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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 659 exam-style questions, each with its mark scheme and example answers. Print it, or answer it on paper and then open the mark schemes. Or browse the questions by topic.

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4 questions · 7 marks

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1Short recall1 markAddressing Swap Remove

Routers forward data packets across the internet.

State the part of a data packet that a router uses to decide where to send it.

[1 mark]
Mark scheme

Award one mark for:

  • (Destination) IP address (1)

Allow IP address on its own (the destination is implied).

Do not accept source IP address/IP address of the sender.

Do not accept MAC address.

Do not accept domain name/web address.

Example answers and how they were marked
Full marks1/1

The destination IP address.

Why: Names the destination IP address (1).

No marks0/1

The domain name.

Why: A domain name is not used by a router to route a packet; it must be translated to an IP address first, so no mark.

No marks0/1

The MAC address.

Why: A MAC address is not used to route packets across the internet; the Do not accept line applies.

2Explain2 marksPacket Switching Swap Remove

A file is sent across the internet in packets.

Explain why packets from the same file may take different routes.

[2 marks]
Mark scheme

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

  • Each router chooses the best route at the time (1) so when a route becomes busy/congested or fails, later packets are forwarded along a different path (1)
  • Routers forward each packet separately (1) so the path a packet takes depends on the traffic conditions when that packet arrives (1)
  • A router may send a packet to a different next router (1) if its routing table shows a better/less congested route for that packet (1)
  • Traffic on the internet changes (1) so no single path is kept for the file and each packet can use whichever route is best when it is sent (1)

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

Allow reference to a routing table, or to how a router decides the route, as part of the linked reason.

Do not accept 'the packets have different IP addresses' because all packets from the same file have the same destination IP address, even though their routes can differ.

Do not accept 'the internet is busy' or 'there is a lot of traffic' on its own without linking this to the router choosing a different route.

Do not accept 'different routers send the packets' on its own without a reason why a different router/route is chosen.

Do not accept an answer that only says the packets take different routes without explaining why.

Example answers and how they were marked
Full marks2/2

Each router chooses the best route at the time, so if one route becomes busy or fails, later packets are sent a different way.

Why: Linked point (1) that each router chooses the best route at the time and reason (1) that a busy or failed route means later packets take a different path.

Some marks1/2

Routers send packets along the least congested route.

Why: States that a router chooses the least congested route (1) but gives no linked reason why this makes the packets from the file take different routes.

No marks0/2

Because each packet is given a different IP address so they go to different places.

Why: Misconception named in the mark scheme: all packets from the same file share the same destination IP address, even though their routes can differ.

3Explain2 marksProtocols & Layers Swap Remove

The TCP/IP model has four layers.

Explain one function of the transport layer when a file is sent over a network.

[2 marks]
Mark scheme

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

  • Splits the data/file into packets (1) so each packet can be sent separately across the network (1)
  • Adds a packet/sequence number to each packet (1) so the packets can be put back into the correct order at the destination (1)
  • Detects lost/missing packets (1) so they can be requested/resent (1)
  • Creates a connection between the two computers/hosts (1) before the file is sent (1)

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

Allow 'segments' for 'packets' (TCP divides the data into segments, which become packets at the internet layer).

Do not accept 'sends the data/file' on its own without saying what the transport layer does to the data.

Do not accept naming TCP or a port number on its own without expansion.

Do not accept routing/addressing packets using IP addresses, which is the internet layer.

Example answers and how they were marked
Full marks2/2

The transport layer splits the data into packets so each packet can be sent separately across the network.

Why: Linked point (1) and reason (1): splitting into packets lets each one be sent separately.

Some marks1/2

It splits the data into packets.

Why: Point (1) identified, but no linked reason given, so only the first mark is awarded.

No marks0/2

It routes the packets using IP addresses so they reach the right destination.

Why: Routing using IP addresses is the internet layer, not the transport layer, so no credit is given.

4Explain2 marksWireless Connections Swap Remove

A library has one wireless access point fixed at one end of the building.

Explain one effect of the range of the wireless access point on the performance of the wireless network.

[2 marks]
Mark scheme

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

  • Devices near the edge/limit of the range receive a weaker signal/lower signal strength (1) so data is transferred more slowly/the connection speed/bandwidth is lower (1)
  • Devices near the edge/limit of the range receive a weaker signal/lower signal strength (1) so latency increases (1)
  • Devices outside the range cannot connect to the access point (1) so users in that area cannot use the network/access its resources (1)
  • A device that moves out of range loses its connection (1) so the user's work is interrupted until it is back in range (1)

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

For the second mark, the reason must state the effect on the user/network (e.g. cannot use the network/access resources, slower speed, higher latency), not just repeat that the device is out of range.

Do not accept a definition of range on its own (e.g. 'range is how far the signal reaches') without an effect on performance.

Do not accept 'a larger range means more devices can connect' (range is not about the number of devices/capacity).

Do not accept range confused with bandwidth/speed, e.g. 'range is the maximum amount of data that can be transferred'.

Example answers and how they were marked
Full marks2/2

A device at the edge of the range has a weak signal, so its connection speed is slower.

Why: Linked point (1): weak signal at the edge of the range; reason (1): connection speed is slower.

Some marks1/2

Devices outside the range cannot connect to the network.

Why: Point only (1): outside the range a device cannot connect. No linked reason about the effect on use/performance.

No marks0/2

Range is the distance that a wireless signal can travel.

Why: A definition of range, not an effect on performance; the mark scheme says not to accept this on its own.

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5.3 Cybersecurity

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