The controller sends a notification to the agent when the file updates are retrieved, and the agent retrieves {HEAD ~ the file} updates from {TAIL ~ the controller} 
updates from
The controller sends a notification to the agent when the file updates are retrieved , and the agent retrieves { HEAD ~ the file } updates from { TAIL ~ the controller }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL