GPON (Gigabit Passive Optical Network)

What It Means

GPON (Gigabit-capable Passive Optical Network) is the ITU-T G.984 standard that underpins the majority of FTTH deployments in the United States, including AT&T Fiber, Verizon Fios, Google Fiber, Frontier Fiber, and most municipal and rural fiber networks. A GPON deployment starts with an Optical Line Terminal (OLT) at the ISP's central office or regional headend, which drives a single-mode fiber out to an Optical Splitter located in a neighborhood cabinet. The passive splitter divides the optical signal across up to 32, 64, or 128 homes (common split ratios are 1:32), each of which terminates in an Optical Network Terminal (ONT) on the customer's premise. GPON provides a total of 2.488 Gbps downstream and 1.244 Gbps upstream shared across all homes on a splitter, though real-world per-home speeds typically reach 900 Mbps to 1 Gbps symmetrical because customers rarely utilize bandwidth simultaneously. XGS-PON, the next-generation standard ratified in 2016, operates at 10 Gbps symmetrical and is being deployed by AT&T, Frontier, and others for new builds. 25G-PON and 50G-PON are already in ITU-T standards pipelines. GPON is capital-efficient because passive splitters require no power, no cooling, and virtually no maintenance. For the Broadband Grade, any GPON or XGS-PON deployment counts as fiber availability (20% of the grade), typically moving a ZIP code from C to A grade territory.

Frequently Asked Questions