a blog from CenturyLink

What’s the difference between a modem, a router, and a gateway?

by | Oct 11, 2021


When it comes to getting online, internet service providers may use a lot of different terminologies. It can be really confusing if you’re unfamiliar with the terms, especially during troubleshooting. To make it easier to understand, let’s explore the difference between a modem and router. We’ll also cover  what internet providers mean when they call hardware a “gateway.”

A modem sits on a table next to a plant.

The difference between a modem and a router

A modem is the device that connects a home network to the internet. It receives signals from the internet provider and decodes them into something everything on the home network can understand.  High-speed internet services use broadband modems designed for cable or digital subscriber line (DSL). Where cable internet service uses the same technology as cable TV service, DSL internet access requires a telephone line.

A router is a device that connects your computers, printers, game systems, DVRs, media players, and mobile devices to each other to create a home network. The router “routes” data between those devices. It also shares the internet connection among those devices that need it. Another service a router usually offers is a firewall, which prevents a lot of malicious traffic from getting from the internet to the home network.

So, what’s a gateway?

For home networks, a combination modem/router device is often called a residential gateway. A business may have a gateway that connects two different local area networks (LANs) to each other, while in a home, the gateway is the modem/router that connects all devices to each other and to the internet. This makes sense because the internet is a network; it’s a wide area network. Your home network is a local area network.

Fiber-optic internet with its super high-speed technology is available to more and more homes each year. But fiber equipment is different than typical cable and DSL equipment. For fiber, the provider’s technician installs a device called an optical network terminal (ONT) either inside or outside of your home. That’s the equivalent of a modem. Inside the home is the fiber residential gateway, which your internet provider might refer to as a fiber router.

A router rests on a side table in a living room.

Do I need both a router and a modem for cable or DSL service?

If you have only one computer, all you need is a modem and an internet service plan to connect directly to the internet and surf the web, download and upload data, and so on. You don’t need a router.

If you don’t need internet access, you could use a router on its own to create a local network and share files among your devices only, such as printing to a shared printer or streaming movies and music from one part of the house to another. But to get information to and from the world wide web, you need a modem and an internet service plan.

Do I need wired or wireless?

Most modem/router combos today are designed for both wired and wireless connections. That means you can set up wireless devices, like WiFi-enabled mobile phones, laptops and tablets, to connect by WiFi, but you can also use a cable when you need a more reliable connection than wireless.

Some devices, like a gaming PC, usually get better performance over a wired (cabled) connection. In those cases, you just plug an Ethernet or USB cable into the PC and into the modem/router.

What's the difference between a modem and router?

Can I bring or buy my own equipment?

Although your service provider will likely provide both a modem and a router or a modem/router combo (the gateway) when you sign up for service, subscribers can also choose to buy a separate router and/or modem and connect them with the correct cords and network settings.

You will have to know how to install and configure the equipment on your own. The same applies if you get everything running but run into performance problems down the road. Your internet provider’s tech support will be able to confirm if they can detect your modem and whether it appears to be connected to the network. Other than that, you will need to work with the equipment vendor when problems arise. For fiber customers, bringing your own equipment can be even more complicated.

If you want to handle your own equipment, be sure to check your internet provider’s website for information on compatible equipment before you choose that route.

Remember, where a router creates a home network, a modem makes the connection between the provider network and the internet. For a complete internet and network experience, you need both. A modem/router combo, or residential gateway, is an all-in-one box that handles everything for you.

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<a href="https://discover.centurylink.com/author/kim-lindros" target="_self">Kim Lindros</a>

Kim Lindros