Dependencies are parent-child relationships between network objects that allow you to account for constraints on the network. The constraints can be the result of the design of a specific device, such as interfaces on a switch or router, or the result of the physical architecture of the network itself.
For example, when a parent object, such as a switch, goes down or becomes unresponsive all interfaces on the switch will also be unresponsive, even though they may be working.
To account for this situation, the Unreachable status is used for the interfaces, because their parent node reports as down, and their own status cannot be determined.
Enable Auto Dependencies in the Polling Settings page to create 1:1 parent-child node dependencies automatically. You can choose to ignore dependencies created this way in the Manage Dependencies view.