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