Monitored nodes send AES a health status message (HLTH0001) every two minutes. There is an agent that runs in AES that checks if health status message has been received. The server does not tell AES that it is going down when it is crashing - AES does not receive health status message and assumes the server has gone down.
Health status messages are persisted to class PegaAES-Data-NodeStats. Agent maintains the most recent node health state in class PegaAES-Data-NodeHealth. The AES dashboard data is in class PegaAES-Data-Indicator.