Internet technologies.

1. Basic concepts Internet. The universal identifier of resources (URI), its assignment and components.Service DNS.

A URL (Uniform Resource Locator) is a form of URI and is a standardized naming convention for addressing documents accessible over the Internet and Intranet. An example of a URL is http://www.computerhope.com, which is the URL for the Computer Hope website.

Overview of a URL

Below is additional information about each of the sections of the http URL for this page.

http://

The "http" stands for HyperText Transfer Protocol and is what enables the browser to know what protocol it is going to use to access the information specified in the domain. After the http is the colon( : ) and two forward slashes ( //) that separate the protocol from the remainder of the URL.

www.

Next, www.stands for World Wide Web and is used to distinguish the content. This portion of the URL is not required and many times can be left out. For example, typing "http://computerhope.com" would still get you to the Computer Hope web page. This portion of the address can also be substituted for an important sub page known as a subdomain. For example, http://support.computerhope.com forwards you to the main help section of Computer Hope.

computerhope.com

Next, computerhope.com is the domain name for the website. The last portion of the domain is known as the "domain suffix", or TLD, and is used to identify the type or location of the website. There are dozens of other domain suffixes available. To get a domain, you would register the name through a domain registrar.

/jargon/u/

Next, the "jargon" and "u" portions of the above URL are the directories of where on the server the web page is located. In this example, the web page is two directories deep, so if you were trying to find the file on the server, it would be in the /public_html/jargon/u directory. With most servers, the public_html directory is the default directory containing the HTML files.

url.htm

Finally, url.htm is the actual web page on the domain you're viewing. The trailing .htm is the file extension of the web page that indicates the file is an HTML file. Other common file extensions on the Internet include .html, .php, .asp, .cgi, .xml, .jpg, and .gif. Each of these file extensions performs a different function, just like all the different types of files on your computer.

The structure of the URL is shown in the figure below.

Figure 22: Structure of the URL

There are several domains available in the web such as:

edu = education institute

com = commercial enterprise

gov = government

org = organization

net = network provider

mil = military

2. Web technologies: HTTP, DHTML, CSS, and JavaScript.

Internet Protocols

Table 10- The Internet Protocols

The Internet uses a variety of languages to transmit information from one place to the other. These languages are called protocols. Using these protocols we can acquire the services from the Internet. Each protocol has a specific functionality and www is considered to be the largest service acquired amongst the services provided by the Internet.

Internet is an interconnection of computer networks all around the world. In other words, it is the hardware which forms the physical layer to these connections is what we refer to as the Internet. Hence, the Internet comprises of network of computers, fiber-optic cables, copper wires and wireless networks. But www is the software which is used to access the information from the Internet. It consists of files, folders and the documents which are stored in different computers. Now it is crystal clear to you that the www depends on the Internet to work.