The IPv6 128-bit address space was designed as a solution for the 32-bit limitation of IPv4, but the proliferation of IPv4 in the global Internet continues via private addressing domains behind Network Address Translators (NATs). For these reasons, deployment of IPv6 at the end nodes with minimal perturbation of IPv4 networks presents a natural long-term transition and coexistence alternative. This document proposes a coexistence scenario with IPv6 for end to end addressing and IPv4 for network traversal.