If you have adopted the NetMonitor agent for monitoring ping time and have upgraded to Foglight 5.5.8 or higher, check out the custom dashboard cartridge for NetMonitor: Custom Dashboards for Device Availability metrics captured by the NetMonitor agent
Hopefully you'll find these views useful for visualizing device availability in your environment.
Please feel free to mark this thread 'Answered' if your original question has been resolved to your satisfaction.
The link to this article is now available, do we still have this agent available
We do have rule (Ping Response Time Check) in newer NetMonitor cartridge can alert you this