MAC addressing in Computer Networks - Practice Problems & Coding Challenges

Challenge - 5 Problems

📋 Factual

intermediate

What is the length of a MAC address?

A MAC address is a unique identifier assigned to network interfaces. How many bits long is a standard MAC address?

A 48 bits

B 32 bits

C 64 bits

D 128 bits

💡 Hint

Think about the common format shown as six groups of two hexadecimal digits.

A MAC address is 48 bits long, usually displayed as 6 pairs of hexadecimal digits (e.g., 00:1A:2B:3C:4D:5E).

🧠 Conceptual

intermediate

What does the first half of a MAC address represent?

A MAC address is split into two parts. What does the first 24 bits (first half) of a MAC address usually identify?

A The manufacturer or vendor

B The device's serial number

C The device's IP address

D The network subnet

💡 Hint

This part is assigned by a central authority to companies making network devices.

The first 24 bits of a MAC address are called the Organizationally Unique Identifier (OUI) and identify the manufacturer.

🔍 Analysis

advanced

Identify the error in this MAC address format

Which of the following MAC addresses is incorrectly formatted?

A 00:1A:2B:3C:4D:5E

B 00-1A-2B-3C-4D-5E

C 00:1A:2B:3C:4D:5G

D 001A.2B3C.4D5E

💡 Hint

Check if all characters are valid hexadecimal digits (0-9, A-F).

Option C contains '5G' where 'G' is not a valid hexadecimal digit, making it an invalid MAC address.

🚀 Application

advanced

How many unique MAC addresses can exist?

Given that a MAC address is 48 bits long, how many unique MAC addresses are possible?

A 2^32 (about 4 billion)

B 2^48 (about 281 trillion)

C 2^24 (about 16 million)

D 2^64 (about 18 quintillion)

💡 Hint

Calculate 2 raised to the power of the number of bits in a MAC address.

Since a MAC address is 48 bits, the total number of unique addresses is 2^48, approximately 281 trillion.

❓ Reasoning

expert

Why can't two devices on the same local network have the same MAC address?

Consider a local network where devices communicate using MAC addresses. What is the main reason two devices cannot share the same MAC address on this network?

A Because MAC addresses are used to route packets across the internet

B Because MAC addresses are encrypted for security and must be unique

C Because MAC addresses determine the device's IP address automatically

D Because MAC addresses uniquely identify devices on the local network to avoid communication conflicts

💡 Hint

Think about how devices find each other on the same network segment.

MAC addresses uniquely identify devices on a local network to ensure data is sent to the correct device without confusion or conflict.