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Showing papers on "Service-level agreement published in 2008"


Proceedings ArticleDOI
01 Dec 2008
TL;DR: This work investigates the design, implementation, and evaluation of a power-aware application placement controller in the context of an environment with heterogeneous virtualized server clusters, and presents the pMapper architecture and placement algorithms to solve one practical formulation of the problem: minimizing power subject to a fixed performance requirement.
Abstract: Workload placement on servers has been traditionally driven by mainly performance objectives. In this work, we investigate the design, implementation, and evaluation of a power-aware application placement controller in the context of an environment with heterogeneous virtualized server clusters. The placement component of the application management middleware takes into account the power and migration costs in addition to the performance benefit while placing the application containers on the physical servers. The contribution of this work is two-fold: first, we present multiple ways to capture the cost-aware application placement problem that may be applied to various settings. For each formulation, we provide details on the kind of information required to solve the problems, the model assumptions, and the practicality of the assumptions on real servers. In the second part of our study, we present the pMapper architecture and placement algorithms to solve one practical formulation of the problem: minimizing power subject to a fixed performance requirement. We present comprehensive theoretical and experimental evidence to establish the efficacy of pMapper.

938 citations


Proceedings ArticleDOI
09 Nov 2008
TL;DR: In this article, the authors present an implementation to derive on-line monitors for web services automatically from SLAs using an Eclipse plugin, and evaluate the efficiency and scalability of this approach using a large-scale case study in a service-oriented computational grid.
Abstract: If an organization depends on the service quality provided by another organization it often enters into a bilateral service level agreement (SLA), which mitigates outsourcing risks by associating penalty payments with poor service quality. Once these agreements are entered into, it becomes necessary to monitor their conditions, which will commonly relate to timeliness, reliability and request throughput, at run-time. We show how these conditions can be translated into timed automata. Acceptance of a timed word by a timed automaton can be decided in quadratic time and because the timed automata can operate while messages are exchanged at run-time there is effectively only a linear run-time overhead. We present an implementation to derive on-line monitors for web services automatically from SLAs using an Eclipse plugin. We evaluate the efficiency and scalability of this approach using a large-scale case study in a service-oriented computational grid.

161 citations


Patent
James Michael Ferris1
26 Nov 2008
TL;DR: In this paper, the authors propose a system and methods for service level backup using a re-cloud network, where one or more users can accept service based on a service level agreement (SLA).
Abstract: Embodiments relate to systems and methods for service level backup using a re-cloud network. A set of operating clouds can support one or more users. In embodiments, the one or more users can accept service based on a service level agreement (SLA), according to which the user is assured a certain level of service or support from the cloud, such as a minimum amount of uptime, a minimum amount of processor cycles or network bandwidth, or other guaranteed parameters of the usage of their virtual machine. In embodiments, the set of operating clouds in which the user's service is supported can be configured to communicate a service level augmentation request to a backup cloud to request additional resources to maintain the delivery of one or more SLA-specified support to one or more users. In embodiments, the backup cloud network can in turn be nested with other backup clouds or resources.

157 citations


Journal ArticleDOI
TL;DR: This paper proposes a statistical technique for run-time monitoring of soft contracts, which consist of a probability distribution for the considered QoS parameter and shows how to compose such contracts, to yield a global probabilistic contract for the orchestration.
Abstract: Service level agreements (SLAs), or contracts, have an important role in Web services. They define the obligations and rights between the provider of a Web service and its client, about the function and the quality of the service (QoS). For composite services like orchestrations, contracts are deduced by a process called QoS contract composition, based on contracts established between the orchestration and the called Web services. Contracts are typically stated as hard guarantees (e.g., response time always less than 5 msec). Using hard bounds is not realistic, however, and more statistical approaches are needed. In this paper we propose using soft probabilistic contracts instead, which consist of a probability distribution for the considered QoS parameter-in this paper, we focus on timing. We show how to compose such contracts, to yield a global probabilistic contract for the orchestration. Our approach is implemented by the TOrQuE tool. Experiments on TOrQuE show that overly pessimistic contracts can be avoided and significant room for safe overbooking exists. An essential component of SLA management is then the continuous monitoring of the performance of called Web services, to check for violations of the SLA. We propose a statistical technique for run-time monitoring of soft contracts.

127 citations


DOI
01 Sep 2008
TL;DR: The state of practice in service level agreement specification is surveyed and guidelines on how to assure that services are provided with high availability, security, performance, and other required qualities are offered.
Abstract: Quality attribute requirements play an important role in service selection in a service-oriented architecture environment. It is easy to envision finding several services that fulfill the functional requirements but fail to meet important quality attribute measures. Service level agreements provide the architect with a specification of the verifiable quality characteristics that the service will provide. Such a specification allows the architect to select the service that best supports the system's quality attribute requirements. This report surveys the state of practice in service level agreement specification and offers guidelines on how to assure that services are provided with high availability, security, performance, and other required qualities. In addition, this report discusses the quality properties that have been expressed in service level agreements, and it considers the mechanisms used to assure service quality by contract and those used by service providers to achieve and monitor quality properties. Also, this report examines the support for expressing service quality requirements in existing service technologies and describes areas where more research is needed.

102 citations


Proceedings ArticleDOI
06 Jul 2008
TL;DR: By leveraging a multiobjective genetic algorithm, E3 heuristically solves the QoS-aware service composition problem in a reasonably short time and can consider multiple SLAs simultaneously and produce a set of Pareto solutions, which have the equivalent quality to satisfy multipleSLAs.
Abstract: In service oriented architecture, each application is often designed as a set of abstract services, which defines its functions. A concrete service(s) is selected at runtime for each abstract service to fulfill its function. Since different concrete services may operate at different quality of service measures, application developers are required to select an appropriate set of concrete services that satisfies a given service level agreement when a number of concrete services are available for each abstract service. This problem, the QoS-aware service composition problem, is known NP-hard, which takes a significant amount of time and costs to find optimal solutions (optimal combinations of concrete services) from a huge number of possible solutions. This paper proposes an optimization framework, called E3, to address the issue. By leveraging a multiobjective genetic algorithm, E3 heuristically solves the QoS-aware service composition problem in a reasonably short time. The algorithm E3 proposes can consider multiple SLAs simultaneously and produce a set of Pareto solutions, which have the equivalent quality to satisfy multiple SLAs.

89 citations


Book ChapterDOI
01 Jan 2008
TL;DR: In this article, the authors focus on identifying particular penalty clauses that can be associated with an SLA, and identify how SLOs may be impacted by the choice of specific penalty clauses.
Abstract: A Service Level Agreement (SLA) represents an agreement between a service user and a provider in the context of a particular service provision. SLAs contain Quality of Service properties that must be maintained by a provider. These are generally defined as a set of Service Level Objectives (SLOs). These properties need to be measurable and must be monitored during the provision of the service that has been agreed in the SLA. The SLA must also contain a set of penalty clauses specifying what happens when service providers fail to deliver the preagreed quality. Although significant work exists on how SLOs may be specified and monitored, not much work has focused on actually identifying how SLOs may be impacted by the choice of specific penalty clauses. The participation of a trusted mediator may be necessary to resolve conflicts between involved parties. The main focus of the paper is on identifying particular penalty clauses that can be associated with an SLA.

83 citations


Patent
31 Oct 2008
TL;DR: In this article, a technique for evaluating service level agreement (SLA) violations occurring in a computing system with agreed-upon model for exemptions is provided, which includes storing in a memory a model of the SLA and identifying occurrence of an SLA violation.
Abstract: A technique for evaluating service level agreement (SLA) violations occurring in a computing system with agreed-upon model for exemptions is provided. The technique includes storing in a memory a model of the SLA and identifying occurrence of an SLA violation in a computing system that is providing services under the SLA. Based on the stored model, the technique further determines if the SLA violation is exempted from a penalty.

83 citations


Proceedings ArticleDOI
07 Jul 2008
TL;DR: This paper demonstrates how to analyze SLAs during development phase and how to monitor these dependencies using event logs during runtime, and calls it MoDe4SLA (monitoring dependencies for SLAs).
Abstract: In service oriented computing different techniques for monitoring service level agreements (SLAs) are available. Many of these monitoring approaches focus on bilateral agreements between partners. However, when monitoring composite services it is not only important to figure out whether SLAs are violated, but we also need to analyze why these violations have occurred. When offering a composite service a company depends on its content providers to meet the service level they agreed upon. Due to these dependencies a company should not only monitor the SLA of the composite service, but also the SLAs of the services it depends on. By analyzing and monitoring the composite service in this way, causes for SLA violations can be easier found. In this paper we demonstrate how to analyze SLAs during development phase and how to monitor these dependencies using event logs during runtime. We call our approach MoDe4SLA (monitoring dependencies for SLAs).

74 citations


Patent
Head Bubba1
06 Nov 2008
TL;DR: In this paper, the authors propose an approach to change the allocation of computing resources to an application program based on an established service level requirement for utilization of the resource by the application program.
Abstract: Allocating computing resources comprises allocating an amount of a resource to an application program based on an established service level requirement for utilization of the resource by the application program, determining whether the application program's utilization of the resource exceeds a utilization threshold, and changing the allocated amount of the resource in response to a determination that the application program's utilization of the resource exceeds the utilization threshold. The utilization threshold is based on the established service level requirement and is different than the established service level requirement. Changing the allocation of the resource based on the utilization threshold allows allocating sufficient resources to the application program prior to a breach of a service level agreement for the application program.

71 citations


Proceedings ArticleDOI
25 Feb 2008
TL;DR: The proposal, SALMon, is based on monitoring the services for service level agreement (SLA) violations and is composed of three types of components: Monitors that are composed of measure instruments, the measured quality attributes being taken from an ISO/IEC 9126-1-based service oriented quality model; analyzers that check the SLA rules; and decision makers that perform corrective actions to satisfySLA rules again.
Abstract: One of the most successful architectural styles nowadays is service oriented architecture (SOA). In this type of architecture there are a lot of dependencies between services, but each service is an independent element of the system. In this situation we need some way to ensure that every service is working correctly and to take actions when something goes wrong to evolve the architecture as fast as we can. For example, if one of the lower level services of the service composition stops working, it could lead to a total or partial system malfunction. In this situation there is a need to be able to build reliable SOA systems. Our proposal, SALMon, is based on monitoring the services for service level agreement (SLA) violations. The SALMon architecture is composed of three types of components: Monitors that are composed of measure instruments, the measured quality attributes being taken from an ISO/IEC 9126-1-based service oriented quality model; analyzers that check the SLA rules; and decision makers that perform corrective actions to satisfy SLA rules again. These 3 types of components are mostly technology-independent and they act as services inside of a SOA system making our architecture very scalable and comfortable for its purpose.

Proceedings ArticleDOI
15 Sep 2008
TL;DR: This paper defines a method how a service provider can aggregate the SLAs of the individual services within a business process into a single SLA and proposes a framework that helps in carrying out the SLA aggregation within business processes.
Abstract: One can observe that more and more companies are focusing on their core compenetency and are outsourcing parts or even complete business processes to service providers. Service Level Agreements (SLAs) are used as a contractual basis to define certain non-functional properties (e.g. response time) a service has to provide. To determine the SLA of a business process a priori, the SLAs of the invoked services need to be aggregated into a single SLA for the business process. This paper defines a method how a service provider can aggregate the SLAs of the individual services within a business process into a single SLA. This provides a service provider with the capability to annotate the service that the business process implements with an appropriate SLA. We propose a framework that helps in carrying out the SLA aggregation within business processes. The framework consists of two parts: (i) a formal model for SLAs and (ii) a concept to aggregate SLAs, where algorithms can be plugged in.

Book ChapterDOI
26 Aug 2008
TL;DR: The objectives of this work are to identify classes of penalty clauses that can be associated with an SLA, define how to specify penalties in an extension of WS-Agreement, and specify to what extent penalty clauses can be enforced based on monitoring of anSLA.
Abstract: A Service Level Agreement (SLA) is an electronic contract between a service user and a provider, and specifies the service to be provided, Quality of Service (QoS) properties that must be maintained by a provider during service provision (generally defined as a set of Service Level Objectives (SLOs)), and a set of penalty clauses specifying what happens when service providers fail to deliver the QoS agreed. Although significant work exists on how SLOs may be specified and monitored, not much work has focused on actually identifying how SLOs may be impacted by the choice of specific penalty clauses. A trusted mediator may be used to resolve conflicts between the parties involved. The objectives of this work are to: (i) identify classes of penalty clauses that can be associated with an SLA; (ii) define how to specify penalties in an extension of WS-Agreement; and (iii) specify to what extent penalty clauses can be enforced based on monitoring of an SLA.

Proceedings ArticleDOI
Asit Dan1, Robert D. Johnson1, Tony Carrato1
11 May 2008
TL;DR: This paper details the key challenges in achieving service reuse, and advocates taking a pro-active position in addressing these challenges by putting in place governing key aspects of service life-cycle and supporting technical capabilities.
Abstract: Reuse of services in supporting new business processes, in addition to alignment of IT with business functions, is a key motivation in using Service-oriented Architecture (SOA) for developing business solutions. The three key benefits of service reuse are improving agility of solutions by quickly assembling new business processes from existing services to meet changing marketplace needs, reduction of cost by not just avoiding duplication of code for enabling similar business functions across multiple business processes, but also throughout the SOA life-cycle spanning service deployment and management, and also reducing risks by reusing well-tested code and runtime environments. However, currently there are many organizational challenges and lack of accepted SOA solution development methodologies and supporting technical capabilities in customer environments in achieving service reuse. This paper details the key challenges in achieving service reuse, and advocates taking a pro-active position in addressing these challenges by putting in place governing key aspects of service life-cycle and supporting technical capabilities.

Journal ArticleDOI
TL;DR: This work considers that a typical electronic-layer demand requires only a fraction of the capacity of the single wavelength bandwidth and investigates a new algorithm for traffic grooming of sub-wavelength connections in an optical mesh network, relying on the knowledge of the holding time of connection requests to exploit lightpath capacity.
Abstract: Progress in network technologies and protocols is paving the road towards flexible optical transport networks, in which dynamic leasable circuits could be set up and released on a short-term basis according to customers requirements. Recently, new solutions for automated network management promise to allow customers to dinamically specify the terms of the Service Level Agreement (SLA) to be guaranteed by the service provider. Since this new information is made available, we propose to exploit the knowledge of connection holding time, among the other Service Level Specifications (SLS), to improve the routing efficiency. In this work, we consider that a typical electronic-layer (e.g., SDH or MPLS) demand requires only a fraction of the capacity of the single wavelength bandwidth and we investigate a new algorithm for traffic grooming of sub-wavelength connections in an optical mesh network. We rely on the knowledge of the holding time of connection requests to exploit lightpath capacity and hence to achieve significant reduction in blocking probability for the traffic grooming problem. Our new methodology is applied on a typical US nation-wide network and results are compared with those given by previous known approaches.

01 Jan 2008
TL;DR: This paper proposes a SOA system, named Service Level Agreement Monitor (SALMon), for monitoring and adapting SOA Systems at run time, based on monitoring the services for detecting Servicelevel Agreement (SLA) violations.
Abstract: Adaptability is a key feature of Service-Oriented-Architecture (SOA) Systems. These systems must evolve themselves in order to ensure their initial requirement as well as to satisfy arising new ones. In SOA Systems there are a lot of dependencies between services, but each service is an independent element of the system. In this situation it is necessary not only ensuring that the system fulfils its requirements but also that every system satisfies its own requirements, and dynamically adapting the system when some of them cannot be ensured. In this paper we propose a SOA system, named Service Level Agreement Monitor (SALMon), for monitoring and adapting SOA Systems at run time. SALMon is based on monitoring the services for detecting Service Level Agreement (SLA) violations. The SALMon architecture is composed of three types of components: Monitors, which are composed of measure instruments themselves; the Analyzer, which checks the SLA rules; and the Decision Maker that performs corrective actions to satisfy SLA rules again. These three types of components are mostly technology-independent and the act as service inside of a SOA system making our architecture very scalable and comfortable for its purpose.

Book ChapterDOI
01 Dec 2008
TL;DR: This paper presents the novel COmposite Sla MAnagement (COSMA) approach for an integrated management of atomic and composite SLAs during their entire lifecycle and serves as the basis for managing and optimizing the SLAs involved in composite services.
Abstract: Service provisioning is largely built on agreements specifying the mutual responsibilities of service providers and their customers with respect to functional and non-functional parameters. Current SLA management approaches, i.e. WSLA, WS-Agreement, or WSOL, provide extensive SLA language formalizations and management frameworks. However, they focus on bi-lateral service requester/provider constellations neglecting the SLA management requirements of composite service providers, i.e. managing SLAs with atomic service providers and with composite service requesters and aligning both with each other. A SLA management solution for composite services has to consider the contribution of sourced services - formalized in their (atomic) SLAs (ASLA) - in the management of the provided service - formalized in its respective (composite) SLA (CSLA). This paper presents the novel COmposite Sla MAnagement (COSMA) approach for an integrated management of atomic and composite SLAs during their entire lifecycle. It can be utilized for controlling the relationships between ASLAs/CSLAs and thus serves as the basis for managing and optimizing the SLAs involved in composite services.

13 Jun 2008
TL;DR: In this paper, an instrument for supporting organization splitting, allying and post-merger integration, consisting of organization construction rules, algorithms for calculating a plausible organization splitting proposal, a method for finding subjects for contracting split organizations, and a real-life tested combination of all this in a way of working with a known return on modeling effort (ROME).
Abstract: Organizations increasingly split off parts and start cooperating with those parts, for instance in Shared Service Centers or by using in- or outsourcing. What is the right spot and way for finding the organization split? And on what subjects should organizations agree to cooperate effectively across the organization split? To find managerial handles for this problem, we applied action research to four large real-life case-studies in which ontology and architecture were used. This resulted in an instrument for supporting organization splitting, allying and post-merger integration, consisting of (1) organization construction rules, (2) algorithms for calculating a plausible organization splitting proposal, (3) a method for finding subjects for contracting split organizations, and (4) a real-life tested combination of all this in a way of working with (5) a known Return On Modeling Effort (ROME). Future research should make this instrument more broadly applicable, more thoroughly tested and delivering faster decision-support, and it should clarify the mutual dependency of organization splitting versus ICT splitting.

Proceedings ArticleDOI
16 Mar 2008
TL;DR: This paper presents SLA monitoring and management framework for telecommunication services that is focused on the general mapping between observed activities of the underlying telecommunication infrastructure elements and corresponding SLA instance object state construction.
Abstract: This paper presents SLA monitoring and management framework for telecommunication services. The basic requirements of this class of systems are specified and verified in context of existing SLA standards and tools. The proposed system architecture is very general and may interoperate with the existing performance monitoring systems and management tools. The key design effort is focused on the general mapping between observed activities of the underlying telecommunication infrastructure elements and corresponding SLA instance object state construction. The proposed framework application is illustrated by the simple case study.

Journal ArticleDOI
TL;DR: A scheme for advancing and managing Quality of Service (QoS) attributes contained in Service Level Agreement (SLA) contracts of Grids that follow the Open Grid Services Architecture (OGSA).

Patent
08 Aug 2008
TL;DR: In this article, a network gateway application is described that provides throttling, prioritization and traffic shaping for incoming requests from client applications, and a request is received by a plug-in manager component of the gateway application.
Abstract: A network gateway application is described that provides throttling, prioritization and traffic shaping for incoming requests from client applications. A request is received by a plug-in manager component of the gateway application. The plug-in manager can then invoke the budget service in order to determine a current available budget for the request. The budget can be computed according to a service level agreement for the service provider, application or network node. The requests can be of high or low priority. If the budget is greater than a specified priority threshold value, the low priority requests can be denied, while the high priority requests can be processed as long as there is some available budget left. If the budget for the request has reached the restricted level, the request can be denied and optionally enqueued to a traffic shaping queue to be processed at a later time.

Journal ArticleDOI
14 Oct 2008
TL;DR: Between the Identity and Access Management Office (IAMO) and the designated Purdue University administrative or academic group (the Client) for the electronic distribution of Purdue University network services to the Client for purposes of identification, authentication and authorization.
Abstract: Between the Identity and Access Management Office (IAMO) and the designated Purdue University administrative or academic group (the Client) for the electronic distribution of Purdue University network services to the Client for purposes of identification, authentication and authorization.

Patent
Kirk A. Beaty1, Norman Bobroff1, Gautam Kar1, Gunjan Khanna1, Andrzej Kochut1 
22 May 2008
TL;DR: In this article, a technique for automatically managing a first set of virtual machines being hosted by a second set of physical machines comprises the following steps/operations: an alert is obtained that a service level agreement (SLA) pertaining to at least one application being hosted on one of the virtual machines in the first set.
Abstract: Techniques for dynamic management of virtual machine environments are disclosed. For example, a technique for automatically managing a first set of virtual machines being hosted by a second set of physical machines comprises the following steps/operations. An alert is obtained that a service level agreement (SLA) pertaining to at least one application being hosted by at least one of the virtual machines in the first set of virtual machines is being violated. Upon obtaining the SLA violation alert, the technique obtains at least one performance measurement for at least a portion of the machines in at least one of the first set of virtual machines and the second set of physical machines, and a cost of migration for at least a portion of the virtual machines in the first set of virtual machines. Based on the obtained performance measurements and the obtained migration costs, an optimal migration policy is determined for moving the virtual machine hosting the at least one application to another physical machine.

Proceedings ArticleDOI
14 Apr 2008
TL;DR: This paper presents an approach for computer resource allocation in such an environment that minimizes the total cost of computer resources used by a service provider for an e-business application while satisfying the quality of service (QoS) defined in an SLA.
Abstract: Resource allocation is a fundamental but challenging problem due to the complexity of cluster computing systems. In enterprise service computing, resource allocation is often associated with a service level agreement (SLA) which is a set of quality of services and a price agreed between a customer and a service provider. The SLA plays an important role in an e-business application. A service provider uses a set of computer resources to support e-business applications subject to an SLA. In this paper, we present an approach for computer resource allocation in such an environment that minimizes the total cost of computer resources used by a service provider for an e-business application while satisfying the quality of service (QoS) defined in an SLA. These QoS metrics include percentile response time, cluster utilization, packet loss rate and cluster availability. Simulation results show the applicability of the approach and validate its accuracy.

Patent
Mark Cameron Little1
26 Nov 2008
TL;DR: In this paper, a repository receives a policy enforcement point from a service-oriented architecture, and a repository manager identifies a service associated with a service level agreement that specifies the policy enforcement points.
Abstract: A repository receives a policy enforcement point. The repository is a component of a service oriented architecture. A repository manager identifies a service associated with a service level agreement that specifies the policy enforcement point. The policy enforcement point is transmitted to the service. The policy enforcement point is then installed on the service without interrupting the service.

Proceedings ArticleDOI
02 Jun 2008
TL;DR: A novel framework for a QoS-constrained resource provisioning problem is presented, and a capacity planning approach to optimizing computer resources for all service sites owned by service providers subject to multiple QoS metrics defined in the SLA and their violation penalties is proposed.
Abstract: The composition of services has been a useful approach to integrating business applications within and across organizational boundaries. In this approach, individual services are federated into composite services which are able to execute a given task subject to a service level agreement (SLA). An SLA is a contract agreed between a customer and a service provider who define a set of several quality of services (QoS). An SLA violation penalty is a way to ensure the credibility of an advertised SLA by a service provider. In this paper, we consider a set of computer resources used by a service broker who represents service providers to host enterprise applications for differentiated customer services subject to an SLA and its violation penalty. We present a novel framework for a QoS-constrained resource provisioning problem, and propose a capacity planning approach to optimizing computer resources for all service sites owned by service providers subject to multiple QoS metrics defined in the SLA and their violation penalties. Simulation results show that the proposed approach is efficient for reliable resource planning in service composition.

Proceedings ArticleDOI
13 Apr 2008
TL;DR: It is shown that it is possible to further reduce the capacity requirements of backup reprovisioning techniques exploiting the knowledge, among the other service level specifications (SLS), of the connection holding-time.
Abstract: Protection techniques for optical networks mainly rely on pre-allocated backup bandwidth, which may not be able to provide full protection guarantee when multiple failures occur in a network. To protect against multiple concurrent potential failures and to utilize the available resources more efficiently, strategies such as backup reprovisioning rearrange backups of protected connections after one failure occurs or, more generally, whenever the network state changes, e.g., when a new request arrives or terminates. Recently, new solutions for automatized management in Optical networks promise to allow customers to specify on-demand the terms of the service level agreement (SLA) to be guaranteed by the service provider. In this paper we show that is possible to further reduce the capacity requirements of backup reprovisioning techniques exploiting the knowledge, among the other service level specifications (SLS), of the connection holding-time. Our main contributions are as follows. First, we prove that the problem of backup reprovisioning for all the lightpaths requiring shared-path protection under a current network state is NP-complete. Second, we provide a mathematical ILP model of the reprovisioning problem considering the additional holding-time information. Third, since the problem is NP-complete and we can not efficiently rely on exact approaches, a new global reprovisioning algorithm called Ph-GBR is proposed which can significantly reduce the resource overbuild exploiting the information about connection durations. By means of simulative experiments, we compare capacity requirement and computational complexity of Ph-GBR to those of another holding-time unaware, yet efficient algorithm, called GBR, considering a dynamic traffic in a wavelength-convertible WDM mesh network scenario.

Proceedings ArticleDOI
07 Jul 2008
TL;DR: This paper proposes an extension to the W SLA language to capture multi-party collaborations, called WSLA+.
Abstract: The Web service level agreement (WSLA) is a Web Service specification language developed to provide a SLA template to capture all the information negotiated and agreed upon by a service provider and service consumer. Though this specification is suitable for many business-to-business collaborations involving two parties, it does not fulfil the requirement of a new business model involving multiple parties, where a party provides multiple services to other parties and consumes services provided by other parties. To address this requirement, this paper proposes an extension to the WSLA language to capture multi-party collaborations, called WSLA+.

Patent
23 Oct 2008
TL;DR: In this article, the authors present a web service management system where a service level agreement is represented ontologically and queries are provided corresponding to the policies, and then the determined policies used in the service.
Abstract: A web service management system manages a web service 12 with one or more policies. A service level agreement is represented ontologically and queries are provided corresponding to the policies. To determine which policies are required for a consumer with a specific instance of the service level agreement the queries are run against the service level agreement, and then the determined policies used in the service. An engine 26 may monitor metrics relating to the service 12 provided by a service intermediary 22 and run queries using the metrics as data to determine if the service level agreements are breached.

Journal ArticleDOI
TL;DR: It is shown that constraints and operations on them can be smoothly incorporated in COWS, and a disciplined way to model multisets of constraints and to manipulate them through appropriate interaction protocols is proposed.