Each of the levels of scheduling hierarchy might have {TAIL ~ one or more corresponding mapping tables} in {HEAD ~ Queue Engine} 308 
Each of the levels of scheduling hierarchy might have { TAIL ~ one or more corresponding mapping tables } in { HEAD ~ Queue Engine } 308
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH