A modem router is a combination device that manages your local network and connects it to the Internet through your ISP. Modems and routers perform separate functions, but some users enjoy having them combined in a single box. This setup generally simplifies network set-up and maintenance for most people at the expense of some flexibility.
Do You Need a Router If You Have a Modem?
If you have more than one device on your network (and you almost certainly do), you require a router to manage the local network those devices comprise together. Since most home users today have multiple devices (taking into account computers, mobile devices, streaming boxes, gaming consoles, and more), network device manufacturers made life easier by building these into a single package for some models.
What Is the Difference Between a Router and a Modem?
As the name suggests, the modem router consists of a combination of circuits and wires which perform two main functions (see our Modem vs. Router article for more detail on the differences):A modem, which stands for "modulator-demodulator," converts data from your local network into information ready to be sent over your ISP's infrastructure. Whether you get your Internet service from a cable provider, telephone carrier, or even over fiber optic cable (lucky!), the standards that carry data over these connections are different from the network inside your home, which likely uses Ethernet or Wi-Fi. For example, if you're a cable customer, the modem converts activity from your phone over Wi-Fi to the DOCSIS standard. It then travels on through the cable company's network to the internet.A router is responsible for shuffling traffic around a local network. One element of this includes managing the IP addresses of local network clients. Another is passing traffic from local clients to the internet and ensuring the results get sent to the suitable device. Many routers also have advanced features such as Quality of Service (making certain services such as video or gaming have priority) or built-in VPNs.
The Pros and Cons of a Modem Router
An all-in-one device comes with several advantages. Firstly, it's easier to set up: one plug for power and the coaxial (for cable customers) or a DSL line-in for data. Compare this to requiring two outlets for a separate modem and router, as well as the Ethernet cable connecting the two. It's also more manageable from the networking perspective, as you don't run the risk of the router not being set up correctly for the modem.
There are drawbacks as well, however. Combined modem-routers typically don't have all the networking bells and whistles standalone routers do. For that matter, having two devices in one means if one part ever needs upgrading, you'll end up trading in the whole device. But perhaps the biggest drawback is the fact since your ISP generally needs to issue you your modem, they're effectively choosing your router for you as well. If you have any special requirements (such as a VPN), you'll end up having to make other arrangements, such as setting up a dedicated VPN server.
If you're trying to decide between a modem router and two standalone devices, it boils down to simplicity versus flexibility. Choosing an all-in-one modem router will get you up and running quickly while only supporting basic networking. This setup is perfectly OK if all you require is to get all your devices online with a minimum of fuss. On the other hand, power users looking to perform some fancier networking tricks like hosting servers at home, using two separate devices might be required to get the features and customizability you want.