This has the advantage that {TAIL ~ data} can be transferred simultaneously by {HEAD ~ packet switching} and line switching 
This has the advantage that { TAIL ~ data } can be transferred simultaneously by { HEAD ~ packet switching } and line switching
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH