What is a Router?
A router is a piece of hardware that is used to route data from one computer network to another computer network. OK, that may seem a little confusing since you might not know that when computers are connected together, they create a network. So let's use something you might be familiar with, like a public transportation system.
Moving Data is Like Moving People
Public transit systems often include high-speed transportation, such as bullet trains, local trolleys, and buses. High-speed trains require special rails, so any high-speed train can only run on those rails. Local trolleys use rails also, but a different kind and buses use roads. The high-speed rails, trolly rails, and roads are different kinds of networks. Each type has a different speed, and they don't always connect together.
If we want to travel from point A to point B, we might start out walking on the sidewalk in our neighborhood (one network), take a bus (another network) to a trolly station (another network), and then transfer to a high-speed train (yet another network). Our little trip has taken us on four different networks so far. Then when we exit the high-speed train, we might take another bus route (another network) to get close to our destination, and then walk (using the sidewalk) to our location.
While we've used several networks to get from point A to point B, we transferred across several networks since Point A and point B aren't connected directly to each other. Since we recognize how to follow public transit (well, I grew up in Chicago, so I used it a lot) we can direct ourselves from one network to another at certain points where the networks connect. These are the train stations, bus stops, and intersections we use to move people, as well as vehicles that transport people.
Routers are what's used to connect data networks to each other so the data can transfer from one route to another, eventually making its way to its destination.
What Data do Routers Direct?
Data is any information in digital form, usually in the form of files. When your computer wants to send data to another computer on a network, it sends a file that includes information about where the data is located. Routers are the devices that read the destination information and send the request to the proper location where the computer is located. The computer that receives the request then packages up the data and sends it back to your computer using your location information. Let's take a look at a common example of how routing helps you browse the World Wide Web.
When you visit a Web page, your computer, smartphone, or tablet sends a request over the Internet that includes the address of the Web page. Something like www.yahoo.com, or www.google.com, which is the address of the Web page you want to view. To deliver your request from your computing device to the Web page location, routers use the address information of the Web page to direct your request to the right location on the Internet. The computer with the Web page then sends the Webpage back to your computer's address, which was included in the request.
Types of Routers
While all routers have the ability to direct traffic, they differ in size and capacity. For example, routers used in homes and small businesses are designed to handle small networks of computers, printers, and wireless devices like tablets and smartphones, and connect all of them to a larger network, usually provided by the Internet Service Provider (last week's newsletter).
Other routers, used by large companies like Google, Apple, Facebook, and Microsoft, have high capacity routers for handling lots of data. In fact, the Internet often resembles a public transit system, with a combination of speeds and capacity that vary depending on the amount of data that needs to be moved or routed.
Private and Public Routing
Some routers connect one network to another network to create an even larger network. An example is a chain restaurant with many locations. Each restaurant location usually has several computer terminals where food orders are recorded which makes up a local network. Each restaurant also has a router that is connected to the corporate office. The router knows which computers are in the restaurant (local), and the path, or route, to the corporate office, so it can send and receive data from the corporate office computers.
By connecting all the restaurant locations together, a larger network is created for the entire restaurant chain. Since the routers know the computers on their local network, and they know how to send and receive information from the corporate office, the entire restaurant chain is connected in one large network. In most cases, restaurants are not connected to the Internet, and this creates what's called a private network.
Your home or small business network also has a router which probably connects you to your Internet Service Provider. The Internet is a public network and can be used by anyone that can connect to it. Don't worry though, all routers have a security feature called a firewall which stops unwanted traffic from the public network getting to your local computer network.
Wired and Wireless
One last piece about routers has to do with wired and wireless connections. Routers usually come with several Ethernet cable connection jacks. Using these, you can connect computers, printers, and other Ethernet devices to your router and create your own local network.
Most home and small business routers also include an antenna for wireless connections. These routers broadcast a signal which allows wireless devices to connect to the router. The wireless signal is called WiFi and creates a connection from a computer or device to the router wirelessly, instead of using an Ethernet cable.