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