Re: I-D Action: draft-ietf-6man-rfc6434-bis-01.txt

[Lorenzo Colitti <[e-mail]>]

vOn Sun, Jul 16, 2017 at 2:14 PM, Nick Hilliard <[e-mail]> wrote:

> There is no conflict here.
>
> The "SHOULD" that you quoted in rfc7934 refers to how an opinion about
> people ought to run their networks, but does not conflict with the
> SHOULD in 6434bis, which refers to what the IETF is proposing ought to
> be supported on host devices.  These two things are very different indeed.
>

It's not an opinion, it's an IETF best practice. And I really don't see how
you can say there's no contradiction. For the moment, let's consider mobile
hosts that follow the anonymity profile.

This document says that hosts SHOULD support DHCPv6 because operators might
use it. But our current recommendations say that:

   1. Such hosts SHOULD prefer SLAAC over DHCPv6
   2. DHCPv6-only networks are NOT RECOMMENDED

Due to #1, such hosts will always prefer SLAAC over DHCPv6 on networks that
have both. So a "SHOULD support DHCPv6" requirement will only matter on
networks that don't do SLAAC, which are NOT RECOMMENDED.

So we're basically saying that they SHOULD implement IPv6 only for the
purpose of connecting to networks that are NOT RECOMMENDED. How can we
recommend something that is only used for something that is NOT RECOMMENDED?