IPv4 vs IPv6: What's the Difference

An address is a data structure understood by a network which uniquely identifies the recipient endpoint within the network.

What is IP address?

Internet Protocol address (IP address) is the set of rules that dictate the format of data that is shared over the internet. It is a hardware-independent convention which in principle allows every devices attached to the Internet to be given a unique logical address . Also, it facilitates the communication of connected computers or smart devices over the internet. By using your IP address , the location of your device can be identified and differentiated from a host of other devices. The IP address that you're most familiar with probably looks something like this:


Originally IP addresses were divided into five (5) classes as shown below. Classes A, B and C are the most important; the initial bits determine which class an address belongs to, and the classes differ in how much of the address is taken up with the network address and how much with the host address.

IPv4 vs IPv6: Understanding the Critical Differences

Internet Protocol Versions

As the IoT (Internet of Things) continues to grow exponentially, more devices connect online daily. The enormous growth of the connecting devices and the way the addresses were assigned (classes A, B and C), resulted in a serious lack of addressing problems . The problem of the limited addresses (IPv4) could be solved in different alternative technologies such as: subnetting , NAT (Network Addresses Translation), or CIDR (Classless InterDomain Routing). IP addresses might be solved for a while, but they will no longer be able to handle the fast growth of Internet. To overcome this shortage of the IP pool, Internet protocol version 6 (IPv6) which enhances the address capabilities of IPv4 by deploying 128 bits addressing instead of 32 bits, was introduced. The biggest improvement of IPv6 was the huge increase of possible addresses. At present, IPv4 coexists on the internet with its newer version, though eventually, everything will use IPv6.

What is IPv4?

Internet Protocol version 4, generally referred to as IPv4, is the fourth version of the Internet Protocol (IP) and it is the first version of the protocol to be widely deployed. It was launched all the way back in 1983 and, even today, it's still the most well-known version to identify devices on a network. IPv4 is a protocol for use on packet-switched Link Layer networks (e.g. Ethernet)and it uses a 32-bit address scheme , and therefore has 4.3 billion possible addresses. Till date, it is considered the primary Internet Protocol and carries 94% of Internet traffic. IPv4 addresses are usually represented in dot-decimal notation, consisting of four decimal numbers, each ranging from 0 to 255, separated by dots, for example:

What is IPv6?

Internet Protocol version 6 (IPv6) is the next generation Internet Protocol (IP) address standard intended to supplement and eventually replace IPv4, the protocol many Internet services still use today.

IPv6 addresses are 128 bits long or 16 octets. It is four times longer than IPv4 addresses. If you're interested in the exact number, here's how many unique addresses IPv6 offers: 340,282,366,920,938,463,463,374,607,431,768,211,456. The hexadecimal system is used to assign the addresses, instead of the decimal system in Internet Protocol version 4 (IPv4). Eight groups of numbers, separated by a colon (:), are used, each group contains pair of hexadecimal numbers , for example:

FEDC: BA88:45DF:9810:0008:417A:0000:0FB6

Key Differences Between IPv4 and IPv6

IPv4 IPv6
32-Bit IP address 128-Bit IP address
Separated by a dot(.) Separated by a colon(:)
4.29×109 address space 3.4×1038 address space
Numeric addressing method Alphanumeric addressing method
Header of 20-60 bytes Header of 40 bytes fixed
Offers 12 header fields Offers 8 header fields
Supports broadcast Doesn't support broadcast
Supports VLSM (Virtual Length Subnet Mask) Doesn't support VLSM
Detected and computed the checksum error Checksum error is not computed in IPV6
QoS feature is not very efficient In-built QoS feature and is very efficient
Fragmentation performed by Sender and forwarding routers Fragmentation performed only by sender
Supports Manual and DHCP address configuration Supports Auto and renumbering address configuration
Encryption and Authentication facility not provided Encryption and Authentication are provided
Uses ARP (Address Resolution Protocol) to map to MAC address Uses NDP (Neighbour Discovery Protocol) to map to MAC address
Still in use by the remaining 94% Used by less than 6% of the networks

Differences between IPv4 and IPv6

IPv6 brings several advantages, including:

  1. More Efficient Routing
  2. Auto-configuration
  3. More Efficient Packet Processing
  4. Multi cast and any cast functionalities
  5. Built-in authentication and privacy support
  6. Simplified Network Configuration
  7. Improved security and authentication features
Benefits of using IPv4 and IPv6 together:
  1. Dual-Stack Network
  2. Tunneling
  3. Network Address Translation-Protocol Translation (NAT-PT) aka RFC-2766

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