The OLT restarts communication with {HEAD ~ the ONU} over {TAIL ~ the optical line} upon receipt of data traffic for the ONU 
over
The OLT restarts communication with { HEAD ~ the ONU } over { TAIL ~ the optical line } upon receipt of data traffic for the ONU
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH