IPv6 Multihoming without Network Address Translation

Network Address and Port Translation (NAPT) works well for conservingglobal addresses and addressing multihoming requirements because anIPv4 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-to-IPv6 Network PrefixTranslation (NPTv6). However, NAT and NPTv6 should be avoided, if atall possible, to permit transparent end-to-end connectivity. In thisdocument, we analyze the use cases of multihoming. We also describefunctional requirements and possible solutions for multihoming withoutthe use of NAT in IPv6 for hosts and small IPv6 networks that wouldotherwise be unable to meet minimum IPv6-allocation criteria. Weconclude that DHCPv6-based solutions are suitable to solve themultihoming issues described in this document, but NPTv6 may berequired as an intermediate solution.