Modem And Router in Home Network - fiberopticnetworking/vocanoman GitHub Wiki

To build a home network, you have to prepare ethernet cable, modem and router. Among them, modem and router are regarded as core components in home network building. Both of them are small plastic or metal box-shaped electronic devices, but they serve two different purposes. How much do you know about them? To carry out the home network building smoothly, it is necessary to learn as much as possible about modem and router. This article will introduce modem and router to you.

The word “modem” is a contraction of the word modulator-demodulator. A modem is a device that provides access to the Internet. Generally, a modem has one LAN port and one service-related port (LINE port), such as a telephone port (DSL modems) or a coaxial port (cable modems), which typically provides either cable or DSL Internet service. DSL modems have a telephone connector, also called an RJ-11 jack, which connects to a telephone socket on the wall. Cable modems have a coaxial (or “coax”) connection, which is the same type of connector found on a TV or cable box. This connects to a cable port on the wall. As for LAN port, it is used to connect to a router’s WAN port, or to an Ethernet-ready device, such as a computer. The following figure shows the appearance of modem.

If you have just a modem, you’ll be able to connect just one Ethernet-ready device, such as a computer, to the internet. To allow more than one device to join the same network, you will need a router. On the front or back of the router, there are several physical ports, one WAN port, four LAN ports and one power input port. Also, there are some LED lights to display device status. For WAN port, it is connected to the LAN port on a modem via an ethernet cable; while for LAN port, it is connected to the rj45 port on Ethernet-ready device via ethernet cable.

From the above content, it is not difficult to find that modem and router not only have differences, but also have similarities. This part will make a summary.

• Both modem and router are small plastic or metal box-shaped electronic devices.
• Both modem and router have LAN port and power input port.
• The LAN port on both modem and router are rj45 port. And they use rj45 cable to achieve connection.

• Router has WAN port while modem has service-related port.
• The LAN port on router is connected to the rj45 port on Ethernet-ready device, while the LAN port on modem is connected the router’s WAN port or to an Ethernet-ready device.
• The modem is connected to other device via rj45 cable (LAN port) and rj11 cable (service-related port), while the router is connected to other device only via rj45 cable (WAN port and LAN port).

By connecting your modem to your router (instead of directly to a computer), all devices connected to the router can access the modem, and therefore, the Internet. The router provides a local IP address to each connected device, but they will all have the same external IP address, which is assigned by your ISP. Here is a figure for you to have a better understanding of modem and router in home network.

Modem and router are two of the most common components in home network. Though the two devices may look similar, they each serve a difference purpose. I hope this article can make the functions of the two devices easier to understand.