The Network

Computers can connect to each other. They can transfer files between each other. The Internet is just a huge network of computers; it is called a WAN (Wide Area Network). A WAN is any network of computers located in different buildings over a large area. I can be between two buildings (like LCJ and NIC have), or it can be worldwide, like the Internet.

Computers can also connect locally, inside one building or one room. This is called a LAN (Local Area Network). A local network consists of a server--the main computer which runs the network--and "client" computers. See an example of a LAN in the diagram at right, which shows LCJ's two LANs (one for students, in red, and one for the main office, in blue). In the diagram, the big squares on the second floor are servers.

When networks were first made, most computers were different, and used different languages. It was difficult or impossible for computers made by different companies to communicate. To make networking easier, protocols were invented. A protocol is a universal language and/or set of rules, that all computers share and agree on. Most network activities, especially on the Internet, use protocols. For example, HTTP is the Hyper Text Transfer Protocol. POP, used for e-mail, is Post Office Protocol. FTP, for moving files over the Internet, is File Transfer Protocol. And the main protocol for computers to connect with each other is called TCP/IP, or Transmission Control Protocol/Internet Protocol.

One of the rules for a network is that each computer must have an address. This is called an IP (Internet Protocol) address. The IP address has four numbers (0-255) separated by periods. For example, 68.180.0.57 is an IP address.

Usually, there is an IP address for the Internet, and then there is a local IP address, which is different. Commonly, the local IP address for a server is 192.168.0.0. The other computers will take a number which begins with192.168.0 and ends with any number between 1 and 255.

You can find your computer's IP address by going to the Network Connections control panel, opening the first "Local Area Connection" icon, and clicking on the "Support" tab. (On a Mac, go to System Preferences, click on Network, Built-in Ethernet, and then TCP/IP.)

Recently, most LANs use a simple way to get an IP address. It is called DHCP. With DHCP, your computer will automatically get an IP address any time you plug in the network cable. You don't have to do anything. Without DHCP, you must carefully type in an IP address and other information that the network manager gives you.

If you want to see other computers on your network, go to the Start Menu and open My Network Places. If the folder you are looking for is not there, then you can either look for it by clicking "View Workgroup Computers" in the task management area, or you can add the place permanently to "My Network Places" by clicking "Add a Network Place" in the task management area, and choosing the folder you want to add.

In order for a folder to appear in everyone's "My Network Places" folder, it must be Shared. To share folders, a computer must be set up for sharing by running the Network Setup Wizard. Once the computer has been set up, just right-click on a folder and select "Sharing and Security." Select the "Sharing" tab, and click "Share this folder on the network."