The web Service MEDiator system (WSMED) provides general query capabilities over data accessible through web services by reading WSDL meta-data descriptions. Based on imported meta-data, the user can define views that extract data from the results of calls to web service operations. The views can be queried using SQL. The views are specified in terms of declarative queries that access different...

With Grid computing adopting Service Oriented Architecture (SOA), resources are represented by services with standardized interfaces and the management of resources converges to the more general management of services (i.e. the Service Level Management). The key to Service Level Management is the management of Service Level Agreement (SLA), a formal contract between the provider and consumer of...

SLA is a negotiated agreement between a customer and the service provider on levels of service characteristics and the associated set of metrics. In this paper, we propose a policy-based SLA management system. We present an approach to react not only when an SLA is violated, but also before imminent SLA violations. We provide a common generic framework capable of components to interwork via XML...

The aim of this paper is to introduce and present the main drivers and basic concepts for SLA management. We discuss the business requirements according to two points of view: the Customer and the Service Provider, and we go into more detail on the technical requirements for both the SLA contract itself and the SLA Management system. Finally, we give an overview of SLA management open issues in...

This paper describes a hierarchical architecture of active policies [1] that performs the management of a differentiated services (DiffServ) network. These policies monitor quality of service (QoS) parameters and dynamically optimize some aspects of the existing equipment and services to provide the best possible QoS to users. This helps the enforcement of Service Level Agreements (SLA) between...

Service Level Agreements require a monitoring system that checks that no party violates the agreement. Current monitoring techniques either have a high performance overhead or are not reliable enough. This paper proposes a new theoretical hybrid monitoring system that we call reactive monitoring. It tries to balance the disadvantages of established monitoring techniques, in particular online an...

In On Demand Service environments, both a client and a service provider need to make sure of their common agreements on the quality of service (QoS), i.e., performance, reliability and availability, prior to accessing a managed service. This is due to the fact that varied and customized requests of individual clients may not always match the QoS supported by an autonomous service. To mitigate s...

In practice, call center service levels are reported over periods of œnite length that are usually no longer than 24 hours. In such small periods the service level has a large variability. It is therefore not su£cient to base sta£ng decisions only on the expected value of the service level. In this paper we consider the classicalM/M/s queueing model that is o en used in call centers. We develop...

1.1 General In the paper for CMG99, author described an approach to automated service level reporting (Literature, 1). During the conference, a number of requests to “elaborate” on the experience of implementing such a system were received. A CMG99 Referee made the same request. In this paper, attempt is made to do just that. The paper tried to emphasize the general nature of the described syst...

In a previous column, I discussed how to build distributed systems from quality-of-service (QoS)-aware software components.1 I also described a design by which individual components can engage in QoS negotiation and perform admission control so that new incoming requests don’t violate committed QoS requirements.2 But what happens in a distributed application made up of several QoS-aware compone...