Edexcel GCSE Computer Science (1CP2) Exam Questions

• B The destination IP address (1)
• The only correct answer is B. The correct answer is the destination IP address.
• A is not correct because a domain name is converted to an IP address by a DNS server before routing begins
• C is not correct because the sender's MAC address is only used to deliver the packet on the local network
• D is not correct because the file name is not used to route packets

• C To reassemble the packets in the correct order (1)
• The only correct answer is C. The correct answer is To reassemble the packets in the correct order.
• A is not correct because error checking uses the error checking data in the packet, not the packet number
• B is not correct because the destination IP address identifies the destination device, not the packet number
• D is not correct because routers use the destination IP address to choose the route, not the packet number; routers may briefly buffer packets but do not use the packet number to store them

Award one mark for:

• So the packets can be put/reassembled back into the correct order (at the receiving computer/recipient) (1)

Allow 'to show the order of the packets' / 'so the packets can be reordered (by the receiving computer)'

Do not accept 'to number the packets' without a purpose

Do not accept 'to count the packets'

Do not accept 'to identify the packet' on its own

Do not accept 'so packets can be checked/resent' unless linked to putting the packets in order

Do not accept answers about choosing a router or the route

Award one mark for any of the following up to a maximum of two marks:

• The size of the file / amount of data to be transmitted (1)
• The file size in bits/bytes/MB/GB (1)
• The transmission rate / speed of the network (1)
• The bit rate / number of bits per second (1)
• The network speed / connection speed (1)

Award a maximum of one mark for the file size/amount of data and a maximum of one mark for the transmission rate/speed/bit rate.

Do not accept bandwidth on its own.

Do not accept the time taken, as this is what is being calculated.

Do not accept latency (it is a delay, not a transmission rate).

Do not accept a conversion factor such as 8 bits per byte as one of the two pieces.

Award one mark for any of the following up to a maximum of two marks:

• Files/data download/upload more quickly (1)
• More employees can use the connection at the same time without it slowing down (1)
• Web pages/streamed video load more quickly with less buffering (1)
• Video calls/conferencing run at a higher quality (1)
• Updates/backups can be completed in less time (1)

Allow 'multiple users' or 'more devices' for the shared-use point

Allow 'video streams more quickly' or 'less buffering' on their own

Do not accept lower latency, as a higher bandwidth does not reduce latency

Do not accept 'more data can be transferred per second' or 'a bigger bandwidth', as these repeat what bandwidth is

Do not accept 'more reliable' on its own, as a higher bandwidth does not make a wired connection more reliable

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

• Covers a small geographical area/one building/site (1) so all the computers can be connected on the same network (1)
• The devices are close together (1) so short cables can be used to connect them (1)
• Uses the practice's own cabling/equipment (1) so no leased lines/third-party provider are needed (1)

A feature on its own (e.g. 'A LAN covers a small area') earns the first mark only.

Award the second mark only where the feature is linked to why it suits the dental practice.

Do not accept 'A LAN is cheap' or 'A LAN is quick to set up' unless linked to the single site/close devices.

Do not accept a response that says a LAN is fast/secure without a linked statement about the site or the distance between devices.

Do not accept responses that only describe sharing printers/files without linking this to the single site.

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

• It connects many separate networks/LANs together (1) that are located all over the world (1)
• It covers a large geographical area/is worldwide (1) so networks/devices in different countries can be connected together (1)
• It uses infrastructure/leased lines provided by many different companies (1) so no single organisation owns/controls it (1)

Allow a statement that the internet is worldwide/covers a large geographical area (1), but the second mark needs the link to networks/devices being connected across that distance (1).

Do not accept a bare 'it is very big/large' with no reference to the area covered, the distance or networks.

Do not accept answers that describe a LAN instead of the internet/WAN, such as 'it covers one building'.

Do not accept descriptions of what the internet is used for, such as sending emails or viewing websites.

Do not accept descriptions of the internet's hardware/structure (cables, routers, servers) unless they refer to the wide area covered.

Do not accept responses that say the internet is wireless or has no cables.

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

• The router reads/checks the destination (IP) address in the packet (1) so it can forward/send the packet towards that address/destination (1)
• The router looks up/compares the destination (IP) address (1) to choose the route/next network/next router for the packet (1)
• The router uses the destination (IP) address to choose/select the outgoing connection/network (1) so the packet is sent one step closer to its destination (1)

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

Do not accept a restatement of the question, such as 'the router uses the IP address to forward the packet', without saying how the address is used, e.g. checking the destination address or choosing the route/next network.

Do not accept answers that say the router gives/adds an IP address to the packet, or that the router uses a MAC address instead of the destination IP address.

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

• The router reads the destination IP address (1) so it knows which network/device the packet is for (1)
• The router looks up the destination IP address in its routing table (1) to find the next router/route for the packet (1)
• The router forwards the packet to the next router (1) that leads towards that IP address / is on the best route (1)

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

Do not accept MAC address - routers use the IP address to route packets between networks.

Do not accept 'it finds the exact device' without saying how the router uses the address, e.g. routing table/next router.

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

• (All) devices share the bandwidth of the access point (1) so each device gets a smaller share, which reduces its speed/slows down transfers (1)
• Bandwidth is the maximum amount of data that can be transferred at one time (1) so when devices send more data than this, the data must wait/queue, which slows down transfers (1)
• (Many) devices send data at the same time (1) so the devices take turns, which reduces the amount of data each one can send/the speed each device gets (1)

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

Allow 'connection speed'/'download speed' for speed.

Do not accept 'the signal is shared' without saying that this reduces the bandwidth/data each device can send.

Do not accept the idea that adding devices increases the bandwidth.