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A network is nothing more than two or more computers connected by a cable or by a wireless radio connection so that they can exchange information.

You can create a simple computer network by using a device called a switch to connect all the computers in your network to each other. You do that by stringing a network cable from the switch to each computer. The cable plugs into a special jack on the back of each computer; this jack is connected to a network interface, which is an electronic circuit that resides inside your computer to facilitate networking. Voilà! You have a working network.

If you don’t want to mess with cables, you can create a wireless network instead. In a wireless network, the computers use wireless network adapters that communicate via radio signals. All modern laptop computers have built-in wireless network adapters, as do most desktop computers. (If yours doesn’t, you can purchase a separate wireless network adapter that plugs into one of the computer’s USB ports.) You’ll need a device called a wireless access point (WAP) to enable the computers to properly connect. In small office or home networks, the WAP is bundled with a device called a router, which lets you connect your network to the Internet. The combination of a WAP and a router is called a wireless router.

Figure 1-1 shows a typical network with five computers. This network is a home network used by a family that bears only a totally coincidental similarity to a famous TV family you may or may not have heard of. You can see that each family member has a computer that connects to the network — two of them wirelessly, three of them through cables. There’s also a printer that connects wirelessly.

In this example, the wireless router also has a built-in switch that provides several jacks for connecting computers via cable. Most wireless routers include this feature, typically with three to five wired network ports.

Although the network is a small one, it has much in common with larger networks that contain dozens, hundreds, or even thousands of connected computers.

FIGURE 1-1: A typical network.

Here’s the rundown for each of the devices connected to this network:

 Lisa has a laptop computer that connects wirelessly. She uses it mostly for school.

 Bart has a fancy gaming computer that’s cabled directly to the router.

 Marge doesn’t have a full-fledged computer, but she does use an iPad, which is connected wirelessly.

 Homer has an old computer he bought at a garage sale in 1989. He doesn’t know how to use it, but he doesn’t know that so no one tells him. Lisa set it up for him and repairs it when Homer breaks it (which happens every few months); she gets repair parts from eBay.

 The printer connects wirelessly to the network and is set up so that any member of the family can print on it.

 The wireless router connects to the Internet using the family’s cable TV provider. This allows everyone in the family to access the Internet.