John Levine <johnl@iecc.com> wrote:
FWIW, I also don't think that repurposing 240/4 is a good idea. To be useful it would require that every host on the Internet update its network stack, which would take on the order of a decade...
Those network stacks were updated for 240/4 in 2008-2009 -- a decade ago. See the Implementation Status section of our draft: https://datatracker.ietf.org/doc/draft-schoen-intarea-unicast-240/ Major networks are already squatting on the space internally, because they tried it and it works. We have running code. The future is now. We are ready to update the standards. The only major OS that doesn't support 240/4 is Microsoft Windows -- and it comes with regular online updates. So if IETF made the decision to make it unicast space, most MS OS users could be updated within less than a year.
It's basically the same amount of work as getting everything to work on IPv6.
If that was true, we'd be living in the IPv6 heaven now. It doesn't take any OS upgrades for "getting everything to work on IPv6". All the OS's and routers have supported IPv6 for more than a decade. Whatever the IPv6 transition might require, it isn't comparable to the small effort needed to upgrade a few laggard OS's to support 240/4 and to do some de-bogonization in the global Internet, akin to what CloudFlare did for 1.1.1.1. John