BASIC CONCEPT


BASIC CONCEPT OF NETWORK	NETWORK ARCHITECTURE	NETWORK TOPOLOGY

Network

a collection of computers and mobile devices connected together via communications devices and transmission media, often wirelessly allowing computers to share resources.

Computer networks usage:

- Sharing an internet connection among several users.

- Sharing application software, printers and other resources.

- Exchanging files among network users and over the internet.

Communication device

Hardware component that enables a computer to transmit and receive data, instructions, and information to and from one or more computers.

Examples	Function
Hub/Switch	A communication device that enables a computer or device that does not have built-in networking capability to access a network
Modem	A device that enables a computer to communicate over analog networking media Wireless modem: modem that connects to the serial port but does not connect to telephone lines because it receives through air.
Wireless Access Point	A device on a network that connects wireless devices to that network
Router	A device that connects multiple network together.
Hub	The device that provides a common central connection point for nodes on network
Switch	A device used to connect multiple devices on a single network
Network interface card	An adapter card that connects a computer to a network.
Repeater	A device that enhance the weaken signal and repeat it at its original strength.

Transmission media

The materials or substances capable of carrying one or more signals

Physical : Send signals through cable, wire or tangible materials	Twisted-pair cable	Physical transmission media which the cable consisting of pairs of copper wire that are twisted together
	Coaxial cable	A networking cable consisting of centre wire inside a grounded, cylindrical shield, capable od sending data at high speeds
	Fiber optic	Physical transmission media that consists of dozens of hundreds of thin strands oc glass that use light to transmit signals
Wireless : send signal through the air or space	Infrared	Send signals using infrared light waves from one device to another.
	Microwaves	Radio waves that provide a high speed signal transmission using electromagnetic radio wave.
	Cellular radio	Is a form of broadcast radio that is in wide ise for mobile communication
	Broadcast radio	Distributes radio signal through the air over long distances and short distances.
	Communication sattelite	Is a space station that receives microwave signals from an earth based station.
	Bluetooth	A networking standard for every short range wireless connection.

Advantages of network

Disadvantages of
  network

  Hardware sharing

  -         
  Network facilitate the
  sharing of hardware devices such as printers, plotters and modem

  Undesirable sharing

  -         
  Viruses are easily spread
  over network and the internet.

  Data and information sharing

  -         
  Enable many people to access and
  share the same data such as database and group software development

  Security issues

  -         
  A computer hacker can get unauthorized
  access by using different tools

  Facilitate communication

  -         
  People communicate
  efficiently and easily via e-mail, IM, VoIP

  Network Hardware, Software and Setup Costs

  -         
  Setting up a network requires
  an investment in hardware, software of network