Overview of OLT and its application in GPON network

OLT Overview

OLT is an optical line terminal, the core equipment of the access network, and a hardware device that can serve as the endpoint of the passive optical network.

Its main functions are: connecting to the upper network to complete the upstream access of the PON network; connecting to the user-end device ONU through ODN; realizing the control of the user device ONU and other functions, providing interfaces with the central office equipment (photoelectric conversion, physical interface);providing optical interfaces with ODN, separating different services, and managing and configuring numerous ONUs.

With the development of technology, copper wire transmission is gradually withdrawing from the market. OLT equipment is connected to the front-end (aggregation layer) switch with a network cable and converted into optical signals. As a central office, it can realize the access of home users, mobile users, and enterprise users through various network construction modes and various media. This heterogeneous access network is becoming a trend.

Currently, the common OLT types on the market include HUAWEI MA5600T, MA5800, ZTE C300, C320, and FiberHome AN5516. Taking Huawei products as an example, the following figure sorts out the single board types and differences between the MA5600T and MA5800 series.

Application of GPON

In the communication era, PON (Passive Optical Networks) consists of three parts, namely OLT (Optical Line Terminal), ODN (Optical Distribution Network) and ONU (Optical Network Unit). GPON is a PON technology that supports ultra-long transmission distances of up to 20km in physical distance and 60km in logical distance.

Due to the update and iteration of communication technology, it has evolved from the initial APON, BPON, and EPON to the current GPON. GPON is a gigabit passive optical network technology and is the most widely used mainstream optical access technology to date.

The working principle of GPON network is shown in the figure below:

Taking Huawei products as an example, the following is a list of GOPN, XGPON and XGSPON board types for your reference.