How the World Wide Web Works

The Web is based on a set of rules for exchanging text, images, sound, video, and other multimedia files, which is collectively known as HTTP, or hypertext transfer protocol. Web pages can be exchanged over the Net because browsers (which read the pages) and Web servers (which store the pages) both understand HTTP.

But everything would still be chaos if the Web didn't have an addressing scheme that every computer on the network understands. An IP address is a 4- to 12-digit number that identifies a specific computer connected to the Internet. The digits are organized in four groups of numbers (which can range from 0 to 255) separated by periods. Depending on how the university or your ISP assigns IP addresses, you may have the same address all the time (static IP) or a different address each time you connect (dynamic IP).

Web servers (administered by the university, or your ISP) always have the same address. In addition, web servers also use an alias system that allows one or more non-numeric or symbolic addresses, when typed into a web browser, to connect to the webserver.

Internet domain names are the next level of Internet addressing, just as the street name is followed by the city and state. Domain names create a single identity for a series of computers used by a company or an institution. So while there may be 38 servers at a given company, each with its own IP address, they all share a common domain name, such as CNET.COM. The Domain Name Service (DNS) is responsible for mapping symbolic names to their numeric equivalents.

The domain name identifies all the computers in a group. But if you want to get to a specific page stored on any of those computers, you'll need an even more precise address. That's why every Web page on the Internet, and even the objects you see displayed on Web pages, has its own unique address, known as a Uniform Resource Locator (URL), which tells your browser exactly where to go on the server to find a page.

High level domain names refer to the final suffix in the full domain name. A high level domain name identifies the type of site where the web server resides. The "edu" suffix indicates that the web server is part of an aeducation site. The following are some common high-level domain names suffixes:

.com
A commercial organization
.edu
An educational site in the US
.gov
A government agency in the US
.mil
A military site in the US
.net
A network site
.org
A non profit organization

The following are new domain names that has recently been approved. Look for these 7 new high level domain names some time next year:

 

.aero
Aviation-related businesses
.biz
General business and to augment, replace, and compete with .com
.coop
Co-ops or cooperative businesses as defined by the proposing registrar
.info
Businesses in the information industry
.museum
Museums
.pro Professionals, such as accountants, attorneys, dentists, and physicians
.name
Personal names, with the most likely application being “myhomepage.name”

Back to Syllabus