I am trying to monitor an interface to insure it is running OK. There are two things that I am trying to get to work.
I have set up two health tags for the interface: "Device Status" and "Heartbeat"
In notifications I have set up a trigger that alarms if "Device Status" <> "Good". This seems to work.
The other thing I am trying to get setup is if the heartbeat become stale. To do this I have created a PE tag that I will us in notifications, it looks like like this:
prevval('heartbeat', '*') = 'heartbeat'
The PE is schedule to execute every 30 seconds.
My PE is not working, it is always returning 1, so I must be missing something. It seems like the previous value should never equal the current value.
Any help would be appreciated. Also if there are any suggestions on a better way to do this I'm open to ideas, I a novice when it comes to working with interface health points.