Re: [6lo] Adam Roach's Discuss on draft-ietf-6lo-nfc-13: (with DISCUSS and COMMENT)

[최영환 <[e-mail]>]

Dear Adam Roach,

Thanks for your feedback. 
Please find the answer inline bellows.

BRs,
Younghwan

> -----Original Message-----
> From: Adam Roach <[e-mail]>
> Sent: Wednesday, June 26, 2019 2:06 AM
> To: 최영환 <[e-mail]>; The IESG <[e-mail]>
> Cc: [e-mail]; Carles Gomez <[e-mail]>;
> Samita Chakrabarti <[e-mail]>; [e-mail];
> [e-mail]
> Subject: Re: Adam Roach's Discuss on draft-ietf-6lo-nfc-13: (with DISCUSS
> and COMMENT)
> 
> Sorry for the relatively slow response. Comments inline.
> 
> On 6/7/19 3:01 AM, 최영환 wrote:
> >
> >> ---------------------------------------------------------------------
> >> -
> >> DISCUSS:
> >> ---------------------------------------------------------------------
> >> -
> >>
> >> Thanks to everyone who has worked on this document.
> >>
> >> I generally agree with Benjamin's discuss points, and in particular
> >> agree with his comment that it's kind of hard to figure out how all
> >> these pieces work together. I have an additional issue that is
> >> somewhat related to some of the points he raised, but which is (I think)
> not completely covered.
> >>
> >> I'm really confused about what the purported privacy properties of
> >> this protocol are. In section 4.3 (which I *think* talks about
> >> globally- routable IP addresses, although this is a bit unclear), the
> document says:
> >>
> >>     such an IID SHOULD guarantee a stable IPv6 address
> >>     because each data link connection is uniquely identified by the pair
> >>     of DSAP and SSAP included in the header of each LLC PDU in NFC
> >>
> >> (Aside: this "should" is a simple statement of fact, not a described
> >> behavior of the protocol, and so the use of RFC-2119-style all-caps
> >> is not
> >> appropriate.)
> > Agreed. I will fix it.
> >
> >> The presence of "a stable IPv6 address" inherently implies the
> >> ability to track devices.
> > Agreed. I will change them with "a secured and stable IPv6 address".
> This is ok?
> 
> 
> I don't think this changes the issue. Your response below implies that the
> address is stable only over very short periods of time, and that would
> address my concern. If that's true, then the solution would be to add text
> here that qualifies how long the address is stable (e.g.:
> "...such an IID should guarantee a stable IPv6 address during the course
> of a single connection, because...")
> 

I got it. I will put  the text. Thanks for your comment again.

> 
> >
> >> Then, in section 7, I find the following text:
> >>
> >>
> >>     ...the short address of
> >>     NFC link layer (LLC) is not generated as a physically permanent
> value
> >>     but logically generated for each connection.  Thus, every single
> >>     touch connection can use a different short address of NFC link with
> >>     an extremely short-lived link.
> >>
> >> This text seems to imply that addressing information is, in general,
> >> not stable, which appears to flatly contradict the text in section 4.3.
> >>
> >> Please clarify, in section 4.3, what the duration of stability of
> >> these identifiers is.
> > This texts means "NFC applications use short-lived connections, and the
> every connection is made with different address."
> > Just one permanent address is not used for a NFC device. If it looks
> like the texts appears to flatly contract the texts in section 4.3, I need
> to rephrase the texts for clarification. Thanks. It's good point, I think.