行动态调度和以及在组合服务执行期间根据QoS对组合服务进行动态调整。 相似文献
18.
随着Web的发展,可供选择的功能相同或相似的Web服务越来越多,因此有必要为用户提供一种高效的基于服务质量(QoS)的Web服务查询机制.然而现有的Web服务QoS管理模型并不能很好的支持如动态查询等查询需求,其查询性能也有待提高.鉴于此,本文提出一种新的Web服务管理模型——多维QoS模型(MQM:Multi-dimensional QoS Model),并介绍了该模型的创建方法和相关算法.MQM通过多维模型来管理QoS数据,提供查询和OLAP操作.实验证明MQM能够使用户能更准确和快速的按QoS查询现有服务,很好地解决了传统查询方法无法确定查询条件、无法动态改变查询区间、查询性能不高等问题,进而改善了用户体验. 相似文献
19.
论文探讨了WebGIS应用中瓦片地图的加载方式,提出了一种地图加载的方法,该方法能解决传统加载方法存在的地图浏览时边缘白边,服务器负载大等问题。该方法综合内存LRU调用算法、浏览器缓存机制和异步调用技术,是一种多层架构模式的优化方法,并给出了该架构模式的实现策略与步骤,为封装功能更强、用户体验更好的WebGIS组件提供了技术理论依据。 相似文献