http://www.rfc-editor.org/rfc/rfc6264.txt
RFC 6264: An Incremental Carrier-Grade NAT (CGN) for IPv6 Transition, S. Jiang, D. Guo, B. Carpenter2011-06-01T23:00:00-00:00This document proposes an incremental CGN approach for IPv6 transition. It can provide IPv6 access services for IPv6 hosts and IPv4 access services for IPv4 hosts while leaving much of a legacy ISP network unchanged during the initial stage of IPv4 to IPv6 migration. Unlike CGN alone, incremental CGN also supports and encourages smooth transition towards dual-stack or IPv6-only ISP networks. An integrated configurable CGN device and an adaptive home gateway (HG) device are described. Both are reusable during different transition phases, avoiding multiple upgrades. This enables IPv6 migration to be incrementally achieved according to real user requirements. This document is not an Internet Standards Track specification; it is published for informational purposes.