Concept
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 existing dark fiber. This is the ITU-T's next generation standard following on from GPON or Gigabit-capable PON. Optical fibre is shared by many subscribers in a network known as FTTx in a way that centralises most of the telecommunications equipment, often displacing copper phone lines that connect premises to the phone exchange. Passive optical network (PON) architecture has become a cost-effective way to meet performance demands in access networks, and sometimes also in large optical local networks for "Fibre-to-the-desk". 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. The 10 Gbit/s shared capacity is the downstream speed broadcast to all users connected to the same PON, and the 2.5 Gbit/s upstream speed uses multiplexing techniques to prevent data frames from interfering with each other. Users have a network device that converts optical signals to the signals used in building wiring, such as Ethernet and wired analogue plain old telephone service. XGS-PON is a related technology that can deliver upstream and downstream (symmetrical) speeds of up to 10 Gbit/s (gigabits per second), first approved in 2016 as G.9807.1. ITU-T G.987 is the standard for 10G-PON. Asymmetric 10G-PON is specified as XG-PON1: 10 Gbit/s downstream and 2.5 Gbit/s upstream (nominal line rate of 9.95328 Gbit/s downstream and 2.48832 Gbit/s upstream). Symmetric 10G-PON is also proposed as XG-PON2 with 10 Gbit/s upstream, but would require more expensive burst-mode lasers on optical network terminals (ONTs) to deliver the upstream transmission speed. Another symmetric 10G-PON standard is XGS-PON (ITU-T G.9807.1, approved 2016-06-22).