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Practise 35 exam-style questions on Network hardware: NIC, MAC and IP addresses, routers for Cambridge IGCSE Computer Science (Paper 1). Write your answer as you would in the exam and get it marked in seconds against the mark scheme, point by point, with an AI tutor on hand if you get stuck.
Here are 4 of the questions in this topic, each with a model answer, an explanation of why it earns the marks and the mark scheme an examiner would use.
State which type of IP address can change each time a device connects to a network.
A dynamic IP address.
A dynamic IP address is allocated each time a device connects, so it can change. A static IP address stays the same. Both IPv4 and IPv6 addresses can be static or dynamic.
Dynamic (IP address)
do not accept IPv6 or MAC address
Describe the difference between a static IP address and a dynamic IP address.
A static IP address stays the same every time the device connects to the network. A dynamic IP address is allocated by the network each time the device connects, so it can be different each time.
Static means fixed and dynamic means it can change. Dynamic addresses are given out automatically, usually by a router, each time a device joins the network; static addresses are kept for devices that must always be found at the same address, such as servers.
A static IP address does not change / stays the same each time the device connects
A dynamic IP address is allocated each time the device connects and can change
accept 'is temporary'
A MAC address is written as 12 hexadecimal digits. The first 6 digits are the manufacturer code and the last 6 digits are the serial code.
Calculate:
• the number of bits in the whole MAC address
• the number of bytes in the whole MAC address
• the number of different serial codes that one manufacturer code can have, as a power of 2.
Show your working.
Each hexadecimal digit represents 4 bits.
Bits in the whole MAC address = 12 × 4 = 48 bits
Bytes = 48 ÷ 8 = 6 bytes
The serial code has 6 hex digits = 6 × 4 = 24 bits
Number of different serial codes = 2²⁴
One hex digit is one nibble (4 bits), so 12 digits is 48 bits, or 6 bytes. With n bits there are 2ⁿ different patterns, so the 24-bit serial code allows 2²⁴ (16 777 216) devices per manufacturer code. A common slip is to use 8 bits per hex digit.
12 × 4 = 48 bits
working must show 4 bits per hex digit
48 ÷ 8 = 6 bytes
follow through from an incorrect number of bits
Serial code is 6 × 4 = 24 bits, so 2²⁴ different serial codes
accept 2^24 or 16 777 216
The table shows a comparison of IPv4 and IPv6 addresses. Four values are missing, labelled A to D.
Give the missing values A to D.
A: hexadecimal
B: 4
C: colon
D: 32
IPv4 is 32 bits written as four denary groups (0 to 255) separated by full stops. IPv6 is 128 bits written as eight groups of four hexadecimal digits separated by colons. Each IPv6 group is 16 bits, and each IPv4 group is 8 bits.
A: hexadecimal
accept hex / base 16
B: 4
accept four
C: colon
accept :
D: 32
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