Description GPON (Gigabit‐capable Passive Optical Network) OLT is the “head‐end” device at the telecom/ISP side that connects into the passive optical access network and serves many customer ONUs/ONTs (Optical Network Units/Terminals). In a typical FTTH (Fiber to the Home) scenario, the OLT transmits downstream data (from the network to users) and receives upstream data (from users back to the network) over a passive split‐fiber plant.The OLT handles service provisioning, traffic control, bandwidth management, authentication of ONUs, QoS, VLANs, etc.