IP/MAC addressing, standards, protocols and layers – GCSE Computer Science exam questions with mark scheme

1Grade 6–75 marks

Identify the most suitable protocol for each task. Choose from: HTTP, HTTPS, FTP, SMTP, IMAP, TCP/IP. Each protocol may be used once or not at all. [5]

(a) Sending an email from a user's device to a mail server.

(b) Paying for shopping on a website securely.

(d) Reading emails stored on a mail server so that they stay synchronised on a phone and a laptop.

(e) Splitting data into packets and routing them to the correct address across the internet.

(a) SMTP(1)
(b) HTTPS; do not accept HTTP(1)
(c) FTP(1)
(d) IMAP; do not accept POP (not in list / does not keep devices synchronised)(1)
(e) TCP/IP(1)
Answer: (a) SMTP (b) HTTPS (c) FTP (d) IMAP (e) TCP/IP
Examiner tip: SMTP sends email; IMAP (and POP) retrieve it – remember 'S for Send'.

2Grade 6–74 marks

Networking protocols are organised into layers.

(a) Give two benefits of using layers. [2]

(b) Devices on a network have both an IP address and a MAC address. Describe two differences between an IP address and a MAC address. [2]

(a) Any two from: each layer can be developed / changed / updated independently without affecting other layers; breaks a complex problem into smaller parts, so easier to understand / develop / debug (allow: each layer has a specific, self-contained purpose); allows hardware and software from different manufacturers to work together (interoperability / layers follow standards); allows developers to specialise in / focus on one layer. Credit 'self-contained' and 'changed independently' once only if they make the same point(1)
(a) Second benefit from the list(1)
(b) Any two differences from (each must compare both addresses): an IP address can change / is assigned by the network the device joins, whereas a MAC address is fixed / permanently assigned to the NIC by the manufacturer (allow: IP is a logical / software address, MAC is a physical / hardware address); an IP address is used to route data across networks / the internet, whereas a MAC address is used to identify a device / deliver data within a LAN; length: IPv4 is 32 bits (IPv6 is 128 bits) whereas a MAC address is 48 bits; notation: IPv4 is written as four denary numbers 0–255 separated by dots whereas a MAC address is written as six pairs of hex digits (allow: IPv6 is eight groups of four hex digits separated by colons, MAC is six pairs separated by colons/hyphens)(1)
(b) Second, different difference from the list(1)
Answer: (a) e.g. layers can be changed independently; allows hardware/software from different manufacturers to work together (b) e.g. IP can change but MAC is fixed by the manufacturer; IP routes data across networks but MAC identifies a device on a LAN
Examiner tip: Each difference must compare both addresses – 'a MAC address is in hex' alone does not make a difference.

Still losing marks on this topic?