Re: [v6ops] [dhcwg] IPv6-Only Preferred DHCPv4 option

[Mark Smith <[e-mail]>]

On Thu, 5 Dec 2019 at 12:37, Roy Marples <[e-mail]> wrote:
>
> On 05/12/2019 01:19, Mark Smith wrote:
> > Going by the now almost entire lack of existence of Appletalk, IPX,
> > DECNET, XNS, VINES (I haven't seen or heard of any of them in a
> > network since 1999),  it's likely IPv6 will be the single network
> > layer protocol in the future. Running a single network layer protocol
> > is cheaper and easier, which is why those others have gone away (that
> > also explains why nearly all links use or emulate (Wifi) Ethernet
> > framing, unless they specifically can't).
> >
> > IPv6 will have a life, just as IPv4 has had a life, and those other
> > past protocols have had a lives. IPv6 is designed to last for much
> > longer than almost any of them, centuries most likely, so I don't
> > think we shouldn't be worrying about accommodating "IPv8" now at the
> > cost of making IPv4 easier to move away from. We don't have any idea
> > what "IPv8"'s transition requirements are or what it will even look
> > like.
>
> And this affects the wording and intent of my proposal how?
>

I wasn't addressing your specific proposal.

I was addressing this comment.

"> It assumes that IPv6 is the be-all and end-all. Maybe one day we will
> have IPv8?"

and indirectly this comment:

> BUT - what if we need to enable DHCP again? Should clients still listen
> for FORCERENEW? It does pose a small dilema because there isn't actually
> anything to renew."

A network/link using the sort of mechanism in this draft and the past
IPv6-Only RA flag draft have made conscious decision to switch off
IPv4. They have actively decided that "IPv6 is the be-all and end-all"
is their intent from now on.

They know they're very unlikely to need to switch IPv4 back on on that
link (otherwise, why would they enable these types of mechanisms?),
which means we don't have to place much if any weight on situations
such as "BUT - what if we need to enable DHCP again? Should clients
still listen for FORCERENEW? "

If somebody wanted to switch IPv4 back on on that link, after they've
actively enabled one of these IPv4 switch off types of mechanisms,
then it would be reasonable for us to assume they're willing to reboot
all of the hosts or similar to boot strap DHCPv4 again. They they're
not willing to go to that effort, then they're not ready to switch
IPv4 off yet.



>



> 1 client sends DISCOVER with I CAN WORK WITHOUT DHCP ADDRESS option
> 2 server sends I HAVE NO DHCP ADDRESS option with T2 timer
> 3 client reads this and will retry in T2 seconds
>
> This satisfies the use case the OP put forward and makes no mention of
> any other protocol than DHCP
>AND makes things much simpler to actually
> implement.
> What did I miss?
>


> Roy