IP packet structure in Computer Networks - Mini Project: Build & Apply

Understanding IP Packet Structure

📖 Scenario: You are learning about how data travels over the internet. Every piece of data is sent inside a package called an IP packet. This packet has different parts that help computers send and receive data correctly.

🎯 Goal: Build a simple representation of an IP packet using a dictionary. You will create the packet with its main fields, add a version number, fill in the core fields, and finally complete the packet with the header checksum.

📋 What You'll Learn

Create a dictionary named ip_packet with specific fields and values

Add a version field to the packet

Fill in the core fields: header_length, total_length, source_ip, and destination_ip

Add the header_checksum field to complete the packet

💡 Why This Matters

🌍 Real World

IP packets are the basic units of data sent over the internet. Understanding their structure helps in networking, troubleshooting, and security.

💼 Career

Network engineers, cybersecurity experts, and software developers working with internet protocols need to understand IP packet structure.

1

Create the initial IP packet dictionary

Create a dictionary called ip_packet with these exact entries: 'type_of_service': 0, 'identification': 54321, and 'flags': 2.

Computer Networks

# Create the ip_packet dictionary with initial fields
# Your code here

Need a hint?

Use curly braces {} to create a dictionary and separate each key-value pair with commas.

2

Add the version field to the IP packet

Add a new key 'version' with the value 4 to the existing ip_packet dictionary.

Computer Networks

ip_packet = {'type_of_service': 0, 'identification': 54321, 'flags': 2}
# Add the 'version' field with value 4
# Your code here

Need a hint?

Use square brackets [] to add a new key to the dictionary.

3

Fill in the core IP packet fields

Add these keys and values to ip_packet: 'header_length': 20, 'total_length': 60, 'source_ip': '192.168.1.1', and 'destination_ip': '192.168.1.2'.

Computer Networks

ip_packet = {'type_of_service': 0, 'identification': 54321, 'flags': 2}
ip_packet['version'] = 4
# Add header_length, total_length, source_ip, and destination_ip
# Your code here

Need a hint?

Add each field one by one using the dictionary key assignment syntax.

4

Complete the IP packet with header checksum

Add the key 'header_checksum' with the value 0x1c46 to the ip_packet dictionary to complete the packet.

Computer Networks

ip_packet = {'type_of_service': 0, 'identification': 54321, 'flags': 2}
ip_packet['version'] = 4
ip_packet['header_length'] = 20
ip_packet['total_length'] = 60
ip_packet['source_ip'] = '192.168.1.1'
ip_packet['destination_ip'] = '192.168.1.2'
# Add the header_checksum field with value 0x1c46
# Your code here

Need a hint?

The header checksum is a hexadecimal number. Use 0x prefix to write it.