Re: [Gen-art] Gen-ART Last Call review of draft-ietf-trill-ia-appsubtlv

[Donald Eastlake <[e-mail]>]

Hi Paul,

I believe we are generally in agreement.

On the table in the IANA Considerations, I have read
https://tools.ietf.org/html/draft-leiba-cotton-iana-5226bis-15#section-1.1
and I can understand why you commented as you did. But, since all the
table entries were created by IANA actions, I still think the draft is
OK in having that table in the IANA Considerations Section. This is
not a case of including some technical specification in with the IANA
Considerations.  It's still all code points.

Thanks,
Donald
===============================
 Donald E. Eastlake 3rd   [phone] (cell)
 155 Beaver Street, Milford, MA 01757 USA
 [e-mail]


On Mon, Jul 4, 2016 at 6:50 PM, Paul Kyzivat <[e-mail]> wrote:
> Donald,
>
> On 7/4/16 5:26 PM, Donald Eastlake wrote:
>>
>> Hi Paul,
>>
>> Thanks for your comments. Sorry for the delay in response.
>> Please see below.
>
>
> No problem. I was just concerned that my review hadn't been received.
>
>
>> On Mon, Jun 27, 2016 at 6:46 PM, Paul Kyzivat <[e-mail]>
>> wrote:
>>>
>>> I am the assigned Gen-ART reviewer for this draft. The General Area
>>> Review Team (Gen-ART) reviews all IETF documents being processed by
>>> the IESG for the IETF Chair. Please treat these comments just like
>>> any other last call comments. For more information, please see the
>>> FAQ at <http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>.
>>>
>>> Document: draft-ietf-trill-ia-appsubtlv
>>> Reviewer: Paul Kyzivat
>>> Review Date: 2016-06-27
>>> IETF LC End Date: 2016-06-28
>>> IESG Telechat date: 2016-07-07
>>>
>>> Summary:
>>>
>>> This draft is on the right track but has open issues, described in
>>> the review.
>>>
>>> This is a well written document. I was generally able to follow it
>>> even though I know nothing about the subject.
>>>
>>>
>>> Issues:
>>>
>>> Major: 0
>>> Minor: 7
>>> Nits:  2
>>>
>>> (1) MINOR: (Section 2)
>>>
>>> "Addr Sets End" is described as follows:
>>>
>>>    o  Addr Sets End: The unsigned integer offset of the byte, within
>>>       the IA APPsub-TLV value part, of the last byte of the last
>>>       Address Set. This will be the byte just before the first
>>>       sub-sub-TLV if any sub-sub-TLVs are present ...
>>>
>>> But the remaining text of this section, and the examples, imply that
>>> this is really the length of the leading portion of this TLV ending
>>> with the last Address Set. The programmer in me says these differ by
>>> one, and that the implied definition is the reasonable one, while
>>> the action definition, and the name used to identify it, are wrong.
>>>
>>> I expect it would be difficult at this point to rename this field,
>>> but at least the definition can be rewritten to be consistent with
>>> the intended usage.
>>
>>
>> Right. How about
>>
>>    Addr Sets End: The unsigned integer byte number, within the IA
>>    APPsub-TLV value part, of the last byte of the last Address Set,
>>    where the first byte is numbered 1. This will be the number of the
>>    byte just before ...
>
>
> OK. If you count starting from one. (I don't, but it is your draft.)
>
>>> (2) MINOR: (Section 5.1)
>>>
>>> Normally I would expect this section to request IANA to assign new
>>> values from the AFN table for OUI...RBridge Port ID. However it is
>>> worded as "IANA has allocated". Perhaps this is because they have
>>> already been (pre)allocated. I have no problem with that if IANA is
>>> OK with it.
>>
>>
>> Yup, it say "IANA has allocated" because they are already allocated. See
>>
>> http://www.iana.org/assignments/address-family-numbers/address-family-numbers.xhtml
>
>
> OK.
>
>>> But IMO the references to IPv4...64-bit MAC are gratuitous and
>>> inappropriate in an IANA Considerations section. If it is desired to
>>> include a list of "useful" AFN values then that belongs in some
>>> other portion of the document.
>>
>>
>> I disagree. It's "IANA Considerations", not "IANA Allocation Actions".
>> Someone looking for code points is likely look in the IANA
>> Considerations section.  All the values shown are from the same IANA
>> registry.  I can see no advantage to splitting this table between two
>> different parts of the draft.
>
>
> When I wrote this comment I had in mind the following that I recently read:
>
> https://tools.ietf.org/html/draft-leiba-cotton-iana-5226bis-15#section-1.1
>
>>> (3) MINOR: (Section 5.1)
>>>
>>> The "new" values here (OUI, MAC/24, MAC/40, IPv6/64) give "This
>>> document" as their reference. But anyone consulting the IANA
>>> registry and following it to this document would have difficulty
>>> finding any *definition* of these things.
>>>
>>> Section 6 discusses some operational issues with them, but at best
>>> implies a definition. (RFC7042 might be considered a definition of
>>> OUI, though it doesn't seem to say how big it would be.)
>>>
>>> I think what is needed are explicit definitions of all of these,
>>> including their widths. (In order to provide enough bits to complete
>>> a MAC/24 it must be at least 24 bits wide, but that would be bigger
>>> than needed for a MAC/40.  So I guess it must be at least 24 bits,
>>> and when used to expand a MAC/24 or MAC/40 an appropriate number of
>>> its high order bits are used.)
>>>
>>> It would be good for there to be a section, appearing in the TOC,
>>> for each of these so that someone coming here from the IANA registry
>>> will easily be able to find the definition.
>>
>>
>> This is a good point. Better definitions of these AFN types and better
>> references, either to within this document by explicit pointers to a
>> section within another document or both, are good points. Probably
>> Section 6 should be expanded and sub-sections added to it...
>
>
> WFM
>
>
>>> (4) MINOR: (Section 5.2)
>>>
>>> This section defines a new registry with Expert Review as the
>>> procedure for approving new entries. What I don't see is any
>>> guidance to the expert on appropriate criteria to use to judge
>>> suitability of new entries. Without any guidance, relying on the
>>> whim of the expert can lead to variable, and perhaps biased,
>>> results.
>>>
>>> It would be good to give guidance on: what sorts of document
>>> reference are acceptable, what information needs to be included in
>>> the reference document, whether "special" values may be requested
>>> (versus just assignment in order requests are received), and the
>>> sorts of properties that are appropriate.
>>
>>
>> OK. Some guidance can be added.
>>
>>> (5) MINOR: (Section 6)
>>>
>>> This section talks about the handling of OUI and IPv6/64 when they
>>> appear in a Fixed Address sub-sub-TLV. It says nothing about their
>>> meaning if these appear elsewhere, such as in a Template. I presume
>>> this kind of usage is nonsense, but it would be better to explicitly
>>> state it.
>>
>>
>> OK, the draft should explain their processing wherever they occur.
>>
>>> (6) MINOR: (Section 6)
>>>
>>> The description of IPv6/64 says:
>>>
>>>    For this purpose, an 48-bit MAC address is expanded to 64
>>>    bits as described in [RFC7042].
>>>
>>> It wasn't entirely apparent to me what part of 7042 covers that. It
>>> would be helpful to provide the section where this aspect is
>>> specified. (After some study I guess that it is section 2.2.1.)
>>
>>
>> OK.
>>
>>> (7) MINOR: (Section A.2)
>>>
>>> I believe that the values of both 'Length' and 'Address Sets End'
>>> are too small by 7 - presumably because they forgot to count the
>>> fixed fields. This also applies to the "alternative" using explict
>>> AFN encoding.
>>
>>
>> Thanks for catching that there is an error here.
>>
>> Length should be the size everything after the 2-byte length
>> field. That's
>>   7  fixed fields
>>  36  three address sets, each 12 bytes
>>   7  sub-sub-tlv one
>>  14  sub-sub-tlv two
>> for a total of 64 so the value is off by 10.
>>
>> Address Sets End should be the above less the sub-sub-tlvs, so that
>> would be 43 and the value shown is also off by 10.
>
>
> I guess I also got it wrong.
>
> But it was obvious to me that the examples weren't all done the same way.
>
>>> (8) NIT: (Section A.2)
>>>
>>> Based on a very quick reading, ISTM that section 2.2.1 of 7042
>>> suggests that the IPv6 addresses being constructed this way should
>>> start with 0x02 rather than 0x20. But I'm far from sure I understand
>>> this correctly.
>>
>>
>> Ahhh, there is indeed an error here but it is in the bottom 64 bits,
>> which should be a Modified EUI-64 identifier, as described in Section
>> 2.2.1 of RFC 7042. Thus the top byte of the bottom 64 bits of the
>> resulting IPv6 addresses should be 0x02. The top byte of the entire
>> IPv6 128-bit address should be 0x20 as shown.
>
>
> OK. Like I said, I didn't really understand the details.
>
>         Thanks,
>         Paul
>
>
>>> (9) NIT: (Section A.2)
>>>
>>> There seems to be a typo in the following:
>>>
>>>    The OUI would them be supplied
>>>    by a second Fixed Address sub-sub-TLV proving the OUI.
>>>
>>> I think "proving" should be "providing".
>>
>>
>> OK.
>>
>> Thanks,
>> Donald
>> ===============================
>>  Donald E. Eastlake 3rd   [phone] (cell)
>>  155 Beaver Street, Milford, MA 01757 USA
>>  [e-mail]
>>
>