Internet and Networking
Internet and Its Uses · 4 question types
Exam Frequency Analysis
Past paper frequency (2018 to 2024)
This topic accounts for approximately 7% of your exam marks.
Network topologies, protocols (HTTP, TCP/IP, FTP, DNS) and network hardware appear consistently.
Devices on a network need an address so that data can be sent to the right one. Two addressing schemes are examined: MAC and IP.
MAC address
The (short for Media Access Control) acts as a unique identifier for each network card. The manufacturer burns it into the NIC during production, and it is used to recognise the device on a Local Area Network ().
Key facts:
- Static: the MAC address is set at the factory and never changes for the life of the NIC.
- 48 bits long, usually written as 12 hexadecimal digits grouped into six pairs separated by colons: AA:BB:CC:DD:EE:FF.
- The first three pairs identify the manufacturer (Organisationally Unique Identifier, OUI).
- The last three pairs are a serial number assigned by the manufacturer.
- A device's MAC address stays the same even after the device joins a new network.
- The 48-bit address space allows for about 281 trillion different MAC addresses, far more than the number of devices ever made.
IP address
An IP (Internet Protocol) address is a unique identifier assigned to a device when it joins a network, used to identify the device on the internet ().
Key facts:
- Can be static (fixed, used for servers and websites that need a permanent location) or dynamic (changes each time the device joins a network, assigned automatically by a DHCP server).
- A device's IP address typically changes whenever it joins a different network.
- Two versions exist: IPv4 and IPv6.
IPv4
IPv4 is the older version, using 32-bit addresses written as four denary numbers in the range 0 to 255, joined by dots.
Example: 192.168.1.1
- Each block (called an octet) is one byte (8 bits).
- A full IPv4 address occupies 32 bits in total (4 bytes).
- The total number of possible IPv4 addresses is 2³² ≈ 4.3 billion.
- That seemed like plenty in 1983, but with 8 billion+ people, smart phones, IoT devices and servers, the 4.3 billion addresses are now exhausted.
IPv6
IPv6 is the newer version, using 128-bit addresses written as eight blocks of four hexadecimal digits, separated by colons.
Example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
- Every block holds 16 bits (2 bytes).
- The full IPv6 address spans 128 bits (16 bytes) overall.
- The total number of possible IPv6 addresses is 2¹²⁸ ≈ 3.4 × 10³⁸, enough to give every person on Earth about 10²⁸ unique addresses.
- IPv6 is now being rolled out worldwide alongside IPv4.
Side-by-side comparison
| Feature | MAC address | IP address |
|---|---|---|
| Stands for | Media Access Control | Internet Protocol |
| Assigned by | The NIC manufacturer | The network (router / DHCP server) |
| Static or dynamic? | Static (never changes) | Can be static OR dynamic |
| Length | 48 bits (12 hex digits) | IPv4: 32 bits. IPv6: 128 bits |
| Format | AA:BB:CC:DD:EE:FF | IPv4: 192.168.1.1. IPv6: 2001:0db8::1 |
| Used on | LAN (locally) | WAN / internet (globally) |
| Changes when device moves networks? | No | Yes |
| Used to forward data by | Switches | Routers |
Why both addresses are needed
The two address systems do different jobs:
- The gets a packet from a sender, somewhere on the internet, to the destination network. Routers around the world use it.
- The MAC address then delivers the packet within the destination network, from the router to the specific device. Switches use it.
Think of it like postal delivery: the IP address is the street address of the building, while the MAC address is the specific person's name on that floor.
MAC address vs IP address — term-and-definition table
What comes up: a table with terms or definitions left blank; you must supply the missing term or its definition for MAC address and IP address.
Write (two marks): (1) An IP address is assigned by the network (via the router or DHCP server) and is used to identify a device on a network — it can change when the device joins a different network. (2) A MAC address is assigned by the manufacturer and is permanently built into the NIC — it uniquely identifies the specific device and does not normally change.
Watch out: the mark scheme credits "assigned by the manufacturer" for MAC and "assigned by the network" for IP — swapping these (e.g. saying IP is permanent or MAC is assigned by the router) loses the mark.
IPv4 vs IPv6 differences
What comes up: state two or more differences between IPv4 and IPv6 addresses.
Write (two marks per pair): each mark requires both sides of the contrast — (1) IPv4 uses 32 bits written as four denary (decimal) groups separated by dots (e.g. 192.168.1.1); IPv6 uses 128 bits written as eight groups of four hexadecimal digits separated by colons. (2) IPv4 digits in each group range from 0 to 255; IPv6 groups range from 0000 to FFFF. A third contrast: IPv4 has far fewer possible addresses than IPv6 (approximately 4.3 billion vs 3.4 × 10³⁸).
Watch out: each difference must state both what IPv4 does AND what IPv6 does — writing only one side (e.g. "IPv6 is 128-bit" without the IPv4 half) earns no mark for that point.