A network is a collection of data communication hardware, computers, data communication software and data communication media, all connected in a meaningful way to allow users to share information, resources and equipment.

Networks are becoming increasingly important in today's computing world. Almost every large office has a network, and more are set up daily.

Networks can be made up of anything from telephones or telegraphs to computers connected by fibre optic cable. They can also be used for many things, from playing games with multiple players to connecting various universities together.

There are 3 types of general networks:

Private
This is a network that is owned and used by one firm for its needs. It is not accessible by the rest of the world. It is not restricted to a geographical area.

Public
It is a network offered to the public, for a fee. Often these public networks are based in a geographical area within a country. The telephone system is an example.

International
This is a collection of private and public networks connected to each other over international boundaries. The Internet is a good example of this category of network.

In order to serve such varied needs, a number of configurations is used for different networks.

Network Configuration

In order to serve the needs of the organization, networks are organized into three configurations:

LAN Local Area Network
This is a network that is located in one small geographical area, such as a building. This is the type of network most commonly used. The Internet is a network of over 40,000 networks and is considered a Global Network. In addition to these configurations, there are various topologies used when setting up a local area network.

Network Configuration Topologies

Network topologies have gone through many evolutions since the first network was introduced. After the development of new technologies and methods, better, more efficient designs have been introduced.

There are three main topologies that are used:

1. Bus Network
2. Ring Network
3. Star Network

Bus Network

A bus network is a line of computers connected together by a cable. The cable is called the bus. The bus must be terminated at both ends.

Data can flow between machines, and each machine has some of the software used by the entire network. This can lead to data clashes if the same request is made at the same time by two machines. Ethernet uses a modified type of bus network.

This sharing of information between machines means that only one copy of the software and/or data has to exist.

Ring Networks

A ring network is a bus network that has been attached at both ends. The data in a ring network travels in 1 direction only. Data clashes can occur for the same reasons as in a bus network.

In order to eliminate data crashes, an improvement was made to the ring network by adding a token. A token is an electronic impulse that runs around the ring. In a ring network with a token, called a Token Ring Network, the token travels around the ring, from machine to machine. A machine can only send a request or receive data when the token is at its machine. This eliminated data clashes since two requests could no longer be entered at the same time.

Star Networks

A star network is a network where each machine is connected to a central machine, called a server. The server holds all the software, and the other machines, called nodes, request the software from it. Since the server receives all the requests, it can handle them one by one, and there are no data crashes. It is possible to have a star network spawn another star network.

This is an example of a star network:

A star network is a form of hierarchical network because each machine can use the resources of higher networks and machines, but not of the ones below it. The Novell network in Computing Services in the Computer Centre is a star network.

Star networks are one of the most popular forms of network.