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