A leased line provides a dedicated connection with higher reliability and an SLA similar to fiber. It's often used as a backup for critically important services such as high-availability online retail systems, providing a suitable level of redundancy. While a DSL connection is widely used, its uptime and speed may be insufficient for a commercial operation as a backup for a fiber connection in case of an outage. Satellite can experience latency and disruptions due to weather, which is not ideal for backup purposes with high uptime demands. Similarly, a cable connection, though typically reliable, shares bandwidth with other users and doesn't always offer the level of SLA that a leased line would.