Re: Adoption call for <draft-hinden-ipv4flag-03>

[Brian E Carpenter <[e-mail]>]

On 31/03/2018 09:51, Michael Richardson wrote:
> 
> Brian E Carpenter <[e-mail]> wrote:
>     >> The ISP has no business setting this flag on the customer side.  It is
>     >> a customer flag.  Only the customer can know if they want IPv4 to be
>     >> disabled or not on their side of the router.
> 
>     > That's another reason that the semantics of the flag are about *what
>     > the router setting it is configured to do*. It makes no statement about
>     > whether IPv4 packets are allowed or forbidden; it simply says whether
>     > they will be handled by the router in question.
> 
>     >> The ISP sets what is required to communicate upstream.
> 
>     > Sure. But if there is no IPv4 service upstream, the router could say so.
> 
> In DHCPv4, we have no way to say that a particular router does not offer a
> default route.  All a router in such a situation can do is not run DHCPv4.
> IPv4 only hosts, if they are lucky, might be able to use LLv4, or they might
> conclude that there network is dead.
> 
> But, we *can* signal that there is no uplink in v6.
> (Which perhaps explains how we might handle a future transition)
> 
> So perhaps that is really what we can do with this bit:
>    "The router setting this bit is indicating that the lack of
>     DHCPv4 response is not an error.  This router has no IPv4 uplink."
> 

Yes, that paraphrases what the draft says.

    Brian