Subject: [6lo] Warren Kumari's No Objection on draft-ietf-6lo-nfc-13: (with COMMENT)

From: Warren Kumari via Datatracker <[email-masked]>
Date: Thu, 14 Mar 2019 01:24:10 -0700

Warren Kumari has entered the following ballot position for
draft-ietf-6lo-nfc-13: No Objection

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COMMENT:
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I apologize - I've read the document, but it doesn't seem like it contains
enough information to allow a full implementation.

The document keeps talking about the fact that the range is limited to 10cm,
and makes some security assertions from this - from the little that I
understand about this technology (and I wasn't able to follow all the
references), ISO 15693 tags using NDEF are now part of the NFC specification -
these  work up to 1M. I have no idea if this protocol is supposed to work over
that, but if so, 1M is greater than 10cm.

Also, I see you did respond to the OpsDir review (
https://datatracker.ietf.org/doc/review-ietf-6lo-nfc-12-opsdir-lc-wu-2018-12-19/
-- thank you very much, Qin) , but there are things in these which don't seem
fully addressed. As an example, Qin asked: ----
 Section 3.4 said ” the MTU size in NFC LLCP MUST be calculated from the MIU
   value as follows:
                             MIU = 128 + MIUX.”
Can you provide formula to calculate MTU from MIU? Not clear how MTU is related
to MIU? ---

You responded: "YH >> Actually, MIU is the same as MTU. Specifications in NFC
forum use 'MIU', and we use 'MTU'. But these two has the same meaning."

I read version 13 of this document and had the exact same question -- how do I
calculate the MTU from the MIU? If they really are the same thing (which I'm
not sure they are), the document should state that, so readers can more easily
implement.