Minggu, 10 Juli 2011

GRADE 8-UNIT 2

UNIT 2

Network Components
1.1          What is a Network?
You may have come across other types of network such as a bussines network or a friendship network. An example of such a friendship network is facebook.com where people from all over the word can echange information with each other.
A network is anny collection of idependent computer or device that communicate with one another over a shared network medium.
1.2          Component of a Network
A network is simply a group of device that are inter-connected. Some examples of these device are:
  • Computers
  • Printers
  • Scanners
  • Modems
The function of a network is to pass information between device that are connected. When you use a computer to communicate with another computer that someone else is using, you must use a network.
The network may be formed by using:
  • Copper cables
  • Fibre-optic cables
  • Radio waves
  • Infra-red rays
1.2.1      Network Interface Cards
Network interface cards, commonly referred to as network cards or NICs, are use to connect a PC to a network. The network card provides a connection between the network cable and the computer.
Your Computer can use a network card in order for it to connect to a network. These are also other types of devices that your computer uses to connect to a network.
1.2.2      Hub
The hub performs a very important role in connecting different computers together.  All members of the network share the same media to transmit data onto a single network. This means that each member will only get a percentage of the available network bandwith.
1.2.3      Cables
Network cables are used to connect the computer and device together. These cables carry the data that is sent in the network.
1.3          Types of Networks
There are several types of networks:
1.3.1      LANs (Local Area Networks)
A LAN is network ussualy confined to a small geographical area. This can be a building or a college campus.
A LAN can be small, linking as few as 3 computer. A large LAN can also link hundred of computers.
LANs are commonly found in bussines and educational organizations.

1.3.2      MANs (Metropolitan Area Network

 A MAN covers an area larger than a LAN and smaller than a WAN. It Connects 2 or more LANs, and usually covers an entire metropolitan area, such as a large city and its suburbs. Most universities use MANs.

1.3.3      WANs (Wide Are Network)

WANs connect multiple LANs and MANs tha are located id different places. This often done because computers may be located in different plaaces. A WAN ma be located throughout a country and even around the world.

WANs are created by connecting the different LANs and MANs using dara servise. Some example of data services are dedicated leased phone lines, dial-up phone lines, satellite link, and data packet carrier service. The Internet is a MAN. Banks and other organizations tha have a substansial presence in multiple countries use MANs.

1.4          The Internets

The Internet is a system of networks that are linked worldwide and facilities data communication services.

Some examples of data communication services are remote login, file transfer, electronic mail, the World Wide Web and newsgroups.

Internet websites provide personal, educational, political an economic resources to the entire planet.