Internet Protocol version 4 (IPv4), on which the Internet has been running for more than 20 years now is reaching its design limits mainly with the depletion of number resources associated with it, known as Internet Protocol (IP) addresses. This is essentially due to the rapid growth of the Internet during the past few years.

Only 18% of the total IPv4 space is now available and at the rate of current consumption, despite the very strict evaluation measures implemented by all Regional Internet Registries, would not last longer than than 2010-2011.