COMPUTER NETWORKING:OVERVIEW OF NETWORKING SERVICES

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OVERVIEW OF NETWORKING SERVICES

Thirty years ago, at the beginning of the evolution of computer networking, the principal goal was to create a communication system that would provide some or all of the following functional services:

• Exchanging (electronic) messages between computers (or their users)—today the popular name of this service is e-mail

• Transferring files between computers

• Providing remote access to computers

• Sharing resources between computers

E-mail is perhaps the most popular and most widely used service provided by wide area computer networks. E-mail provides easy-to-use, fast, cheap, and reliable offline communication for the users of the network. It allows not only one-to-one communication but one-to-many. Thus, mailing lists can be created as comfortable and effective communication platforms for a group of users interested in the same topics.

Of course, file transfer is essential. Computer files may contain different kinds of digitized infor- mation, not only texts and programs but formatted documents, graphics, images, sounds, movies, and so on. File transfer allows this information to be moved between hosts.

With the remote access service, one can use a distant computer just as if one were sitting next to the machine. Although not all operating systems allow remote access, most of the multiuser operating systems (UNIX, Linux, etc.) do.

Sharing resources makes it possible for other machines to use the resources (such as disk space, file system, peripheral devices, or even the CPU) of a computer. Well-known examples of resource sharing are the file and printer servers in computer networks.

Besides the above-listed basic functions, computer networks today can provide numerous other services. Operating distributed databases (the best example is the World Wide Web), controlling devices, data acquisition, online communication (oral and written), teleconferencing, radio and video broadcasting, online transaction management, and e-commerce are among the various possibilities.

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