RFC 8215: Local-Use IPv4/IPv6 Translation Prefix published Thumbnail
Deploy360 25 August 2017

RFC 8215: Local-Use IPv4/IPv6 Translation Prefix published

By Kevin MeynellFormer Senior Manager, Technical and Operational Engagement

IPv6 BadgeRFC 8215 “Local-Use IPv4/IPv6 Translation Prefix” was recently published, reserving the IPv6 prefix 64:ff9b:1::/48 for local use within domains enabling IPv4/IPv6 translation mechanisms.

This allows the coexistence of multiple IPv4/IPv6 translation mechanisms in the same network, without requiring the use of a Network-Specific Prefix assigned from an allocated global unicast address space.

The well-known prefix 64:ff9b::/96 was originally reserved by RFC6052 for IPv4/IPv6 translation, but several new translation mechanisms such as those in RFCs 6146 and 7915 have subsequently been defined that target different use cases. It’s therefore possible that a network operator may wish to make use of several of these simultaneously, hence why a larger address space has been defined to accommodate this.

The shortest translation prefix being deployed in a live network was observed as being a /64, hence /48 was chosen as being on a 16-bit boundary whilst being able to accommodate multiple instances of /64.

If you’re interested in finding out more about IPv4/IPv6 translation mechanisms, there’s a few Deploy360 blogs on NAT64 and 464XLAT amongst others.

Disclaimer: Viewpoints expressed in this post are those of the author and may or may not reflect official Internet Society positions.

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