Re: [v6ops] ULA precedence [Thoughts about wider operational input]

[Philip Homburg <[e-mail]>]

In your letter dated Mon, 25 Apr 2022 11:00:20 +0000 you wrote:
>What you proposed (separate ULA prefix for NAT) is robust and solid but very h
>eavy - it would need a big change for many RFCs (new address type).

Why would that change many RFCs? The introduction of ULA didn't touch
many RFCs.

We would need an RFC that defines the new space and update the policy
table (if it needs updating at all).

>Would you agree to the tradeoff: assume that GUA PIO is absent for ULA+NPT cas
>e.
>Then I do not see a problem in the implementation: just ULA priority about IPv
>4 (it is not mandatory to put it in priority above GUA) would be enough.
>This is the minimal change for RFC 6724 only.

This a good example of something that is not robust. And why we need a
good description of use cases.

You imply that ULA+NPT only happens in networks that do not have GUA. A
counter example would a be network that wants to use ULA+NPT for all 
outgoing traffic, but has GUAs on servers to receive requests.