[perennialmind]

CLNP had existing implementations and was fundamentally sound. On its technical merits, RFC1347 TCP and UDP with Bigger Addresses (TUBA) wins hands-down. But it took too long for the ISO to agree to a hand-off (the IETF wanted to be able _fork_ it, which seems nuts to me) and the IAB required ownership.

But aside from that, I actually do think we could have baked address extensions into the existing packet format's option fields and had a gradual upgrade that relied on that awful bodge that was (and is) NAT. And had a successful transition wherein it died a well-deserved death by now. :-)

[Dagger2]

> we could have baked address extensions into the existing packet format's option fields and had a gradual upgrade that relied on that awful bodge that was (and is) NAT

We did and do have this. I wrote about the option fields part in [1] but we also have NAT as part of the migration, in the form of NAT64.

Not only was doing these things not enough for us to be done by now, they weren't even enough to stop you from moaning that we didn't do them! How could anything have been good enough if these are the standards it's judged by?

[1]: https://news.ycombinator.com/item?id=47829991

[perennialmind]

My point was meant purely as an intellectual exercise, not a critique of engineering choices made in the face of adverse practical realities. My apologies if it came across otherwise.

With the luxury of hindsight, allowing an admixture of 32-bit and 64-bit addresses strikes me as an obviously clean solution to the one real problem IPv6 solves. But in 1992, that was a complete non-starter.

[Dagger2]

But mine was that you don't need to do this as an intellectual exercise, because we got basically all the things you're asking for.

We have address extensions in v4 packets, we have NAT to help with partial upgrades, and we have a mix of 32-bit and 128-bit addresses (which should be just as obviously clean as a mix of 32-bit and 64-bit addresses, or rather more so due to 64-bits being too small). You don't need to think about whether any of this would have been doable, because we already went and did it.

[convolvatron]

I didn't have too much visibility in the CLNP world, although we did have a test network where I worked. My personal issue was that I just couldn't read the massively overwrought ISO specs. My admittedly biased viewpoint there wasn't anything really wrong with Ipv6, but the providers were quite happy with the way things were and actually kind of liked the internet-as-television model that we ended up with.

I do think that the IETF didn't realize that they were losing their agency, so its very likely that TUBA would have made the difference. not for any technical reason, but that it would have been a few years earlier when people were still listening.

[perennialmind]

I only read up on CLNP based on a fascination with counterfactuals. I will say there is a fair bit to IS-IS and ES-IS that's directly relevant to the original articles points on the circuits-to-bus-to-circuits physical evolution. There was no blanket assumption that the underlying layer look like Ethernet. The subnet equivalent was at a higher level and the assumptions were that there would be an actual network of links to manage.

The fact that IS-IS survived as a relevant IP routing protocol says a lot on its own.