I think the question is about failure of revenue ports and not HA links. In this case, both devices will realize the failure. The devices will get into a non-functional loop as described below. One of the device will remain active. A non-functional loop is when both devices in an HA pair have link or path monitoring failures that are not detectible while in non-functional state. This happens when the link state on passive device is set to shutdown in layer 3 mode. The link state on the passive device is always shutdown in vwire and layer2 deployments. If device in HA cluster starts in active state, detects a link or path down and it changes state to non-functional. The peer device at this time will go active. The non-functional device will remain in this state for monitor-fail-holddown time and change state to passive. The active device upon seeing the peer device as passive will change to non-functional because of the link failure. At this point, if monitoring fails again, the device gets into a loop to repeat the active ->non-functional ->passive->active transitions. This state transitions are referred to as flaps. The device will remain in the suspended state even if the link or path connectivity is restored. The default number of flaps is 3. A value of “0” means infinite flaps. The maximum number of flaps defined will have to happen within 15 minutes after which the device enters suspended state. Once the device enters the suspended state, it requires user intervention to transition to functional state. This is accomplished by using the operational command “request high-availability state functional “.
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