Factors Influencing Digital Communication (Edexcel IGCSE ICT)

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?

Wired & wireless communication

What are the advantages and disadvantages of wired & wireless communication?

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