Modem vs. router: What’s the difference?

Everything you need to know about routers, modems, combos, and mesh networks

modem vs router plugging in
Piotr Adamowicz

When we open our laptops, or wake up our smartphone, the internet is seemingly always there. We’ve come a long way since the days of hearing PCs dial into America Online and creep along a constantly-disconnecting world wide web. Our connections are now fast, quiet, typically reliable, and always there given you’re keeping up with subscription payments. But you may not know quite how networks function, thus enter our modem vs. router comparison.

Both are necessary components for wired and wireless internet access in your home. Understanding the difference between the two can help you diagnose and possibly fix networking problems before placing time-consuming calls with technical support.

We provide an explanation of each, and illustrate how and why each device is important. We also explain a new alternative to using the standard router if you’re considering an upgrade to your current home network setup.

Modem

TP-Link DOCSIS 3.0 343Mbps High Speed Cable Modem

The modem is your on-ramp to the world wide web. In the old days, they were bulky external devices that required you to either insert a rotary/push-button telephone’s hand-held receiver, or plug in a telephone cable. Once the internet grew to become a mainstream household product in the early 1990s, modems became add-in cards for desktops and USB adapters for laptops. Cable-based broadband producing speeds faster than 56Kbps seemingly re-introduced the external modem at the beginning of the century, thus here we are today.

Right now, Charter Spectrum is the largest broadband provider in North America, blanketing 43 states with coverage after acquiring Time Warner Cable in 2016. Behind Charter is Comcast’s Xfinity service covering 40 states, and Cox Communications service in 19 states. These broadband providers “rent” modems as part of their subscription plans so you can access their subscription-based service. But you can purchase compatible modems separately from any retailer to cut down on the monthly cost. Either way, you’ll one to access the internet.

How it works

A modem includes a physical connector for the coaxial cable installed in your home. That cable typically exits the home through a hole, and is tunneled around and/or underneath the house until it reaches the Cable Distribution Box mounted on your home’s exterior. An additional cable buried underground connects this box to the service provider’s node mounted on a nearby utility pole.

That said, the internet feed leaves the utility pole, arrives at your home’s Cable Distribution Box, and ends at the modem’s coaxial cable connector. After that, the output depends on the type of modem that’s included with your broadband subscription. Some models only have one square-shaped Ethernet port while others have up to four.

Modems usually include lights/LEDs along their front, so you can see what’s going on at a glance. One light indicates that the unit is receiving power, one signals that its receiving data from your internet service provider, and one shows that the modem is successfully sending data. This is where you start in a troubleshooting scenario: If the send and/or receive lights are blinking, then your internet service provider is likely having issues, or something is going on with the connection outside. Another LED is provided indicating that wired devices are accessing the internet.

Before we move on, note that modems aren’t just for a coaxial cable connection. Broadband can be served up through a Digital Subscriber Line too, or DSL. This internet on-ramp is accessed through telephone lines instead of coaxial cables, so the connecting jack looks no different that what you would see on physical, land-based phones. DSL is typically slower than cable-based broadband, and useful in rural areas where phone lines already exist, but there’s no infrastructure supporting cable-based TV and internet services.

Whether the router is designed for DSL or cable-based broadband, the four Ethernet ports are used for wired devices with a matching port or adapter. These can include desktops, laptops, HDTVs, gaming consoles, printers, and more. If you want the most out of your broadband connection, using these ports for your hardware is the best option, especially if the ports support speeds of up to one gigabit per second (aka gigabit Ethernet).

Router

ASRock X10 IoT Router

But not everyone wants to line Ethernet cables all over their house, and that’s where the router come in. It’s a stand-alone device that connects to an Ethernet port on the modem, and “routes” networking/internet traffic to its connected devices. Routers typically have a dedicated, color-coded Ethernet port that it uses to physically connect to the router (WAN, or Wide Area Network), and four additional Ethernet ports for wired devices (LAN or Local Area Network).

Thus, the router sends and receives networking traffic from the modem with one connection, and routes all that data through its four Ethernet ports, and through the air via the 2.4GHz and 5GHz bands. Despite advertised numbers, wired is faster than wireless, and we still suggest using Ethernet if you want every ounce of bandwidth out of your subscription. But obviously you can’t do that with smartphones, and draping Ethernet cables along every wall is just downright ugly.

To that extent, you’re not going to get gigabit speed if you’re only paying for a 300Mbps connection. There’s no magic wand or device that will widen your provider’s internet spout unless its installed by the company for additional fees. Sure, you can pass files from wired PC to wired PC at up to one gigabit per second on your Ethernet-based network, and you may even get great wireless transfers between smartphone to smartphone, depending on the router you buy, and the capabilities of those phones.

Unfortunately, routers come in all sizes, prices, and exaggerated promises. On the wireless side, they can include two external antennas or more, depending on the model. The more antennas they have protruding in the air like a dead spider’s legs, the higher the prices will soar. Of course, the added antennas mean increased range, but your connection speed will depend on your proximity to the router, and the technology powering that connection.

The current wireless standard is Wireless AC. It’s first implementation enables three outgoing streams and three incoming streams (3×3) on the 5GHz band at up to 433Mbps each. They’re accompanied by three incoming and three outgoing Wireless N streams (3×3) on the 2.4GHz band at 200Mbps each. The latest update to the Wireless AC specification, aka Wave-2, adds a fourth stream for additional bandwidth. Problem is, smartphones typically only support between one (1×1) or two (2×2) incoming/outgoing streams, so they can’t get the full benefits of routers supporting 3×3 broadcasts.

How it works

If all of this is confusing, just imagine a high-speed train. It enters your home through the modem, travels to the train station (router) at full speed, and is redirected to a destination. If the destination is a wired connection, then it plows full speed ahead. If the destination is wireless, it’s speed is based on how many tracks/streams it can use at once (one, two, three, or four), the amount of congestion these tracks must penetrate, and the distance between the train station and the destination. The train will lose speed the further it travels away from the station.

The “up to” term means the hardware is physically capable of supporting those maximum speeds, but again you won’t see them. Part of the “congestion” slowing your local data train is your neighbor’s network spreading the love in the same air space. There’s also interference from devices within and outside your home. Having a router with multiple, external antennas with amplifiers will help push back all that unwanted noise.

Typically, routers will choose the ideal channel for the 2.4GHz and 5GHz bands that have the least interference. The 2.4GHz band is divided into 14 channels while more than 20 are set aside for the 5GHz band. But if you’re having connectivity issues, manually changing the channels within the router’s web-based interface can sometimes help. There’s a lot more at play regarding speed that gets into heavy technical territory and can make your head spin.

Check out our list of the best wireless routers you can buy right now. Some of the routers we’ve reviewed include the ZyXEL Armor Z2, the Linksys Max-Stream AC2200, the Linksys WRT3200ACM, and more.

Router/modem combo

modem vs. router

Unfortunately, there’s no official name for this specific device. Comcast calls it a “gateway” while Spectrum simply calls it a modem. There are even listings that merely call it a modem/router combo. Regardless, you get the idea: it’s an all-in-one device that looks like your typical modem, but crams a router inside. This combo unit can be beneficial and a drawback, depending on how well you want to manage your network.

In the typical stand-alone modem, you can adjust firewall settings, open ports for specific traffic, assign addresses, and so on. The add-on router essentially provides a secondary firewall for better protection along with parental controls, device management, usage statistics, and more. When combining the two, you lose that second firewall aspect, and possible customization not provided by equipment rented from ISPs.

Another aspect to consider is that even though you’re “renting” one all-in-one device, your broadband provider may be charging you an additional fee for wireless service. Spectrum calls this a “Home WiFi” charge that shows up on your bill for an additional $5 per month, and only applies to modems with a built-in router rented out by the company. For complete control and a lower monthly bill, you’re better off supplying your own stand-alone router.

Combo devices typically include everything you would find hardware-wise on stand-alone modems and routers. For example, Spectrum rents out the Arris Touchstone TG1672 Cable Voice Gateway, which includes four gigabit Ethernet ports, two RJ-14 ports for digital phone service, and one USB-A 2.0 port for possibly sharing files or a printer on the network. It’s an older Wireless N device with a 3×3 broadcast setup, meaning its theoretical peak wireless speed is only 450Mbps (aka 150Mbps per stream).

Combo devices also have a few additional LEDs on the front. One will signal that the 2.4GH wireless band is active and in use while another is dedicated to the 5GHz band. If your combo supports digital phone service, LEDs for sending and receiving are provided as well. These LEDs will not be active if you don’t have an active digital phone subscription.

Mesh

modem vs. router

But wait! There’s more! A newcomer has arrived to crash the networking party. It’s similar in nature to routers, but different in delivery. More specifically, the router is a single unit that broadcasts an internet connection like a radio tower. The further away those broadcasts travel, the weaker the signal thus a resulting slower speed. You get the same effect in a moving car: the further away you move from the city, the harder it is to hear your favorite music station.

Even more, the 2.4GHz band is great for penetrating objects and walls, but it’s throughput speed is slower than the 5GHz connection mostly due to congestion. Meanwhile, 5GHz is faster and less congested, but it has difficulty penetrating objects and walls.

One way to solve this problem is to purchase a second wireless extender device. It grabs the signal produced by the router, and repeats it to areas outside the router’s reach. This is helpful in dead spots, but the drawback is that repeaters are grabbing an already-degraded signal unless you actually have a wired Ethernet connection between the router and the extender. These extenders are sold in various sizes and strengths ranging from wall-based units to solutions just as big as routers.

Arriving to alleviate all those woes is mesh-based networking. Kits are typically sold with two or three identical units, thus the setup doesn’t consist of a router and an optional extender. Instead, one plays the router role by physically connecting to the modem’s output, and then routes all traffic to and from the wirelessly connected nodes. So instead of a single unit broadcasting an internet bubble, you have multiple units creating a mesh-based blanket of coverage.

What’s great about these kits is that you have one connection: the kit determines if your device should use 2.4GHz or 5GHz. You also can’t tell that your wireless devices are shifting from one node to another as you move through the house. The drawback is that typically these mesh-networking kits aren’t cheap, thus the investment can be long term unless you’re willing to shell out the big bucks each time an upgraded kit hits the market.

How does it work?

To understand how this works, let’s imagine the train again. Once it leaves the modem, it travels to the unit that serves as a train station. If the destination is wired, the train moves ahead at full speed. If the destination is wireless, the train leaves the station and travels to the closest junction (node). From there, the train reaches its destination or travels from junction to junction until it reaches the end.

Again, the overall speed will depend on how many physical antennas each node will have, and how many tracks/streams they support. It will also depend on the hardware specifications of the destination: how many antennas does it have, and how many tracks does it support.

The difference with this node-based route is that the train doesn’t lose steam due to travel distance: it “refuels” at each node. Plus, these nodes route their tracks to avoid obstacles for the best pathway possible, whether the train is traveling horizontally, or to an office on the second floor. There’s no way to completely avoid furniture, walls, and floors, but the technology is smart enough to find the ideal path, and will even re-route paths if major changes are made in the house, or if a node is relocated.

Another drawback to mesh networking kits is that they typically don’t offer the depth of customization offered in stand-alone routers. They’re typically installed in the home using a mobile device and Bluetooth, and controlled by mobile apps that can test the internet connection, set parental controls, and assign devices to profiles. These kits are designed for customers who want an easy, maintenance-free plug-and-play system that provides great coverage… and looks good in the process. That could change as the mesh-based networking market grows, but current kits available today appear to lean more on simplicity than customizability.

But keep in mind that you can expand a mesh-based network. Manufacturers serve up stand-alone nodes in addition to their kits so that all you need to do is power up the new node, and get the currently installed kit to recognize the device via the company’s network management app. There’s likely a limit to how many mesh-based nodes you can have in one setup, but the coverage should be spectacular if you’re willing to spend the big bucks.

Some of the kits we put to the test include Eero, Luma, Velop, and Google WiFi.

Kinda Sorta Mesh

modem vs. router

Finally, this category mashes two connectivity styles into one product. We saw this with Netgear’s Orbi kits, which provide two near-identical units that perform like a mesh networking kit. But at its root, one unit is clearly a router, offering everything you will find feature- and customization-wise in most stand-alone routers. The second unit is a satellite, but it doesn’t “repeat” the signal stemming from the router-class unit.

In this setup, the two units have three connections: one 2.4GHz band and one 5GHz band accessible by all wireless devices. The third is another 5GHz connection that’s only used by the Orbi units: a private, high-speed highway if you will that’s not accessible by any other device. That’s the big difference between Orbi and other mesh-based kits: those nodes use the same 5GHz space as all the connected devices, thus data transfers will be slower due to traffic. With the Orbi’s dedicated freeway, there’s nothing on the road except for Orbi-to-Orbi chatter.

We reviewed the Orbi RBK40 kit here, and the more expensive (and larger) Orbi RBK50 kit here.