IPv4 vs IPv6 – Difference and Comparison

What is IPv4?

In the early 1980s, IPv4 (Internet Protocol version 4) was developed (Jinesh et al, 2012). It is a fourth version of the Internet Protocol (IP). One of the major TCP/IP protocols is the Internet Protocol, which is one of the major ones.

It works at the Network layer of the OSI model, and its primary function is to identify hosts by their logical addresses in order to route data between them. In a network, a host’s logical address is its IP address, and IPv4 addresses are what have been used for a while and currently to identify hosts. IPv4 addresses are based on 32-bit logical addresses (Amer, 2012). 

There are five classes of IPv4, A, B, C, D, and E. Each class has a different bit length in order to address a network host. Class D addresses are reserved for multicasting, and class E addresses are reserved for future use.

 An IPv4 address with a 32-bit address equals 4,294,967,296 unique addresses (Amer, 2012). For example, “” uses four octets with each 8 bits to create a 32-bit address (Virgeniya and Palanisamy, 2013).

What is IPv6?

It is the successor of IP version 4, which is widely used nowadays. The next generation of IP (IPv6 or IPng) began in 1991, was completed in 1997 by the Internet Engineering Task Force (IETF), and was officially implemented in 2004 when ICANN introduced IPv6 addresses to its DNS servers (CISCO, 2002).

Using IPv4 and IPv6, data packets can identify their origins and also find their destinations across networks. These packets can be identified using addressing schemes. Internet devices require IP addresses to communicate with each other, and as the Internet developed, IPv4 was no longer able to provide the number of IP addresses needed globally (Saurabh and Shilpa, 2011). Therefore, a new alternative to IPv4 was needed.

IPv6 has a much larger address space than IPv4, with a 128-bit address space. It provides unique addresses to every person on earth. As a result of this expansion in address space, not only will there be more unique addresses, but also routing will become easier and cleaner due to hierarchical addressing and a simpler IP header (CISCO, 2002).

As part of the IPv6 addressing scheme, existing IPv4 networks can be compatible with IPv6 networks and both can exist simultaneously. Besides solving the shortage caused by IPv4, IPv6 enhances and improves some of IPv4’s features as well.

Using this 128-bit addressing format allows IPv6 to operate more efficiently and error-free than IPv4 because it uses 16-bit hexadecimal number fields separated by colons “.

Difference Between IPv4 and IPv6

  1. The address space of IPv4 is 32 bits, while the address space of IPv6 is 128 bits
  1. In comparison to IPv4, IPv6 does not require DHCP or manual configuration. It supports stateless auto-configuration without the need for DHCP (Amer, 2012), while IPv4 needs to be configured manually and with the use of a DHCP server.
  1. It is not mandatory to use IPSec when using IPv4 but it is compulsory when using IPv6.
  1. With IPv4, broadcasts are used to send traffic to all hosts on a subnet, however with IPv6, broadcasts are not used instead multicasts are used. This results in a reduction of the broadcast flood that is seen in IPv4.
  1. When using IPv4, the IP header has a variable length of 20-60 bytes depending on the options associated with the IP header. Using IPv6, however, the IP header has a fixed length of 40 bytes and there are no options associated with the IP header.

Comparison Between IPv4 and IPv6

Parameters of comparisonIPv4IPv6
Allocation of addresses  Addresses were originally allocated based on network class. But as address space is depleted, smaller allocations are made. The allocation has not been equal among institutions.  Allocating subnets is in the early stages. The Internet Engineering Task Force (IETF) and Internet Architecture Board (IAB) recommend giving every organization, home, or entity a /48 subnet prefix length. There will be 16 bits available for subnetting. In order to provide each person with their own /48 subnet prefix length, the address space is large enough.  
Address mask             Used to designate network from host portion.Not used
FragmentsIt is possible for the sender (host or router) to fragment packets if the size of the packet exceeds the bandwidth of the next link.The fragmentation extension header is used for IPv6 for reassembling after fragmentation. You can fragment IPv6 at the source and reassemble it at the destination.
IP header  Depending on the IP options, the length will vary from 20 to 60 bytes.This header has a fixed length of 40 bytes. There are no options for IP headers, and IPv6 headers are simpler than IPv4 headers.
Routing Information Protocol (RIP)RIP is a routing protocol supported by the routed daemon.Currently, RIP does not support IPv6.


  1. https://doi.org/10.1145/2486001.2486006
  2. https://doi.org/10.1049/ip-com:20040283