In some cases, multiple computer systems may be connected, each residing at {HEAD ~ a node} of {TAIL ~ a network} 
In some cases , multiple computer systems may be connected , each residing at { HEAD ~ a node } of { TAIL ~ a network }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL