What is a Network?
First things first. You need to know what this thing is. Quite simply, a network is simply a group of two or more personal computers linked together. When configured in this way, the PC’s can share files, use a common printer or modem, etc.

What Types of Networks Exist?

There are many different network types. Let’s run through them here in order to define these terms for you.

• Local Area Network (LAN) : This is a network of computers that spans a relatively small space. Common LANs would be in an office or home. Some LANs span a series of buildings, usually in close proximity. Most LANs connect a series of workstations (a very powerful computer used usually in engineering applications) or PCs together. Each computer on the network, called a node, has its own hardware and runs its own programs like any normal PC, but they can also access any other data or devices connected to the LAN. This is useful so that many users can share expensive pieces of equipment, such as laser printers. Users can also use the LAN to communicate via e-mail or chat.
  
• Wide Area Network (WAN) : This is a network that spans a larger area. It consists of two or more LANs connected to each other via telephone lines or some other means of connection.
  
• Ethernet : a type of LAN. It is more or less a LAN protocol developed by Xerox Corporation back in 1976. We will get into more specifics later. The original supported transfer rates of 10 Mbps. A newer version of Ethernet, called 100Base-T (or Fast Ethernet), supports data transfer rates of 100 Mbps. And the newest version, Gigabit Ethernet supports data rates of 1 gigabit (1,000 megabits) per second.
  
• Metropolitan Area Network (MAN) : This is a term not used as often. Nonetheless, this is a network that spans a town or city, usually connected by fiber optic cable, so it boasts high speeds.
  
• VLAN : Short for virtual LAN, a network of computers that behave as if they are connected to the same wire even though they may actually be physically located on different segments of a LAN. VLANs are configured through software rather than hardware, which makes them extremely flexible. One of the biggest advantages of VLANs is that when a computer is physically moved to another location, it can stay on the same VLAN without any hardware reconfiguration.
  
• The Internet is a system of linked networks that are worldwide in scope and facilitate data communication services such as remote login, file transfer, electronic mail, the World Wide Web and newsgroups. With the meteoric rise in demand for connectivity, the Internet has become a communications highway for millions of users. The Internet was initially restricted to military and academic institutions, but now it is a full-fledged conduit for any and all forms of information and commerce. Internet websites now provide personal, educational, political and economic resources to every corner of the planet.
  
• With the advancements made in browser-based software for the Internet, many private organizations are implementing intranets. An intranet is a private network utilizing Internet-type tools, but available only within that organization. For large organizations, an intranet provides easy access to corporate information for employees.
  
• Token Ring is another form of network configuration which differs from Ethernet in that all messages are transferred in a unidirectional manner along the ring at all times. Data is transmitted in tokens, which are passed along the ring and viewed by each device. When a device sees a message addressed to it, that device copies the message and then marks that message as being read. As the message makes its way along the ring, it eventually gets back to the sender who now notes that the message was received by the intended device. The sender can then remove the message and free that token for use by others.