{TAIL ~ TCP Selective acknowledgement} may also be supported by the software to minimize {HEAD ~ retransmission data requirements} 
{ TAIL ~ TCP Selective acknowledgement } may also be supported by the software to minimize { HEAD ~ retransmission data requirements }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD