What Is a Router and How Does It Work?

Everything to know about setting up your residential gateway

The router, at least the common home network device that we usually call a router, is the piece of network hardware that allows communication between your local home network—like your personal computers and other connected devices—and the internet.

The router used in home and small networks is more accurately called a residential gateway, but you'll never see them called that.

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What Is a Router and How Does it Work?

What Is a Router For?

A router is the first line of security from intrusion into a network. Enabling the highest level of security on the router turns on things like the firewall, and is the best way to keep your computer system and information safe from attack.

Routers contain software called firmware that should be updated as released by the router manufacturer.

Most routers connect to other network devices only via network cables and don't require drivers to operate in Windows or other operating systems. However, routers that connect to a computer via a USB or FireWire typically require drivers to operate properly.

Routers often act as the DHCP servers in small networks, issuing unique IP addresses.

Most routers are manufactured by companies like Linksys, 3Com, Belkin, D-Link, Motorola, TRENDnet, and Cisco, but there are many others.

Routers come in many shapes and sizes, as you can see below:

ASUS router
 Asus
Netgear router
 Netgear
eero router
 eero
Netgear router
 Netgear
TP-LINK router
 TP-Link
TP-LINK router
 TP-Link

How Routers Work

Routers connect a modem—like a fiber, cable, or DSL modem—to other devices to allow communication between those devices and the internet. Most routers, even wireless routers, usually feature several network ports to connect numerous devices to the internet simultaneously.

A router typically connects physically, via a network cable, to the modem via the internet or WAN port and then physically, again via a network cable, to the network interface card in whatever wired network devices you may have. A wireless router can connect via various wireless standards to devices that also support the particular standard used.

Although they're used in the same context, modems and routers are different devices, though there are cable/modem combos.

The IP address assigned to the WAN or internet connection is a public IP address. The IP address assigned to the LAN or local network connection is a private IP address. The private IP address assigned to a router is usually the default gateway for the various devices on the network.

Wireless routers, and wired routers with multiple connections, also act as simple network switches allowing the devices to communicate with each other. For example, several computers connected to a router can be configured to share printers and files among themselves.

Routers are like small computers, so there's a CPU and memory to deal with incoming and outgoing data. Different software, such as DD-WRT, can be loaded on the router much like an operating system on a computer.

A router operates on the Network layer (layer 3) of the OSI model, and uses routing tables to understand where traffic is coming from and where it should go.

Managing a Router

There will most likely come a time where you need to make changes to how your network works. This is done by accessing the software on the router.

Some other common tasks related to managing a router involve rebooting the router and completely resetting the router's software.

Buying a Router

There are several things to consider before buying a router, such as how fast it needs to be to support your internet speed and devices, as well as its power to ensure that all your devices can receive internet access.

For example, maybe you're buying a Wi-Fi router to serve lots of devices, like gaming consoles, computers, tablets, and phones. If your house is small, you might be able to get away with just one router, whereas larger homes or businesses with several rooms might be better off with a mesh network or a Wi-Fi extender.

See these lists if you're having trouble deciding on a new router:

Mobile Wi-Fi hotspots are similar to routers because they connect multiple devices to the same internet connection.