Hello Masataka-san

For that issue at least there was some effort.
Though ATM and FR appear to be long gone, the problem got even worse with pseudo wires / overlays and wireless.

It was tackled in the IoT community 10+ years ago and we ended up with RFC 8505 and 8928. This is implemented in LoWPAN devices and deployed by millions. Allowing IPv6 subnets of thousands on constrained radios. 

I spent a bit of time explaining the architecture issue (in mild terms) and solutions in https://datatracker.ietf.org/doc/html/draft-thubert-6man-ipv6-over-wireless-12

So far we failed to get those RFCs implemented on the major stacks for WiFi or Ethernet.

There’s a new thread at IETF 6MAN just now on adopting just the draft above - not even the solution. It is facing the same old opposition from the same few and a lot of silence. 

Somehow the group can spend years of heated discussions figuring out if you can insert a header or how you can build a 64 bits IID, but looking at a fundamental architecture issue like the one you point out does not raise much interest.

My suggestion is still to fix IPv6 as opposed to drop it, because I don’t see that we have another bullet to fire after that one. For that particular issue of fixing ND, new comments and support at the 6MAN on the draft above may help. 

All the best;

Pascal

Le 12 janv. 2023 à 05:34, Masataka Ohta <mohta@necom830.hpcl.titech.ac.jp> a écrit :

Randy Bush wrote:

three of the promises of ipng which ipv6 did not deliver
  o compatibility/transition,
  o security, and
  o routing & renumbering

You miss a promise of

  o ND over ATM/NBMA

which caused IPv6 lack a notion of link broadcast.

                       Masataka Ohta