The switching fabric comprises a plurality of {TAIL ~ data ports} through which {HEAD ~ data frames} enter or exit the switching fabric 
through exit
The switching fabric comprises a plurality of { TAIL ~ data ports } through which { HEAD ~ data frames } enter or exit the switching fabric
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL REL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL OTH OTH OTH