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Saturday, February 25, 2017

Solving a minor half-baked mystery of IP extension specs

Sometimes I get to close old mysteries. Tonight is one of those times.

Earlier today, I got a feedback comment on the site referencing an old post on the topic of non-IPv6 extensions to the IP address space. It's been almost four years since that post went out, but they were hoping I could help out.

This time I got lucky. I found some notes of mine from a decade before the above post, and in it, there was info on the other specs. That's when my mistake was made clear. I mentioned looking for "ABCDE". That's not it. It's actually "AEIOU".

The confusion in remembering it is clear. Five letters long, all uppercase letters, and representing an ordered set (vowels, as it turns out). My mistake was thinking it was the beginning of a different ordered set, namely the alphabet itself. That little brain glitch hid the results from me while writing that post in 2013.

But here in 2017, you can enjoy the results of a fresh look back. The filename became clear and I went looking. It took a while to get somewhere, because it's hard to find that document. Lots of places claim to have it, but when you go there, it just tells you it's been deleted because "it never became a RFC". It's a huge memory hole, and it's just getting bigger.

To head off further bit-rot, I found a copy, but this time, kept a copy for myself.

Say hello to draft-carpenter-aeiou-00.txt!

Now, finally, I would not recommend pursuing this. Having actually used IPv6 at massive scale these past few years, the answer is clear: just use it. Rip off the bandage and make it happen. The sooner you start, the sooner you will get through the adaptation challenges everyone hits.

(Pro tip: if you have code which splits IP:port combos on a colon, you'd better figure out what you're going to do about IPv6 addresses first. Trust me.)