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Understanding the Internet

How the Internet Works

The Internet is a collection of millions of computers joined together on a computer network. The network allows all of the computers to communicate with one another. When you connect to the Internet from home, you normally would use a telephone line and a modem that dials GRU.net, your Internet Service Provider (ISP).

GRU.net then connects to a larger ISP, which connects to an even larger ISP. The largest ISPs maintain fiber-optic "backbones" for an entire nation or region. Backbones around the world are connected through fiber-optic lines, undersea cables or satellite links. In this way, every computer on the Internet is connected to every other computer on the Internet.

Exploring the World Wide Web

Information on the Web is stored on Web pages. A Web page is a document that can contain words, pictures, sounds, and much more. To view Web pages, you use a software program called a Web browser. GRU.net recommends that you use Microsoft Internet Explorer, which is already installed on computers running any version of Microsoft Windows operating systems.

If you know what page you want to read, you can go right to it. You can do this by typing the Web page address into the Web browser. This address is called the Uniform Resource Locator, or URL.

If you want to randomly browse for information, you can "flip" through pages until you find something that interests you. Most Web pages have links to other Web pages. A link can be a word, a group of words, or an image. You can click a link to view another Web page. If you don't know a Web page's address, links are a convenient way to find related information.

You can also use search engines to locate information based on a subject. After you type a subject, a list of Web pages about that subject appears.

How Web Browsers Work

Every Web page on the World Wide Web includes a unique address so that Web browsers can find it. This address is called the Uniform Resource Locator, or URL. For instance, the visitor's page for the University of Florida is located at http://www.ufl.edu/visitors.html. When you type a URL into a Web browser, the page appears. This happened because your browser connected to a Web server, requested a page from that server, and the server sent it back to you.


Figure 1: How a Web page is brought to your screen.

However, there are more detailed steps that occurred for this to work. These are the steps that occurred behind the scenes:

  • The browser broke the URL into 3 parts:
    1. The protocol ("http")
    2. The server name ("www.ufl.edu")
    3. The file name ("visitors.html")
  • The browser communicated with a name server to translate the server name "www.ufl.edu " into an IP Address, such as 128.227.10.2.
  • The browser then formed a connection to the server at that IP address.
  • Following the HTTP protocol, the browser requests the file "http://www.ufl.edu/visitors.html" from the server.
  • The server then sent the HTML text and images for the Web page to the browser.
  • The browser read the HTML tags and formatted the page onto your screen.

As you can imagine, viewing a Web page is dependent on many different computers and servers, so it might take some time to see the page. Most of the time this occurs in a matter of seconds, but other times there's a small delay, or lag. Sometimes a page won't be able to be viewed at all because one of the servers is temporarily offline.

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