A web service level agreement (WSLA) is a standard for monitoring compliance with web services according to the service level agreement. It allows authors to indicate performance metrics assigned to a web application, desired performance goals, and actions to perform if performance is not achieved. Service level agreements are also defined at different levels: it is not uncommon for a basic internet service provider (or network service provider) to explicitly state its own ALS on its website.   The U.S. Telecommunications Act of 1996 does not specifically require companies to have ALS, but it does provide a framework for companies to do so in Sections 251 and 252.  Section 252 (c) (1) (“Duty to Negotiate”) obliges z.B. established local exchange operators (CIDs) to negotiate in good faith matters such as the sale of dentes` and access to whistleblowing channels. 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 projectexplores aspects of multi-level, multi-supplier slas within service-based infrastructure and cloud computing, while another EU-funded project, VISION Cloud, has delivered results in terms of content-based ALS. SLAs often include many elements, from the definition of services to the termination of the contract.
 In order to ensure rigorous compliance with ALS, these agreements are often designed with specific lines of demarcation and the parties concerned must meet regularly to create an open communication forum. Rewards and penalties that apply to the supplier are often set. Most ALS also leave room for regular (annual) revisions to make changes.  Since the late 1980s, ALS has been used by fixed-line operators. Today, ALS is so widespread that large organizations have many different ALSs within the company itself. Two different units in an organization script an ALS, one unit being the customer and another the service provider. This helps maintain the same quality of service between different units of the organization and in several sites within the organization. This internal ALS script also compares the quality of service between an internal service and an external service provider.  As applications are moved from dedicated hardware to the cloud, they must reach the same level of service, or even more sophisticated than conventional installations. SLAs for cloud services focus on data center features and more recently include network features (see Carrier`s Cloud) to support end-to-end SLAs.
 The fundamental advantage of cloud computing is the joint use of resources that are supported by the underlying nature of a common infrastructure environment.