1. Networks Mr Hewitt

2. Objectives By the end of this lesson you will be able to: Compare stand alone, networked and laptop computers Define a Network Explain the terms LAN and WAN Understand network topology

3. Types of computer Stand alone PCNetwork A PC that is not connected to any other computer Laptop PC A lightweight portable computer A collection of computers linked together CAN YOU GIVE A DEFINITION OF EACH?

4. What is a Network? What is a Network ‘A collection of computers are linked together so they can communicate’ ‘Networked computers can share hardware software and data’ Stand alone PCNetwork

5. What is a LAN LAN stands for a ‘Local Area Network’ The School network is a LAN All computers are in the same building Computers are permanently connected Each computer is a workstation There is a server with applications software, a list of users and passwords Lans users need a password to log on

6. What are the advantages of LAN’s? Shared software and peripherals e.g. printers Workstations can be lower spec Centralised information storage Users can communicate & share data

7. What are the disadvantages of LAN’s? Security is needed to protect programs A network technician is needed Faults can affect all users

8. What is a WAN? WAN stands for Wide Area Network Computers are spread over a large area Computers are linked by phone lines radio or satellite links The Internet is one big WAN Computers are not permanently connected

9. What are the advantages of WAN’s Ease of communication Access to information Work from home Advertising and E-business

10. What are the disadvantages of a WAN? Viruses - need firewall Lack of face to face interaction Costly Risk of data being intercepted

11. Line or Bus Networks All data is sent to and from the file server along a central line of cable. All terminals are connected to the central line Good Points: Cheap – doesn’t use much cable Bad Points: Can be slow as all data goes down the central line If the central cable fails, the whole network goes down

12. Ring Networks Terminals are linked in a ring, data flows around the network in one direction only Good Points Cheap to add computers Fast as data only flows one way Bad Points The system gets slow when there are lots of users If the central cable fails the whole network goes down

13. Star Networks In a Star Network, a large number of computers are directly connected to the server Good Points If one computer or a cable fails, the others will be unaffected This is the fastest network Bad Points If the central computer fails, the whole network will go down Uses lots of cable so is expensive

14. Wireless Networks In a wireless network, there are no wires! Computers have a wireless network card The server will act as a base station which will be able to receive wireless transmission of data