http://www.rfc-editor.org/rfc/rfc4925.txt
RFC 4925: Softwire Problem Statement, X. Li, S. Dawkins, D. Ward, A. Durand2007-07-01T23:00:00-00:00This document captures the problem statement for the Softwires Working Group, which is developing standards for the discovery, control, and encapsulation methods for connecting IPv4 networks across IPv6-only networks as well as IPv6 networks across IPv4-only networks. The standards will encourage multiple, inter-operable vendor implementations by identifying, and extending where necessary, existing standard protocols to resolve a selected set of "IPv4/IPv6" and "IPv6/IPv4" transition problems. This document describes the specific problems ("Hubs and Spokes" and "Mesh") that will be solved by the standards developed by the Softwires Working Group. Some requirements (and non-requirements) are also identified to better describe the specific problem scope. This memo provides information for the Internet community.