Fundamentally the Service Level Agreement (SLA) is a contract between the IT service provider and the business customer receiving the service.
As service providers, IT organizations must demonstrate “value” to business customers. In this case, demonstrating value means delivering support services that meet or exceed the needs of the business at a cost that represents value. SLA’s help demonstrate value by clearly identifying the service responsibilities of the IT organization and performance expectations of the business customer.
In order to demonstrate “value” the IT service provider must develop an SLA that clearly defines what support services are being delivered and the level of performance required by the business customer.