Subject: [6lo] Quick update on draft-ietf-6lo-6lobac

From: Kerry Lynn <[email-masked]>
Date: Wed, 22 Jul 2015 23:59:56 -0400

Greetings,

I regret that I will be unable to remotely provide an update on 6LoBAC
due to a scheduling conflict, so Samita asked me to post a quick update
to the list.  For those who may not be familiar, this is a proposal for
conveying IPv6 over RS-485 twisted pair using a token-passing MAC.

We received the required Frame Type assignment from ASHRAE (the
organization that defines the underlying MS/TP MAC) just prior to IETF
92, so there are no remaining external dependencies.

The draft has been reviewed by two group members, Peter van der Stok
and James Woodyatt (thanks guys) and their comments have been
addressed in the latest draft.  The summary of changes is in the slides
and I won't repeat it here.

The technical details of 6LoBAC have been stable for quite some time.
The major change in this draft was the elimination of the uncompressed
IPv6 header Dispatch Value (since Carsten and a few others were strongly
in favor of this).  I missed the discussion of Dispatch Values at this IETF,
but I guess we need to keep this value in the registry even if we're not
going to use it.

I continue to have concerns about the direction of the default-iids
discussion.  In the case of this proposal, I think there are good
engineering
reasons to specify MAC-address-derived IIDs for use in link-local addresses
and I expect a debate when this draft makes it through last call.  My take
on
the matter is the perceived threat is mainly to users of mobile personal-use
devices that use static EUI identifiers.  6LoBAC has none of these
attributes.

There will be another draft forthcoming.  One major oversight on my part
was not updating the Acknowledgments section to include those who have
contributed valuable comments.  I also plan to reverse myself (again) in
Section 8 and left-justify the short address to agree with the format of RFC
4944.  Additional reviews and comments are welcomed.

Finally, I have a running implementation based on Contiki plus a wireshark
dissector that I plan to open source by the early fall.  6LoBAC is a
candidate
for the ETSI plugtest in Yokohama and I am happy to assist anyone who
might want to try implementing this.  Contact me if you need a copy of
who BACnet Clause 9 (the MS/TP specification).

Regards, Kerry Lynn

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From: Carsten Bormann <[email-masked]>
Date: Thu, 23 Jul 2015 11:44:47 +0200

As I said before, the question is not whether addresses are MAC-derived
or randomized, the question is whether they are trackable/linkable and
at the same time exposing personal information (they do not need to be
mobile to do this).
I believe in this case a short paragraph of explanation why this is not
the case should suffice.

Grüße, Carsten

Kerry Lynn wrote:
> and I expect a debate when this draft makes it through last call.  My
> take on