1. Computer Networks

2. Lesson Objectives
You will learn basic terminology associated with Networks
You will learn about different network types
You will be able to list the advantages and disadvantages to using networks
You will understand several security issues which need to be understood.

3. Student task
Using the information on this presentation, Prepare a poster to include the following:
Definition of a network; firewall and router.
Two advantages of a computer network
Drawing of at least one type of network and their name.
One advantage and disadvantage of this network type.

5. WHAT IS A NETWORK?
A group of two or more computers connected (linked) together in order to share data or hardware.
Data – files eg, documents, videos
Hardware - Printers

6. Network Types (Layouts)
MESH
RING
STAR
FULLY CONNECTED
BUS
TREE
LINE

7. Advantages of a computer network
Files can be shared with many people who can work on these documents at the same time.
Hardware devices such as printers can be share among many computer users. (1 printer can be used by many people)
Software such as Microsoft office can be shared among users. This can save money.
A network can allow different users different access to information, for example, teachers have access to student information but not school finances.

8. Networks can be different sizes, and different layouts
The different sizes of network include LAN and WAN
The different layouts of network include Line, Ring, Tree, Hybrid and Star

9. LAN & WAN
LAN: Local Area Network. This is usually confined to a single room or building such as a school. Computers are connected with cables (wires).
WAN: Wide Area Network. This could be national, international or even global. Computers will only connect when they need to, using either telephone cables or satellite technology.

10. ROUTER WAN WAN WAN LAN Router Router LAN LAN
Allows safe sharing of resources among devices on a network.
LAN
Router
Router
LAN
WAN
LAN
WAN
WAN

11. Key terms for computer networks
Firewall
A firewall protects your network against unwanted access.
Key terms for computer networks

12. WHAT ABOUT THE INTERNET?
The Internet be described as a network of networks, that is a collection of networks.
For example, your school has a Local Area Network.
This network can connect with other networks over the whole world, to create the Internet

14. A LINE NETWORK
A line network is when all of the computers are connected to a main network cable, in a line.

15. LINE NETWORKS Advantages A line network is very easy to set up.
It is very easy to add to in the future.
Disadvantages
Data needs to travel in both directions along the main cable, and this can slow the data down, or cause crashes

16. A RING NETWORK
A ring network is when all of the computers are connected to a main network cable, but this cable is looped in a complete circle.

17. RING NETWORKS Advantages A ring network is very easy to set up.
Data travels in one direction only, meaning that it is faster, and less likely to crash
Disadvantages
It is not easy to add extra computers in the future.
In order to add a computer, the ring needs to be broken, preventing many computers from using the network at all

18. A STAR NETWORK
A star network is when all of the computers are individually connected to a central, very powerful computer.

19. STAR NETWORKS Advantages Each computer has its own connection
There is no problem with adding computers to the network.
If one or more should crash or be removed, the network doesn’t suffer.
Disadvantages
A star network much more complex to set up,
It is expensive to set up because more cable are involved.

20. A WIRELESS MESH NETWORK

21. WIRELESS MESH NETWORKS
A wireless mesh network uses a series of connection nodes
These nodes use standard Wi-Fi technologies ( a/b/g/n)
The nodes are programmed to choose the quickest path for data transmission (Dynamic Routing)

22. Cloud Computing

23. SECURITY ISSUES
Because data may be accessible from any computer, security needs to be very high
Users are likely to have different levels of access
Each user will have a username and password
Passwords will be changed regularly
Data needs to be regularly backed up
External connections need to be highly secure to prevent unauthorised access to the data
Physical security needs to be included