10G-PON (also known as XG-PON or G.987) is a 2010 computer networking standard for data links, capable of delivering shared Internet access rates up to 10 Gbit/s (gigabits per second) over dark fiber.
[1] Passive optical networks are used for the fibre-to-the-home or fibre-to-the-premises last mile with splitters that connect each central transmitter to many subscribers.
An optical network terminal (ONT) is an ONU that functions as a demarcation point servicing a single subscriber; e.g., a dwelling or office.
ONU devices supply Ethernet and possibly other services to the users, either directly (by bridging) or through a gateway device such as a residential gateway, firewall, and/or router, POTS, CATV signals to buildings wired for RF video, and some may even be compatible with the emerging G.hn home networking standard.
The ONU receives the downstream data from the Internet or private networks, and also uses time slots allocated by the OLT to send the upstream traffic in burst-mode.
TDMA time slots prevent collisions with upstream traffic from other users sharing the same physical PON.
The OLT (optical line terminal) connects the PON to aggregated backhaul uplinks, allocates time slots for ONUs and ONTs to transmit upstream data, and transmits shared downstream data in broadcast-mode over the PON to users.
Locating OLTs in outside plant cabinets may be an option for reach extension as a way to minimise the number of central offices covering low population density areas.
"An Optical Distribution Network (ODN) being installed today will likely need to support four or more generations of PON over its expected 30 – 40 year life...