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