ITK Funday: Understanding Network Subnetting

Introduction

• Continuation from a previous video on IP addressing.
• Focus on network subnetting, a fundamental networking concept.
• Recap of IPv4 basics.
• Real-life examples and fundamental blocks of subnetting will be covered.
• Importance of subscribing to the channel for updates.

Quick Recap of IPv4 Basics

• An IPv4 address consists of a 32-bit logical address with dotted decimal notation.
• Divided into four 8-bit segments known as octets.
• Components of an IP address: network bits and host bits.
• Network bits are denoted as 1, host bits as 0.
• IP address classes: A, B, C, D, E (Focus on A, B, C):
  • Class A: 0-126, first octet for the network.
  • Class B: 128-191, first two octets for the network.
  • Class C: 192-223, first three octets for the network.

Understanding Subnetting

• Real-life Example: Eurorail coaches reserved for specific countries; redistribution of passengers based on availability.
• Subnetting helps utilize network bandwidth intelligently.
• Subnetting divides a network into multiple sub-networks based on usage.
• Class-based defaults:
  • Class A: 8 bits for network, 16 million hosts.
  • Class B: 16 bits for network, 64,000 hosts.
  • Class C: 24 bits for network, 256 hosts.

Subnetting Mechanism

• Subnet Mask: Specifies how many bits are network vs host.
• CIDR (Classless Inter-Domain Routing) notation simplifies subnet identification.
• Network ID: The first IP address of a subnet range.
• Broadcast ID: The last IP address of a subnet range, used for communication within the subnet.

Calculating Subnet Details

• Example: IP 205.150.65.26/26
  • Subnet mask for /26: 255.255.255.192
  • Logical AND operation to find Network ID.
  • Formula for the number of subnets: 2^n (n = number of bits borrowed).
  • Formula for the number of hosts: 2^n - 2 (n = number of host bits remaining).
  • Number of subnet: 4, Hosts per subnet: 62.
  • Broadcast IP: Calculated by extending host range.

Advanced Subnetting Scenarios

• Example: Creating 10 subnets out of a Class C IP range with /24 notation.
  • Requires adjustment of subnet mask to /28.
  • Uses 4 bits from the host portion for subnetting.
  • Subnet mask: 255.255.255.240
  • Host range: 14 hosts per subnet.
  • Broadcast address calculation based on host range.

Conclusion

• Subnetting enables efficient network resource utilization.
• It is a crucial skill for network management and design.
• Encouraged to explore subnetting further for advanced scenarios.
• Recap of the video: basics, layman example, fundamental concepts, and practical examples.
• Invitation to engage with content and subscribe for more educational videos.