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Re: [dhcwg] Last Call: <draft-ietf-dhc-anonymity-profile-06.txt> (Anonymity profile for DHCP clients) to Proposed Standard

2016-02-24 12:38:35
At Tue, 23 Feb 2016 12:50:01 +0000,
Tim Chown <tjc(_at_)ecs(_dot_)soton(_dot_)ac(_dot_)uk> wrote:

That's actually the contrary of what the specs say today: if M=1 you do
DHCPv6, not SLAAC.

I don't see any statement in 4861 that says that. Per 4861, M=1 means 
"DHCPv6 is available", not "nodes should do DHCPv6". Relevant text:

      M              1-bit "Managed address configuration" flag.  When
                     set, it indicates that addresses are available via
                     Dynamic Host Configuration Protocol [DHCPv6]

I agree. It’s always just been a hint, no more, no less. And it’s been 
discussed many times...

+1.  I understand it may look subtle and could be confusing probably
because it was a kind of compromise as we could reach consensus on how
M/A flags should actually work.  But, however it looks, I'm pretty
sure that the intent of RFC4861 is that we do NOT say "if M=1 you do
DHCPv6", and that was intentional.  Let alone RFC4862 (for which I
happen to be a document editor): it even removed references to the M/O
flags:

   o  Removed the text regarding the M and O flags, considering the
      maturity of implementations and operational experiences.
      ManagedFlag and OtherConfigFlag were removed accordingly.  (Note
      that this change does not mean the use of these flags is
      deprecated.)

As such, I don't see the need for adding the "update: RFC 4682" mark
because of the proposed text.  (I don't have a particular opinion on
the text itself, btw).

--
JINMEI, Tatuya


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