面向服务的服务等级协议实现框架的研究

对面向运营支撑系统的服务等级协议（SLA）实现框架进行了研究，为了实现基于SLA驱动的下一代运营支撑系统的业务管理层的流程自动化，在WfMC工作流参考模型和面向服务框架的基础上，提出了基于工作流管理的服务等级协议实现框架，并采用面向服务架构（SOA）的商业处理执行语言（BPEL），详细给出了基于该体系结构的SLA实现框架的应用实例。     

基于服务等级的网格服务质量描述语言

针对网格服务质量管理中使用服务水平协议(SLA)带来较大协商开销的问题,提出基于服务等级的网格服务质量描述语言即网格服务等级语言(CGSL)及建立在CGSL之上的网格服务质量管理框架.服务等级是轻量级SLA,提供一种区分不同服务质量的机制.CGSL基于XML技术和WSRF规范,与Web服务描述语言(WSDL)兼容,用于描述网格服务提供方所能提供的不同服务等级,为监控服务质量提供具体信息.网格服务质量管理框架建立在CGSL之上,并通过Mobile Agent监控服务质量是否得到满足.一个具体的文件存储网格服务实例用来展示CGSL在网格服务质量管理中的应用.该实例表明CGSL以少量的服务等级代替复杂的SLA,能有效降低运行时消耗,适合异构多变的网格环境.     

基于模糊动态阈值机制的能效虚拟机合并决策方法

动态虚拟机合并是云数据中心改善功耗和资源利用率的有效方法,但负载变化使数据中心较难维持服务等级协议SLA和最优能效.针对该问题,提出一种模糊动态阈值方法对虚拟机合并过程进行决策,在动态负载环境下实现最小化的虚拟机迁移量.该算法利用模糊推理系统动态调整主机资源利用阈值,使得超载主机上的虚拟机迁移大幅降低,并可以满足服务等...     

云计算背景下面向服务组合的SLA动态管理机制研究

组合服务通过组合和调用互联网环境中已有的Web服务实现更加复杂的业务功能。由于面向服务体系结构的分布式和松散耦合特征,稳定的QoS对于服务双方之间稳定的业务关系具有重要的作用,而服务等级协定SLA(Service Level Agreement)为云计算背景下的QoS管理提供了基础。针对服务组合场景下基于SLA的QoS管理问题,提出一个动态SLA管理框架,其中充分考虑到云计算环境下动态变化的客户数量和类型对于服务组合前端服务质量的不同需求。提出并实现了两种管理模式:定制模式与分级模式,并着重解决了管理过程中的后端SLA冲突问题。通过对服务组合绑定结构的动态规划和优选实现了组合服务前后端SLA的协调。根据所提出的管理框架实现了一个原型系统,验证了所提出框架和管理模式的有效性。     

基于SLA与用户评价的云计算信任模型

针对用户对云服务提供商缺乏信任的问题,提出一个基于服务等级协议(SLA)与用户评价的云计算信任模型。通过分析云服务提供商的SLA确认其承诺的服务质量,根据用户的评价确定云服务提供商对SLA的履行情况,综合两方面内容计算云服务的可信度。分析结果表明,借助该模型,用户可以准确地选择可信的云服务提供商。     

一种基于QoS的业务管理SLS信息模型

为在迅速发展的IP网络上提供各种基于IP的差异性业务,业务提供商必须为客户提供业务等级协议(SLA)以对客户做出服务质量(QoS)的保证。业务等级规范(SLS)是SLA的技术部分,它从技术层面上描述了双方对业务及其QoS要求所达成的协定。为使SLA双方的协商以及QoS的验证能有效进行,必须建立一个能满足不同业务特性的SLS信息模型。文章首先对SLA、SLS以及相关概念进行了阐述,然后提出了一种有效的通用的SLS信息模型并对该模型的组织机制进行了研究。     

I-WSLA:基于WSLA的云计算IaaS协商协议

随着云计算的兴起,云计算的服务质量(QoS)问题也越来越受到关注,服务等级协议(SLA)是保证云计算服务质量的重要解决途径。IaaS作为云计算服务的重要模式之一,具有虚拟化、动态化等特点,已有的WS-A及WSLA服务等级协议不适应IaaS的具体描述,同时也未涉及协商过程。以WSLA为基础,提出一个适用于云计算IaaS服务的SLA框架I-WSLA,该框架针对IaaS设计了一些合适的度量,给出定义参数的方法,特别加入协议的协商过程定义,结合参数化的概念,通过协商类型与协商实例的方式定义协商及其过程。     

基于SLA的网络监测系统的设计与实现

SLA是对服务水平的约定,本文从网络的服务质量出发,结合网络监测在实际中的应用,设计并实现了基于SLA的网络监测系统。     

基于Web Services的分布式标准化学习资源服务系统的研究与实现

学习资源的管理是网络教育的重点和难点，由于网络教育资源数量巨大，格式不一，位置分散，造成了资源使用效率不高的现状。如何提高教育资源的服务质量是一个亟待解决的问题。针对这一问题，本文提出了一种基于WebServices的分布式标准化学习资源服务系统模型，并对其进行了实现和应用。该模型遵循学习资源相关技术标准，采用分层的学习资源管理机制，利用WebServices技术实现不同层次间通信，将资源开发、存储、共享等环节贯穿起来，提高了学习资源的服务质量。     

基于Web Services的SLA监测系统体系结构

为解决现有SLA监测系统存在的不足,提出了基于Web Services的SLA监测系统体系结构,描述了该体系结构中相关服务的功能和SLA监测流程。为规范化不同层次SLA参数的映射,提出了通用的SLA参数映射模型。原型系统的实现验证了该体系结构能够满足下一代互联网环境下的多业务的监测需求。     

PROQOS—Dynamic SLA Management in DiffServ Space Links

Several base elements for the provision of quality of service guarantees have been developed in the recent past. Of these, the Differentiated Services (DiffServ) architecture stands out as the most promising. In spite of this, various issues remain, especially when multidomain DiffServ services are concerned. In this case, some forms of distributed management of Service Level Agreements that allow the specification, exchange, enforcement and monitoring of quality of service data must be in place. Although, again, some isolated solutions exist for each of these problems, considerable effort is necessary to make them work together. The project presented in this paper tried to assess the feasibility of providing differentiated quality of service in satellite IP networks, by developing a dynamic Service Level Agreement management solution for an IP over Digital Video Broadcast Satellite system. The functionality of the implemented system comprises system configuration, dynamic SLA negotiation, QoS monitoring and metering, SLA conformance checking, and QoS reporting to customers.     

云计算服务等级协议初探

云服务已经渗透到各行各业,如何保证其良性发展,如何让用户获得应有的服务质量成为摆在眼前的重要问题。服务等级协议作为一种服务提供商与用户之间协商并签订的一个具有法律约束力的合同,规定了在服务提供过程中双方所承担的商务条款,该协议的研究对云服务的健康持续发展有着重要意义。     

The WSLA Framework: Specifying and Monitoring Service Level Agreements for Web Services

We describe a novel framework for specifying and monitoring Service Level Agreements (SLA) for Web Services. SLA monitoring and enforcement become increasingly important in a Web Service environment where enterprise applications and services rely on services that may be subscribed dynamically and on-demand. For economic and practical reasons, we want an automated provisioning process for both the service itself as well as the SLA managment system that measures and monitors the QoS parameters, checks the agreed-upon service levels, and reports violations to the authorized parties involved in the SLA management process. Our approach to these issues is presented in this paper. The Web Service Level Agreement (WSLA) framework is targeted at defining and monitoring SLAs for Web Services. Although WSLA has been designed for a Web Services environment, it is applicable as well to any inter-domain management scenario, such as business process and service management, or the management of networks, systems and applications in general. The WSLA framework consists of a flexible and extensible language based on XML Schema and a runtime architecture comprising several SLA monitoring services, which may be outsourced to third parties to ensure a maximum of objectivity. WSLA enables service customers and providers to unambiguously define a wide variety of SLAs, specify the SLA parameters and the way they are measured, and relate them to managed resource instrumentations. Upon receipt of an SLA specification, the WSLA monitoring services are automatically configured to enforce the SLA. An implementation of the WSLA framework, termed SLA Compliance Monitor, is publicly available as part of the IBM Web Services Toolkit.     

网络服务质量评估体系研究

讨论了QoS中的一项关键技术,即网络服务质量评估技术。基于SLA的核心思想,提出一个QoS评估模型,从6个方面描述了评估体系模型的构成。根据内容提供商、网络运营商、其它服务提供商和用户所处位置的不同,定义了两种网络性能参数的采集方法。给出业务分层和SLA服务性能指标的对应关系。以SLA高层应用为例详细介绍了6个性能指标的计算方法。     

Quality of Service Negotiation for Commercial Medical Grid Services

The GEMSS project has developed a service-oriented Grid that supports the provision of medical simulation services by service providers to clients such as hospitals. We outline the GEMSS architecture, legal framework and the security features that characterise the GEMSS infrastructure. High levels of quality of service are required and we describe a reservation-based approach to quality of service, employing a quality of service management system that iteratively finds suitable reservations and uses application specific performance models. The GEMSS Grid is a commercial environment so we support flexible pricing models and a FIPA reverse English auction protocol. Signed Web Service Level Agreement contracts are exchanged to commit parties to a quality of service agreement before job execution occurs. We run four experiments across European countries using high performance computing resources running advanced resource reservation schedulers. These experiments provide evidence for our Grid’s rational behaviour, both at the level of service provider quality of service management and at the higher level of the client choosing between competing service providers. The results lend support to our economic model and the technology we use for our medical application domain.     

Monitoring web services’ quality of service: a literature review

Monitoring Quality of Service (QoS) compliance is an important procedure in web service environment. It determines whether users’ expectations are met, and becomes the vital factor for them to decide whether to continue paying for the service or not. The monitoring is performed by checking the actual services performance against the QoS stated in Service Level Agreement (SLA). In relation to that, the need for monitoring vague QoS specifications in SLA has become more apparent nowadays. This paper reviews the published literature on web services QoS monitoring. A total of 60 selected articles were systematically analyzed. There were 23 of the articles selected through restrictive search criteria while the other 37 were selected based on unrestrictive search criteria. The review shows that little evidence exists on monitoring vague QoS specifications of web services. Providing ability for monitoring QoS that is specified vaguely in SLA could give new insights and implications to web services field. This paper concludes with some recommended future works to construct the theory and perform the empirical research.     

基于延时测量的端到端路径性能检测

网络路径的端到端性能直接决定了为用户提供服务的质量,网络路径性能的测量是网络运营和SLA(ServiceLevelAgreement)验证的重要组成部分。文章在描述端到端路径性能检测的一般性问题的基础上,提出了延时差平稳系数和绝对平稳系数作为测量检测网络路径性能的几个评价指标,作为已有的测量标准化工作的补充和利用网络测量进行端到端性能管理的参考方法。     

A cost-aware auto-scaling approach using the workload prediction in service clouds

Service clouds are distributed infrastructures which deploys communication services in clouds. The scalability is an important characteristic of service clouds. With the scalability, the service cloud can offer on-demand computing power and storage capacities to different services. In order to achieve the scalability, we need to know when and how to scale virtual resources assigned to different services. In this paper, a novel service cloud architecture is presented, and a linear regression model is used to predict the workload. Based on this predicted workload, an auto-scaling mechanism is proposed to scale virtual resources at different resource levels in service clouds. The auto-scaling mechanism combines the real-time scaling and the pre-scaling. Finally experimental results are provided to demonstrate that our approach can satisfy the user Service Level Agreement (SLA) while keeping scaling costs low.     

基于Parlay/OSA的服务水平协议分析与改进

服务水平协议是保证服务提供的关键技术,在服务提供领域日显其重要性。文章首先概述了服务水平协议的组成与功能,分析了Paraly/OSA架构下引入的商业模型,讨论组成商业模型的四个商业角色之间的服务关系。在此基础上,进一步分析了目前的Parlay规范对服务水平协议的支持,对组成服务水平协议的离线协议与在线协议的分析可知Parlay规范对服务水平协议的支持存在着极大的不足。最后,提出定义链表型的数据结构增强服务能力水平区分,完善服务水平协议,并分析了其优点、可行性以及带来的挑战。