Edexcel IGCSE ICT
Factors Influencing Digital Communication
The Big Idea
How well digital communication "feels" to a user — smooth video calls, lag-free gaming, fast downloads — comes down to a handful of physical and technical factors: how much data can flow at once (bandwidth), how long it takes to arrive (latency), what it travels through (wired vs wireless, copper vs fibre), and what gets in its way (interference, distance, blockages).
Summary — The Whole Chapter in One Look
- Bandwidth = how much data can travel through a connection per second (measured in bits per second). Bigger bandwidth = more data flowing at once.
- Latency = the delay between data being sent and received. Lower latency = faster response, less lag.
- Streaming relies on a buffer — a temporary store of pre-loaded data — to keep playback smooth even if the network briefly slows.
- Data transfer speed and volume are affected by interference, transfer method, blockages, and distance.
- Wired connections are generally faster and more secure; wireless connections are more portable but more easily disrupted.
- ISPs (Internet Service Providers) deliver broadband using fibre optic (light through glass — fast, high bandwidth, long range) or copper cable (electrical signals — cheaper, but slower and degrades over distance).
Topic 1 — Bandwidth
What Is Bandwidth, Really?
Imagine a motorway. The number of lanes on that motorway determines how many cars can travel down it at the same time. Bandwidth works exactly the same way, except instead of cars, it's data — and instead of lanes, it's the capacity of the connection.
Formally: bandwidth is the amount of data that can be carried by a connection in one second, measured in bits per second (also called the bit rate). You'll see it written as things like Mbps (megabits per second) or Gbps (gigabits per second) in real life.
A narrow connection (low bandwidth) is like a single-lane country road — only a small amount of data can get through per second. If you try to push more data down it than it can handle, things back up, slow down, and in the worst case the network becomes practically unusable.
The Rule
Higher bandwidth → more data sent/received per second → smoother experience.
In plain English: bigger "pipe", more water flows through per second.
Higher bandwidth directly improves things you actually notice day to day:
- Faster upload and download speeds
- Smoother online gaming (though this depends more on latency — see below)
- Streaming high-definition (and 4K) video without constant pausing
How Streaming Actually Uses Bandwidth: The Buffer
This is a part students often gloss over — but it's genuinely clever and worth understanding properly, because exam questions love it.
When you press play on a streamed video, your device doesn't just play data the instant it arrives. Instead, it downloads a few seconds' worth of video ahead of time and stores it in a temporary area of memory called a buffer. Think of the buffer like a water tank sitting between the tap (the incoming internet connection) and the sink (what you're actually watching right now).
INTERNET (data arriving) ---> [ BUFFER TANK ] ---> VIDEO PLAYING ON SCREEN
^ fills up ^ drains as it plays
without interruption
faster than it's being used up