[IPv6]Re: Analysis of Ungleich ULA Registry

[Ole Trøan <[e-mail]>]

> On 23 May 2024, at 22:42, Brian E Carpenter <[e-mail]> wrote:
> 
> On 23-May-24 15:25, Lorenzo Colitti wrote:
>> On Thu, May 23, 2024 at 11:36 AM Brian E Carpenter <[e-mail] <mailto:[e-mail]>> wrote:
>>    Right. If I want to use fd00:bec0::/32 (BEC being my initials), I certainly can, and it will disturb nobody.
>> I believe Jen presented some data a few years ago on what prefixes are in use, based on backscatter. I don't have the link right now, but I remember that what emerged from the data is that people did not commonly use their initials. They commonly used fd00:: or fd01::. In other words, the chance of collision for human-picked ULA prefixes is very much larger than for randomly-assigned prefixes.
>> To use your words... will it "disturb" anyone to pick fd00::? I don't know. Networks that picked fd00:: will be disturbed if they ever interconnect with other networks that picked fd00::. Do you thik they are more likely to try to fix this using renumbering, or via NAT or NPTv6? I'd say the latter. If they do that, they will disturb application developers and users.
>> Is it "foolish" to pick fd00::? Well, I would say yes. But the people who picked it didn't think it was. Or maybe they just didn't know.
>> I don't have an issue when people make unwise or broken deployment choices. I just don't like it when people make unwise or broken deployment choices, and app developers and users end up paying the price. That's not fair.
> 
> I completely agree.

To what though? I would like to see specifics otherwise it is tempting to call FUD. 

Applications have to deal with multi-addressing, ephemeral addresses, NAT64, HE and SAS/DAS selection.
I struggle to see that the tiny probability of ULA conflict is what breaks the camel’s back. 

I’m not particularly concerned about a few networks using ULA as RFC1918, nor that many networks will end up with various forms of locator rewriting.

Cheers,
Ole