Unit 3. Network and Communications

3.1: Types of Networks

• A network is created when different websites are connected together usually by wires or Wi-Fi. A network can vary a lot in size. It can be two devices connected together or billions, like the Internet.

• There are three main types of networks; PAN, LAN and WAN.

• PAN is known as Personal Area Network and refers to a network with a small number of devices where the devices are usually very close to each other. All the network hardware belongs to the user, including the cables, router and the wireless access point (WAP) that provides the connection. It’s designed for low-data-rate uses and things like linking a laptop to a printer or phone to headphones.

• LAN is Local Area Network where devices are close together, can be connected with wired or wireless connections, and is centralised. Data goes at speeds like Mbps and Gbps. It often uses Ethernet cables or Wi-Fi. In a house, LAN can be used for multiple devices and the family owns the Wireless Access Point.

• WAN is Wide Area Network where devices can be far away. Some of the devices belong to the owner while others belong to the Internet Service Provider or ISP, which is a company that provides connection to a house or business.

• A network can be wired or wireless. Wireless includes Wi-Fi, Bluetooth, etc. Wired connections can be copper connections or fibre-optic cables. Fibre optic cables are made up of thin strips of glass and are used as a more modern type of network.

• Copper cables are traditional cables and made up of thin strips of copper wires. They are installed and used in many countries. They transmit data using electric signals that travel down the wires and the speed is usually up to 300 Mbps. They are cheap and easy to install but suffer from electromagnetic interference which is why they have to be built thick. They are used in ethernet cables, HDMI cables and most phone chargers.

• Fibre optic cables are modern cables that transmit data through glass at speeds up to 10 Gbps. Electromagnetic interference does not affect them so they are thinner but they are expensive to make and difficult to install. They are growing in popularity because they have a very fast transmission speed and are not affected by electromagnetic interference.

Wireless Vs Wired Connections

• Wired connections are usually more reliable as they don’t suffer from interference from objects like walls and other radio waves. The connection is more secure as a hacker would need to physically get to the network hardware. It is difficult to add new devices as you would have to buy a cable, make space, manage wires, etc. It is also more expensive to buy the cables. However wired connections usually have a faster speed of transmission.

• Wireless connections can suffer from interference and are less secure. It is easier to add new devices as you simply have to enter the WiFi password and enable access. The connection is less secure as the hacker simply needs to guess the password to get access. They also usually have a slower speed of transmission, but wireless connections are cheaper than wired.

3.2: Data Transmission and Security

• Echo checks: To check whether data from one computer to another is being sent properly, echo checks can be used. It is an echo detection system that compares two sets of data to see if they match. The sender sends an item to the receiver who sends a copy of the item they received back to the sender. The sender compares the sent and received data and if they match there are no errors.

• Firewalls: To help keep data secure, people can use firewalls which are hardware or software based ‘bodyguards’ for the computer. It has specific rules for data that is allowed to enter the computer.

• Antivirus: When data is downloaded there is a risk it can contain a virus or spyware. A virus is a type of software that can corrupt or damage the data on a computer. Spyware can record information about the usage of someone’s device, like the keys which they press. Antivirus and anti-spyware are softwares that can be used to make sure there is no virus or spyware on the system by scanning the file while it is being downloaded and outputting a warning if a virus is found.