Networking Concepts and Components

Networking Concepts and Components

A network is a group of interconnected systems sharing services and interacting by means of a shared communications link (see Figure 1.1). A network, therefore, requires two or more individual systems with something to share (data). The individual systems must be connected through a physical pathway (called the transmission medium). All systems on the physical pathway must follow a set of common communication rules for data to arrive at its intended destination and for the sending and receiving systems to understand each other. The rules that govern computer communication are called protocols.

In summary, all networks must have the following:

Something to share (data)
A physical pathway (transmission medium)
Rules of communication (protocols)

Merely having a transmission pathway does not produce communication. When two entities communicate, they do not merely exchange data; rather, they understand the data they receive from each other. The goal of computer networking, therefore, is not simply to exchange data, but to be able to understand and use data received from other entities on the network.

Because all computers are different, are used in different ways, and can be located at different distances from each other, enabling computers to communicate is often a daunting task that draws on a wide variety of technologies.

Remembering that the term "network" can be applied to human communication can be useful. When you are in a classroom, for example, the people in that class form a human information network (see Figure 1.2). In computer terms, the instructor is the server, and the students are network clients. When the instructor speaks, the language he uses is equivalent to a computer protocol. If the instructor speaks French, and the student understands only English, the lack of a common protocol makes productive communication difficult. Likewise, air is the transmission medium for human communication. Sound is really nothing more than wave vibrations transmitted across the air to our eardrums, which receive and interpret the signals. In a vacuum, we cannot communicate via speech because our transmission pathway is gone.

The goals of computer networking are to provide services and to reduce equipment costs. Networks enable computers to share their resources by offering services to other computers. Some of the primary reasons for networking PCs are as follows:

Sharing files
Sharing printers and other devices
Enabling common administration and security
Supporting network applications such as electronic mail and database services

You learn more about these important network functions later in this chapter.