On Mon, 22 Jul 2019, Owen DeLong wrote:
2. It was decided that the effort to modify each and every IP
stack in order to facilitate use of this relatively small block (16 /8s being
evaluated against a global
run rate at the time of roughly 2.5 /8s per month, mostly to
RIPE and APNIC) vs. putting that same effort into modifying each and every IP
stack to support
IPv6 was an equation of very small benefit for slightly smaller
cost. (Less than 8 additional months of IPv4 free pool vs. hopefully making
IPv6 deployable
before IPv4 ran out).
Well, people are working on making 240/4 usable in IP stacks:
https://raw.githubusercontent.com/dtaht/unicast-extensions/master/rfcs/draft-gilmore-taht-v4uniext.txt
There have been patches accepted into some BSDs and into Linux
tools/kernel and other operating systems to make 240/4 configurable and
working as unicast space.
I don't expect it to show up in DFZ anytime soon, but some people have
dilligently been working on removing any obstacles to using 240/4 in most
common operating systems.
For controlled environments, it's probably deployable today with some
caveats. I think it'd be fine as a compliment to RFC1918 space for some
internal networks.
--
Mikael Abrahamsson email: swm...@swm.pp.se