What is a service-level agreement (SLA) for network connectivity?

A service-level agreement (SLA) is a contracted agreement between the Internet service provider (ISP) and the customer. This agreement defines the level of service. SLAs are based on uptime, quality of service, bandwidth, and any other stipulations the customer might deem necessary. Uptime is usually the most important when shopping for a provider. SLAs are not exclusive to ISPs and their customers; anywhere there is a service that requires uptime, an SLA can be found.