The optical access network is an access network that uses light as the transmission medium, instead of copper wires, and is used to access every household. Optical access network. Optical access network generally consists of three parts: optical line terminal OLT, optical network unit ONU, optical distribution network ODN, among which OLT and ONU are the core components of optical access network.
What is OLT?
The full name of OLT is Optical Line Terminal, optical line terminal. The OLT is an optical line terminal and a central office equipment of telecommunications. It is used to connect optical fiber trunk lines. It functions as a switch or router in a traditional communication network. It is a device at the entrance of the external network and the entrance of the internal network. Placed at the central office, the most important executive functions are traffic scheduling, buffer control, and provision of user-oriented passive optical network interfaces and bandwidth allocation. To put it simply, it is to achieve two functions. For the upstream, it completes the upstream access of the PON network; for the downstream, the acquired data is sent and distributed to all ONU user terminal devices through the ODN network.
What is ONU?
ONU is Optical Network Unit. The ONU has two functions: it selectively receives the broadcast sent by the OLT, and responds to the OLT if the data needs to be received; collects and buffers the Ethernet data that the user needs to send, and sends it to the OLT according to the assigned sending window Send the cached data.
In the FTTx network , different deployment 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 corridor FTTH (Fiber To The Home): ONU is placed in the home user.
What is ONT?
ONT is the Optical Network Terminal, the most terminal unit of FTTH, commonly known as “optical modem”, which is similar to the electric modem of xDSL. ONT is an optical network terminal, which is applied to the end user, while ONU refers to the optical network unit, and there may be other networks between it and the end user. ONT is an integral part of ONU.
What is the relationship between ONU and OLT?
The OLT is the management terminal, and the ONU is the terminal; the service activation of the ONU is issued through the OLT, and the two are in a master-slave relationship. Multiple ONUs can be connected to one OLT through the splitter.
What is ODN?
ODN is Optical Distribution Network, optical distribution network, is the optical transmission physical channel between OLT and ONU, the main function is to complete the two-way transmission of optical signals, usually by optical fiber cables, optical connectors, optical splitters and installation to connect these The component of the device’s supporting equipment, the most important component is the optical splitter.
Post time: Oct-15-2021