By way of example, {HEAD ~ less important data} such as correspondence is transferred by {TAIL ~ packet switching} and audio data is transferred by line switching 
is transferred by
By way of example , { HEAD ~ less important data } such as correspondence is transferred by { TAIL ~ packet switching } and audio data is transferred by line switching
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH