First Olt is the optical line terminal, ONU is the Optical Network Unit (ONU), they are all optical transmission network connection devices. is a prerequisite in PON two modules: Pon (Passive optical Network: Passive optical network). PON (passive optical network) means (optical wiring network) does not contain any electronic devices and electronic power supply, ODN all by optical splitter (Splitter) and other passive components, do not need valuable active electronic equipment. A passive optical network includes a light path terminal (OLT) mounted at a central control station and a set of optical network units (ONUS) installed at a user site at a level. The optical Wiring Network (ODN) between the Olt and the ONU comprises a fiber optic and a passive optical splitter or coupler.
Routers and switches are data exchange devices.
Router (Router) is the main node device of the Internet. Routers determine the forwarding of data through routing. Forwarding policy is called routing selection (routing), which is also the origin of router names (router, forwards). As the hub of interconnection between different networks, the router system constitutes the main thread of Internet based on TCP/IP, and it can be said that routers form the backbone of Internet. Its processing speed is one of the main bottlenecks of network communication, and its reliability directly affects the quality of network interconnection.
Switch (English: switch) is a network device used for electrical signal forwarding. It provides an exclusive electrical signal path for any two network nodes connected to the switch. The most common switch is the Ethernet switch. Other common telephone voice switches, fiber switches and so on.
The main functions of the switch include physical address, network topology, error checking, frame sequence and flow control. At present, the switch also has some new features, such as VLAN (virtual LAN) support, link aggregation support, and even some of the firewall features.