The connection of a group of computers is called a computer network and they are often classified by the network layer at which they operate.
In the industry the standards usually generate from a four layer protocol some use the seven layer reference model.
The largest difference between networks is size. These are classified on a scale such as Personal area network (PAN), Local area network LAN),
Campus area network (CAN), Metropolitan area network (MAN), or Wide area network (WAN).
Ethernet is the soul of the network because all of the other classifications are more important to the administrator than to the end user.
Computer networks can be further classified by the hardware technology that is used to connect the network.
Ethernet, being the most popular is physical wiring that connects the networking devices along with hubs, switches, bridges, and routers.
Wireless networking is also an option and these devices rely on radio frequency to connect.
There are different types of computer networks but some are much more common than others such as a personal area network (PAN) which is mostly
used for computer devices that are close to one person.
With PAN you would usually hook up scanner, printers, fax machines, telephones, and so forth all with the reach of a PAN which is between
LAN's are networks that are most often used in smaller areas such as a home or office. They are also based on Ethernet technology. It is very
important to understand the network layer or the three layer network because they are handling many subnets.
Sometimes the computer networks are connected using cables and hubs while others might be connected completely wireless. It all depends on the
number of computers that you are trying to connect, how your workspace is laid out, and your needs.
Any interconnection between public, private, commercial, industrial, or governmental networks is also considered an internet work. Today
interconnected networks use the Internet Protocol.
Which one will be used all depends on who administers them, that is what will determine if Intranet, Extranet, or Internet is used. Intranet
and extranets sometimes have connections to the Internet and if this is the case then both the intranet and the extranet are protected from being
accessed from the Internet without permission.
To build a simple computer network is done from two or more computers and adding a network adapter to each computer and connecting them
together with a special cable, often called a crossover cable. Ideally this process would consist of two computers and would be used for basic
home networking applications.
The purpose is so that two computers that would not normally be connected to each other would now have the ability to not only communicate
with each other but share virtually the same files and programs.
It is also possible to connect two computers without any extra hardware but by using a standard connection such as the RS-232 serial port on
both computers connecting through a special null modem cable.
Other devices that are used are hubs, switches, and routers.