Clarify Project Policy on Default Writes to NVRAM

[Goetz Goerisch]

Thank you for the feedback.

> > 3. Saving the current IPv6 prefix on the WAN port (obtained from
> > the ISP) to a file. If the router reboots due to power loss, and
> > the ISP changes the IPv6 prefix in the next boot, the old prefix
> > can be invalidated in a Router Advertisements to prevent IPv6
> > outages in the LAN due to stale addresses. This is known as "Flash
> > Renumbering Workaround Across Reboot", a recommended feature by
> > RFC 9096 to work around broken ISPs. This need is raised in a recent
> > odhcpd development discussion [3], and is my motivation of sending
> > this mail.
>
> I think this is the most useful feature.
>
> If implemented properly, it should result in a single write (per prefix assignment from the ISP, which, for sane ISPs, means only 1) which is no worse than the writes performed during firstboot: it shouldn’t be very controversial.

Unfortunately at least for residential users in Germany this means
typically one write per 24h. As the prefix assignments are dynamic and
ISPs even today still do force reconnects every 24h. Although
recommendations on best current operational practice e.g., RIPE 690
[1] exist.

[1] https://www.ripe.net/publications/docs/ripe-690/

I would fully support that RFC9069 should be implemented for OpenWrt.

Goetz