The number of bits in each submask equates to the number of {HEAD ~ exit ports} in {TAIL ~ fabrics} 602 and 604 
in
The number of bits in each submask equates to the number of { HEAD ~ exit ports } in { TAIL ~ fabrics } 602 and 604
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH