What Is a Router for Computer Networks?

Routers are small electronic devices that join multiple computer networks together via either wired or wireless connections.

What is a Router For?

A router is the first line of security from intrusion into a network. Enabling the highest level of security on the router is the best way to keep your computer system and information safe from attack.

Routers contain software called firmware that should be updated as released by the router manufacturer.

Most routers connect to other network devices only via network cables and do not require drivers to operate in Windows or other operating systems. However, routers that connect to a computer via a USB or FireWire typically require drivers to operate properly. Routers often act as the DHCP servers in small networks, issuing unique IP addresses.

How Routers Work

In technical terms, a router is a Layer 3 network gateway device, meaning that it connects two or more networks and that the router operates at the network layer of the OSI model.

Routers contain a processor (CPU), several kinds of digital memory, and input-output (I/O) interfaces. They function as special-purpose computers, one that does not require a keyboard or display.

The router's memory stores an embedded operating system (O/S). Compared to general-purpose OS products like Microsoft Windows or Apple Mac OS, router operating systems limit what kind of applications can be run on them and also need much smaller amounts of storage space. Examples of popular router operating systems include Cisco Internetwork Operating System (IOS) and DD-WRT. These operating systems are manufactured into a binary firmware image and are commonly called router firmware.

By maintaining configuration information in a part of memory called the routing table, routers also can filter both incoming and outgoing traffic based on the addresses of senders and receivers.

Routers and Modems Do Different Things

Although some people think of a router what interfaces to the Internet, home networks rely on a separate device called a modem to actually make the connection. The distinction between the two is blurred as some consumer devices integrate both the router and the modem into a single unit called a residential gateway.

Routers for Business Networks and the Internet

Before home networking became popular, routers could be found only the closets of businesses and schools. Each cost thousands of dollars and require special technical training to set up and manage.

The largest and most powerful network routers from the Internet backbone. These routers must manage many terabits of data flowing through and between Internet Service Provider (ISP) networks

Home Broadband Routers

Routers became mainstream consumer devices when households began to accumulate multiple computers and wanted to share the home Internet connection

Home networks use Internet Protocol (IP) routers to connect computers to each other and to the Internet. Early generations of home routers supported wired networking with Ethernet cables while newer wireless routers supported Wi-Fi together with Ethernet. The term broadband router applies to any home wired or wireless router being used for sharing a broadband Internet connection.

Home routers often cost USD $100 or less. They are manufactured to be much more affordable than business routers in part because they offer fewer features. Still, home routers provide many essential home networking functions:

-sharing of home Internet connections for dozens of devices

-basic home network firewall and other security support

-ability to change router configuration settings from a Web browsers

See our updated Best Wireless Routers to buy guide for help choosing which is best for you.

Routers Can Cost More or Less for Many Reasons

Price comparison shopping for routers requires patience and attention to detail. Router A can cost twice as much as Router B, yet the differences between them may be absolutely critical to some people and immaterial to others.

The primary factors that determine the selling price of a consumer broadband router are:

1.      Wi-Fi generation: 802.11ac routers carry a cost premium over prior generation 802.11n models

2.      Speed rating: Routers that can claim higher data rates bring higher prices over routers with lower dates, all other factors being equal.  A 600 Mbps router with 802.11n, for example, will have a larger selling price than the same model configured for 300 Mbps 802.11n.

3.      Industrial design: Home routers have traditionally featured plain, box-like designs, some with antennas poking out the top or side. Vendors have gradually started introducing different shapes, rounded corners, and more variety of colors and materials in an attempt to differentiate their products and get a higher price.

4.      Brand name: Many different brands of consumer routers exist. Better-known brand names may sometimes carry a higher price tag based on vendor reputation.

5.      Temporary price reductions: Like many other consumer electronics, sellers occasionally discount the prices of their routers. Purchasing a router during a major sale can have a significant cost savings.

Other Types of Routers and Routing Devices

A class of portable Wi-Fi routers called travel routers are marketed to people and families who want to use the functions of a personal router at other locations besides home.

Routing devices called mobile hotspots that share a mobile (cellular) Internet connection with Wi-Fi clients are also available. Many mobile hotspot devices only work with certain brands of cell service.