An active fail-open switch sends control signals or heartbeat signals to the Sensor to determine its operational state. Active fail-open switches are faster than passive fail-open switches in its transition from normal mode to bypass mode during a Sensor outage.
An active fiber fail-open switch sends a heartbeat signal to the Sensor. This signal returns to the fail-open switch during normal operation. If the fail-open switch does not receive a response, it transitions to bypass mode thereby removing the Sensor from the path of traffic.
During normal operation, the bypass status of the switch remains OFF. To confirm this, you must see the OFF LED on the switch lit up. When the Sensor fails or reboots, bypass status changes to ON, which is indicated by the ON LED coming on. When the fail-open switch is in bypass mode, there is no traffic monitoring by the Sensor.
Note
Active fail-open kits are not compatible with NS3500 Sensors.