1. WJEC GCSE Computer Science
Unit 1
Networks

2. Objectives Describe network topologies and connections including:
Local Area Network (LAN) and Wide Area Network (WAN)
Bus, Ring, and Star Topologies
Different methods of connection including wired and wireless connection

3. Networks
A network consists of a number of computer systems connected together. There are many advantages and disadvantages of using a computer network over a standalone computer.

4. Advantages of Networks

5. Disadvantages of Networks

6. LAN and WAN There are two different types of network:
Local Area Network (LAN)
Wide Area Network (WAN)

7. LAN
A LAN is a network in which the computer systems are all located relatively close to each other, e.g. in the same building or on the same site, such as a school.

8. WAN
A WAN is a network in which the computer systems are all located relatively distant from each other, e.g. in different buildings all over the country or in different countries.
The Internet is an example of a WAN.
Many LANs could be linked using a WAN.

9. Workbook
Complete section 4a Q1

10. Network Topologies
A network topology is the theoretical layout of computer systems on a network. There are a number of different network topologies:
BUS
RING
STAR

11. Bus Network
The computer systems, also called nodes of the network, are each connected to a single cable on which data can be sent, called the bus. A bus network has terminators on each end, which is needed to ensure that the network functions correctly.

12. Bus Network

13. Bus Network

14. Ring Network
In a ring network, computer systems are connected in a ring or a loop. Around the ring, packets are sent, being passed from one computer system to the next until they arrive at their destination.

15. Ring Network

16. Ring Network

17. Star Network
In a star network, each computer system is connected to a central node - a hub or switch.

18. Star Network

19. Star Network

20. Workbook
Complete section 4a Q2