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