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