Passive Optical Networks (PON) - Commonly Used Terms & Definitions

Posted by Kevin Miller on Fri, Apr 1, 2011 @ 15:04 PM

What exactly is a PON?  What is the difference between EPON and GPON?  With passive networks becoming very prominent across the communications industry, we’ve outlined some of the most commonly used terms along with their definitions, to help readers become more familiar with this particular technology.  (If you would like to suggest additional related PON terms, feel free to comment and we will update the list accordingly)

Passive Optical Network:  A point-to-multipoint, passive fiber network architecture in which a single fiber utilizes optical splitters to serve multiple premises.


ATM PON:  The first type of PON standard, based on ATM (Asynchronous Transfer Mode) which is a protocol in telecom networking

Broadband PON:  Coming after APON, BPON supports WDM, higher upstream bandwidth, and a standard management interface that enabled shared vendor networks

Gigabit PON: Based on the previous PON types, GPON supports higher data rates and increased security, and has been deployed around the world by major telecom operators.

Ethernet PON:   EPON is part of IEEE standard Ethernet for 1/1 Gbit/s,  10/1 Gbit/s,  and 10/10 Gbit/s. With over 40 million installed EPON ports, it is the most widely deployed PON technology worldwide. Cable operators are utilizing EPON for business services as part of the DOCSIS initiative.

XG-PON:  Is a new standard from 2010 that enables the delivery of 10Gbit/s speeds using PON network architecture.  As the next generation of GPON, devices can operate on the same network as GPON devices.


Optical Distribution Network:  Refers to the optical fiber and splitters between the OLT/ONU/ONT

Optical Line Terminal: A Central Office node that is the interface between the PON and the service providers network services

Optical Network Unit: Terminates the PON and includes an interface towards the end user, such as coax, multi-service Ethernet, xDSL, etc.

Optical Network Terminal: An ITU-T term to describe a single-user case of an ONU

Network Termination Equipment:  Service interface directly used by the end user (part of the ONU/ONT)


Wavelength-Division Multiplexing: Allows for a number of optical carrier signals to be put onto a single fiber at different wavelengths, thus enabling bidirectional traffic as well as increased capacity

Monitor All Fibers for Breaks and Issues in a PON Network

Topics: PON