{HEAD ~ The control portion} may also contain {TAIL ~ control parameters} for each specific component along the transmit or receive path to coordinate the processing of the packets 
contain
{ HEAD ~ The control portion } may also contain { TAIL ~ control parameters } for each specific component along the transmit or receive path to coordinate the processing of the packets
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH