Introduction to networks

Intoduction
Communication begins with a message, or information, that must be sent from one individual or device to another. People exchange ideas using many different communication methods. All of these methods have three elements in common. The first of these elements is the message source, or sender. Message sources are people, or electronic devices, that need to send a message to other individuals or devices. The second element of communication is the destination, or receiver, of the message. The destination receives the message and interprets it. A third element, called a channel, consists of the media that provides the pathway over which the message can travel from source to destination.
Consider, for example, the desire to communicate using words, pictures, and sounds. Each of these messages can be sent across a data or information network by first converting them into binary digits, or bits. These bits are then encoded into a signal that can be transmitted over the appropriate medium. In computer networks, the media is usually a type of cable, or a wireless transmission.
The term network in this course will refer to data or information networks capable of carrying many different types of communications, including traditional computer data, interactive voice, video, and entertainment products.