The ingress module is configured to receive data from {HEAD ~ the ONU} over {TAIL ~ the optical line} 
over
The ingress module is configured to receive data from { HEAD ~ the ONU } over { TAIL ~ the optical line }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL