Uptime is also a common metric that is often used for data services such as shared hosting, virtual private servers and dedicated servers. General agreements include network availability percentage, operating time, number of planned maintenance windows, etc. A. Keller, G. Kar, H. Ludwig, A. Dan and J. L. Hellerstein, Managing Dynamic Services: A contract based approach to a conceptual architecture.

To R. Stadler and M. Ulema, eds. Proceedings of the Eighth IEEE/IFIP Network Operations and Management Symposium (NOMS 2002), Florence, Italy, IEEE Publishing, 513-528, April 2002. The main point is to create a new level for the grid, cloud or SOA middleware, capable of creating a trading mechanism between service providers and consumers. For example, the EU-funded Framework SLA@SOI 7 research project[12]explores aspects of multi-level, multi-supplier slas within service-based infrastructure and cloud computing, while another EU-funded project, VISION Cloud[13], has delivered results in terms of content-based ALS. We describe a new framework for defining and tracking service level agreements (ALS) for web services. Monitoring and implementation of ALS is increasingly important in a web environment where applications and business services depend on services that are dynamically and responsively subscribed. For economic and practical reasons, we want an automated deployment process for both the service itself and the SLA management system, which measures and controls QoS parameters, verifies agreed service levels and reports violations to authorized parties involved in the ALS management process. Our approach to these issues is presented in this paper. The WSLA (Web Service Level Agreement) framework aims to define and monitor ALS for web services. Although WSLA was designed for a web service environment, it also applies to all multi-domain management scenarios.

B to managing business processes and services or managing networks, systems and applications in general. The WSLA framework consists of a flexible and expandable language, based on an XML scheme, and an execution architecture consisting of several SLA monitoring services that can be outsourced to third parties to ensure maximum objectivity. WSLA allows service customers and providers to clearly define a large number of ALSs, identify ALS parameters and their measurement, and link them to managed resource tools. After receiving an SLA specification, WSLA monitoring services are automatically configured to force ALS. The implementation of the WSLA framework, called the SLA Compliance Monitor, is available to the public as part of IBM Web Services` toolkit. Customers can create common metrics with multiple service providers that take into account the multi-supplier impact and impact the creditor may have on processes that are not considered to be in compliance with the contract. The ALS should contain not only a description of the services to be provided and their expected levels of service, but also metrics to measure the services, obligations and responsibilities of each party, corrective measures or penalties in the event of a breach, and a protocol for adding and removing measures. This last point is crucial. Service requirements and supplier functions are changing, so it is necessary to ensure that ALS is kept up to date. Service elements include the specifics of the services provided (and what is excluded if in doubt), the conditions of availability of services, standards as well as slots for each level. B service (e.g., prime time and non-prime time) may have different levels of service, responsibilities of each party, escalating procedures and compromise costs/services.

IT outsourcing agreements, in which the remuneration of service providers is linked to the results obtained, have gained popularity, with companies developing from time and pure materials or full-time price models.