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Logical Addressing | IPV4 Addressing: Address Space, Notations

In this tutorial, we will learn about the IPV4 addressing, its address space and notations in Computer Network. By Radib Kar Last updated : May 04, 2023

Overview

Usually, computers communicate through the Internet. The packet(data) transmitted by the sender computer may pass through several LANs or WANs before reaching the destination computer. For this level of communication, we need a global addressing scheme what we call logical addressing. An IP address is used globally to refer to the logical address in the network layer of the TCP/IP protocol.

The Internet addresses are 32 bits in length; this gives us a maximum of 2³² addresses. These addresses are referred to as IPv4 (IP version 4) addresses or popularly as IP addresses.

What are IPV4 Addresses?

An IPv4 address is a 32-bit address that uniquely and universally defines the connection of a device (for example, a computer or a router) to the Internet. They are unique so that each address defines only one connection to the Internet. Two devices on the Internet can never have the same IPV4 address at the same time.

On the other hand, if a device operating at the network layer has m connections to the Internet, it needs to have m addresses, for example, a router.

The IPv4 addresses are universal in the sense that the addressing system must be accepted by any host that wants to be connected to the Internet. That means global addressing.

Address Space

IPv4 has a certain address space. An address space is the total number of addresses used by the protocol. If a protocol uses N bits to define an address, the address space is 2^N

IPv4 uses 32-bit address format, which means that the address space is 2³² or 4,294,967,296

Notations

There are two notations to show an IPv4 address:

1. Binary notation
2. Dotted decimal notation

1. Binary Notation

In binary notation, the IPv4 address is displayed as 32 bits. Each octet is often referred to as a byte. So it is common to hear an IPv4 address referred to a 4-byte address. The following is an example of an IPv4 address in binary notation: 01110111 10010101 00000001 00000011

2. Dotted-Decimal Notation

IPV4 addresses are usually written in decimal form with a decimal point (dot) separating the bytes since it’s more compatible. The following is an example: 119.149.1.3 (above one and this one is same just different notation)

N.B: Each number in dotted-decimal notation is a value ranging from 0 to 255.

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