A Web Service Level Agreement (WSLA) is a standard for monitoring compliance with Service Level Agreements for Web services. Authors can specify the performance assigned to a web service application, the desired performance goals, and the actions to take if performance is not achieved. A service level agreement (SLA) is an obligation between a service provider and a customer. Particular aspects of the service – quality, availability, responsibilities – are agreed between the service provider and the service user.  The most common component of an SLA is that services must be provided to the customer as contractually agreed. For example, Internet service providers and telecommunications companies will typically include service level agreements in the terms of their contracts with customers to define the service level(s) sold in plain language. In this case, the SLA usually deconstructs a technical definition in the intermediate period between failures (MTBF), average repair time or mean recovery time (MTTR); identification of the party responsible for reporting errors or paying fees; responsibility for different data rates; throughput; Jitter; or similar measurable details. As applications are moved from dedicated hardware to the cloud, they must achieve the same or even more demanding service levels as traditional installations. SLAs for cloud services focus on data center characteristics and more recently include network features (see carrier cloud) to support end-to-end SLAs.  SLAs typically include many elements, from the definition of services to the termination of the agreement.  In order to ensure strict compliance with the AGREEMENTS, these agreements are often designed with specific dividing lines and the parties concerned must meet regularly to create an open forum for communication. The rewards and penalties applicable to the supplier are often indicated.
Most LTC also leave room for periodic (annual) audits to make changes.  Since the late 1980s, SLAs have been used by fixed operators of telecommunications companies. Today, SLAs are so prevalent that large organizations have many different SLAs in the company itself. Two different units in an organization write an SLA, one being the customer and the other the service provider. This approach helps maintain the same quality of service across different units of the organization and across multiple locations in the organization. This internal SLA scripting also makes it possible to compare the quality of service between an internal department and an external service provider.  The main point is to create a new layer on the network, cloud or SOA middleware, capable of creating a negotiation mechanism between service providers and consumers. For example, the EU-funded Framework 7 research project SLA@SOI, which investigates aspects of multi-tier, multi-vendor SLAs within service-oriented infrastructure and cloud computing, while another EU-funded project, VISION Cloud, has delivered results for content-oriented ASAs.
SLAs are running information from the Technology Infrastructure Library, but also in IT services. The abbreviation SLA comes from the English name “Service Level Agreement”, which means in Polish “Service Level Agreement”. In practice, however, in many Polish companies, the name english is used….