Internet Protocol (IP) address is assigned to electronic devices that can communicate with other networking devices via the Internet. There are two versions of IP that are currently available, one is IPv4, and another is IPv6. Although both these versions’ main task is to connect devices over the Internet and assign IP addresses,  IPv4 vs IPv6 battle is always on as most users want to know and understand which is better.

The IPv4 vs. IPv6 comparison can give you a proper understanding of the differences between them. IPv4 is the older version, and IPv6 is the newer version of IP. They work in different ways and have many things uncommon in them.

What is IPv4?

ipv4 vs ipv6 - details for IPv4

The fourth version of Internet Protocol, developed in the 1980s, is IPv4 (Internet Protocol version 4). Even though it was deployed in the 1980s, it is still the most used version of IP. The addressing scheme used by IPv4 is 32 bit, allowing 2^32 addresses, which is approximately more than 4 billion unique addresses.

You can connect to other networking devices with the Internet and send data to them using the unique IP address assigned to you with the help of IPv4. Dots separate this individual address in IPv4 in between, for example – You can configure the IPv4 addresses manually or automatically, depending on your device configuration.

With the advancement in technology, there are chances to run out of 4.3 billion addresses. The smartphones, computers, smart TVs, and IoT devices all required a unique address, and hence IPv6 was developed.

Benefits of IPv4

  • Has numeric IP address and hence easy to remember them
  • Supports Unicast, broadcast, and multicast addresses
  • IPv4 uses Network Address Translation (NAT), allowing to have one unique address for all the network devices connected in the network
  • Connectionless protocol
  • Supported and used by many devices using IP to communicate over the Internet
  • Requires less space compared to IPv6

What is IPv6?

ipv4 vs ipv6 - details for What is IPv6

IPv6 (Internet Protocol version 6) is the latest version of IP, developed by Internet Engineering Task Force (IETF) in the 1990s. It has a 128-bit addressing scheme, allowing 2^128 addresses, which is 340 undecillion unique addresses. You can have far more unique IP IPv6 addresses compared to the permitted addresses in IPv4.

The IPv6 addresses are separated by colons, example – 2001:0db8:85a3:0000:0000:8a2e:0370:7334. Although IPv4 is the most used address even today, IPv6 is taking over slowly and will soon be used to assign unique IP addresses and connect to other networking devices.

IPv6 is also called Internet Protocol Next Generation (IPng). It was mostly developed to overcome IPv4 limitations like security, limited addresses, and many more. The new devices now come with both IPv4 and IPv6 compatibility, giving users the freedom to use the IP version of their choice. This internet protocol has been designed with a view of allowing the internet to grow to its fullest potential, in terms of the number of hosts connected and the amount of data transferred.

Benefits of IPv6

  • Quality of Service is supported (QoS)
  • Have inbuilt security feature
  • Supports Unicast, multicast, and anycast types of addresses
  • Has alphanumeric addresses
  • There is no need for manual configuration; it supports autoconfiguration of IP addresses
  • The addressing and routing infrastructure is hierarchical

Now, as you know what about IP address versions, we can move towards the actual difference between them. Some of the differences can be observed in the initial explanations as well. And to know IPv4 vs IPv6 in detail, refer to the next section.

IPv4 vs IPv6 – The Comparison

The below table shows the similarities and difference between IPv4 and IPv6.

Points for Differences IPv4 IPv6
Addressing scheme 32-bit address space 128-bit address space
IP address pattern Supports numeric addresses separated by a dot (.) Supports alphanumeric addresses separated by colon (:)
Number of fields in the header 12 8
Header field length 20 – 60 bytes 40 bytes fixed
IP address assigning Manual and automatic, depending on the device Mostly automatic
Number of unique address 2^32 that is around 4.3 billion 2^128 that is around 340 undecillion
Checksum The header consists of the checksum field The header does not contain a checksum field
Support for Virtual Length Subnet Mask (VLSM) IPv4 does support VLSM IPv6 does not support VLSM
Security The security aspect in IPv4 depends on the application as it does not have built-in support for security IPv6 takes care of the security aspect by using IPSec (Internet Protocol Security)
Mapping to MAC address IPv4 uses Address Resolution Protocol (ARP) IPv6 uses the Neighbour Discovery Protocol (NDP)
Support for mobile devices IPv4 is not compatible with mobile networks as the address is separated by dots IPv6 is compatible with mobile networks as a colon separates the address.
IP to MAC resolution Broadcast ARP Multicast Neighbour Solicitation
Optional Fields Present Not available, you need to add an extra header for optional fields
Dynamic host configuration Server (DHCS) Users can access DHCS whenever they want to connect to a network There are permanent address in case of IPv6, so there is no need to access DHCS
IPSec In IPv4, the choice of using IPSec is on the network provider In IPv6, it is mandatory to use IPSec and hence guaranteed security
SNMP Supports and uses SNMP for system management Does not support or use SNMP
Routing Information Protocol (RIP) Supports RIP Does not support RIP
Packet flow identification Not available Available with flow label field in the header
Packet size 576 bytes is the minimum size 1028 bytes is the minimum size
Example 2001:0db8:85a3:0000:0000:8a2e:0370:7334


Based on the above comparison table, one can easily see IPv6 takes care of the security aspect by using IPSec, which was neglected in IPv4. Although the security option is available in IPv4, it is not mandatory, and therefore the security is neglected. The elimination of NAT transition in IPv6 makes peer to peer communication easy and improves Quality of Service (QoS). You get a secure connection and more unique IP addresses with IPv6.

When a computer uses IPv4 to connect to a network, it uses the Dynamic Host Configuration Protocol (DHCP) to establish an address. This process of assigning an IP address is called stateful auto-configuration. IPv6 is a little more advanced and uses DHCPv6 protocol to obtain the IP address.

DHCPv6 supports stateful auto-configuration and stateless auto-configuration of nodes. Stateless auto-configuration simplifies address configuration and management and allows automatic address configuration and reconfiguration. This feature of IPv6 is especially useful for administrators because it allows them to renumber network addresses without having to access all clients.

Some other points in IPv4 vs IPv6 are IPv4 supports Virtual Length Subnet Mask (VLSM), whereas IPv6 doesn’t. In the case of IPv4, the fragmentation is done by both sender and forwarder routes. And in IPv6, only sending routes does fragmentation. The similarities of IPv4 and IPv6 is that they both support the same transport layer protocol above them. Also, both the IP version support unicast and multicast type of addresses. There are packer headers in IPv4 and IPv6.

The depletion of IPv4 addresses was predicted decades ago because of less address space provided by it, and therefore the switch has been in progress since then. However, the full migration won’t be possible unless the IPv4 addresses are depleted completely.

Which is faster IPv4 or IPv6?

As per Sucuri Blog, IPv4 address and IPv6 address have the same speed when it comes to speed comparison. Practically, IPv6 should be faster than IPv4 because it does not have to check checksum at each hop and also doesn’t need NAT translations. The same speed results can be because the constant use of IPv4 has made it highly optimized. It is used across many devices and applications and improved with time.

The header size in Internet Protocol version 4 varies in the range of 20 to 60 bytes, depending on the optional field. The size of IPv6 is fixed to 40 bytes. The size difference also affects the speed of these Internet Protocol versions. And lastly, the location and your setup can make the speed vary. We feel that IPv6 will be optimized with time, just like IPv4, and it will work faster compared to IPv4 based on the various factors.

Why do we use IPv4 instead of IPv6?

IPv4 is used by the majority of us to connect to other devices over the Internet. Although now systems and devices come with the dual-stack, that is, you have the freedom to use IPv4 address and IPv6 address. However, the sudden migration from IPv4 to IPv6 is not possible because of the cost factor and implementation challenges.

People take time to migrate from old technologies that are successfully doing the job. People are switching to IPv6 slowly and progressively. Now, many countries and companies have started adopting IPv6. But, still, the complete migration from IPv4 to IPv6 is decades far.

Switching from IPv4 to IPv6

Though IPv6 has been around since the late 90s, it is still not as widely used as IPv4. Today, about 23% of all networks across the world support IPv6. Biggies such as Google, Facebook, Yahoo, YouTube, and others have already made the switch, with more websites and service providers joining in every day.

The percentage of users that access Google with IPv6
The percentage of users that access Google with IPv6 (Source: Google)

When it comes to IPv4 vs IPv6, IPv6 is undeniably more efficient in every way, and the switch has been a long time coming. One of the reasons is the financial and manpower costs accrued in making the switch. Since there is no instant switch to change from IPv4 to IPv6, as companies use partial adoption techniques like tunneling technologies to transport IPv6 over IPv4. These workarounds are not very efficient and sometimes can lead to misconfiguration and gaps in security.

Which is better – IPv4, or IPv6?

IPv6 is future-ready with its features and a never-ending option for unique IP addresses. IPv4 is historic, and we will soon run out of IP addresses if we keep on using only IPv4. When it comes to speed, both are on the same level. However, when we see it from the view of Quality of Service, ease of connection, and security, IP address v6 is a better option.

We are used to IPv4, and it has been highly optimized since the 1980s, but with time the switch will take place, and IPv6 is something everyone is going to use to connect to other devices over the Internet. So, when it comes to IPv4 vs IPv6, IPv6 is better than IPv4 in many terms. And in the near future, some of the limitations of IPv6 will be overcome with updates.

The above comparison can give you a better way of understanding the similarities and difference between IPv4 vs IPv6. With the clear explanation given above, you can better judge which Internet Protocol version is better.

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