B2B – Understanding Modems and Routers

Asking the age old question. Which box do I restart for the internet to start again?

A simple explanation for a perplexing dilemma. What box do I have to power cycle?

For far too long, or at least longer than I could care to admit, I never really understand the difference between a modem and a router. Growing up, they were just two boxes that I had to turn off for 30 seconds, in order for the internet connection to fix itself. They were the two things I had to play with, whenever I had to call the ISP to check for area outages, in place of my mom due to her terribly broken English. And I think for many others as well, it was the mystical and magical box that provided us access into the world called the internet.

I wish I could say that I learned the difference once I began school, but because my dad was always the handyman type of person, he would be the person that would fix everything. A man of many talents and passions, he takes on any challenge head on, learns about it, and overcomes it. It wasn’t until I hit college and settled into my Information Technology and Management major, did I start to learn more about the hardware behind the internet networking that pervades our everyday life. In my Introduction to Networking course, we broke everything down into the analog and digital signals that they were and learned about the layers of OSI, did I revisit the hardware pieces of the modem and the router.

Simply put, here is a description of a modem and a router. I’ll expand a little more about it throughout this piece:

Modem – A modulator and demodulator that converts data to a signal that can be transmitted over a phone or cable line. This communication is between 2 and only 2 devices. Think of the old dial-up modems that turn ones and zeros into the computer sound you would hear if you picked up the extension. A second modem would demodulate that noise back into ones and zeros that the computer could use. In most homes, this would be that pointy thing sticking out of the wall.

box modem router image

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Router – A router routes packets to a specific connection. This basically is what makes a network or the internet, which is just a really big network of networks. Take one router and connect 2 computers to it. Now you have build a very simple network and those computers can talk to each other. Add a third computer and each computer can talk to every other computer separately. If you have more computers than the router has network ports, you can add a second router to expand your network. Now every computer connected to either router can talk to any other computer connected to either router. At his point it’s all one big network.

Now connect a modem to either router. All the modem does is act like a very long network cable and connects to a router at your ISP. Now every computer on your network can talk to every other computer connected to that router, and that router is connected to lots and lots of routers. Your network is now a part of the internet. The router connects to the Internet through the modem and the router itself receives a single public IP address on the Internet. Servers on the Internet communicate with your router, and the router routes that traffic to the appropriate devices on your home network. Your modem communicates with your Internet service provider’s network. If it’s a cable modem, it plugs into your cable provider’s infrastructure via a coaxial cable. If it’s a DSL modem, it plugs into your telephone line.

One last thing. You might be wondering what role your IP address plays in all of this. The answer? It is at the heart of it all. In simple terms, the networking software in your computer follows guidelines (Internet protocols) that connect you to the Internet. These protocols allow you to send emails and information back and forth through your modem and router–and your IP address helps directs the data YOU requested to YOUR computer and not to someone else’s.

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So remember this simple distinction between a modem and router.

Modem connects from your internet line and provides a single node output for a computer. A router connects to the modem to provide a multinode network for the area.

Article by Sir. Lappleton III

I'm a happy-go-lucky recent graduate that started a blog as a way to not only document my education and my experiences, but also to share it with whoever stumbles upon my site! Hopefully I can keep you guys entertained as well as learn about a few things from IT as well as from my time and experiences as I plunge deeper and deeper into healthcare! A couple of my areas of focus is data management, system security (cyber security), as well as information technology policy.