Re: [IPv6] RFC 6724 shouldn't prefer partial reachability over reachability

[Lorenzo Colitti <[e-mail]>]

I like this text and including something like it would make me much happier
about making this change.

On Tue, Nov 14, 2023 at 1:29 AM David Farmer <[e-mail]> wrote:

> How about something like the following;
>
> Since ULAs are defined to have a /48 site prefix, an implementation SHOULD
> automatically add rows for all covering ULA site prefixes received in
> Router Advertisements (RAs) [RFC4861] within Prefix Information Options
> (PIOs) or Route Information Options (RIOs) [RFC4191]. These known-local ULA
> /48s SHOULD have a precedence of 45.
>
>
In general PIOs are going to be /64s. Are you suggesting that we add the
covering /48? I assume yes, and I think it makes sense to do so.


> All Nodes SHOULD provide a mechanism to configure the policy table. Any
> Node that does not provide a mechanism for policy table configuration MUST
> implement the automated increased precedence for known-local /48s of ULA.
>
> Nodes implementing the automated increased precedence for known-local /48s
> of ULA MAY set the default precedence for the ULA label (fc00::/7) to 10.
> Otherwise, the default precedence for the ULA label (fc00::/7) MUST be 30.
>
>
So you're saying that if the host implements the "SHOULD elevate local ULA
preference" bit above, then it will prefer local ULAs over IPv4, and IPv4
over non-local ULAs? That makes sense. That still leaves anything that
doesn't implement the SHOULD at risk of breakage though..


> All Nodes SHOULD implement HEv2 [RFC8305].
>
>
Note that even if the node implements HE, many apps ship their own
networking libraries that might not use it.