The blocking time interval is preferably greater than {HEAD ~ the round trip propagation time} for {TAIL ~ a message packet} 
The blocking time interval is preferably greater than { HEAD ~ the round trip propagation time } for { TAIL ~ a message packet }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL