Links and Webs - HTML and XHTML: The Definitive Guide - page 296

6.2.3. The http URL
The http URL is by far the most common. It is used to access documents
from a web server, and it has two formats:
http:// server : port / path # fragment
http:// server : port / path ? search
Some of the parts are optional. In fact, the most common form of the
http URL is simply:
http:// server / path
which designates the unique server and the directory path and name of
a document.
6.2.3.1. The http server
The server is the unique Internet name or IP numerical address of the
computer system that stores the web resource. We suspect you'll mostly
use more easily remembered Internet names for the servers in your
URLs. [*] The name consists of several parts, including the server's ac-
tual name and the successive names of its network domain, each part
separated by a period. Typical Internet names look like www.oreilly.com
or hoohoo.ncsa.uiuc.edu. [ ]
[*] Each Internet-connected computer has a unique addressa numeric (Internet Protocol, or IP) ad-
dress, of course, because computers deal only in numbers. Humans prefer names, so the Internet
folks provide us with a collection of special servers and software (the domain name system, or DNS)
that automatically resolve Internet names into IP addresses.
[ ] The three-letter suffix of the domain name identifies the type of organization or business that oper-
ates that portion of the Internet. For instance, "com" is a commercial enterprise, "edu" is an academ-
ic institution, and "gov" identifies a government-based domain. Outside the United States, a less-de-