During normal inline fail-open operation of the Sensor, the Control port on the Sensor supplies power and a heartbeat packet to the Fail-Open switch. If this signal is not sent to the Fail-Open switch within the 3-millisecond interval, the Fail-Open switch removes the Sensor from the data path and moves into Bypass Mode, providing continuous data flow with little network interruption.
While the Fail-Open switch is in bypass mode, traffic passes directly through it, bypassing the Sensor.
When normal Sensor operation resumes, you may or may not need to manually re-enable the monitoring ports from the Manager interface, depending on the activity leading up to the Sensor's failure.
The following section describes how to return the Sensor to inline mode: