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, all monitored objects behind an edge router are dependent on that router for connectivity. If the router has problems or goes down, any dependent devices will also appear to have problems, and you will receive status alerts about those devices as well.

However, if you define those nodes as being dependent on the edge router, you will not get false alerts about the status of dependent nodes when the parent object has issues.

When you use dependencies, consider the following:

• Dependencies themselves do not prevent alerts from being triggered. Instead, dependencies display the child objects as Unreachable instead of Down, and as a result, down node alerts are not triggered. By using dependencies, status alerts are prevented from triggering, but all other alerts are triggered.
• A child object can have several parents, and the child's status only turns to Unreachable if all parents in all defined dependencies go down.

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.