Why: IPv4 vs IPv6

Why use IPv6? What are the differences between IPv4 and IPv6? Why is IPv6 better than IPv4? Here is a comparison of IPv4 and IPv4 in six important areas showing the benefits of using IPv6.

There are also problems ahead for organisations that don't move to IPv6. For more about the positives of IPv6 and the negatives of not using it, have a look at our tutorial on the carrots and sticks of IPv6: Tutorial: Reasons for IPv6.

Why IPv6? IPv4 IPv6
IPv6 has massive address abundance 4.29 x 109 = 4.3 billion addresses - far less than even a single IP address per person on the planet. 3.4 x 1038 = 340 trillion trillion trillion addresses - about 670 quadrillion addresses per square millimetre of the Earth's surface.
IPv6 networks are easier and cheaper to manage Networks must be configured manually or with DHCP. IPv4 has had many overlays to handle Internet growth, which demand increasing maintenance efforts. IPv6 networks provide autoconfiguration capabilities. They are simpler, flatter and more manageable, especially for large installations.
IPv6 restores end-to-end transparency Widespread use of NAT devices means that a single NAT address can mask thousands of non-routable addresses, making end-to-end integrity unachievable. Direct addressing is possible due to vast address space - the need for network address translation devices is effectively eliminated.
IPv6 has improved security features Security is dependent on applications - IPv4 was not designed with security in mind. IPSEC is built into the IPv6 protocol, usable with a suitable key infrastructure.
IPv6 has improved mobility capabilities Relatively constrained network topologies restrict mobility and interoperability capabilities in the IPv4 Internet. IPv6 provides interoperability and mobility capabilities which are already widely embedded in network devices.
IPv6 encourages innovation IPv4 was designed as a transport and communications medium, and increasingly any work on IPv4 is to find ways around the constraints. Given the numbers of addresses, scalability and flexibility of IPv6, its potential for triggering innovation and assisting collaboration is unbounded.