OVERVIEW OF THE INTERNET

ARPANET

• Network become internet.
• First published: 1967(under the directions of the U.S. Advanced Research Projects Agency (ARPA)
• 1969 : ARPANET  took advantage of the new idea which is sending information in small unit called packets that could be routed on different paths and reconstructed at  their destination. 
• 1970 : Expand the size of the network which had become a network of networks, in an orderly way.
• 1980 : ARPANET handed over to separate new military network, the Defense Data Network, and NSFNet, network of scientific and academic computers funded by the National Science Foundation.
• 1995 : NSFNet turn began a phased withdrawal to turn the backbone of the internet over to a consortium of commercial backbone providers.
• 1971 : ARPA's name changed to Defense Advance Research Projects Agency(DARPA)

INTERNET

A means of connecting a computer to any other computer anywhere in the world via dedicated routers and servers. When two computers are connected over the internet, they can send and receive all kinds of information such as text, graphics, voice, video, and computer programs.No one own Internet , although several organizations the world over collaborate inits functioning and development. The high-speed, fiber-optic cables (backbones) through which the bulk of the Internet data travels are owned by telephone companies in each country. Later universities and other US institutions connected to it. this result in ARPANET growing beyond everyone's expectations and acquiring the name 'internet'.

Resource : http://www.businessdictionary.com/definition/internet.html

INTRANET

An intranet is a private network that is contained within an enterprise. It may consist of many interlinked local area networks and also use leased lines in the wide area network. Typically, an intranet includes connections through one or more gateway computers to the outside Internet. The main purpose of an intranet is to share company information and computing resources among employees. An intranet can also be used to facilitate working in groups and for teleconferences.

Resource : http://searchwindevelopment.techtarget.com/definition/intranet

EXTRANET

An extranet is a controlled private network allowing customers, partners, vendors, suppliers and other businesses to gain information, typically about a specific company or educational institution, and do so without granting access to the organization's entire network. An extranet is often a private part of a website. It is restricted to select users through user IDs, passwords and other authentication mechanisms on a login page.

ADVANTAGES 

INTERNET	INTRANET	EXTRANET
Gain information, knowledge and learning. Example :            Search engine like google, can ask virtually any question and find a web page with an answer.            Millions of videos on site like youtube that help to explain various topics .           Online course can be taken to help teach you about many different subjects.	Communication within an organization or business company , landscape or potrait.          Helpful to converse planned intiative that has transportation are chat, email,  and blogs.            Actual world example of intranet is nestle had a number of food processing plants.	Reduced margin of error.         Reduce your margin of error, especially when you use it to give specific groups access to internal applications.          Involve something as simple as giving customers access to their order histories, or something as complex as processing orders from distributors and suppliers.
Connectivity, communication, and sharing Example :           Send an e-mail to anyone in the world.         Its delivered in less than a minute.	Offering business operations and administration solutions because it also being used as a platform of mounting and organizing applications across the internet world.	Flexibility.           Everyone can operate when and where it’s most convenient.           This self-serve approach frees you from unnecessary meetings and phone tag, and it cuts down on the costs associated with in-person information exchanges. For example, an extranet may allow you to provide customer-service information outside of regular business hours.
Banking, bills and shopping Example :            Everyone easy access to compare prices between companies.            See what others thinks about a product through online reviews to help make better purchasing decisions.	Time saving           There is no need to maintain physical documents such as procedure manual, requisition forms, and internet phone list.	Timely and accurate information.            On an extranet you can instantly change, edit, and update sensitive information such as price lists or inventory information.
Selling and making money	Offer improve teamwork through which teamwork is enabled and all certified users can get access to information.	Reduced inventory.            By linking your inventory system directly to a supplier, you can process orders as soon as the system knows you need them, thus reducing the stock you keep on hand and making the procurement process more efficient.
Donations and funding Example : People can quickly make a donation to their favourite charity Help fund projects and idea at their blog	Intranet providing cross platform capability for UNIX, Mac, Windows.	Build customer loyalty.            Extranets make business easier for your customers. The more you make timely, accurate information available to your customers, the more likely it is you’ll keep their business.

DISADVANTAGES

Disadvantages of Internet

• Theft of personal information such as name, address, credit card number etc.
• Virus threats nothing but a program which disrupts the normal functioning of your system.
• Spamming refers to receiving unwanted e-mails in bulk, which provide no purpose and needlessly obstruct the entire system.
• Pornography this is perhaps the biggest threat related to children’s healthy mental life. A very serious issue concerning the Internet.Though, internet can also create havoc, destruction and its misuse can be very fatal,

Disadvantages of Intranet

•Collaborative applications for Intranet are not as powerful as those offered by traditional groupware 

 For instance, Intranet includes no built-in data replication or directory services for remote users, while groupware packages such as Lotus Notes do.

•Short-term risk -

There are limited tools for linking an Intranet server to database or other  back-end mainframe-based applications. Programming standards for the Web, such as common gateway interface (CGI) and Java are fairly new and just maturing.

•Less back-end integration -

With Intranets, firms have to set up and maintain separate applications such as E-mail and Web servers, instead of using one unified system as with group ware.

 Disadvantages of Extranet

• Extranets can be expensive to implement and maintain within an organization (e.g.: hardware, software, employee training costs) — if hosted internally instead of via an ASP.
• Security of extranets can be a big concern when dealing with valuable information. System access needs to be carefully controlled to avoid sensitive information falling into the wrong hands. 
• Extranets can reduce personal contact (face-to-face meetings) with customers and business partners. This could cause a lack of connections made between people and a company, which hurts the business when it comes to loyalty of its business partners and customers.
• People who are illiterate & don’t have any technology knowledge can feel some problem that how to use it.
• Face to face contact is impossible .so we can not meet personally to any customer or dealer.
• As eye to contract is impossible so we cannot judge that who is using our information is true or wrong. It is possible that he or they can misuse our secrets or our information.
• Small business or small corporate cannot bear this technology’s cost as it can increase their expenses.
• Our business competitors or our business enemies can misuse our secrets information.
• It reduces the number of employment.
• There are many places, where the technology is not developed so it could not work there.