How do you address a message so that it reaches the appropriate destination? Traffic on the Internet reaches the correct destination through the use of name and address conventions. The "address" of a Web resource consists of the domain (for example, yahoo.com) plus additional information regarding the resource on the Web server (for example, yahoo.com/news/). The full "address" is called a Uniform Resource Locator, or "URL."
- www.amazon.com is a URL, while
- Amazon.com is a domain name.
A URL specifies a unique address to a resource on the Internet.
A resource can be a specific
- web page,
- a document, or
- an image.
URLs are sometimes called URIs, or Uniform Resource Identifiers, but URL is the more common term.
Delimiters, or marks, separate the parts of a URL address. In general, the first part of a URL indicates which protocol to use;
the second part specifies where the resource is located. The following MouseOver identifies and defines each part of a URL:
In addition to specifying an address, URLs can make requests of host computers. For example, the URL,
is a request for the computer named www in the domain
This type of URL was used for building interactive Web sites using CGI scripts and other programming techniques.
In the next lesson, the specifics of domain names will be discussed.