Re: [EXTERNAL] 64bit MAC addresses and SLAAC

[Carsten Bormann <[e-mail]>]

> If such reliance is because the overhead is simply unacceptable, then yes, I believe it is a valid question whether IPv6 is the right protocol for whatever device/technology needs such compression to keep the overhead track-table.

Valid question indeed.  The answer may very well be yes.

> YI also agree that there may be valid reasons for which, even if IPv6 was not the best fit for your application, but you might still want to use it, and hence resort to the hacks such as "header compression".

Header compression is not a “hack”.  Jeez.

Seriously, I don’t know where to start.

Even if there still is no Wikipedia page for header compression yet (I’ve been using that as in intro to talks about the subject for quite a while), that is not an excuse for not getting educated about the 30 years of history that header compression has in IP, starting with Van Jacobson’s RFC 1144.

> The fact that such hack somewhat introduces a requirement that is not present anywhere in the ipv6 address architecture (the IID can be anything, since you could e.g. manually configure your addresses, they could be dhcpv6-leased, etc.), should be a hint in that direction.

It is not a requirement; we designed things carefully so it isn’t.
But using the redundancy does supply some additional efficiency, so some deployments may want to use that efficiency to stay within a (technical) budget.
(The privacy-relevant ones don’t have that luxury, of course.)

> Much of what I've seem to remember seeing in the 6lo et al area seem to be tricks to somewhat make IPv6 tractable for the "constrained" scenarios.

Yes, that is the point.
It may not be your area of work, but that doesn’t make it invalid or “tricks” or “a hack”.
(Insert a couple of expletives here, because you have been around for a while and could know all this.)

> Anyway, believe the IID generation should be the least of your concerns here: at the end of the day there's a recommendation (RFC8064) for the general case... but you're free to override it. I seem to remember there was a proposal by Dave Thaler in this area, meant for constrained nodes, too.

Yes.  RFC 8065, and the number is *not* a coincidence.

Grüße, Carsten