What is the difference between a Missed Heartbeat and a Device Down?

The way the monitoring of devices work is that we send six (6) pings every 30 seconds to each device on the network. If one or more of those pings are returned, then we count this as a Heartbeat. A device can “miss” three Heartbeats without being marked as Down. If a device doesn’t return any of the pings within a two (2) minute period, then the device is marked as Down. If the device starts to respond to pings again, it gets a new Heartbeat and is marked as Up again.