1. 1.4 wired and wireless networks lesson 1

2. The Big Picture: Wired and wireless networks
Types of networks:
LAN (local area network) & WAN (wide area network)
The different roles of computers in a client-server and a peer-to-peer network
Factors that affect the performance of networks
Network topologies
The hardware needed to connect stand-alone computers into a local area network:
Wireless access points
Routers/switches
NIC (network interface controller/card)
Transmission media
The internet as a worldwide collection of computer networks:
DNS (domain name server)
Hosting
The cloud
The concept of virtual networks

3. Thought for the day - Networks
What is the biggest network that we use?
How many networks do you think you use in a day?
How many have you used today?

4. Introduction to networks
Consider this:
Why do we think it is a good idea to network computers together?
What did we hope to gain from networking computers together?
Watch video:

6. Learning Objectives By the end of today’s lesson, you will:
Understand why we network computers together
Be able to describe what is meant by a LAN
Be able to describe what is meant by a WAN
Understand what is meant by a client-server network
Understand what is meant by a peer-to-peer network

7. Starter What is the biggest network that we use?
How many networks do you think you use in a day?
How many have you used today?

8. Thinking about networks
Identify 5 daily activities that you use a network for
Could you carry our these activities without the use of a network.
Are there any activities that you cannot do, or would need to change without the use of a network?

9. What is a computer network?
Two or more computers connected together to share information and resources.
This could be a wired network using physical cables or wireless connections, or both

10. Benefit 1 – Sharing resources
Benefits of a network
Benefit 1 – Sharing resources
Sharing an Internet connection
Sharing folders and files so you can access your own documents and shared documents from any computer on the network
Sharing software (legally)
Sharing peripheral devices such as printers and scanners

11. Benefit 2 - Communication
Benefits of a network
Benefit 2 - Communication
Using to communicate with colleagues
Transferring files between computers
Using messaging systems/video calls to hold remote meetings, conference calls, to talk online using VOIP

12. Benefit 3 – Centralised Management
Benefits of a network
Benefit 3 – Centralised Management
Centralised backup of all files
Users can use any PC on the network but still see their own files
Software can be distributed across the network rather than having to install it on each computer
User profiles and security can be managed centrally
Security can be set up across the network eg user access, firewalls, virus checking etc

13. Possible issues with a network
Security – need to be vigilant in protecting data, setting appropriate access policies, and maintaining high standard of security
Expertise is needed to create and maintain them
Issues when the network “goes down”
Reliance on internet

14. Ways to describe a network
There are several ways to describe a network of computers:
The relationship between the computers that make up the network
The geographic area the network covers
Topology – the layout of the computers

15. Client Server vs Peer-Peer
There are two ways of setting up a network to share data and services where computers have different relationships with each other
Client Server
Peer-Peer
The network relies on a central server
All clients (devices) request services from the server (e.g. print services / file services)
Additional hardware would be needed e.g. high end powerful servers
Client computers are a lower spec than the server
Servers can be specialised eg printer server, server
Server can be a computer or the software
All computers have equal status
Each device can act as a client and a server
All devices can request and provide network services
No additional hardware / software needed to set up this type of network so are easy to set up

16. Client Server vs Peer-Peer

17. Client Server vs Peer-Peer
File/Software Storage
All files can be stored centrally on a Client-server
Workers can access files from any computer
All computers can update central databases
On Peer-Peer all files are stored on their own computers
Users have to log-in to the same computer every time to acces their files

18. Client Server vs Peer-Peer
File/Network Back-up
Backups are easily managed on a Client-Server as these can be done centrally from the File Server
All data is backed up in one go
Individual computers do not need to be backed up
With Peer-Peer all computers are responsible for backing up their own files

19. Client Server vs Peer-Peer
Network security
Centralised security on Client-Server – antivirus and firewall can be installed and configured from a central location
Peer-Peer – individual security may need to be installed on individual machines, so may not be consistent. Also, direct file sharing, whilst a useful feature, has led to much illegal file sharing online

20. Client Server vs Peer-Peer
Amount of network traffic
Peer-Peer is appropriate for a small number of computers and a low traffic environment. Can become unpredictable and slow
Client-server is useful for if there are lots of computers and it will be a high traffic environment.

21. Show your understanding
Complete the worksheet by ticking the correct box(es) to show whether the statements apply to a client-server, a peer-to-peer or both networks
Wired and Wireless Networks_L1_P2P_CS.docx

22. LAN vs WAN
Networks can also be described by the geographic area they cover.
There are 2 main
LAN (Local area network)
WAN (Wide area network)
And also
PAN (Personal area network)

23. LAN vs WAN LAN (Local area network)
Computers are connected together over a small geographical area such as a single building or a single site
LAN has its own infrastructure of cabling and network hardware due to distance and practicalities
E.gs of LANs
Home network
School network
Network in a shop

24. LAN vs WAN WAN (Wide area network)
Computers are connected over a large geographical area. This could be several buildings/sites, town wide, county wide or even country wide.
WAN uses external hardware and external infrastructure e.g. use of satellite, phone lines or The Internet, provided by a telecoms company
The biggest WAN would be a global collection of networks (known as The Internet)

25. Other geographic networks
PAN - Personal Area Network
Personal devices are connected, often in the home
Transmission over a short distance (10m) by devices such as laptops, phones, tablets, media players, speakers, printers
Bluetooth could be used as well as wi-fi/cables
MAN – Metropolitan Area Network
Devices are connected in a city
Less common now that it used to be due to the widespread availability of fast mobile data using 4G
VPN - Virtual Private Network: will come back to this!

26. Show your understanding
Complete the worksheet by filling in the characteristics and functions of a LAN and a WAN:
>Log into Moodle>Go to ICT & Computing>GCSE Computer Science >Computer Systems>
1.4 – Wired and Wireless Networks >
iBytes Wired and Wireless Networks_L1_LAN_WAN_PAN.docx
You may need to do some further research to complete the sheet

27. Plenary: Key Words Define: Network LAN WAN PAN Client-server
Peer-to-peer