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What is OLT ONU ODN ONT for optical access network?

Views: 399     Author: Krystal     Publish Time: 2021-07-29      Origin: Site

Optical access network is the optical transmission medium access network, instead of copper wire, used for access to every home.Optical access network An optical access network generally consists of three parts: optical line terminal OLT, optical network unit ONU, and optical distribution network ODN. The OLT and ONU are the core components of the optical access network.

What is the OLT?

OLT is an Optical Line Terminal. It is an office-end device of telecommunications. It is used to connect Optical trunk linesPlaced in the office, the most important execution functions are traffic scheduling, buffer control, and the provision of user-oriented passive fiber network interface and bandwidth allocation.Downstream, the obtained data is sent to all ONU user terminals through ODN.

What is the ONU?

The ONU is an Optical Network Unit.The ONU has two functions: selectively receives broadcasts sent by the OLT. If the data needs to be received, it needs to respond to the OLT.The Ethernet data that needs To be sent by The user is collected and cached, and The cached data is sent To The OLT end according To The allocated transmission window. Different deployments of The FTTx network have different access modes. For example, Fiber To The Curb (FTTC):The ONU is placed in The central machine room of The cell.FTTB(Fiber To The Building): The junction box where The ONU is placed in The corridor;FTTH(Fiber To The Home): The ONU is placed in The Home user.

What is ONT?

ONT is an Optical Network Terminal and the Terminal unit of FTTH.Similar to xDSL, an ONT is an optical network terminal that is applied to the end user, while an ONU is an optical network unit that may be part of other networks between the end user and an ONT.

What is the relationship between ONU and OLT?

OLT is the management end, and ONU is the terminal.ONU services are delivered through OLTS. The two services are in a primary-to-secondary relationship. Multiple ONUs can be connected to an OLT through an optical splitter.

What is the ODN?

ODN is an Optical Distribution Network. The ODN is an FTTH Optical cable Network based on PON devices. It is a physical channel for Optical transmission between OLT and ONU and is mainly used for bidirectional transmission of Optical signalsOptical splitter and the installation and connection of these devices of supporting equipment, among which the most important component is optical splitter.

In terms of function,ODN from the office end to the client can be divided into four parts: feeder cable subsystem, distribution cable subsystem, entry line cable subsystem and optical fiber terminal subsystem.


In the development of FTTx, access layer needs to build a huge new fiber optic distribution network, namely ODN network.

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