IVI Translation refers to a stateless IPv4/IPv6 translation technique. It allows hosts in different address families (

IPv4 Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version de ...

and IPv6) communicate with each other and keeps the end-to-end address transparency. Stateless NAT64 can be used in 4 different scenarios:RFC 6144 Framework for IPv4/IPv6 Translation *An IPv6 network to the IPv4 Internet *The IPv4 Internet to an IPv6 network *An IPv6 network to an IPv4 network *An IPv4 network to an IPv6 network Stateless NAT64 is a replacement of SIIT (RFC 6145).

Naming

The name "IVI" represents the number 4 (IV) and 6 (VI) in

roman numerals Roman numerals are a numeral system that originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. Numbers are written with combinations of letters from the Latin alphabet, eac ...

merged to represent the IPv4/IPv6 translation.

How it works

Stateless NAT64 building blocks

*Address translation defined in RFC 6052 RFC 6052 IPv6 Addressing of IPv4/IPv6 Translators is a stateless mapping scheme, which embeds IPv4 address in network specific IPv6 prefix and forms IPv4-converted and IPv4-translatable addresses. The IPv4-converted IPv6 addresses are the IPv6 addresses used to represent IPv4 nodes in an IPv6 network. The IPv4-translatable IPv6 addresses are the IPv6 addresses assigned to IPv6 nodes for use with stateless translation. *Header translation and ICMP translation defined in RFC 6145 RFC 6145 IP/ICMP Translation Algorithm are algorithms to perform header translation between

and IPv6, as well as between ICMP and

ICMPv6 Internet Control Message Protocol version 6 (ICMPv6) is the implementation of the Internet Control Message Protocol (ICMP) for Internet Protocol version 6 (IPv6). ICMPv6 is an integral part of IPv6 and performs error reporting and diagnostic func ...

. *

DNS The Domain Name System (DNS) is a hierarchical and distributed naming system for computers, services, and other resources in the Internet or other Internet Protocol (IP) networks. It associates various information with domain names assigned to ...

record translation (

DNS64 An IPv6 transition mechanism is a technology that facilitates the transitioning of the Internet from the Internet Protocol version 4 (IPv4) infrastructure in use since 1983 to the successor addressing and routing system of Internet Protocol Vers ...

) defined in RFC 6147 RFC 6147 DNS64: DNS extensions for Network Address Translation from IPv6 Clients to IPv4 Servers describes mapping from A record to AAAA record defined in RFC 6052.

Stateless NAT64 extensions

*Address sharing stateless NAT64 enables multiple IPv6 nodes sharing a single public IPv4 address, with each node managing a different range of ports. This can be achieved by defining suffix of the address format RFC 6052.draft-bcx-address-fmt-extension Extended IPv6 Addressing for Encoding Port Range (https://datatracker.ietf.org/doc/draft-bcx-address-fmt-extension/) *Dual stateless translation is also called dIVI Translation. Due to the stateless nature, after the second translation, the original IPv4 address can be restored. The advantage of stateless NAT464 is that the

and

application-level gateway An application-level gateway (ALG, also known as application layer gateway, application gateway, application proxy, or application-level proxy) is a security component that augments a firewall or NAT employed in a computer network. It allows cust ...

(ALG) are not needed.

Case study

*RFC 6219: China Education and Research Network (CERNET)'s IVI translation design and deployment for the IPv4/IPv6 coexistence and transition.RFC 6219 China Education and Research Network (CERNET)'s IVI translation design and deployment for the IPv4/IPv6 coexistence and transition *RFC 7599: MAP-T is being used on the IPv6-only "CERNET2", expanding on the work done with CERNET.

Relation to Stateful NAT64

*The stateless NAT64 also forms the basic building blocks for stateful

NAT64 NAT64 is an IPv6 transition mechanism that facilitates communication between IPv6 and IPv4 hosts by using a form of network address translation (NAT). The NAT64 gateway is a translator between IPv4 and IPv6 protocols, for which function it need ...

. Additional building block is the maintaining of the translation states defined in RFC 6146.RFC 6146 Stateful NAT64: Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers

Relation to Stateless NAT464 (dIVI, dIVI-PD)

*Due to stateless nature, the second stateless translator can be introduced to translate the IPv4-translatable IPv6 address back to IPv4. In this case, the DNS64 and ALG are not required. See dIVI Translation

References

{{IPv6 Routing software IPv6 transition technologies