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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 693 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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3 questions · 5 marks

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1Multiple choice1 markAddressing Swap Remove

Every device that connects to the internet is given an IP address.

Identify the number of bits in an IPv4 address.

[1 mark]
  • A4
  • B8
  • C32
  • D128
Mark scheme
  • C 32 (1)
  • The only correct answer is C. The correct answer is 32.
  • A is not correct because 4 is the number of groups of numbers in an IPv4 address
  • B is not correct because 8 is the number of bits in each group of an IPv4 address
  • D is not correct because 128 is the number of bits in an IPv6 address
Example answers and how they were marked
Full marks1/1

C 32

Why: Correct option (1): an IPv4 address is 32 bits long.

No marks0/1

B 8

Why: 8 is the number of bits in one group of an IPv4 address, not the whole address (mark scheme line B), so no mark.

No marks0/1

D 128

Why: 128 is the length of an IPv6 address, not an IPv4 address (mark scheme line D), so no mark.

2Explain2 marksPacket Switching Swap Remove

Data is split into packets before it is sent across the internet.

Explain why each packet has a packet number in its header.

[2 marks]
Mark scheme

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

  • The receiver can put the packets back into the correct order (1) because packets may arrive out of order/take different routes (1)
  • The receiver can see if a packet is missing (1) because the sequence of numbers shows a gap (1)
  • The receiver knows when the whole file has arrived (1) because the total number of packets/last packet number is known (1)

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

Allow 'so the packets can be put back in the correct order/reassembled' for the first mark, but the second mark needs the reason, i.e. packets may arrive out of order/take different routes.

Do not accept 'so the packets can be identified' without stating what the number is used for, e.g. reordering or spotting a missing packet.

Do not accept 'so the router knows where to send it' - the router uses the destination IP address, not the packet number.

Example answers and how they were marked
Full marks2/2

The receiver can put the packets back in the correct order because they may arrive out of order.

Why: Linked point (1) and reason (1): the packet number allows reordering because packets can arrive out of order.

Some marks1/2

It shows the receiver the order of the packets.

Why: The point is given (1) but there is no linked reason, such as packets arriving out of order.

No marks0/2

So the router knows which route to use.

Why: Routers use the destination IP address, not the packet number, so this earns nothing; it is named in the mark scheme as a 'Do not accept'.

3Explain2 marksTopologies Swap Remove

A bus topology uses one main cable shared by all devices.

Explain why a bus topology can be a security risk.

[2 marks]
Mark scheme

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

  • All devices receive every data packet (1) because the main cable is shared by all nodes (1)
  • Data can be read by any device on the network (1) because there is no central switch to send it only to the destination (1)
  • A device can intercept/capture data not meant for it (1) because all transmissions travel along the same cable (1)
  • Any device can view all data on the cable (1) so data is not private/secure (1)

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

Do not accept 'it is easy to hack' without saying data can be seen/intercepted on the shared cable.

Do not accept 'the central switch can be hacked' because a bus topology has no central switch.

Example answers and how they were marked
Full marks2/2

Any device on the bus can see all the data because every packet travels along the same shared cable.

Why: Linked point (1) and reason (1): data is visible to all devices because the cable is shared.

Some marks1/2

All devices can see the data.

Why: Awarded 1 mark for stating that all devices can see the data, but no linked reason about the shared cable is given.

No marks0/2

It is less secure because the central switch can be hacked.

Why: No credit: a bus topology has no central switch; the answer gives a misconception and no valid point about the shared cable.

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