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Understanding Subnetting Simplified

May 6, 2025

Lecture Notes: Subnetting by Sunny

Introduction

  • Topic: Subnetting
  • Definition: Logical subdivision of an IP network.
  • Purpose:
    • Relieve network congestion
    • Improve network performance
    • Enhance security
  • Relevance:
    • Important for network professionals
    • Part of certifications like Kampuchea National Network Plaza
    • Often made complex in textbooks, but this presentation simplifies it.
  • Pre-requisites:
    • Understanding subnet mask, network ID, host ID, and broadcast ID.

Example Problem

  • Scenario: Create three subnets from a given network ID.
  • Use Case: For a coffee shop (Sunny Café) with different subnets for office, front desk, storage, and public use.
  • Task: List each subnet's network ID, subnet mask, host ID range, number of usable host IDs, and broadcast ID.

Building the Sunny Subnetting Table

  • Purpose: Simplify subnetting questions.
  • Structure:
    • Row 1 (Subnets): 1, 2, 4, 8, 16, 32, 64, 128, 256 (each is double of the previous)
    • Row 2 (Hosts): 256, 128, 64, 32, 16, 8, 4, 2, 1 (each is half of the previous)
    • Row 3 (Subnet Masks): /24 to /32

Solving the Example

  • Given: Network ID 192.168.4.0/24
  • Objective: Create 3 subnets
  • Process:
    • Use 4 subnets column from Sunny Table (4 subnets cover the requirement)
    • Subnets:
      • Network IDs: 192.168.4.0, 192.168.4.64, 192.168.4.128, 192.168.4.192
      • Subnet Mask: /26 for each
      • Usable Hosts: 64 total - 2 (network and broadcast) = 62
      • Broadcast IDs: 63, 127, 191, 255 (next network ID - 1)
      • Host ID Ranges:
        • 0-63
        • 64-127
        • 128-191
        • 192-255
  • Conclusion: Choose any 3 out of 4 subnets as required; 1 subnet is left unused.

Conclusion

  • Challenges: Subnetting can seem tedious but becomes quick and simple with practice.
  • Next Steps: Further explore subnetting of subnets in upcoming videos.
  • Engagement: Viewers are encouraged to practice with provided example and reach out with questions.

Note: The lecture emphasizes the simplicity and effectiveness of the "Sunny Table" for subnetting tasks.