Networks Intro & Performance
Understanding LANs, WANs, and what makes a network fast or slow.
Types of Network
LAN (Local Area Network)
Covers a small geographical area (e.g., a single building, a school, or a house).
- The infrastructure and hardware are owned and managed by the network owner.
- Allows sharing of hardware like printers.
- Enables central deployment of software.
WAN (Wide Area Network)
Connects devices across a large geographical area (e.g., different cities or countries).
- Always relies on external, third-party telecommunications infrastructure.
- E.g., satellite links, telephone lines, trans-oceanic cables.
- The Internet is the world's largest WAN.
Examiner's Eye
When modifying or defining a WAN, do not merely mention the geographical distance. To secure the mark, you must state that a WAN leases third-party telecommunications infrastructure (like BT or Virgin cables), whereas a LAN's infrastructure is fully owned by the organisation itself.
Check Your Understanding
1. A local high school expands and buys another building in the next town over. They connect the two school networks together. What type of network have they created?
2. Which of the following is true regarding the infrastructure of a Local Area Network (LAN)?
3. Which of the following is considered the world's largest Wide Area Network (WAN)?
Network Performance Factors
Four main factors affect how well a network performs and transfers data successfully.
Bandwidth
The amount of data that can be successfully transmitted in a given timeframe (measured in bits per second, bps).
Number of Connected Devices
More users mean the available bandwidth is split. This results in less bandwidth per device, increased latency, and a higher chance of data collisions.
Interference
Physical obstructions (e.g., thick walls blocking Wi-Fi) or conflicting signals from other wireless devices causing data loss or packet retransmission.
Hardware & Traffic Type
The performance capabilities of the central hardware (e.g., Gigabit Switch vs an old Hub) and the type of network traffic (streaming HD video vs sending text).
Examiner's Eye
When asked about adding users to a network, do not simply write 'the internet gets slower'. To get the mark, you must state that 'overall bandwidth is split between devices, meaning less bandwidth is available per device.'
Check Your Understanding
1. Which of the following describes 'Bandwidth' accurately?
2. What is the effect of having too many devices connected to the same network at once?
3. Which performance obstacle are wireless networks distinctly more vulnerable to compared to wired networks?
Stretch & Challenge (AO2 Application)
Written Exam Scenario (AO2/AO3)
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