Showing papers on "Service-level agreement published in 2007"

Dynamic Placement of Virtual Machines for Managing SLA Violations

Abstract: A dynamic server migration and consolidation algorithm is introduced. The algorithm is shown to provide substantial improvement over static server consolidation in reducing the amount of required capacity and the rate of service level agreement violations. Benefits accrue for workloads that are variable and can be forecast over intervals shorter than the time scale of demand variability. The management algorithm reduces the amount of physical capacity required to support a specified rate of SLA violations for a given workload by as much as 50% as compared to static consolidation approach. Another result is that the rate of SLA violations at fixed capacity may be reduced by up to 20%. The results are based on hundreds of production workload traces across a variety of operating systems, applications, and industries.

An Evaluation of Amazon's Grid Computing Services: EC2, S3, and SQS

Abstract: Amazon.com’s Elastic Compute Cloud (EC2), Simple Storage Service (S3) and Simple Queue Service (SQS) offer enterprise-class computing, storage and coordination facilities to any organization or individual in the world with a valid credit card. This paper details our experience working with these commodity grid computing services between November 2006 and May 2007, including an analysis of the overall system’s API and ease-of-use; an analysis of EC2’s management and security facilities; an end-to-end performance analysis of S3’s throughput and latency as observed from Amazon’s EC2 cluster and other locations on the Internet; and an analysis of the SQS operation and performance. We conclude with a report of our experience moving a large-scale research application from dedicated hardware to the Amazon offering. We find that this collection of AmazonWeb Services (AWS) has great promise but are hobbled by service consistency problems, the lack of a Service Level Agreement (SLA), and a problematic Web Services Licensing Agreement (WSLA).

CC-Pi: a constraint-based language for specifying service level agreements

Abstract: Service Level Agreements are a key issue in Service Oriented Computing. SLA contracts specify client requirements and service guarantees, with emphasis on Quality of Service (cost, performance, availability, etc.). In this work we propose a simple model of contracts for QoS and SLAs that also allows to study mechanisms for resource allocation and for joining different SLA requirements. Our language combines two basic programming paradigms: name-passing calculi and concurrent constraint programming (cc programming). Specifically, we extend cc programming by adding synchronous communication and by providing a treatment of names in terms of restriction and structural axioms closer to nominal calculi than to variables with existential quantification. In the resulting framework, SLA requirements are constraints that can be generated either by a single party or by the synchronisation of two agents. Moreover, restricting the scope of names allows for local stores of constraints, which may become global as a consequence of synchronisations. Our approach relies on a system of named constraints that equip classical constraints with a suitable algebraic structure providing a richer mechanism of constraint combination. We give reduction-preserving translations of both cc programming and the calculus of explicit fusions.

Method and apparatus for network distribution and provisioning of applications across multiple domains

Abstract: Techniques are disclosed for network distribution and provisioning of applications, such as transactional applications and parallel applications, across multiple administrative domains that ensure compliance with service level agreements. For example, a method of provisioning one or more resources in a distributed computing network to ensure compliance with a service level agreement associated with a computer application includes the following steps. Network performance is monitored between a local domain and one or more cooperating domains connected to the local domain by network paths. A present or predicted violation of the service level agreement is identified based on at least a portion of results of the monitoring step. One or more cooperating domains are selected that can effect compliance with the service level agreement by instantiating one or more network resources within at least one of the selected cooperating domains in response to a request from the local domain. Reconfiguration of the local domain is effectuated to allow the computer application to make use of the one or more newly instantiated network resources within the selected cooperating domain.

Reliable QoS monitoring based on client feedback

Abstract: Service-level agreements (SLAs) establish a contract between service providersand clients concerning Quality of Service (QoS) parameters. Without properpenalties, service providers have strong incentives to deviate from theadvertised QoS, causing losses to the clients. Reliable QoS monitoring (andproper penalties computed on the basis of delivered QoS) are thereforeessential for the trustworthiness of a service-oriented environment. In thispaper, we present a novel QoS monitoring mechanism based on quality ratings from theclients. A reputation mechanism collects the ratings and computes theactual quality delivered to the clients. The mechanism provides incentives forthe clients to report honestly, and pays special attention to minimizing costand overhead1.

Software as a Service: An Integration Perspective

Abstract: Software as a Service (SaaS) is gaining momentum in recent years with more and more successful adoptions. Though SaaS is delivered over Internet and charged on per-use basis, it is software application in essence. SaaS contains business data and logics which are usually required to integrate with other applications deployed by a SaaS subscriber. This makes Integration become one of the common requirements in most SaaS adoptions. In this paper, we analyze the key functional and non-functional SaaS integration requirements from an industry practitioner point of view; and summarize the SaaS integration patterns and existing offerings; then point out the gaps from both technology and tooling perspectives; finally we introduce a SaaS integration framework to address those gaps. Considering there is no much academic work on SaaS service modeling, we come up with a SaaS service description framework as an extension of Web Service description, so as to model SaaS unique features in a unified way. With the supported tooling and runtime platform, the framework can facilitate the SaaS integration lifecycle in a model-driven approach.

Service characteristic evaluation in a cellular communication system

Abstract: A cellular communication system (100) comprises a service evaluation server (117) for performing service characteristic evaluation. The server (117) comprises a profile store (201) which stores different service characteristic profiles for a plurality of remote stations. Each service characteristic may correspond to a service level agreement. A measurement operation processor (203) determines a set of measurement operations for a first remote station (101) in response to a first service characteristic profile for the first remote station (101). A measurement command processor (205) then determines a set of measurement commands corresponding to the measurement operations and a network transmit processor (207) transmits the set of measurement commands to the first remote station (101). The first remote station (101) decodes the commands, performs the measurement operations and transmits the resulting measurement data to the server (117). A network receive processor (211) receives the measurement data and a service characteristic processor (213) determines an experienced service characteristic profile for the first remote station (101) in response to the measurement data.

SLA-Driven Clustering of QoS-Aware Application Servers

Abstract: In this paper, we discuss the design, implementation, and experimental evaluation of a middleware architecture for enabling service level agreement (SLA)-driven clustering of QoS-aware application servers. Our middleware architecture supports application server technologies with dynamic resource management: application servers can dynamically change the amount of clustered resources assigned to hosted applications on-demand so as to meet application-level quality of service (QoS) requirements. These requirements can include timeliness, availability, and high throughput and are specified in SLAs. A prototype of our architecture has been implemented using the open-source J2EE application server JBoss. The evaluation of this prototype shows that our approach makes possible JBoss' resource usage optimization and allows JBoss to effectively meet the QoS requirements of the applications it hosts, i.e., to honor the SLAs of those applications

System and method for managing a service level agreement

Abstract: A system and method for managing communications services of users of a packet network Parameters associated with service agreements of users of a packet network may be stored. Network performance information associated with the users may also be stored. The network performance information may be accessed to read a quality of service parameter of communications over the packet network for a user over a given time period. The parameters associated with a service agreement may also be accessed. A quality of service parameter for the user to receive during the time period as contracted by the user may be read. A determination as to whether the user has received a quality of service for communicating over the packet network below the contracted quality of service may be made and the user, in response to determining that the quality of service is below the contracted quality of service, may be compensated.

Search-based testing of service level agreements

Abstract: The diffusion of service oriented architectures introduces the need for novel testing approaches. On the one side, testing must be able to identify failures in the functionality provided by service. On the other side, it needs to identify cases in which the Service Level Agreement (SLA) negotiated between the service provider and the service consumer is not met. This would allow the developer to improve service performances, where needed, and the provider to avoid promising Quality of Service (QoS) levels that cannot be guaranteed. This paper proposes the use of Genetic Algorithms to generate inputs and configurations for service-oriented systems that cause SLA violations. The approach has been implemented in a tool and applied to an audio processing workflow and to a service for chart generation. In both cases, the approach was able to produce test data able to violate some QoS constraints.

Monitoring WS-Agreement s: An Event Calculus–Based Approach

Abstract: In this chapter, we present a framework that we have developed to support the monitoring of service level agreements (SLAs). The agreements that can be monitored by this framework are expressed in an extension of WS-Agreement that we propose. The main characteristic of the proposed extension is that it uses an event calculus–based language, called EC-Assertion, for the specification of the service guarantee terms in a service level agreement that need to be monitored at runtime. The use of EC-Assertion for specifying service guarantee terms provides a well-defined semantics to the specification of such terms and a formal reasoning framework for assessing their satisfiability. The chapter describes also an implementation of the framework and the results of a set of experiments that we have conducted to evaluate it.

Avoiding disruptions during maintenance operations on BGP sessions

Abstract: This paper presents a solution aimed at avoiding losses of connectivity when an eBGP peering link is shut down by an operator for a maintenance. Currently, shutting down an eBGP session can lead to transient losses of connectivity even though alternate path are available at the borders of the network. This is very unfortunate as ISPs face more and more stringent service level agreements, and maintenance operations are predictable operations, so that there is time to adapt to the change and preserve the respect of the service level agreement.

Web Services Regression Testing

Abstract: Service-oriented Architectures (SOA) introduce a major shift of perspective in software engineering: in contrast to components, services are used instead of being physically integrated. This leaves the user with no control over changes that can happen in the service itself. When the service evolves, the user may not be aware of the changes, and this can entail unexpected system failures.

Integrated Risk Analysis for a Commercial Computing Service

Abstract: Utility computing has been anticipated to be the next generation of computing usage. Users have the freedom to easily switch to any commercial computing service to complete jobs whenever the need arises and simply pay only on usage, without any investment costs. A commercial computing service however has certain objectives or goals that it aims to achieve. In this paper, we identify three essential objectives for a commercial computing service: (i) meet SLA, (ii) maintain reliability, and (iii) earn profit. This leads to the problem of whether a resource management policy implemented in the commercial computing service is able to meet the required objectives or not. So, we also develop two evaluation methods that are simple and intuitive: (i) separate and (ii) integrated risk analysis to analyze the effectiveness of resource management policies in achieving the required objectives. Evaluation results based on five policies successfully demonstrate the applicability of separate and integrated risk analysis to assess policies in terms of the required objectives.

Service level agreement management

Abstract: Consistent with embodiments of the present invention, systems and methods are disclosed for providing service level agreement management. The method may include collecting performance data on a data network and collecting service information including at least one rule. The rule may include a service level agreement rule and a contract rule. The method may further include correlating the performance data and the service information and determining a violation of the at least one rule by the data network based on the collected performance data and the at least one rule. The method may further include collecting billing charges or monthly recurring charges corresponding to a service. The method may further include determining the penalties or charges to be given to a service and to a customer according to at least one rule in the event of a violation of the at least one service level agreement rule and a contract rule.

Power management of multi-processor servers

Abstract: A method and system are provided for dynamically managing delivery of power to partitionable elements in a computer system while supporting terms of a Service Level Agreement (SLA). Parameters of the SLA are gathered in conjunction with the topology of the computer system. Transactions associated with the SLA are monitored and high and low usage periods are predicted based upon a history of transactions. Power to partitionable elements of the computer system may be adjusted during high and low usage periods. In addition, dynamic management of the partitionable elements is provided in response to current demands. Management of the partitionable elements is all made in compliance with the SLA.

Methods and apparatus for interactive specification of context-sensitive service level agreements; for provisioning of resources required during service delivery events regulated by service level agreements; and for monitoring compliance with service Level agreements during service delivery events

Abstract: In a first aspect of the present invention, methods and apparatus implement graphical user interfaces for interactively specifying service level agreements used to regulate delivery of services to, for example, computer systems. An interactive graphical user interface allows a user to see the effects of varying values of service delivery variables on the level of service achievable in a particular service delivery context. In a second aspect, methods and apparatus of the present invention provision resources required for service delivery. In the second aspect, the methods and apparatus of the present invention select a service delivery model dependent on context. The selected service delivery model is used to provision resources that will be required during service delivery. In a third aspect, methods and apparatus of the present invention monitor compliance with a service level agreement during a service delivery event. In instances where a given service delivery does not comply with service level attributes specified in a controlling service level agreement, the methods and apparatus of the present invention take corrective action.

End-to-end privacy control in service outsourcing of human intensive processes: A multi-layered Web service integration approach

Abstract: With the recent adoption of service outsourcing, there have been increasing general demands and concerns for privacy control, in addition to basic requirement of integration. The traditional practice of a bulk transmission of the customers' information to an external service provider is no longer adequate, especially in the finance and healthcare sectors. From our consultancy experience, application-to-application privacy protection technologies at the middleware layer alone are also inadequate to solve this problem, particularly when human service providers are heavily involved in the outsourced process. Therefore, we propose a layered architecture and a development methodology for enforcing end-to-end privacy control policies of enterprises over the export of personal information. We illustrate how Web services, augmented with updated privacy facilities such as Service Level Agreement (SLA), Platform for Privacy Preferences Project (P3P), and the P3P Preference Exchange Language (APPEL), can provide a suitable interoperation platform for service outsourcing. We further develop a conceptual model and an interaction protocol to send only the required part of a customer's record at a time. We illustrate our approach for end-to-end privacy control in service outsourcing with a tele-marketing case study and show how the software of the outsourced call center can be integrated effectively with the Web services of a bank to protect privacy.

On automated generation of web service level agreements

Abstract: Before a service invocation takes place, an agreement between the service provider and the service user might be required. Such an agreement is the result of a negotiation process between the two parties and defines how the service invocation has to occur. Considering the Service Oriented Computing paradigm, the relationship among providers and users is extremely loose. Traditional agreements are likely to concern long term relationships and to be manually performed. In this paper, we propose a model to generate service level agreement on-the-fly. Just before the invocation commences, the quality of the service is negotiated in order to generate a service level agreement tied to that specific invocation. Such an approach relies on a quality model that supports both users requirements and providers capabilities definition.

A Declarative Approach for QoS-Aware Web Service Compositions

Abstract: While BPEL language has emerged to allow the specification of Web Service compositions from a functional point of view, it is still left to the architects to find proper means to handle the Quality of Service (QoS) concerns of their compositions. Typically, they use ad-hoc technical solutions, at the message level, that significantly reduce flexibility and require costly developments. In this paper, we propose a policy-based language aiming to provide expressivity for QoS behavioural logic specification in Web Service orchestrations, as well as a non-intrusive platform in charge of its execution both at pre-deployment time and at runtime.

Multiple virtual machine configurations in the scalable enterprise

Abstract: A system and method are disclosed for using directory services to manage resources in a virtual execution environment. A directory repository is populated with resource, administration, roles, policy, and service level agreement (SLA) objects. A service request is received by a virtual machine manager (VMM) administrator, which determines its requirements. The directory repository is queried with a directory service to identify available resources to fulfill the service request. The service request is routed to the VMM of the virtual machine (VM) host comprising the available resources. If an active VM comprises the available resources, then its roles, policy, and SLA objects are retrieved from the directory repository. The objects are then used to respectively determine if the service request has sufficient authentication and authorizations, if the VM's configuration meets the service request's resource requirements, and if service levels requirements can be maintained. If so, then the service request is fulfilled by the target VM. If the resources are available, but not on a currently executing VM, then an administration object is created to execute a new VM and roles, policy, and SLA objects are created that match the requirements of the service request. The newly created objects are then stored in the directory repository and the service request is fulfilled by the new VM.

Improving Temporal-Awareness of WS-Agreement

Abstract: WS-Agreement (WS-Ag) is a proposed recommendation of the Open Grid Forum that provides a schema to describe SLAs and a protocol to create them based on a mechanism of templates However, although it identifies the necessity of specifying temporal-aware agreement terms (eg the response time is 30 ms from 8:00h to 17:00h and 15 ms from 17:00h to 8:00h), to the best of our knowledge, there are no existing proposals that deal with that necessity We propose an extension that gives WS-Ag support to temporality This allows describing expressive validity periods such as those composed by several periodic or non-periodic intervals and it applies not only to the agreement terms themselves but also to other parts of WS-Ag such as creation constraints and preferences about the service properties In addition, in this paper we propose a preference XML schemato describe preferences over any set of service properties using any kind of utility function In further research we will study a concrete specification for those utility functions

Service License Composition and Compatibility Analysis

Abstract: Services enable the transformation of the World Wide Web as distributed interoperable systems interacting beyond organizational boundaries. Service licensing enables broader usage of services and a means for designing business strategies and relationships. A service license describes the terms and conditions for the use and access of the service in a machine interpretable way that services could be able to understand. Service-based applications are largely grounded on composition of independent services. In that scenario, license compatibility is a complex issue, requiring careful attention before attempting to merge licenses. The permissions and the prohibitions imposed by the licenses of services would deeply impact the composition. Thus, service licensing requires a comprehensive analysis on composition of these rights and requirements conforming to the nature of operations performed and compensation of services used in composition. In this paper, we analyze the compatibility of service license by describing a matchmaking algorithm. Further, we illustrate the composability of service licenses by creating a composite service license, that is compatible with the licenses being composed.

Network sniffer for performing service level management

Abstract: A network sniffer where the sniffer learns the structure of a web application, monitors the operation of the application, and optionally controls the processing of incoming requests to achieve optimal performance as defined in a service level agreement (SLA). The network sniffer is operative for example in enterprise web applications and in enterprise data centers that deploy web applications and optimally is adapted to maintain a consistent level of service of web applications.

Partial cross training in call centers with uncertain arrivals and global service level agreements

Abstract: Inbound call center operations are challenging to manage; there is considerable uncertainty in estimates of arrival rates, and the operation is often subject to strict service level constraints. This paper is motivated by work with a provider of outsourced technical support services in which most projects (client specific support operations) include an inbound tier one help desk subject to a monthly service level agreement (SLA). Support services are highly specialized and a significant training investment is required, an investment that is not transferable to other projects. We investigate the option of cross training a subset of agents so that they may serve calls from two separate projects, a process we refer to as partial pooling. Our paper seeks to quantity the benefits of partial pooling and characterize the conditions under which pooling is most beneficial. We find that low levels of cross training yield significant benefit.

Integrating Quality of Service Aspects in Top-Down Business Process Development Using WS-CDL and WS-BPEL

Abstract: Developing cross-organizational business processes is a tedious task. The partners have to agree on a common data format and meaning as well as on the Quality of Service (QoS) requirements each partner has to fulfill. The QoS requirements are typically described using Service Level Agreements (SLAs) among the partners. In this paper, we propose a top-down modeling approach for Web service based business processes to capture the functional and non-functional aspects using a choreography language (WS-CDL) which describes the message interactions among the participants. The choreography is annotated with SLAs for the different partners. For each partner in the process, an orchestration (in WS-BPEL) and the necessary Web service templates are automatically generated. Additionally, the Service Level Objectives (SLOs) from the partner SLAs are automatically translated into policies which can then be enforced by a BPEL engine during execution.

On Leveraging Policy-Based Management for Maximizing Business Profit

Abstract: This paper presents a systematic approach to business and policy driven refinement. It also discusses an implementation of an application-hosting service level agreement (SLA) use case. We make use of a simple application hosting SLA template, for which we derive a low-level policy-based service level specification (SLS). The SLS policy set is then analyzed for static consistency and runtime efficiency. The Static Analysis phase involves several consistency tests introduced to detect and correct errors in the original SLS. The Dynamic analysis phase considers the runtime dynamics of policy execution as part of the policy refinement process. This latter phase aims at optimizing the business profit of the service provider. Through mathematical approximation, we derive three policy scheduling algorithms. The algorithms are then implemented and compared against random and first come first served (FCFS) scheduling. This paper shows, in addition to the systematic refinement process, the importance of analyzing the dynamics of a policy management solution before it is actually implemented. The simulations have been performed using the VS Policy Simulator tool.

The Design, Usage, and Performance of GRUBER: A Grid Usage Service Level Agreement based BrokERing Infrastructure

Abstract: We present GRUBER, a Grid Resource Usage service level agreement (uSLA) based BrokERing infrastructure, aimed at addressing the challenging issues that can arise within virtual organizations (VOs) that integrate participants and resources spanning multiple physical administrative domains. In such environments, participants delegate to one or more VOs the right to use certain resources subject to local policy and service level agreements; each VO then uses those resources subject to VO policy. GRUBER supports the explicit representation, enforcement, and management of service level agreements (SLAs) concerning resource usage (uSLAs) that can serve as an objective organizing principle for controlled resource sharing in distributed systems. uSLAs express how resources must be used over various time intervals and represent a novelty for the Grid domain. This paper provides a detailed overview of the GRUBER infrastructure, the evolution of its design to improve scalability, specifically the distribution of the resource brokering service, and the extended support for dynamic environments. We also present various results achieved over time that demonstrate both the utility and performance of GRUBER under various application workloads and scenarios.