DEFINITIONS AND EXPLANATIONS: INTERNET, INTRATNET, EXTRANET, LAN, MAN, WAN

INTERNET

The Internet is a global system of interconnected computer networks. It is not controlled by a central entity and therefore relies on network devices and accepted conventions and protocols to relay the data traffic until it gets to its destinations. Some countries have imposed rules to censor or otherwise control what kind of content is accessible by its citizen (i.e. China). However, except for the management of Internet Protocol addresses and the Domain Name System by ICANN (the Internet Corporation for Assigned Names and Numbers), the Internet remains unregulated and uncensored.

The beginnings of the Internet can be traced back to the 1960s when the United States funded research by its military agencies to develop a fault-tolerant and robust distributed network of computers. The Internet is now global and in theory can be accessed by anyone who can get access from an Internet service provider

The terms Internet and World Wide Web are often used in everyday speech without much distinction. However, the Internet and the World Wide Web are not one and the same. The Internet is a global data communications system. It is a hardware and software infrastructure that provides connectivity between computers. In contrast, the Web is one of the services communicated via the Internet. It is a collection of interconnected documents and other resources, linked by hyperlinks and URL. The Internet is also often simply referred to as the net.

INTRANET

An intranet is an information portal designed specifically for the internal communications of small, medium or large businesses, enterprises, governments, industries or financial institutions of any size or complexity. Intranets can be custom-designed to fit the exact needs of businesses no matter where they are situated. Users of intranets consist mainly of:

Members of the executive team. Accounting and order billing. Managers and directors. Sales people and support staff. Customer service, help desk, etc

It is a private network that is setup and controlled by an organization to encourage interaction among its members, to improve efficiency and to share information, among other things. Information and resources that are shared on an intranet might include: organizational policies and procedures, announcements, information about new products, and confidential data of strategic value. An intranet is a restricted-access network that works much like the Internet, but is isolated from it. As is the case with the Internet, an intranet is based on TCP/IP protocols. Therefore, a web page in an intranet may look and act just like any other webpage on the Internet, but access is restricted to authorized persons and devices. In some cases, access to an

intranet is restricted by not connecting it to other networks, but in other cases a firewall is used to deny access to unauthorized entities.The difference between an intranet and the Internet is defined in terms of accessibility, size and control

EXTRANET

An extranet is somewhat very similar to an intranet. Extranets are designed specifically to give external, limited access to certain files of your computer systems to:

Certain large or priviledged customers. Selected industry partners Suppliers and subcontractors.etc

Extranet is an extended intranet. In addition to allowing access to members of an organization, an extranet uses firewalls, access profiles, and privacy protocols to allow access to users from outside the organization. In essence, an extranet is a private network that uses Internet protocols and public networks to securely share resources with customers, suppliers, vendors, partners, or other businesses.

Both intranets and extranets are owned, operated and controlled by one organization. However, the difference between intranets and extranets is defined in terms of who has access to the private network and the geographical reach of that network. Intranets allow only members of the organization to access the network, while an extranet allows persons from outside the organization (i.e. business partners and customers) to access the network. Usually, network access is managed through the administration of usernames and passwords, which are also used to determine which parts of the extranet a particular user can access.

DIFFERENCE BETWEEN INTERNET, INTRANET AND EXTRANET

The Internet, extranets, and intranets all rely on the same TCP/IP technologies. However, they are different in terms of the levels of access they allow to various users inside and outside the organization and the size of the network. An intranet allows for restricted access to only members of an organization; an extranet expands that access by allowing non-members such as suppliers and customers to use company resources. The difference between the Internet and extranets is that while the extranet allows limited access to non-members of an organization, the Internet generally allows everyone to access all network resources

LOCAL AREA NETWORK

A local area network (LAN) supplies networking capability to a group of computers in close proximity to each other such as in an office building, a school, or a home. A LAN is useful for sharing resources like files, printers, games or other applications. A LAN in turn often connects to other LANs, and to the Internet or other WAN.

Most local area networks are built with relatively inexpensive hardware such as Ethernet cables, network adapters, and hubs. Wireless LAN and other more advanced LAN hardware options also exist. Specialized operating system software may be used to configure a local area network. For example, most flavors of Microsoft Windows provide a software package called Internet Connection Sharing (ICS) that supports controlled access to LAN resources. The term LAN party refers to a multiplayer gaming event where participants bring their own computers and build a temporary LAN.

For Example, The most common type of local area network is an Ethernet LAN. The smallest home LAN can have exactly two computers; a large LAN can accommodate many thousands of computers. Many LANs are divided into logical groups called subnets. An Internet Protocol (IP) "Class A" LAN can in theory accommodate more than 16 million devices organized into subnets.

METROPOLITON AREA NETWORK

Metropolitan Area Network is a data network designed for a town or city. In terms of geographic breadth, MANs are larger than local-area networks (LANs), but smaller than wide-area networks (WANs). MANs are usually characterized by very high-speed connections using fiber optical cable or other digital media.

Authors Kenneth C. Laudon and Jane P. Laudon of Management Information Systems: Managing the Digital Firm 10th ed. define a metropolitan area network as:

“A Metropolitan Area Network (MAN) is a large computer network that spans a metropolitan area or campus. Its geographic scope falls between a WAN and LAN. MANs provide Internet

connectivity for LANs in a metropolitan region, and connect them to wider area networks like the Internet”

WIDE AREA NETWORK

The wide area network, often referred to as a WAN, is a communications network that makes use of existing technology to connect local computer networks into a larger working network that may cover both national and international locations. A WAN is a geographically-dispersed collection of LANs. A network device called a router connects LANs to a WAN. This is in contrast to both the local area network and the metropolitan area network, which provides communication within a restricted geographic area. Here is how the wide area network functions, and why it is so important to communications today. As the term implies, a WAN spans a large physical distance.

Companies also make good use of the wide area network as well. Internal functions such as sales, production and development, marketing and accounting can also be shared with authorized locations through this sort of broad area network application. The concept of a wide area network as a means of taking individual location based computer networks and using them to create a unified computer network for the entire corporation means that employees can work from just about anywhere. Should one facility be damaged or rendered inaccessible due to natural disaster,

employees simply move to another location where they can access the unified network, and keep on working. A WAN differs from a LAN in several important ways. Most WANs (like the Internet) are not owned by any one organization but rather exist under collective or distributed ownership and management. WANs tend to use technology like ATM, Frame Relay and X.25 for connectivity over the longer distances.