Class C in IP Addressing

Overview

• Part of Classful Addressing: IP addresses divided into 5 classes (A, B, C, D, E)
• Focus: Discussion on Class C in IPv4 (32-bit addresses)
• Dotted Decimal Representation: 32 bits divided into 4 octets

Class C Range

• Determining Range: Based on the first octet
• First Three Bits Fixed: 110
• Remaining 5 Bits: Varying values (00000 to 11111)
  • Minimum value: 11000000 (192 in decimal)
  • Maximum value: 11011111 (223 in decimal)
• Class C Range: 192 to 223
• Approximate Number of IP Addresses: 32 (192 to 223)

Number of Addresses in Class C

• Bits for Addresses: 29 bits (32 total minus the 3 fixed bits)
• Total Number: 2^29
  • Proportion: ~12.5% of all IP addresses (2^32)

Number of Networks and Hosts

Number of Networks

• Reserved Octets for Network: 3
• Last Octet for Host: 1
• Bits for Network: 21 bits (8 bits each for 2 octets + 5 bits = 21 bits)
• Total Networks: 2^21 (~2 million)

Number of Hosts in Each Network

• Host Bits: 8
• Total Hosts: 256
• Usable Hosts: 254 (minus the first and last addresses for network identification and broadcast)

Examples

• Verifying Class: Check if the first octet falls between 192 and 223
• Network ID Calculation: Use subnet mask (255.255.255.0) and AND operation on IP address
  • Example: 194.2.3.4
    • First Octet: 194 (between 192 to 223) = Class C
    • Subnet Mask: 255.255.255.0
    • AND Operation results in Network ID: 194.2.3.0
• Host Assignment:
  • Total Hosts in a Network: 256
  • Usable Hosts: 254
  • First Address (Network Representation): xxxx.xxxx.xxxx.00000000
  • Last Address (Broadcast): xxxx.xxxx.xxxx.11111111 (255)

Summary

• Class C designed for small-sized networks
• Significant for understanding IP addressing in depth