Edexcel GCSE Computer Science (1CP2) Exam Questions

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:

• Devices (can) understand/interpret the data they receive (1) because they follow the same set of rules for communication (1)
• Data is sent in an agreed format/structure (1) so the receiving device can interpret/understand it correctly (1)
• Devices (can) connect/communicate successfully (1) because they agree how the data is transmitted, such as the type of signal used (1)
• Errors (can) be detected/handled (1) because both devices follow the same rules for checking the data (1)

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

Do not accept 'so devices can talk/communicate with each other' or 'so they can understand each other' without saying they follow the same rules/agreed format.

Do not accept an answer that only states protocols are a set of rules, without saying what this allows (e.g. the data can be understood/interpreted).

Do not accept a faster connection/speed as a reason why protocols are needed.

Do not accept naming a protocol (e.g. TCP/IP, HTTP, Wi-Fi) without an explanation of why it is needed.

Do not accept a description of what a protocol does (e.g. 'TCP splits data into packets') without saying why this is needed.

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.