What is Service Level Agreement? (SLA)
A service level agreement (SLA) is a contract between a network service provider and a client that specifies, usually in measurable terms, what the service provider’s network services provide. Many Internet service providers (ISP)s provide their customers with a Service Level Agreement. More recently, the information system departments in large companies have embraced the idea of writing a service level agreement for the services to their customers (users in other departments within the company) can be measured, justified, and such time compared with those of outsourcing network providers.

Some indicators that SLA can specify are:
* What percentage of time that services are available
* The number of users that can serve both
* Performance indicators specific to the actual performance will be regularly compared
* The schedule for notification in advance of network changes that may affect users
* Help desk response time for the various classes of problems
* Availability of dial-in access
* Using the statistics provided