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Modem vs. Router: How They're Different and What They Do

modem vs router

When it's time to set up a home Wi-Fi network, it's important to know exactly what kind of equipment you need. And one of the first steps to picking the right equipment is knowing the modem vs. router differences.

After all, those are the two pieces of networking gear that everything starts with. A modem brings internet into your house, while a router that directs that internet connection to all the computers, tablets, mobile phones and other connected devices you have on hand. The two devices work together to fill your house with cat videos, Snapchats and all the other things that make the web so wonderful.

Here's a quick rundown of both types of networking gear, including what to look for and why you're usually better off opting for a separate modem and router instead of a hybrid device.

Modems: Your gateway to the internet

To bring the internet into your home, you're going to need a modem.

This is a small device that connects to your internet service provider (ISP) to tap into all that internet goodness. The connection is made via a cable (for cable or fiber internet) or phone line (DSL) from outside your house that plugs into the back of your modem. Your modem shares this connection with a computer or a router via an Ethernet cable.  

Modems aren't one-size-fits-all solutions; the type of modem you'll need depends on the type of internet service you receive. If that's DSL, you'll need a DSL modem. If your ISP offers cable internet, you'll need a cable modem. If you choose fiber, you'll get an optical network terminal (ONT) to translate the fiber-optic light signals into electrical signals that your devices can recognize, and maybe another modem-like device to translate from the ONT.

Motorola MB7420 cable modem

Motorola MB7420 cable modem (Image credit: Tom's Guide)

Several ISPs offer both DSL/cable and fiber options, so it can be challenging to determine which type of modem you need for your internet service even when you're looking at only one provider. If that's making your head spin, the good news is that your ISP will tell you which type of modem you need, and will even offer one for you to rent or, in some cases, buy.

A warning about renting your modem, though: It can cost you. While tacking up to $14 a month on to your bill each month may not seem like much, those costs add up over time. At Comcast, where some customers are paying that $14 monthly fee for their modems, that's $168 a year you're paying in modem rental fees. Considering that best cable modems cost anywhere from $60 to $100, you could pay off a modem twice for what you're spending to rent one.

To buy your own modem, all you need to do is check with your ISP to make sure that the model you want to buy works with that provider's service. If you get cable internet, a DOCSIS 3.0 modem such as the Motorola MB7420 or Netgear CM500 can handle speeds for most homes. If your internet service has speeds greater than 300Mbps, consider a high-speed DOCSIS 3.0 modem instead such as the Netgear CM600.

Cable providers are starting to roll out internet service that tops 1 Gbps. If that includes your home, you'll need a DOCSIS 3.1 modem. Be aware that these kinds of devices tend to cost more than $100.

Routers: Taking the web wireless

Picking a modem is only half the battle, because they typically provide connections for just a single, wired device. If you want to go wireless, you're going to need a router, which is a networking device that lets you share your modem's internet connection with all your devices. Routers connect to your modem via an Ethernet cable and pass that internet connection on to other devices in your house either via an additional Ethernet cable or wirelessly over a Wi-Fi network.

Netgear Nighthawk AX8 (RAX80) review

Netgear Nighthawk AX8 (RAX80) (Image credit: Netgear)

Routers come in two primary variants: standard single-unit routers (which can look a bit like spiders — looking at you, D-Link), and whole-home Wi-Fi routers that use multiple devices to create a mesh network that extends your Wi-Fi signal. For smaller homes, single-unit routers generally provide a good enough signal to provide a strong wireless connection to all corners of your home. (And if they don't, you can always pick up one of the best Wi-Fi extenders.)

For larger homes, whole-home Wi-Fi mesh networks are the better option. These mesh routers replace a single router with multiple Wi-Fi points (called nodes). Placed strategically throughout your home, they connect together seamlessly to blanket your home with wireless coverage, without any speed loss or coverage dead zones.

As with cable modems, we've looked at all types of routers and can recommend the best router for your home, with picks based on overall performance, range, price and how well the router handles online gaming. Router needs can very from home to home, but the Netgear Nighthawk AX8 (RAX80) has dominated our recent performance testing.

As for mesh routers, you'll want to consider a system with the reach to cover all areas of your home. Currently, we like the Nest Wi-Fi from Google for its excellent performance and easy set-up.

Combination Modem-Routers: Not the best of both worlds

To complicate things, many ISPs and networking device makers offer combination devices that function as both modems and routers. It's a tempting proposition: You've only got to make room for one multitasker device instead of two pieces of gear performing different functions. But your network will be much better if you use a separate modem and router.

With the growing focus on wireless connections, advances in router technology occur much faster than in modem technology. One such advance is "multiuser multiple input, multiple output," or MU-MIMO, technology for Wi-Fi, a technology found in superfast (802.11ac) networks that can direct separate streams of bandwidth to as many as four different devices simultaneously, without losing bandwidth.

Non-MU-MIMO devices share a single bandwidth pool, so checking social media on your phone while streaming a movie or TV show on your laptop, for example, makes both devices a little slower. MU-MIMO technology is just one example of a newer, advanced wireless technology that exists in several new routers, but in only a few combination devices.

Since we first published this review, Wi-Fi 6 routers have also started to emerge. They support the new standard in wireless technology which means more efficient traffic management fro the Wi-Fi 6-capable devices in your home. If you keep your modem vs. router separate, you can upgrade to a more modern router while keeping your current modem in place.

Buying separate devices also makes it more convenient to troubleshoot when something goes wrong. If your router is fine and the modem is on the fritz (which is typically the case, in my experience), it's much easier to get a new modem. When replacing just the modem, you can simply plug it in and get back online.

  • JohnRS
    Perhaps you should have also mentioned that Routers with WiFi are actually two devices in one: A Router and a WAP (WiFi Application Point). I think that this is important for those who want a good router, which normally does not come with a WAP.
    Reply