CCNC/CCNC Module 1/Networks/Subsection Level CCNC Template16
The internet is the collection of all computers across the world which can access each other in some way. The links between computers might include telephone, fibre optic cable, radio, microwave or satellite. Today tens of millions of computers are able to access each other. The Internet has no central organisation which controls its use. Because the Internet knows no borders, many governments have tried to control the flow of information across the Internet. However, communications technology is so varied and so widespread that this is a near impossible task.
An intranet is similar to the Internet in operation. However, it is limited to an organisation. Users may browse computers within an intranet using a browser but will usually not be able to access the wider Internet. In the same way, outsiders will not be able to access the intranet of an organisation. An intranet can be thought of as a private Internet.
An extranet is an extension of a organisation's intranet to include outside users. In an extranet, outside organisations or individuals are allowed access to certain parts of the intranet. This access is usually controlled by means of passwords and access rights. These restrict which users can access the extranet and what they can do once they have access. The purpose of the extranet is to facilitate business transactions with other organisations.