NETWORK BASICS
  NETWORK ARCHITECTURE
 NETWORK TOPOLOGY

NETWORK DEFINITION
Network is a collection of computers and mobile devices connected together via communications devices and transmission media.

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

  • MODEM: Device that enables a computer to communicate over analog networking media.                       
  • WIRELESS ACCESS POINT: Device on a network that connects wireless devices to that network.
  • ROUTER: Device that connects multiple networks together.                                                                   
  • HUB: Device that provides common central connection point for nodes on network.                                 
  • SWITCH: Device used to connect multiple devices on a single network.                                                 
  • NETWORK INTERFACE CARD: An adapter card that connects a computer to a network.          
  • REPEATER: Device that enhances the weaken signal and repeat it at its original strength.                       

TRANSMISSION MEDIA
The materials or substances capable of carrying one or more signals.

Physical: Sends signals throught cable, wire or tangible materials.
Twisted pair cable: consists of pairs of copper wire that are twisted together
Coaxial cable:consisting of centre wire inside a grounded, cylindrical shield, capable of sending data at high speeds.
Fiber optic: Consists of dozens or hundreds of thin strands of glass or plastic that use light to transmit signals.

Wireless: Sends signals through air or space.
Infrared: sends signals using infrared light waves from one device to another.
Microwaves: radio waves that provide high-speed signal transmission using electromagnetic radio wave.
Cellular Radio: form of broadcast radio that is in wide use for mobile communication.
Broadcast Radio: distributes radio signal through the air over long distances and short distances.
Communication Satellite: earth-orbiting device that relays communication signals over long distances.
Bluetooth: 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 printer
 Undesirable Sharing: Viruses are easily spread over network and the Internet.         
Data and Information Sharing: enables 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 Communications: people communicate efficiently and easily via e-mail.
 Network Hardware, Software and Setup Costs: setting up a network requires an investment in hardware, software of network.
Internet Access Sharing: small computer networks allow multiple users to share a single Internat connection.                              
Illegal or Undesirable Behaviour: Typical problem include the abuse of company resources, distractions that reduce productivity, software piracy.
   
 Expense/Cost: the initial set up costs of a computer network can be high depending on the number of computers to be connected and the number of connecting devices/training/expert support needed.