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Failover is the process of switching network traffic to a backup path when the main connection fails. An industrial router at a remote pumping station normally uses a wired Ethernet connection. If that line goes down, failover switches to a 4G cellular backup automatically – without anyone touching anything.
The switch should happen before the site loses connectivity, not after. Routers monitor the active WAN connection continuously via ping tests or keepalive signals and switch proactively when performance degrades.
- Trigger conditions – signal strength below threshold, failed ping to a target IP, data connection error, data cap hit
- Failback – return to primary connection automatically after it recovers (with configurable delay to avoid flapping)
- Idle SIM protection – secondary SIM stays registered, enabling near-instant switch rather than full re-registration
- Multi-path priority – configure Ethernet WAN → SIM1 → SIM2 as a priority chain