Router Definition | The Interactive Glossary

Routers are used to direct the flow of information that passes over an Internet connection at the homes of private individuals, businesses, Internet Service Providers (ISP), and the along the backbone of the Internet.

When a data packet is received by a router, the router inspects the envelope for instructions and sends the packet along to the next router in the path along the way to the intended final destination.

Routers include a broad range of devices used at homes, businesses, ISPs, and by companies like AT&T, Sprint, and MCI, that manage the backbone of the Internet. Obviously, the routers used by AT&T aren’t the same as the router your ISP provided when you signed up for DSL. The simplest routers are small enough to be held in one hand and cost very little, while the core routers used along the Internet backbone weigh hundreds of pounds and have pricetags that reach into six-figure territory.

Also See: Modem, Gateway, Server

Frequently Asked Questions

What’s the difference between a router, a switch, a modem, a gateway, and a server?

Routers, switches, modems, gateways, and servers are all pieces of equipment used in a computer network. Quite often, there is some overlap between these components, such as a DSL modem that also serves as a wireless router, and most Internet users are unable to distinguish one from another. If you’d like to be in the minority of Internet users who understand what each of these items do, here’s a quick primer.

Modem: The device that negotiates and establishes an Internet connection with your ISP. In order to have Internet access, you must have a modem.

Router: The device that directs traffic and allows multiple devices to use the same Internet connection at the same time. Many modern modems intended for home and small-business use include an integrated router. However, you can purchase a stand-alone router to extend the Internet connection established by a modem to multiple users. An example of this is when a router is connected to a modem to create a WiFi signal.

Gateway: A gateway is a device or application that connects a network to the Internet. The connection between your ISPs network and the broader Internet is made through a gateway. A gateway may be a physical piece of hardware, but more typically it is an application installed on a server.

Switch: A network switch is a physical device used to direct the flow of data within a computer network. While routers send packets through a gateway from one network to the next, switches send traffic between locations in a single network.

Server: A server is a networked computer that waits for, and responds to, requests received from other computers on the network.

To put all of those definitions together, consider the following example:

• Imagine that your sitting at home, using your laptop, and you type http://learnthenet.com into your browser’s address bar.
• Your request will eventually make its way to the server that powers this website.
• The server will respond by sending the requested website files to a router.
• The router will determine where the files need to go and send them to a gateway for transmission over the Internet.
• The files will arrive at a second gateway, this one managed by your ISP.
• A router will receive the files from the gateway, look at them, see that you requested them, and send them through the ISPs network.
• At some point within that network, it is likely that the files will pass through a switch, which will give additional direction on how the files should travel within the ISPs network.
• The files will eventually make their way to the modem that powers your Internet connection.
• Your modem will send the files to your wireless router.
• Finally, your wireless router will send the files to your laptop over a WiFi signal.