Data Communication and networking are changing the way we do business and the way we live. Business decisions have to be made over more quickly, and the decision makers require immediate access to accurate information. Why wait a week for that report from Germany to arrive by mail when it could appear almost instantaneously through computer networks? Business today rely on computer networks and internetworks operate, what types of technologies we are available, and which design best fills which set of needs.
The development of the personal computer brought about tremendous changes for business, industry, science, and education. A similar revolution is occurring in data communications and networking. Technological advances are making it possible for communications links to carry more and faster signals. As a result, services are evolving to allow use of this expended capacity. For example, established telephone services such as conference calling, call waiting, voice mail, and caller ID have been extended.
Research in data communications and networking has resulted in new technologies. One goal is to be able to exchange data such as text, audio, and video from all points in the world. We want to access the internet to download and upload information quickly and accurately at any time.
This chapter addresses four issues: data communications, networks, the internet, and protocols and standards. First we give a broad definition of data communications. Then we define networks as a highway on which data can be travel. The internet is discussed as a good example of an internetwork (i.e., a network of networks). Finally, we discuss different types of protocols, the difference between protocols and standards, and the organizations that set those standards.
1.1 DATA COMMUNICATIONS
When we communicate, we are sharing information. This sharing can be local or remote, between individuals, local communication usually occurs face to face, while remote communication takes place over distance. The term telecommunication, which includes telephony, telegraphy, and television, means communication at a distance (Tele is Greek for “far”)
The word data refers to information presented in whatever form is agreed upon by the parties creating and using the data.
Data communication are the exchange of data between two devices via some form of transmission medium such as wire cable. For data communications to occur, the communicating devices must be part of a communication system made up of a combination of hardware (Physical equipment)
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