The most detailed networking subtopic in the whole syllabus — topologies, addressing, and how data is actually packaged for transmission. Take your time here.
Bounded connection media (recap + weaknesses):
| Weakness | Description |
|---|---|
| Eavesdropping | An unauthorised party intercepts and reads data being transmitted |
| Attenuation | Signal strength weakens the further it travels along a cable |
| Cross talk | Signal from one wire interferes with a signal in an adjacent wire |
| EMI (Electromagnetic Interference) | External electrical/magnetic sources (motors, power lines) disrupt the signal |
Unbounded connection media: Bluetooth (short range, low power), wireless/Wi-Fi (medium range), radio waves (used for various wireless communications).
Network topology — the physical/logical layout of how devices are connected:
| Topology | Layout | Key trait |
|---|---|---|
| Star | All devices connect to one central device (e.g. a switch) | If the central device fails, the whole network fails; easy to add/remove devices |
| Bus | All devices share a single central cable | Simple and cheap, but a cable break can affect the whole segment |
| Ring | Devices connect in a closed loop, data passes around the ring | Data travels in one (or two) direction(s) around the ring |
| Mesh | Every device connects directly to every other device | Very reliable/redundant, but expensive and complex to cable |
| Hybrid | A combination of two or more topologies | Combines advantages of multiple topologies for a specific need |
Star, Bus and Ring topologies — notice the single point of failure in Star (the switch) vs. Bus (the shared cable).
Networking devices:
Network addressing:
| Concept | Description |
|---|---|
| IPv4 | 32-bit IP address format (e.g. 192.168.0.1); a limited number of possible addresses |
| IPv6 | 128-bit IP address format, created to solve IPv4 address exhaustion, allows vastly more unique addresses |
| MAC address | A unique, hardware-burned-in address assigned to a NIC — used for identifying a device on a local network |
| DNS (Domain Name System) | Translates human-readable domain names (e.g. google.com) into IP addresses |
| DHCP (Dynamic Host Configuration Protocol) | Automatically assigns IP addresses to devices on a network |
| ARP (Address Resolution Protocol) | Finds the MAC address associated with a known IP address on the local network |
Broadcast communication sends data to every device on a network; point-to-point communication sends data directly between two specific devices only.
Format of Packets and Frames — how data is actually packaged for transmission:
WLAN (Wireless LAN) devices: wireless access point (lets wireless devices join a wired network), wireless bridge (connects two wired network segments wirelessly), wireless router (combines routing with a wireless access point).
Wi-Fi and hotspots let devices connect wirelessly to a network or share an existing connection.
| Comparison | Bounded (wired) | Unbounded (wireless) |
|---|---|---|
| Bandwidth/speed | Generally higher and more consistent | Generally lower and can vary with interference/distance |
| Mobility | Limited to cable length | High — devices can move freely within range |
Extending a LAN: a fibre optic backbone can be used to connect multiple switches/segments of a large LAN together at very high speed over longer distances than copper cabling allows.
💡 Exam Tip
When comparing topologies, always mention both a strength AND a weakness — e.g. star topology is easy to manage and expand, but a single point of failure at the central device brings down the whole network.