Edexcel GCSE Computer Science (1CP2) Exam Questions

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

• The bandwidth/capacity of the access point is shared between all the connected devices (1) so each device gets less bandwidth as more devices connect, which reduces the speed of data transfer (1)
• The devices have to take turns to transmit (contention) (1) so each device waits longer before it can send data, which increases latency (1)
• The access point can only support a maximum number of connections (1) so once this limit is reached, further devices cannot connect to the network (1)

Allow 'contention' as an alternative to devices having to take turns to transmit.

Allow 'the network becomes slower' as the second mark only where it is linked to shared bandwidth, to devices taking turns to transmit or to the maximum number of connections.

Do not accept a response that only states the network becomes slower, or that there are more devices/more traffic, without saying how this affects performance.

Do not accept responses about range or interference unless they are linked to the number of connected devices.

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

• Data/packets are delivered to the correct device (1) because the IP address identifies that device on the internet (1)
• A reply is sent back to the device that made a request (1) because the sender's IP address is used as the destination address for the reply (1)
• Routers can forward packets to the right device (1) because each packet's destination IP address matches only one device (1)
• A device can be contacted by other devices (1) because other devices use its IP address to send data to it (1)

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

Allow 'so the router knows where to send data' only when expanded to say the IP address identifies the destination device / is used by routers to forward the packet to that device.

Do not accept 'so it can connect to the internet' / 'so it can access the internet' without saying how the address is used to identify the device or deliver data to it.

Do not accept 'so the device can be identified' on its own without saying what the identification is used for, e.g. delivering data or returning a reply.

Do not award a mark for restating that an IP address is unique / every device has a different address.

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'.