1. GCSE ICT Revision
Topic 2: Connectivity

2. Home Networks
Most homes with a home network use it mainly to allow users to share an Internet connection.
A local area network (LAN) connects all the computers in a house so that resources can be shared.
Benefits of a home network include:
Sharing the Internet connection
Sharing files, including backing up files
Sharing peripherals, for example printers
Connecting to the Internet from a home network requires a router.

3. Home Networks
You need to know what is good and bad about cabled connections and the same for wireless connections.
Think of the computers at school – they are connected by cables in computer rooms but the laptops in the Art room are wireless.
There are good and bad things about each type of connection.

4. Cable & Wireless Compared
Cable Connection to Router (Ethernet)
Wireless Connection to Router (Wi-Fi)
Setting up
 Cables have to be run from the router to all rooms
 All you need is a wireless router
Cost
 Installation is expensive
 cheaper; only the cost of the router
Bandwidth
 Very fast (1 Gigabit per second)
 Slower; 54 megabits per second (Mbps)
Interference
 Should not experience any interference
 Can be affected by walls, distance, electronic devices
Security
 Good; users are directly connected to the network
 poor; anyone can connect unless a password/key is set
Mobility
 You cannot connect in a room without a socket
 Connect from any room and stay connected moving

5. Network Security Wireless networks are less secure than cabled ones.
If you do not secure your network, anyone within range can access it.
To secure the network, people should be advised to change the default password on their router.
People should set up some form of encryption.
Encryption scrambles data so that only computers with the right key can read it.

6. Combining Technology Digital devices can be used together.
Mobile phones and laptops, for example, are compatible because they can communicate via Wi-Fi or Bluetooth technology and they both have USB ports.
A photograph can be taken on a mobile phone, for example, and shared online after being uploaded to a laptop.
Exam Question: List two ways in which Jack can transfer the images from his camera to his laptop. (2 marks)

7. Bandwidth and Latency Higher grades:
Bandwidth is the number of bits that can go through the network connection in one second (measured in bits per second, bps).
Latency is the time in milliseconds between a bit leaving one device and arriving at the other. It is measured in milliseconds (ms).
For streaming videos, you need a connection with high bandwidth otherwise the video pauses.
To get quick search results from Google, you need a low latency network connection so that information arrives quickly.

8. Wi-Fi and Mobile Broadband
The most common ways of connecting to the internet on the move are Wi-Fi and mobile broadband.
Wi-Fi devices need to be within range of a wireless access point (‘hotspot’).
This connection is good because it has a good range (60 metres from the hotspot) and is quite widely available.
This connection is not so good because, sometimes, hackers can set up fake hotspots putting users at risk.
3G and 4G can be used which have greater coverage than Wi-Fi.
3G is more secure than Wi-Fi because data is encrypted.
3G costs money though and downloads are limited.

9. Communication Protocols
Protocols are rules that devices follow when they communicate with each other.
VoIP (Voice over Internet Protocol) is the set of rules for transmitting audio messages over the Internet. These help people make free voice calls or, combined with a webcam, video calls.
POP3, IMAP, SMTP – these are the rules used when sending s.
HTTP – this is the protocol of the World Wide Web (WWW). HTTPS is the secure version of this.

10. Security Risks
When you connect a computer to a network, there are security risks that you need to be aware of and how these can be prevented.
When you connect to the Internet, your computer is visible to billions of computers around the world.
To protect yourself, use a firewall. This is software that permits or blocks connections.
Users need to take care of their data when using the Internet too. Data should be encrypted to ensure its safety.

11. Security Risks
Data can also be stolen through unauthorised access. People should set secure passwords consisting of numbers, punctuation and upper and lower case letters.
People should also lock their computer when they leave it unattended.
To prevent physical theft of the computer, chains and locks should be used to further protect data that is saved on the machine itself.