In the illustrated embodiment, {HEAD ~ the least significant bit} of {TAIL ~ each submask} corresponds to port of exit 634, and the most significant bit corresponds to port of exit 646 
In the illustrated embodiment , { HEAD ~ the least significant bit } of { TAIL ~ each submask } corresponds to port of exit 634 , and the most significant bit corresponds to port of exit 646
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH