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ONU vs OLT - What is ONU and OLT?

Uploaded2024/4/7 21:18:51     Hits    Source

ONU and OLT are both optical transmission network connection equipment.OLT is an optical line terminal, and ONU is an optical network unit (ONU). There are many types of ONU and OLT, and usually users are concerned about their speed and usage. From this article you can learn What is ONU and OLT, What ONU and OLT Used for and relationship between onu vs olt.Click here for a variety of OLT and ONU products.

1.What Is OLT?

OLT means Optical Line Terminal. OLT is used to connect to the optical fiber trunk line. It functions as a switch or router in a traditional communication network. The most important execution functions are traffic scheduling, buffer control, and providing user-oriented passive optical network interfaces and allocating broadband.

Simply, it is to realize two functions. For the upstream, it completes the upstream access of the PON network; for the downstream, it sends the obtained data through the ODN network and distributes it to all ONU user terminal equipment.

1.1 What Are OLT Used for?



Take Baudcom 4 ports EPON OLT as an example.

The EPON OLT has 4*EPON ports for downstream, 4*GE ports for uplink, 4 *SFP slots for uplink, supports EMS/CONSOLE/WEB management.

(1)PON port:

The PON ports are connected to a optical fiber splitter, and each PON port is connected to one optical fiber splitter. If we use 1:64 optical fiber splitter, then one EPON port can be connected to 64 ONU, which means that this 4 ports EPON OLT can connect 256 ONU. One GPON port can connect up to 128 GPON ONU, and one EPON port can connect up to 64 EPON ONU.

(2)Uplink port:

Mainly connected to the Ethernet switch. GE uplink ports connect to the switch with Ethernet cables; and SFP uplink slots connect to the switch with optical fiber cables. The optical SFP module needs to be purchased separately.

(3)Console port:

Centralized network management platform. Network element management, security management and configuration management can be realized on the OLT. It can not only monitor and manage devices and ports, but also enable service provisioning and user status monitoring, and can also allocate broadband according to the QoS/SLA requirements of different users.

2.What Is ONU?

ONU means Optical Network Unit, divided into active optical network unit and passive optical network unit.

The ONU has two functions: selectively receive the broadcast sent by the OLT, and respond to OLT when receiving; collect and cache the Ethernet data that the user needs to send, and send the buffered data to the OLT according to the allocated sending window.

In the FTTx network, under different deployments, ONU access methods are also different, such as FTTC (Fiber To The Curb): ONU is placed in the central computer room of the community; FTTB (Fiber To The Building): ONU is placed in the junction box of the corridor; FTTH (Fiber To The Home): The ONU is placed in the home user. By the way, in the FTTH network, ONU is also called ONT(Optical Network Terminal)

2.1What Are ONU Used for?



Take Baudcom dual band wifi GPON ONU as an example.

1.RF/CATV port: connect cable TV

2.Power port

3.USB port: Usually USB 2.0 interface

4.LAN port: FE (10/100BASE-T), GE (10/100/1000BASE-T) optional

5.Phone port: also known as POT, VOIP, Voice, FXS

6.Optical port: connect ODN

7.Antenna: Provide WiFi, 2.4G WiFi or dual band 2.4G/5G WiFi

3.What Is the relationship between ONU And OLT?

The OLT is the management terminal, and the ONU is the terminal; the service provisioning of the ONU is issued through the OLT, and the onu/olt are in a master-slave relationship. Multiple ONU can be connected to one OLT through an optical fiber splitter.

relationship between ONU and OLT

4.What Is ODN?

ODN is Optical Distribution Network, which is the optical transmission channel between OLT And ONU. The main function is to complete the two-way transmission of optical signals, usually composed of optical fiber cables, optical fiber connectors, optical fiber splitters and supporting equipment for installing and connecting, the most important part of which is the optical fiber splitter.


ONU and OLT are indispensable components in the GPON network system. If you are considering to purchase the ONU and OLT devices, Consult us, We have Professional technology and personnel to provide you with Solutions.


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