Embedding IP information in an IPv6 address (OMNI)

["Templin (US), Fred L" <[e-mail]>]

Hi, the OMNI spec defines an IPv6 link-local address format that embeds another
IP address/prefix inside the least significant bits:

https://datatracker.ietf.org/doc/draft-templin-6man-omni-interface/

The idea behind embedding IP information inside an IPv6 address was first published
 in RFC1884 (December 1995) where the "IPv4-compatible" and "IPv4-mapped" IPv6
addresses were defined. (This was the first edition of the IPv6 addressing architecture,
with the latest edition now as RFC4291.) Later, RFC4214 and RFC5214 put a more formal
structuring around embedded IP addresses and RFC5969 even went further to move
the embedded information up into the upper 64 bits of the IPv6 address.

The genesis of the OMNI concept of embedding additional IP information in the IPv6
address was introduced in the "AERO(bis)" draft following the publication of RFC6706.
This format was later cited in RFC7421. Now in the present OMNI draft, we have an
IPv6 link-local address format where embedded IP information begins immediately
after the fe80::/10 prefix thereby utilizing up to 112 available bits for encoding useful
information.

It has come to my attention that some are skeptical about embedded IP information
inside an IPv6 address. But, the OMNI draft shows clear benefits for making use of
these otherwise-wasted bits and follows on from decades-old examples that are
still in use today. Would love to hear everyone's thoughts on this.

Thanks - Fred