Network Performance

Computer Science: OCR GCSE, topic 1.3.3

There are many factors which affect the overall performance on a network:

Bandwidth is the quantity of data that can be transferred in a set amount of time.
Higher bandwidths mean higher performance potential of the network.
If many devices share the same bandwidth, each device may get slower speeds.

Wired networks are usually much faster and more reliable.
There is a greater chance of all of the packets of data arriving at their intended destination when using wired networks. There is very little interference with the signal.
Data packets being sent wirelessly are competing with other wireless signals, which increases the rate at which data will not arrive at its destination.
Wireless performance depends on how well a computer can pick up the signal, but is rarely better than a wired connection would be.

Copper cables (Ethernet) use electrical signals. They are cheap but can suffer from interference and have a limited maximum speed.
Fibre optic cables use light signals, allowing very high speeds, long distances, and no electrical interference.
Network interface cards (NICs) affect performance depending on whether they support faster standards (e.g., 1 Gb/s vs 100 Mb/s).
Routers and switches must be powerful enough to handle the number of connected devices. Weaker devices create bottlenecks.

The topology of the network (how the computers are laid out and connected together) impacts the network performance.
Star topology often gives the best performance because each device has a direct connection to a central switch or server.
In a bus topology, all devices share one cable, so performance drops as more devices are added.
In a mesh topology, many routes exist, so data can travel more efficiently, improving reliability and speed.

Network Performance (cont.)

Lots of devices using the network at the same time can overload it, reducing speed for everyone.
Heavy activities like video streaming or gaming can slow down other users.

The distance that data has to travel affects the performance of a network.
Both wired and wireless connections may need repeaters to boost the strength of the signal carrying the data packets.
Devices are slower, especially on a wireless network, the further away a device is from the wireless access point
Latency is the delay before data begins transferring.
Wireless networks usually have higher latency than wired.
Long distances or too many network hops increase latency.

Certain physical materials do not allow wireless signals to pass through.
This type of interference increases the rate at which data packets are lost.
Have you ever entered a building and lost your phone signal? This may be because of the construction of the building.

Here are some possible ways to improve the performance of a network.

Problem: Wireless networks suffer from interference, weak signal strength, and congestion.
Solution:
Switch to a wired Ethernet connection for devices that need stable, high-speed performance.
Place the Wi-Fi router centrally to improve coverage.
Upgrade to dual-band or tri-band Wi-Fi (2.4 GHz + 5 GHz) to reduce interference.

Problem: Copper cables are slower and more susceptible to interference.
Solution:
Upgrade to fibre optic cables, which provide higher speeds, longer distances, and immunity to electrical interference.
Replace old Cat5 cables with Cat6 or Cat6a Ethernet cables for faster wired connections.

Problem: Inefficient topologies (like bus) reduce performance as more devices join.
Solution:
Use a star topology, where each device connects to a central switch for better speed and reliability.
For large, mission-critical networks, use mesh topology to provide multiple data routes and reduce congestion.

Problem: Many devices share limited bandwidth, slowing the network.
Solution:
Increase the available bandwidth from the ISP (upgrade broadband package).
Use Quality of Service (QoS) settings on the router to prioritise important traffic (e.g., video calls, gaming).
Reduce unnecessary background usage (e.g., cloud backups during peak hours).

Problem: Wireless signals are disrupted by physical barriers or other electronics.
Solution:
Change the Wi-Fi channel to avoid interference from neighbouring networks.
Move the router away from microwaves, cordless phones, and thick walls.
Upgrade to Wi-Fi 5 or Wi-Fi 6, which handle interference better.

Which of the following are true of networks?
Which connection type usually provides the most stable and fastest performance?
What is one disadvantage of wireless networks compared to wired networks?
Which network topology often provides the best performance because each device connects directly to a central switch?
What does bandwidth measure?