Re: [Suit] Fwd: Firmware Update Paper

Michael Richardson <mcr+ietf@sandelman.ca> Thu, 05 December 2019 14:33 UTC

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From: Michael Richardson <mcr+ietf@sandelman.ca>
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Date: Thu, 05 Dec 2019 09:33:47 -0500
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Subject: Re: [Suit] Fwd: Firmware Update Paper
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    mcr> It occurs to me now that the development of an update protocol over
    mcr> 802.15.4
    mcr> (which I mentioned in another email in this thread) might be
    mcr> appropriately
    mcr> done in the 6tisch WG, since I actually think that the bandwidth and
    mcr> scheduling of the update is probably the critical part.
    mcr> SUIT has the security done... so we have the HOW. We just have the WHEN.

Szymon Słupik <simon@silvair.com> wrote:
    > One other approach to explore, very applicable to FW updates, is multi-hop
    > multicast, as in many scenarios you are updating more than one device, and
    > many of them are identical (like lights on a big parking lot).

I agree that this is an important aspect to explore.
It requires that each hop is able to buffer the entire firmware update in a
way that does not break the hash of it.  If the firmware is execute in place
and/or if the device is designed such that the bootstrap code validates the
firmware on each boot, then keeping the firmware image in that form may not
be a big imposition.

We also did MPL ("mipple", RFC7733) in the ROLL WG, which would allow for
the "download" of the firmware to be multicast.  There are bandwidth, CPU and
network scheduling tradeoffs of each, which I think 6tisch is most capable to
consider.   That's why I think that it's not a HOW anymore, but a WHEN.

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