Network hardware, MAC and IP addresses
Explain the roles of NICs, MAC addresses, switches, routers and the structure and allocation of IPv4 and IPv6 addresses.
Section Component 1 · Computer Systems and Logic
Mapped to the Cambridge IGCSE Computer Science 0265 syllabus for exams in 2029. These original explanations and self-checks are independent study support, not Cambridge papers, official marks or grades. Practical programming is taught with worked code and trace tasks; an executable Python workspace and timed digital-exam simulation are not yet available.
Before you begin
- Use the 2029 syllabus for this course. Cambridge specifies Python 3.10 or higher for programming and digital exams for both components. The syllabus currently identifies this route for 2029 only; confirm later-year availability with Cambridge and your school.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Before network hardware, mac and ip addresses, which statement is the safest starting point?
What you will learn
- Explain the purpose of a NIC, MAC address, switch and router
- Compare IPv4 with IPv6
- Distinguish static and dynamic IP addresses
Local delivery uses a network interface
A network interface card (NIC) connects a device to a network and has a unique MAC identifier. A MAC address is commonly written as six hexadecimal pairs (for example, 2A:7C:10:4F:91:B3). A switch learns which MAC addresses are reachable through its ports and forwards frames within that LAN.
An IP address identifies a network and device for communication across interconnected networks. Routers examine destination IP addresses and forward packets toward another network. MAC addresses support local frame delivery, while IP addresses support routing between networks.
IP versions and allocation
IPv4 uses 32 bits and is written as four denary numbers separated by dots. IPv6 uses 128 bits and is written as eight hexadecimal groups separated by colons, providing a much larger address space.
A static IP address remains fixed and suits a host such as a server that should be found consistently. A dynamic IP address is allocated temporarily, often by a router or ISP when a device connects. Dynamic allocation makes address management easier for devices that come and go.
Pause and explain
Which habit best checks your understanding of network hardware, mac and ip addresses?
Worked example
A packet is leaving a home network for a server on the internet. Which address type guides the router toward another network?
Show the worked solution
- The packet needs to be forwarded beyond the local LAN.
- A router examines the packet's destination network address.
- That is the IP address, not the switch's local MAC forwarding table.
Answer The destination IP address
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Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A laptop sends data to a printer on the same LAN. Explain the roles of its NIC, MAC address and switch.
Give me a hint
Follow the local link rather than the internet route.
Compare my reasoning
- The NIC sends and receives network data for the laptop.
- The frame contains a destination MAC address for the printer's interface.
- The switch uses its MAC table to forward the frame to the correct port.
The NIC provides connectivity, the MAC identifies the local interface, and the switch forwards the frame locally.
Look for these in your work
- NIC role
- MAC role
- Switch role
State how IPv4 and IPv6 addresses are written and compare their lengths.
Give me a hint
Recall the bit length, number format and separator for each version.
Compare my reasoning
- IPv4 is 32 bits, written as four denary groups separated by dots.
- IPv6 is 128 bits, written as eight hexadecimal groups separated by colons.
- IPv6 offers a much larger address space.
IPv4: 32-bit dotted denary; IPv6: 128-bit colon-separated hexadecimal.
Look for these in your work
- IPv4 format
- IPv6 format
- Length comparison
A school's public web server must have a stable address, while student phones connect temporarily to the internet. Recommend static or dynamic addressing for each and justify.
Give me a hint
Match fixed reachability to a stable address and temporary client access to automatic allocation.
Compare my reasoning
- A server that must be found consistently is suited to a static IP.
- Phones that join temporarily are suited to dynamic allocation by a router or ISP.
- This avoids manually assigning a permanent address to each short-term client.
Static for the public server; dynamic for temporary client devices.
Look for these in your work
- Server requirement identified
- Client use identified
- Management reason given
Common mistakes
- Using a MAC address as if it routes traffic across the internet.
- Calling IPv6 a 32-bit format.
- Assuming every dynamic IP changes on every single request.
What can you explain now?
Which device learns connected devices’ MAC addresses to forward local frames?
Compare with the explanation
A switch
A switch stores MAC-to-port information for its connected LAN.
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Make it stick
When does a switch use a MAC address, and when does a router use an IP address?
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