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