The receipt and processing of the communication packet may be acknowledged by {TAIL ~ the central controller} to {HEAD ~ computer}  
The receipt and processing of the communication packet may be acknowledged by { TAIL ~ the central controller } to { HEAD ~ computer }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH