Who will/can remove old/unnecessary
entries in a child table. When a sleepy end device executes
emberNetworkLeave(), will the stack of its parent router node remove
the entry for the device in the child table automatically? If the end
device is gone without emberNetworkLeave(), will the parent node keep
the entry forever or discard it with time-out?
Or can/must the application program on the parent router node remove
old/unnecessary entries in a child table?