Introduction to IPv6 Addresses

In the 1990s, the IETF think about the development of the internet and about the limitation and issues with IPv4 (as we discussed earlier) and began to look for an alternate. This movement led to the IPv6 address (IP version 6 addresses). IP version 6 addresses defeat the limitations of IPv4 addresses. It is a great development with features that better suit current and future network demands. It is the successor to the first Internet Protocol version 4.

In contrast to IPv4, which defined an IP address as a 32-bit value, IP version 6 addresses have a size of 128 bits. Therefore it has a vastly enlarged address space compared to IPv4. The 32-bit IPv4 address space provides approximately 4,294,967,296 unique addresses. Although, the IP version 6 address space provides;  340,282,366,920,938,463,463,374,607,431,768,211,456, or 340 undecillion addresses, which is almost equal to each particle of sand on Earth.

IP version 6 has three types of addresses, which is the following:

  • Unicast addresses. A packet delivered to one interface.
  • Multicast addresses. A packet delivered to multiple interfaces.
  • Anycast addresses. A packet delivered to the nearest of multiple interfaces.

The features provide IPv6 address

  • Increased address space – IP version 6 addresses have 128-bit hierarchical addressing as compare to IP version 4 with 32 bits.
  • Improved packet handling – The IP version 6 header has to very simply with a smaller number of fields as compared to IP version 4 packet header.
  • Eliminates the need for NAT – Due to many public IP version 6 addresses, no NAT needed. This avoids some of the NAT-induced application problems experienced by applications requiring end-to-end connectivity.


  • Increased Capacity:  IP version 6 increased  IP addresses and easily accommodates more web addresses.
  • Efficient Routing: IP version 6  allows for easy aggregation of prefixes assigned to IP networks. Also, reduces the size of routing tables and makes routing more efficient and hierarchical.
  • More Efficient Packet Processing: IPv6’s simplified packet header makes packet processing more efficient in contrast with IPv4
  • Efficient Data Flow: IP version 6 supports multicast and not broadcast. Multicast allows bandwidth-intensive packet flows to be sent to several destinations simultaneously, saving network bandwidth.
  • Security: IP version 6 security improved due in part to improved authentication methods built into network firewalls.
  • Simplified Network Configuration: Address auto-configuration (address assignment) is built-in to IPv6. Which makes network configuration simple.
  • Support For New Services: By eliminating Network Address Translation (NAT), true end-to-end connectivity at the IP layer restored, which enabling new and valuable services.
  • Security: IPsec, which provides confidentiality, authentication and also data integrity, is available in IP version 6.


  • Conversion: IPv4 is still widely used all over the world and it is a difficult task to convert to IPv6 Address.
  • Readability:  IPv6 Subnetting can be difficult to understand. In contrast to IPv4, It will be much harder to remember the IP addresses.
  • Communication: IPv4 and IPv6 equipment cannot communicate directly with each other, to communicate between IPv4 and IPv4 required more configuration.
  • Transition: The process of making the switch to IPv6 from IPv4 is very slow and boring.
  • IPv6 Address is not supported in the old operating system and devices.