{TAIL ~ A traffic manager} generates {HEAD ~ a tree scheduling hierarchy} having a root scheduler and N scheduler levels 
{ TAIL ~ A traffic manager } generates { HEAD ~ a tree scheduling hierarchy } having a root scheduler and N scheduler levels
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH