Wired Connections Exam Questions

• B Latency (1)
• The only correct answer is B. The correct answer is latency.
• A is not correct because bandwidth is the capacity of a connection, not a measure of time
• C is not correct because range is the maximum distance a signal can travel, not a measure of time
• D is not correct because speed is the rate at which data is transferred, not a delay

• C Range (1)
• The only correct answer is C. The correct answer is range.
• A is not correct because bandwidth is the maximum amount of data a connection can carry per second
• B is not correct because latency is the delay between sending and receiving data
• D is not correct because speed is the rate at which data is transferred

• D Speed (1)
• The only correct answer is D. The correct answer is speed.
• A is not correct because bandwidth is the maximum amount of data a connection can carry per second
• B is not correct because latency is the delay between sending and receiving data
• C is not correct because range is the maximum distance a signal can travel

• A It is not affected by interference from other wireless devices (1)
• The only correct answer is A. The correct answer is that a wired connection is not affected by interference from other wireless devices.
• B is not correct because a wired connection does not let staff move around the office; being able to move around is a benefit of a wireless connection
• C is not correct because a new device needs a cable and a free port to join a wired network, which takes longer than joining a wireless network
• D is not correct because a wired connection does need a cable; it is a wireless connection that does not need one

Award one mark for:

• A (time) delay between data/a signal being sent and being received (1)

Allow 'the time taken for data to travel from source to destination'

Allow 'the time taken for data to arrive at its destination after it is sent'

Allow 'time lag/time delay'

Do not accept the amount of data that can be transferred per second (this is bandwidth)

Do not accept the speed of the connection/how fast data travels (this is speed, not latency)

Award one mark for:

• The maximum distance data/a signal can be transmitted before it becomes too weak to be received (1)

Allow 'how far a signal can travel'.

Do not accept the number of devices that can be connected to the network.

Do not accept the speed at which data is transmitted.

Do not accept bandwidth/the maximum capacity of a channel.

Do not accept latency/the delay between a signal being sent and received.

Award one mark for any of the following up to a maximum of two marks:

• Faster transmission speed (1)
• Higher bandwidth (1)
• Lower latency (1)
• Not affected by interference (from other devices/walls) (1)
• No blind spots/not affected by distance from the wireless access point (1)

Do not accept benefits of wireless connections, e.g. users can move around the building with their devices

Do not accept 'easier to set up' or 'does not need a password' as these are not about network performance

Award one mark for any of the following up to a maximum of two marks:

• Files/data download/upload more quickly (1)
• More employees can use the connection at the same time without it slowing down (1)
• Web pages/streamed video load more quickly with less buffering (1)
• Video calls/conferencing run at a higher quality (1)
• Updates/backups can be completed in less time (1)

Allow 'multiple users' or 'more devices' for the shared-use point

Allow 'video streams more quickly' or 'less buffering' on their own

Do not accept lower latency, as a higher bandwidth does not reduce latency

Do not accept 'more data can be transferred per second' or 'a bigger bandwidth', as these repeat what bandwidth is

Do not accept 'more reliable' on its own, as a higher bandwidth does not make a wired connection more reliable

Award up to two marks for a linked description such as:

• (Ethernet) cables are not affected by interference from other devices (1) so data is transferred at a consistent/steady speed (1)
• Each device has its own cable to the switch (1) so the full bandwidth is available to that device and speeds do not drop as more users join (1)
• Fibre optic cable has a higher bandwidth than a wireless link (1) so more data can be sent along the cable each second (1)
• The cable gives a direct/physical path to the switch (1) so data is less likely to be lost and resent, which would slow the transfer (1)

Do not accept responses about security, reliability or users being unable to move around, as these are not about speed.

Do not accept answers that only say a wired/cable connection is faster, or that fibre is faster, without saying why.

Award up to two marks for a linked description such as:

• (Twisted pair/copper) cable only carries data over a limited distance (about 100 metres) (1) so sensors further away need another switch/device to pass the data on to the farmhouse (1)
• Fibre optic cable can carry data over much longer distances (1) so wired connections can reach sensors across the whole farm (1)
• Data sent further than the cable's range is not received (1) so the computer in the farmhouse does not get readings from those sensors (1)
• A wireless connection can reach sensors that are out of range of the cables (1) so a mix of the two can give readings across the whole site (1)

Allow responses about signal weakening/being lost over a long cable.

Do not accept responses about bandwidth or speed, as range is about distance, not the amount or rate of data.

Award up to two marks for a linked description such as:

• Data travels along the cable directly to the switch on a single continuous path (1) so the time between sending and receiving the data is short (1)
• A cable is not affected by interference from other devices/wireless traffic nearby (1) so packets are not lost and resent, which would add to the delay (1)
• The switch sends the data only to the port of the correct device, not to every device (1) so the data spends less time travelling and the delay is lower (1)
• Fewer devices share a cable than share a wireless channel (1) so packets do not queue/wait before they are sent (1)

The first mark is for the way the wired connection carries the data; the second mark is for how this reduces the delay between sending and receiving.

Do not accept responses about bandwidth or the amount of data a cable can carry, as latency is the delay between sending and receiving.

Do not accept responses that confuse latency with speed/bandwidth, e.g. 'a wired connection is faster so there is less latency', unless they describe how the delay is reduced.

Do not accept answers that only say a wired connection is faster, with no link to the delay.

Award up to two marks for a linked description such as:

• Bandwidth is the maximum amount/capacity of data that can be carried each second (1) so a higher bandwidth lets editors open the large video files from the server in less time (1)
• The bandwidth of the cable is set by the type/standard of cable used (1) so it limits how much of a large file can be sent in a given time (1)
• A higher bandwidth means the cable can be shared between more transfers at the same time (1) so several editors can open files from the server at once without their transfers slowing down (1)
• If the bandwidth is too low for the size of the files (1) the transfers take a long time and the editors have to wait for their files to open (1)

Allow 'capacity' for 'maximum amount of data'.

A description that only defines bandwidth earns a maximum of one mark.

Do not accept responses about the time a signal takes to travel (latency) or the distance a signal can reach (range).

Do not accept answers that say bandwidth is how fast the signal/data travels along the cable, that a higher bandwidth gives a faster internet connection, or that bandwidth is the number of cables in the network.

Award up to two marks for a linked explanation such as:

• A copper Ethernet cable has a standard maximum segment length of 100 metres (1) so over 150 metres the signal is too weak to be read correctly (1)
• 150 metres is beyond the maximum range of a copper Ethernet cable (1) so the computer does not receive the data with enough signal strength (1)
• The signal weakens/degrades as it travels along the cable (1) so at 150 metres the data is corrupted/lost (1)

For both marks, the expansion must follow/associate with the statement.

Do not accept 'the cable is too long' on its own without saying that the signal weakens/does not reach the computer with enough strength.

Do not accept 'the signal is lost/weak' on its own without linking it to the distance being beyond the maximum range of copper cable.

Do not accept answers that only blame interference from walls or other devices, as the problem here is the distance.

Award up to two marks for a linked explanation such as:

• Fibre optic cables have a higher bandwidth than copper cables (1) so a greater amount of data can be transferred each second (1)
• Fibre optic cables carry data as pulses of light (1) so a greater amount of data can be carried each second than by the electrical signals in a copper cable (1)
• Fibre optic cables are not affected by electromagnetic interference (1) so the maximum amount of data the cable can carry is not reduced by nearby electrical equipment (1)

For both marks, the expansion must follow/associate with the statement.

Do not accept 'faster' on its own without expansion as to what is faster, such as a greater amount of data being carried each second.

Do not accept 'more reliable' or 'less interference' on its own without linking it to the amount of data that can be carried.

Do not accept answers about the cost of the cables or their installation.

Award up to two marks for a linked explanation such as:

• The twisted pair/shielded cable resists interference from the cutting machines (1) so the signal is not disrupted/corrupted and data does not need to be resent, so the network speed/throughput stays high (1)
• The cable is less affected by the interference (1) so fewer data packets are corrupted/need resending, so effective throughput/speed is not reduced (1)
• A wired connection gives a consistent/stable speed (1) because the signal is not disrupted by the machines, so data is not resent and speed is not reduced (1)

For both marks, the expansion must follow/associate with the statement.

Allow 'consistent/stable speed' as a point, but the linked reason must say that interference no longer disrupts the signal so data is not resent/throughput is not reduced.

Do not accept 'wired connections are faster' on its own without saying why the interference no longer affects the signal/speed.

Do not accept 'there is less interference' on its own without saying what this does to the signal/data (e.g. it is not disrupted/corrupted, so data is not resent).

Do not accept 'reliable' on its own without linking it to speed/throughput.

Do not accept answers about the length of the cable or the number of devices on the network.

Award up to two marks for a linked explanation such as:

• The cable provides a direct physical path to the switch/router (1) so data does not have to travel through the air where it can be delayed by obstacles such as walls (1)
• The cable is not shared with other wireless devices (1) so data does not have to wait for a free channel before it is sent (1)
• The data travels straight along the cable to the switch (1) so the time taken for it to reach its destination is short (1)

For both marks, the expansion must follow/associate with the statement.

Do not accept 'the wired connection is faster' on its own without saying why the delay between sending and receiving is shorter.

Do not accept a definition of latency without a reason.

Indicative content

Speed

• Fibre optic cable carries data as pulses of light, so it can transmit data at a higher speed than twisted pair copper cable, which carries electrical signals.
• Twisted pair copper cable has a lower maximum transmission speed than fibre optic cable.
• A high-speed backbone means a file stored on the server opens quickly on a computer in any of the three buildings.
• The backbone carries the traffic of all three buildings, so a slow cable becomes a bottleneck at busy times, such as the start of a lesson.

Bandwidth

• Fibre optic cable has a higher bandwidth than twisted pair copper, so the backbone can carry more data at the same time.
• Higher bandwidth means many students can stream video lessons or use cloud software together without the network slowing down.
• Twisted pair copper has a lower bandwidth, so the backbone would become congested when several classes use online resources at once.
• The backbone needs enough bandwidth for the combined demand of the three buildings, otherwise data queues and performance drops.

Effect on the people using the network

• Students and staff would log on and open files more quickly across the campus if the higher-bandwidth fibre is installed.
• Video and large files, such as design work, would transfer without buffering or long waits.
• If copper is chosen, users in the buildings would notice slow file transfers and lag when the network is busy.
• A fast, consistent connection makes lessons that depend on the network, such as online tests, reliable for every class.

Levels

• Level 0 (0 marks): No rewardable content.
• Level 1 (1–2 marks): Basic, independent points are made, showing elements of understanding of key concepts/principles of computer science. (AO1) The discussion will contain basic information with little linkage between points made or application to the context. (AO2)
• Level 2 (3–4 marks): Demonstrates adequate understanding of key concepts/principles of computer science. (AO1) The discussion shows some linkages and lines of reasoning with some structure and application to the context. (AO2)
• Level 3 (5–6 marks): Demonstrates comprehensive understanding of key concepts/principles of computer science to support the discussion being presented. (AO1) The discussion is well developed, with sustained lines of reasoning that are coherent and logically structured, and which clearly apply to the context. (AO2)

Level 3 requires both cable types to be discussed with the effect on performance.

Do not accept cost, ease of installation or security as performance characteristics.