Importantly, {TAIL ~ all node switches} share {HEAD ~ a common optical fiber} and thus interface losses are avoided 
Importantly , { TAIL ~ all node switches } share { HEAD ~ a common optical fiber } and thus interface losses are avoided
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH