Factors Influencing Digital Communication (Edexcel IGCSE ICT)
Revision Note
Bandwidth & latency
What is bandwidth?
Bandwidth is the amount of data that can be carried by a connection in one second
Measured in bits per second (bit rate)
A smaller bandwidth means that less data can be sent and the network can slow down, potentially to the point of becoming unusable
Impact on user experience
A higher bandwidth means more data can be sent and received in one second
Higher bandwidth can improve:
Upload and download speeds
Online gaming
Streaming high definition video
To stream content, enough data to play a few seconds is downloaded and stored in a temporary area of memory called a buffer
As the contents of the buffer are played, more data is downloaded at the same time to keep the buffer full
If the buffer ever becomes empty playback will pause
To stream successfully, data must be downloaded to the buffer at a faster rate than it is being emptied
What is latency?
Latency is the delay between data being sent and received
If there is a big delay between the two, more data will be on the network causing collisions
This can lead to even more packets of data being sent as the error rate will increase
Impact on user experience
Playing games online smoothly, requires a high bandwidth
A high latency can cause lag and the game will not respond as quickly as a users commands
This can cause big issues when users are playing fast paced games or playing against other users with a lower latency (have an advantage due to quicker response times)
Streaming sport content with a high latency can cause micro-stutters and ruin a users watching experience
Speed & volume of data transfer
What else can affect the speed & volume of data transfer?
Factor | Description |
|---|---|
Interference | Devices that emit electromagnetic signals such as microwaves and fridges can disrupt wireless signals |
Transfer method | Wired connections can carry more frequencies, meaning a higher bandwidth compared to wireless connections |
Blockages | Walls and furniture can block wireless signals, lowering the bandwidth available |
Distance | The strength of a wired and wireless signals reduces as data has to travel further |
Wired & wireless communication
What are the advantages and disadvantages of wired & wireless communication?
Wired | Wireless | |
|---|---|---|
Speed | Fast data transfer | Slower than wired |
Portability | Location is limited by physical cable | Location only limited by range |
Security | Better physical security | Less secure, easier to intercept data |
Range | Less affected by interference | Affected by interference |
Safety | Cables can be trip hazards, need routing along walls, under floors | None |
Cost | Cables are cheap, more devices means more cables needed | No cables required, may require a wireless access point to be purchased |
Broadband, mobile broadband & cellular networks
Internet Service Providers (ISP) provide access to high speed internet (broadband)
ISPs use fibre optic or copper cable to create a wide area network (WAN)
What is fibre optic?
Fibre optic is a type of cable that uses light to transmit data on a wide area network (WAN)
Fibre transmits data at a much higher speed and has a much higher bandwidth compared to copper cables
Fibre optic cable does not suffer from interference which makes them the most secure option to send sensitive data
Fibre optic cables can cover a long distance without any degradation, they can span cities and countries
What is copper cable?
Copper is a type of cable originally used in telecommunication to transmit voice signals, forming the traditional landline phone network
The ability to use copper to deliver network traffic on a wide area network (WAN) made the internet possible
Copper cables degrade over time which limits their range compared to fibre optic
Copper cable suffers from interference which can disrupt data quality
Copper transmits data at a much slower rate, and has a much lower bandwidth compared to fibre optic
Worked Example
Describe how high latency can affect the experience of making a video call from a smartphone
[2]
Answer
It increases the time it takes for data to be transferred between devices [1] meaning his voice/video is out of sync / lagging / delayed [1]
You've read 0 of your 5 free revision notes this week
Sign up now. It’s free!
Did this page help you?
