2011/10/20

The Internet

   The Internet is a network of autonomous computer networks that spans the globe. It provides an infrastructure for global electronic information exchange. Today the Internet is used by millions of people of facilitate various activities such as business, education and plain communication.

   The Internet grew out of a United States Department of Defense project, the ARPANET (Advanced Research Project Agency Network) started in late 1960s. Its main objective was to provide network links between universities, research organizations and remote computer centers.

            The following figure shows how the Internet is structured. At the bottom level are the organizations and home uses connected to the Internet. Typically users connect to the Internet through local Internet Service Providers (ISPs). The ISPs are in turn connected to the Internet Backbone through regional networks. Typically ISPs lease high-bandwidth lines that connect into the Internet and rent that bandwidth to Internet users.

             Typically a home user (client) connects to the Internet via telephone lines. If the telephone network is analog a modem is needed in between the computer and the telephone line to convert digital signals generated by the comuter to analog signals that are being transmitted by the telephone network.

              When a client registers with an ISP for Internet usage he will get an account. To access the Internet by using this account, the client has to dial the ISP and log on to this account.

             On the Internet information is available mainly through three mediums: the World Wide Web (WWW), Usenet News (News) and Electronic Mail (e-mail). The WWW is built on top of the Internet. It can be viewed as a large notice board with posters and printed notices stuck to it. On the WWW Web servers provide information on the Internet. A user can access the information by using a web browser.
  • To Connect to the Internet, your dialer software calls an access number.
  • Your modem converts the signals from your computer to signals that travel over wire lines to an Internet service provider (IPS).
  • Your IPS provides the connection to the Internet.

2 comments:

Nimesh Suranga (නිමේෂ් සුරංග) said...

Good Post keep it up

Administrator said...

Thank You Nimesh..

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