I found out that the AllSeen ControlPanel device (the device) will keep alive and response at the AllSeen router (the router) even though the device already shut down and power off.
I called it dead body. (zombie?)
Now, in my ControlPanelController App (the App), I used a timed out trick to decide the device is dead or alive. That is because the response time of a dead body will lag over 30+ seconds.
By the way, the SessionLost signal of each dead body will lag over 5+ minutes.
How to get the alive status of a ControlPanel device in quickly by AllSeen framework API? (alljoyn 14.02)