What mechanism in 3CX ensures that services remain available despite a primary system failure?

The mechanism that ensures services remain available despite a primary system failure is failover. Failover is a critical feature that automatically transfers operations to a standby system or backup component when the primary system encounters an issue. This process minimizes downtime and ensures continuity of service, which is essential in maintaining reliable communications within an organization. By having a failover system in place, businesses can safeguard against unexpected interruptions, thereby enhancing the overall resilience of their communication infrastructure.

The other options mentioned, such as parking orbit, user group management, and conference setup, serve different functions within a telephony system. Parking orbit allows calls to be placed on hold in a virtual space until they can be retrieved, user group management organizes users for effective communication, and conference setup facilitates group calls. While important, these functions do not relate to maintaining service availability during system failures like failover does.