Re: Extending a /64

[Philip Homburg <[e-mail]>]

In your letter dated Mon, 9 Nov 2020 08:21:33 +0100 you wrote:
>Brian,
>> You need
>> 
>> R-5: Preserve existing security solutions
>> R-6: Preserve existing privacy solutions
>> R-7: Preserve e2e transparency
>
>Yes. Although I'm a little unsure what you think of regarding R-5?

One thing to consider, though I don't know how to formulate that as a
requirement is that if we change the lenght of IIDs, does that render all
devices that only support 64 bit IIDs obsolete?

I.e., should we make changes to IPv6 that render all currently conforming
implementations obsolete?

Of course we can create a nice bit of operatial chaos if we make shorter IIDs
an optional feature.

So the requirement should be something to the effect that a change to the
IPv6 standard that affect all hosts requires use cases that cannot be
solved without updating all hosts.