Service Level Agreement
A set of guarantees which an ISP contractually commits to with the end user. A SLA typically guarantees uptime, also called port availability or availability, latency, and packet loss. With the recent popularity of VoIP, a fourth metric is emerging on many SLAs which is jitter. If a carrier fails to meet specified SLA metrics in given period, the user has certain recourse available often in the form of credits to their account. Carriers will usually set a cap on the amount of SLA credits a user can be granted in any given month. This cap is normally one week or ten days worth of pro-rated service credits. To counter the ceiling, some SLAs will give the user a termination clause that allows them to cancel service without penalty should SLA performance be considerable and repetitive. SLA credits and termination clauses will be clearly defined within an SLA and the carrier will rarely vary from the agreed upon SLA in a credit issue or termination situation.
