Network Address and Port Translation (NAPT) works well for conserving
global addresses and addressing multihoming requirements, because an
IPv4 NAPT router implements three functions: source address
selection, next-hop resolution and optionally DNS resolution. For
IPv6 hosts one approach could be the use of IPv6 NAT. However, NAT
should be avoided, if at all possible, to permit transparent host-to-
host connectivity. In this document, we analyze the use cases of
multihoming. We also describe functional requirements for
multihoming without the use of NAPT in IPv6 for hosts and small IPv6
networks that would otherwise be unable to meet minimum IPv6
Working Group Summary
This was originally posted in May 2010 discussed at IETF-78 in Maastricht,
and reported on in IETF-79 at Beijing. The working group requested that it
become a working group draft; it was originally posted as
draft-ietf-v6ops-multihoming-without-nat66 in December 2010, and reposted
as draft-ietf-v6ops-ipv6-multihoming-without-ipv6nat in March 2011.
It has in essence been a requirement document feeding into 6MAN and MIF.
Related work in those working groups has been proceeding to bring the issues
The document describes a network paradigm being used by certain networks
in Japan, and describes the issues that prevent them from deployment. As such,
its intent and result has been to focus action on the resolution of those problems.
Fred Baker is shepherd.