Connected to the server. For ESX Server, this is always the setting.
The user has explicitly taken the host down. VirtualCenter does not expect to
receive heartbeats from the host. The next time a heartbeat is received, the
host is moved to the connected state again and an event is logged.
VirtualCenter is not receiving heartbeats from the server. The state
automatically changes to connected once heartbeats are received
again. This state is typically used to trigger an alarm on the host.