Port Restricted IP Address Assignment

With the foreseen scarcity of public IPv4 addresses and the hesitation and technical difficulties to deploy IPv6, the transition scenarios which assumed that migration to IPv6 happens before the run-out of IPv4 addresses, need to be revisited. This document defines a method to allocate the same IPv4 address to multiple hosts, thus prolonging the availability of public IPv4 addresses for as long as it takes for IPv6 to take over the demand for IPv4. The document also describes the deployment scenarios where this method is applicable.