develop {HEAD ~ a response message} to be sent to the first computer over {TAIL ~ the communications link} advising the first computer of a successful or unsuccessful receipt of the communications packet, and 
to be sent over
develop { HEAD ~ a response message } to be sent to the first computer over { TAIL ~ the communications link } advising the first computer of a successful or unsuccessful receipt of the communications packet , and
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH