receiving the transport control protocol acknowledgement from the terminal, wherein {HEAD ~ the received TCP acknowledgement} includes the sequence number and corresponds to {TAIL ~ a certain time} 
receiving the transport control protocol acknowledgement from the terminal , wherein { HEAD ~ the received TCP acknowledgement } includes the sequence number and corresponds to { TAIL ~ a certain time }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL