The ONU improves cost and energy efficiency for the PON by entering a sleep mode that disables communication with {HEAD ~ the OLT} to reduce {TAIL ~ energy consumption} when the ONU is idle 
to reduce
The ONU improves cost and energy efficiency for the PON by entering a sleep mode that disables communication with { HEAD ~ the OLT } to reduce { TAIL ~ energy consumption } when the ONU is idle
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH