What is IPv4 Addressing?

An IPv4 address is a unique 32-bit identifier used to distinguish devices on a network. IPv4 (Internet Protocol version 4) operates at the network layer and assigns logical addresses to every interface that needs to communicate using TCP/IP.

These addresses consist of 32 bits represented in binary notation, but to make them human-readable, they are typically expressed in dotted decimal notation. This format uses four decimal numbers (0-255) separated by periods, where each number represents 8 bits (one octet).

Binary to Dotted Decimal Conversion

To convert an IPv4 address from binary to dotted decimal notation, follow these steps:

• Step 1: Divide the 32-bit address into four 8-bit blocks (octets)

  11000000 10101000 00001010 00011001
  

• Step 2: Convert each 8-bit block to decimal

  192      168      10       25
  

• Step 3: Separate the decimal numbers with periods

  192.168.10.25
  

Dotted Decimal Notation and Network Masks

IPv4 addresses can have both fixed and variable parts depending on network allocation. The fixed portion identifies the network, while the variable part identifies individual hosts within that network.

For example, in the address 192.168.10.25, if the first two octets are fixed (network portion) and the last two are variable (host portion), we can represent this using a subnet mask:

• Set network bits to 1: 11111111 11111111 00000000 00000000

• Convert to decimal: 255.255.0.0

• Express as: 192.168.10.25/255.255.0.0 or 192.168.10.25/16

Key Features of IPv4 Addressing

Conclusion

IPv4 addressing uses 32-bit logical identifiers expressed in dotted decimal notation for easy human readability. Understanding the binary-to-decimal conversion and network masking concepts is fundamental for network configuration and troubleshooting.