What will the transition be like?

Originally, the plan was to use IPv6 to develop a mechanism for its coexistence with IPv4. While these protocols were not designed to interact directly, i.e., IPv6 is not “compatible” with IPv4, both can coexist on the same network. The new version of the protocol was designed with a long transition period in mind, one during which the network would gradually incorporate IPv6 long before the exhaustion of the available IPv4 address space.

This, however, did not happen. In absence of any clear, major commercial incentives, Internet Service Providers (ISPs) and Content Providers (ICPs) did not implement the technological changes needed for a smooth transition.
IANA’ central pool of IPv4 addresses was exhausted in 2011. Regional Internet Registries then entered their exhaustion phases as shown below:

RIR IPv4 Status
APNIC The final /8 is being used since April 2011.
RIPE The final /8 is being used since September 14, 2012.
LACNIC Entered Exhaustion Phase 2 in June 2014.
ARIN Entered Exhaustion Phase 4 (final /8 since April 24, 2014)Waiting list policies for requests that cannot be met in force since July 1 st , 2015.
AFRINIC Only registry with an IPv4 address pool that will last a few more years.

As for operating systems and end user devices, servers, desktop computers, tablets and smartphones are already incorporating IPv6. Network equipment such as routers have been adding IPv6 support for over a decade.

More information:

– IPv4 Exhaustion at LACNIC http://www.lacnic.net/web/lacnic/agotamiento-ipv4

– Economic Aspects of the Transition: CAF-LACNIC Report on IPv6 http://portalipv6.lacnic.net/caf-lacnic/asuntos- economicos-de- la-transicion/

– Transition Mechanisms http://portalipv6.lacnic.net/mecanismos-de-transicion/

– Deployment Statistics http://portalipv6.lacnic.net/estadisticas-ipv6/

– Interactive Economic Modeling of Transition Alternatives (CAF)

http://stats.labs.lacnic.net/PROYECTOCAF/modelo/

– IPv6 for Decision Makers