what is ONU/OLT?

ONU is Optical Network Unit. The ONU has two functions: it selectively receives the broadcasts sent by the OLT, and responds to the OLT if it needs to receive the data; it collects and caches the Ethernet data that the user needs to send, and sends it to the OLT according to the assigned sending window. Send this cached data.

The full name of OLT is Optical Line Terminal, optical line terminal. OLT is an optical line terminal, which is the 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 for the entrance and exit of the external network and the internal network. Placed at the central office, the most important execution functions are traffic scheduling, buffer control, and providing user-oriented passive optical fiber network interfaces and allocating bandwidth. Simply put, it implements two functions. For the upstream, it completes the uplink access to the PON network; for the downstream, it sends and distributes the acquired data to all ONU user terminal devices through the ODN network.