Wired and wireless networks
Ethernet, Wi-Fi and Bluetooth
| Connection | Wired or wireless? | Used for |
|---|---|---|
| Ethernet | Wired, by cable | Connecting computers in a LAN, such as desktops in a school |
| Wi-Fi | Wireless, by radio waves through a wireless access point | Connecting phones, laptops and tablets to a LAN and the internet |
| Bluetooth | Wireless, by radio waves, over short distances (typically up to about 10 m) | Connecting two devices directly: headphones, a wireless keyboard, a phone to a car |
You don't need to know how Ethernet, Wi-Fi or Bluetooth work, only what they're used for and their benefits and drawbacks.
Key terms
Wired or wireless?
| Wired | Wireless | |
|---|---|---|
| Speed | Usually faster, and steady | Usually slower; drops with distance and walls |
| Reliability | Reliable: little interference | Affected by interference from walls and other devices |
| Security | Someone needs to plug in to get at the data | Signals reach anyone in range, so they must be encrypted |
| Mobility | Devices stay where the cable reaches | Devices can move around freely |
| Setting up | Cables to buy and fit, which can be costly | Cheaper and quicker: no cables |
Recommending a connection:
- A gaming PC by the router: Ethernet, for speed and a steady connection.
- Customers' phones in a café: Wi-Fi, as they move around and bring their own devices.
- Wireless headphones: Bluetooth, as they connect directly to a phone close by.
Encryption
Wireless signals can be picked up by anyone in range, and data on any network can be intercepted. Encryption protects it.
Encryption scrambles data using a key, so it can only be turned back and read by someone with the right key. Intercepted encrypted data is meaningless to anyone without the key.
- Wi-Fi networks are encrypted, so only devices that know the network's password can read the data. Modern Wi-Fi uses WPA2 or WPA3 encryption.
- Websites use HTTPS, which encrypts data between your browser and the web server.
You don't need to know how encryption works, only the principle.
Key terms
IP addresses
Every device on a network that uses the internet's protocols has an IP address, which identifies it so data can be sent to it. The network gives a device its IP address, so it can change when the device joins a different network.
| IPv4 | IPv6 | |
|---|---|---|
| Size | 32 bits | 128 bits |
| Written as | Four denary numbers from 0 to 255, separated by dots | Eight groups of four hexadecimal digits, separated by colons |
| Number of addresses | About 4.3 billion (2³²) | About 3.4 × 10³⁸ (2¹²⁸) |
For example:
- IPv4: 192.168.1.20
- IPv6: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
With billions of devices online, the supply of new IPv4 addresses has run out, which is why IPv6 was created.
You don't need to know about static, dynamic, public or private IP addresses.
Key terms
MAC addresses
Every NIC has a MAC address, given to it by the manufacturer. It's unique to that device and doesn't change. Within a LAN, switches use MAC addresses to send data to the right device.
A MAC address is 48 bits, written as six pairs of hexadecimal digits, separated by colons or hyphens, such as 3C:22:FB:9A:41:7E.
| IP address | MAC address | |
|---|---|---|
| Given by | The network | The manufacturer |
| Can it change? | Yes, on a different network | No |
| Used to | Send data between networks | Send data within a LAN |
| Format | IPv4: denary, with dots; IPv6: hex, with colons | Hex pairs, with colons or hyphens |
Common mistake
Don't swap them: the MAC address belongs to the hardware and stays the same; the IP address comes from the network.
Key terms
Standards
A standard is an agreed set of rules for an area of computing, such as how Wi-Fi signals are sent, how an Ethernet cable is wired, or how a file format is laid out.
Standards mean hardware and software made by different manufacturers can work together: any Wi-Fi phone can join any Wi-Fi network, and any USB memory stick works in any USB port.
You don't need to know any individual standards.