Dual Stack Hosts using the "Bump-In-the-Stack" Technique (BIS)

This document describes the "Bump-In-the-Stack" (BIS) host based protocol translation mechanism that allows applications supporting only one IP address family to communicate with peers that are reachable or supporting only the other address family. Furthermore, this technology avoids need for unnecessary double protocol translation in the case where destination is dual-stack enabled. This specification addresses scenarios where a host is provided dual stack, IPv6 only or IPv4 only network connectivity. In the dual stack network case, single address family applications in the host will communicate directly with other hosts reachable with the same address family. In the case of IPv6 only network or IPv6 only destination, IPv4-originated communications have to be be translated into IPv6. IPv6 communications may have to translated similarly to IPv4. In the scenario of single address family access network, but dual-stack destination, network based translation is always avoided. Technically, the BIS-enabled host resolves both IPv4 and IPv6 addresses of the destination and behaves according to received responses.