Edexcel GCSE Computer Science (1CP2) Exam Questions

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 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.

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

• The offices are a large distance apart/in different countries (1) so a WAN connects the separate networks over a large geographical area (1)
• A WAN connects two or more LANs together (1) so the separate office networks can communicate (1)
• A WAN can use leased lines rented from telecommunications companies (1) because the company does not own the long-distance cabling between countries (1)

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

Allow 'a WAN covers a large geographical area' as the WAN feature (1) when linked to the company's offices being in different countries/cities (1).

Allow leased lines rented from telecommunications companies as the WAN feature (1) if linked to the company not owning the long-distance cabling (1).

Do not accept 'a WAN is bigger/faster' without saying that it connects networks over a large distance.

Do not accept 'the offices are in different countries' on its own as a linked explanation, because it does not state a WAN feature.

Do not accept 'WAN covers a large area' on its own without linking it to the company's offices.

Do not accept 'the internet is a WAN' on its own.

Do not accept 'more secure/safer' on its own because this does not explain the need to connect distant offices.