Network Definition

Networks are systems that are formed through connections. For example, roads connecting groups of people form physical networks. Connections with your friends make you your personal network. Websites that allow people to link to each other’s pages are called social networking sites.

People use the following networks every day.

Mail delivery system
Telephone system
Public transport system:

The public transportation system is like a computer network. Cars, trucks and other vehicles are like messages that travel across the network. Each driver defines a starting point (a source computer) and an end point (a destination computer). Within this system, there are rules for stopping indicators and traffic lights, which control the flow from source to destination.


Networking Principles


    Host Devices

A computer network consists of a variety of devices. Some devices may act as either hosts or peripherals. A host is a device that sends and receives information over the network. The printer attached to your laptop is on screen. If the printer is directly connected to a network, it is acting as a host.

Many different types of host devices can connect to the network.

Note: An Internet Protocol phone, known as an IP phone, connects to a computer network rather than a traditional telephone network. Computer networks are used in businesses, homes, schools and government institutions. Many networks are connected through the Internet. A network can share different types of resources.



                                                                                                                                          Intermediary Devices

Computer networks have many devices available between host devices. These intermediate devices ensure that data flows from one host device to another host device. The most common central devices are shown in the figure.

A switch is used to connect multiple devices to a network. A router is used to drive traffic between networks. A wireless router connects multiple wireless devices to the network. A modem is used to connect a home or a small office to the Internet .


  Network Media

  • A network is discussed over a medium. The medium provides the channel at which the message travels from source to destination. Medium is assembled for media.

    Network devices are connected to each other using different media. As shown in Figure 1, these media are:

  • Fiber optic cabling – Uses glass or plastic fiber to carry information like light.
    Wireless Connections – The next topics discussed are radio signals, infrared technology, or satellite transmission local area networks (LANs), wide area networks (WANs), and wireless networks. The cloud will be used to represent connections to the Internet throughout the course. The Internet is often the source of communication between one network and another .