Principles Digital Communication System & Computer Networks (Charles River Media Computer Engineering)

24.1 INTERNET APPLICATIONS

From an end user point of view, the Internet provides the following applications:

Electronic mail (e-mail): Users can send messages to one another—the message can be text along with attachments of different types—graphics, audio or video clips, and executable programs (and unfortunately, viruses as well). E-mail is now used extensively for business correspondence in addition to sending personal messages.

File transfer: Users can download or upload files (documents or executable programs) from one computer to another. Nowdays, many software packages are distributed using this mechanism instead of distributing the software on floppies, CD-ROMs, or tapes.

Remote login: Users can log in to another computer and use its resources; of course, the necessary permissions are required to log into the other machine. This provides the scope for collaborative working—a researcher in India can log in to the computer of a U.S. university to carry out research in highly specialized areas.

Interactive applications: Different users can log in to a server for interactive applications such as chat and games. Nowdays, the Internet is also being used for interaction among people using voice and desktop video. Software packages such as Microsoft NetMeeting provide the facility to chat using text, voice, and video and hold a business meeting.

World Wide Web: The World Wide Web (in short, the Web) has revolutionized Internet use. The Web provides the means of accessing information without knowing where the resource is physically present. With the Web site address http://www.iseeyes.com, we get information about the company with that address. Where that information is located (on which server) is not even known to us. The information that is presented on your desktop may contain links to other resources and, when you click on a link, you will automatically get that information. The Web provides the information not just in text, but with multimedia content. In many parts of the world, though, this poses problems because downloading voice and video takes a lot of time. In those parts of the world, WWW is called world wide wait.

Initially, Web pages were noninteractive, but now interactivity is provided whereby the user can input information to be processed by the server, and output is given to the user. This led to many interesting applications, particularly in e-commerce. Business to business commerce and business to consumer commerce are now the most promising applications. Supply chain management, wherein a business can do the paperwork for obtaining raw material and for supplying finished goods through the Internet, will be the next killer application. Workflow automation, wherein the entire movement of information within an organization can be automated, can lead to true paperless office. All these exciting applications are now paving the way for an Internet economy—the whole economy is now centered around the Internet. "Web services" is the term used to provide such applications using standard Web protocols and development tools.

Presently, we access Web services through our desktop PCs. Voice-enabled Web, whereby Web services can be accessed through telephones, is now on the drawing board, using speech recognition and text-to-speech conversion technologies.

Distributed applications: The Internet is a repository of knowledge. One can obtain information available on millions of servers without knowing the exact location of the information. One can use a search engine (such as Google, Yahoo!, or AltaVista) to get this information. If the search engine is provided with keywords, the engine will search various servers and present the user with the various resources corresponding to that keyword. Of course, this is now leading to an information explosion. If you search for the keyword Artificial Intelligence and are provided with a million resources, which one do you select? Intelligent search engines will soon provide more focused information for your requirement.

Broadcasting: Internet can be used to broadcast voice and video programs as well, though bandwidth is a limitation presently. One can tune one's desktop to an Internet radio station (by giving the Web address) and listen to music or watch a video clip.

Web-based learning: The Internet is also revolutionizing education. We no longer need to attend traditional classroom lectures. We can sit in the comfort of our living rooms and attend lectures delivered through the Internet and also interact with the lecturer. We can take online examinations and obtain certification. Distance education using the Internet infrastructure is now catching up and is a threat to all the second-rate universities. Many western countries offer formal degree programs using this approach.

In addition to the basic services such as e-mail, file transfer, remote login, and the World Wide Web, a number of inter-active and distributed applications are supported by the Internet, including audio/video broadcasting, two-way and multiparty audio/video conferencing, distributed database access, e-commerce, and Web-based learning.