Re: [Ace] EDHOC standardization

Michael Richardson <mcr+ietf@sandelman.ca> Tue, 06 November 2018 03:42 UTC

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Comments: In-reply-to Benjamin Kaduk <kaduk@mit.edu> message dated "Mon, 05 Nov 2018 03:38:07 -0600."
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Date: Tue, 06 Nov 2018 10:41:43 +0700
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Subject: Re: [Ace] EDHOC standardization
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Benjamin Kaduk <kaduk@mit.edu>; wrote:
    >> > Are you proposing that the management of the 0/1-to-algorithm mapping
    >> > be managed on a per-deployment basis or by the IETF?
    >>
    >> I think that the existing proposal was that 0 means "negotiated out-of-band",
    >> which implies that it's a per-deployment basis.
    >>
    >> I'm proposing that instead of having 0 mean "some local default",
    >> I'm suggesting that 0 mean, "some local default 0" and 1 mean, "some other
    >> local default 1", which lets the default be updated without a flag day.

    > That feels like a potentially awkward provisioning problem.  I guess the
    > idea is that any given node is only going to do 1 or 0 and not both?  Maybe
    > that helps.

I don't think you get it if you think it's awkward!
Any firmware implements 0 or 1, correct.
[I'm not a fan of such a system. I also don't think it is small enough for
LoRAWAN either]

When a new choice is hard coded into that closed vertical system (via
"out-of-band"), this choice would be baked in at the next firmware update.
(There are many ways to do this of course. Throw dip switches if you like)

Having both 0 and 1 lets the firmware be incrementally updated, otherwise the
operator either has a flag day, or has to keep track of the parameters on an
per-device basis.

--
Michael Richardson <mcr+IETF@sandelman.ca>;, Sandelman Software Works
 -= IPv6 IoT consulting =-