What’s the difference between ONU, Router and Switch?

By Damon Watson |

28

February 2023 |

1

Comments

The Internet has become an indispensable thing in our life. As the carrier of the network, what’s the difference among ONU, router and Switch? How can we distinguish them? In this article, we will answer these questions.

At first, let’s get to know what ONU, router and switch are.
 

Part I. What are ONU, router and switch?

ONU (Optical Network Unit) is also called optical modem, which is a device similar to the baseband modem. But the difference is ONU accesses optical fiber. It converts the digital signal into analog signal through modulation at the transmitting end and transmits the analog signal into digital signal.
 

Electronic signals are divided into analog and digital signals. Telephone transmission adopts analog signals and PCs transmit digital signals. Therefore, ONU is used to modulate the signals if the computer connects to the Internet through the telephone line.

Router is a gateway that connects two or multiple networks, which can read the address in each packet and decide how to transmit it. Router can understand different protocols such as the Ethernet protocol used by LAN or the TCP/IP protocol used by the Internet. In this way, the router can convert the addresses of non-TCP/IP networks into TCP/IP addresses by analyzing the destination addresses of packets from various networks. Then, it will send the packets to the designated location according to the best route chosen. Thus, the router can connect non-TCP/IP networks to the Internet.
 

The switch is a device used for transmitting electronic or optical signals. It’s capable of providing an exclusive electrical signal path for any two network nodes of the access switch. There are Ethernet switch, telephone voice switch, fiber optical switch, etc.

Part II. The difference between ONU, router and switch

Although ONU, router and switch are used for the Internet, there are different applications. Generally, the analog signal transmitted by the network cable is converted into a digital signal through the ONU. Then, the router forwards the signal to the PC. When the number of PC exceeds the number of routers that can connect, a switch needs to be added to expand the interface.

is generally applied in FTTH. It mainly helps the computer connects to the Internet via converting the signal of the telephone line to that of the network cable.

works on the network layer of LAN. It can access the Internet by virtual dial-up with a cable connecting to multiple computers. All computers share one broadband account, which makes the Internet affect each other.

achieves simultaneous Internet access through connecting multiple computers with a cable. Each computer has its own broadband account so there is no influence among them.

is generally applied in FTTH. It mainly helps the computer connects to the Internet via converting the signal of the telephone line to that of the network cable.works on the network layer of LAN. It can access the Internet by virtual dial-up with a cable connecting to multiple computers. All computers share one broadband account, which makes the Internet affect each other.achieves simultaneous Internet access through connecting multiple computers with a cable. Each computer has its own broadband account so there is no influence among them.