Re: [sfc] draft-ietf-sfc-proof-of-transit-04 ready for WGLC? (was RE: PoT review/comments)

[Joel Halpern Direct <[e-mail]>]

Fair question.  No, I do not have any pointers.  The rule of thumb I am 
following (and if the WG disagrees, the WG carriees the day) is that the 
specification has to be implementable.  In the case of IP over Foo, we 
have understood that we will put it in a separate spec.  And people know 
to look for that spec.  Arguably, the informative reference you propose 
provides the "people know to look" mechanism.  At which point it is a 
judgment call.
And I admit, part of my reasoning on the judgment call is that we said 
this is an SFC document, and the normative header for SFC is NSH.  Even 
if other working groups are also doing other things.

Trying to find the right balance (because the suitability for other 
things is important) we said something like:
     When used in conjunct with NSH (RFC 8300), the PoT MUST be carried 
as specified in ...
And made the reference normative.   Essentially a conditional MUST, 
which is allowed my the rules.

Yours,
Joel

On 4/1/2020 6:50 PM, Carlos Pignataro (cpignata) wrote:
> Same here, Joel, I am happy with either normative or informative.
> 
> However, mostly for my understanding and beyond this specific draft:
> The MTI concept seems does not seem to be yes/no binary. I’ve never fully understood MTI as a requirement beyond security features and professional judgement. For example, RFC 8200 does not say how to carry IPv6 over any layer-2 — not ethernet, not PPP. RFC 8300 does not explain how to carry (i.e., transportation encapsulation) NSH over anything.
> 
> MTI makes sense to me within a given layer — but it is less clear to me how far down the layers MTI really applies. For a spec defining how to encapsulate something, sure. For a spec defiling information elements at a given Layer that need to interoperate within themselves regardless the encap, less clear to me.
> 
> Also, MTI seems to be better define within security features, less so as a general criteria for spec completeness.
> 
> Do you have any pointers or normative definitions?
> 
> Thanks,
> 
> Carlos.
> 
>> 2020/04/01 午後3:30、Joel M. Halpern <[e-mail]>のメール:
>>
>> To be clear up front, I can live with an informative reference from sfc-proof-of-transit to sfc-ioam-nsh.
>>
>> However, it seems to me that as a Proposed Standard, we are expected to define an interoperable and implementable protocol.  Without a normative reference to some encoding (and sfc-ioam-nsh does seem the obvious one to reference) we do not seem to have a full PS.  That is not to say that there can not be other encodings.  But NSH is the SFC agreed header format.  So for an SFC document, this seems natural as the MTI.
>>
>> Yours,
>> Joel
>>
>> On 4/1/2020 3:16 PM, Carlos Pignataro (cpignata) wrote:
>>> Dear Greg,
>>>> 2020/04/01 午後2:59、Greg Mirsky <[e-mail]>のメール:
>>>>
>>>> Dear All,
>>>> I agree with Joel that the reference in draft-ietf-sfc-proof-of-transit to draft-ietf-ippm-ioam-data should be normative.
>>> Great. Everyone seems to be aligned on this point.
>>>> I also support the proposal to add in draft-ietf-sfc-proof-of-transit a normative reference to draft-ietf-sfc-ioam-nsh. SFC WG is working on defining SFC that is based on NSH (SFC NSH), and while SFC might be realized using other techniques, draft-ietf-sfc-ioam-nsh is, and likely will remain, the only document that is describing iOAM encapsulation in SFC NSH. Thus, I believe, for SFC WG, implementation of PoT based on iOAM requires implementation of iOAM encapsulation in SFC NSH, as defined in draft-ietf-sfc-ioam-nsh. Hence, the reference must be normative.
>>> This logic is flawed in the onset. The main point is that POT can be realized with a variety of transports and technologies and use-cases, one of which is SFC, and then further within SFC one of which is NSH.
>>> You seem to argue that NSH is somehow in practice the only SFC realization, and because of that the reference “must be normative”.
>>> I disagree with the premise, but regardless, it does not matter since POT applies to other non-SFC(-non-NSH) technologies. Therefore that since-then logic does not apply.
>>> Copying the very first sentence of the Abstract:
>>>     Several technologies such as Traffic Engineering (TE), Service
>>>     Function Chaining (SFC), and policy based routing [...]
>>> And now looking at this fragment, I am more convinced that this is one example and as such Informative.
>>> I would not object to Normative for the right reasons, but the reason above, in my mind, does not follow.
>>> Thanks,
>>> Carlos.
>>>>
>>>> Regards,
>>>> Greg
>>>>
>>>> On Tue, Mar 24, 2020 at 2:25 PM Joel M. Halpern <[e-mail]> wrote:
>>>> I think we all agree that draft-ietf-sfc-proof-of-transit requires the
>>>> normative reference to draft-ietf-ippm-ioam-data.
>>>>
>>>> Regarding a reference from draft-ietf-sfc-proof-of-transit to
>>>> draft-ietf-sfc-ioam-nsh, I think we agree that it is needed.  The
>>>> question then is normative or informative.  If we use the usual IETF
>>>> rule that there has to be a defined normative way to interoperably
>>>> implement a protocol spec (with other options allowed), my inclination
>>>> is that the reference should be normative.
>>>>
>>>> Regarding the informative reference in the other direction from
>>>> draft-ietf-sfc-ioam-nsh to draft-ietf-sfc-proof-of-transit, while I
>>>> personally like the idea, that is up to you / the working group.
>>>>
>>>> Yours,
>>>> Joel
>>>>
>>>> On 3/24/2020 5:20 PM, Carlos Pignataro (cpignata) wrote:
>>>>> Hi, Joel,
>>>>>
>>>>> The way in which the doc hierarchy and relationship is structure seems
>>>>> to support and potentially even require:
>>>>>
>>>>>  From draft-ietf-sfc-proof-of-transit:
>>>>> * A normative reference to [I-D.ietf-ippm-ioam-data], since PoT gives
>>>>> over IOAM explicitly, and that exists.
>>>>> * Optionally, an Informative reference to draft-ietf-sfc-ioam-nsh, since
>>>>> that’s really one out of many ways to carry IOAM over NSH, but separated
>>>>> by document indirection. This does not exist but can be added.
>>>>>
>>>>>   From draft-ietf-sfc-ioam-nsh:
>>>>> * Optionally, an Informative reference to
>>>>> draft-ietf-sfc-proof-of-transit, since that’s one out of many
>>>>> applications. This does not exist but can be added.
>>>>>
>>>>> Thoughts?
>>>>>
>>>>> Best,
>>>>>
>>>>> Carlos.
>>>>>
>>>>>> 2020/03/24 午後5:10、Joel M. Halpern <[e-mail]
>>>>>> <mailto:[e-mail]>>のメール:
>>>>>>
>>>>>> Carlos, it sounds like there should probably be a normative reference
>>>>>> from draft-ietf-sfc-proof of transit to draft-ietf-sfc-ioam-nsh?
>>>>>> Possibly in the same sentence that refers to draft-ietf-ippm-ioam-data?
>>>>>>
>>>>>> Yours,
>>>>>> Joel
>>>>>>
>>>>>> On 3/24/2020 4:54 PM, Carlos Pignataro (cpignata) wrote:
>>>>>>> Greg,
>>>>>>> The very first sentence of the PoT document reads:
>>>>>>>     Several technologies such as Traffic Engineering (TE), Service
>>>>>>>     Function Chaining (SFC), and policy based routing are used to steer
>>>>>>>     traffic through a specific, user-defined path.  This document defines
>>>>>>> Explaining how this document is applicable to various
>>>>>>> traffic-steering technologies.
>>>>>>> Section 3 then explains:
>>>>>>>     The POT information is encapsulated in packets as an IOAM Proof Of
>>>>>>>     Transit Option.  The details and format of the encapsulation and the
>>>>>>>     POT Option format are specified in [I-D.ietf-ippm-ioam-data].
>>>>>>> Which shows how to carry PoT in IOAM, with an appropriate pointer.
>>>>>>> Lastly, draft-ietf-sfc-ioam-nsh-03 defines IOAM over an NSH
>>>>>>> encapsulation.
>>>>>>> This arrangements maximizes specification modularity and
>>>>>>> portability/reusability.
>>>>>>> Best,
>>>>>>> Carlos.
>>>>>>>> 2020/03/24 午後4:48、Greg Mirsky <[e-mail]
>>>>>>>> <mailto:[e-mail]> <mailto:[e-mail]>>のメール:
>>>>>>>>
>>>>>>>> Hi Joel,
>>>>>>>> thank you for the most expedient response. As I understand it, iOAM
>>>>>>>> Data draft describes the format of the informational element that
>>>>>>>> carries POT-related information but it does not define how the
>>>>>>>> element to be carried in case of NSH encapsulation. And that is what
>>>>>>>> I was asking, apologies for not being clear in my first note.
>>>>>>>>
>>>>>>>> Regards,
>>>>>>>> Greg
>>>>>>>>
>>>>>>>> On Tue, Mar 24, 2020 at 1:42 PM Joel M.. Halpern
>>>>>>>> <[e-mail] <mailto:[e-mail]>
>>>>>>>> <mailto:[e-mail]>> wrote:
>>>>>>>>
>>>>>>>>     Regarding the information carriage, the PoT document points to the
>>>>>>>>     IOAM
>>>>>>>>     document.
>>>>>>>> https://tools.ietf.org/html/draft-ietf-ippm-ioam-data-08#section-4.5
>>>>>>>>     gives the format (and ways to have other formats if needed.)
>>>>>>>>
>>>>>>>>     Yours,
>>>>>>>>     Joel
>>>>>>>>
>>>>>>>>     On 3/24/2020 4:26 PM, Greg Mirsky wrote:
>>>>>>>>     > Hi Frank,
>>>>>>>>     > thank you for reminding us about this important work, indeed we
>>>>>>>>     should
>>>>>>>>     > complete it. I've reviewed the draft and have several questions.
>>>>>>>>     Please
>>>>>>>>     > kindly consider:
>>>>>>>>     >
>>>>>>>>     >   * I couldn't find information where, relative to NSH, RND and
>>>>>>>>     CML are
>>>>>>>>     >     transported
>>>>>>>>     >   * for YANG data models using "reference" is strongly
>>>>>>>>     encouraged as it
>>>>>>>>     >     provides a pointer to the specification. Since the POT data
>>>>>>>>     model is
>>>>>>>>     >     in the same document as the POT specification, listing the
>>>>>>>>     >     appropriate section should suffice
>>>>>>>>     >
>>>>>>>>     > Regards,
>>>>>>>>     > Greg
>>>>>>>>     >
>>>>>>>>     > On Thu, Mar 19, 2020 at 6:45 AM Frank Brockners (fbrockne)
>>>>>>>>     > <fbrockne=[e-mail]
>>>>>>>> <mailto:fbrockne=[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     > <mailto:[e-mail]
>>>>>>>>     <mailto:[e-mail]>>> wrote:
>>>>>>>>     >
>>>>>>>>     >     Dear SFC WG,____
>>>>>>>>     >
>>>>>>>>     >     __ __
>>>>>>>>     >
>>>>>>>>     >     It’s been a while since we posted
>>>>>>>>     draft-ietf-sfc-proof-of-transit-04
>>>>>>>>     >     which addressed all known comments – see below.
>>>>>>>>     >     I’ve not seen any more recent comments or questions come up
>>>>>>>>     – and
>>>>>>>>     >     we’ve been through quite a few discussions and reviews of this
>>>>>>>>     >     document already.____
>>>>>>>>     >
>>>>>>>>     >     __ __
>>>>>>>>     >
>>>>>>>>     >     Thus the question: Are we ready for WG LC?____
>>>>>>>>     >
>>>>>>>>     >     __ __
>>>>>>>>     >
>>>>>>>>     >     Thanks, Frank____
>>>>>>>>     >
>>>>>>>>     >     __ __
>>>>>>>>     >
>>>>>>>>     >     *From:* Frank Brockners (fbrockne)
>>>>>>>>     >     *Sent:* Donnerstag, 21. November 2019 08:21
>>>>>>>>     >     *To:* Alejandro Aguado FI <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail] <mailto:[e-mail]>>>;
>>>>>>>>     Diego R. Lopez
>>>>>>>>     >     <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail]
>>>>>>>>     <mailto:[e-mail]>>>; Carlos Pignataro (cpignata)
>>>>>>>>     >     <[e-mail] <mailto:[e-mail]>
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail] <mailto:cpignata@cisco..com>>>;
>>>>>>>>     ALEJANDRO AGUADO
>>>>>>>>     >     MARTIN <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail]
>>>>>>>>     <mailto:[e-mail]>>>; Shwetha
>>>>>>>>     >     Bhandari (shwethab) <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail] <mailto:[e-mail]>>>;
>>>>>>>>     Tal Mizrahi <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail]
>>>>>>>>     <mailto:[e-mail]>>>
>>>>>>>>     >     *Cc:* [e-mail] <mailto:[e-mail]> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail] <mailto:[e-mail]>>
>>>>>>>>     >     *Subject:* RE: PoT review/comments____
>>>>>>>>     >
>>>>>>>>     >     __ __
>>>>>>>>     >
>>>>>>>>     >     We’ve just posted revision -04 of
>>>>>>>>     draft-ietf-sfc-proof-of-transit
>>>>>>>>     >     which now includes support for OPOT configuration in the
>>>>>>>>     yang model;____
>>>>>>>>     >
>>>>>>>>     >     see section 5.2.3 in
>>>>>>>>     > https://www.ietf.org/id/draft-ietf-sfc-proof-of-transit-04.txt.
>>>>>>>> ____
>>>>>>>>     >
>>>>>>>>     >     The main addition is a grouping opot-profile, which adds
>>>>>>>>     upstream
>>>>>>>>     >     and downstream masks that OPOT requires.____
>>>>>>>>     >
>>>>>>>>     >     Thanks to Alejandro for suggesting these updates.____
>>>>>>>>     >
>>>>>>>>     >     __ __
>>>>>>>>     >
>>>>>>>>     >     This fixes the last “known issue” in
>>>>>>>>     >     draft-ietf-sfc-proof-of-transit. It would be great if you
>>>>>>>>     could give
>>>>>>>>     >     the document another careful read through.
>>>>>>>>     >     Are we ready for WGLC?____
>>>>>>>>     >
>>>>>>>>     >     __ __
>>>>>>>>     >
>>>>>>>>     >     Thanks, Frank____
>>>>>>>>     >
>>>>>>>>     >     __ __
>>>>>>>>     >
>>>>>>>>     >     __ __
>>>>>>>>     >
>>>>>>>>     >     *From:* Alejandro Aguado FI <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail] <mailto:[e-mail]>>>
>>>>>>>>     >     *Sent:* Donnerstag, 12. September 2019 15:40
>>>>>>>>     >     *To:* Diego R. Lopez <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail]
>>>>>>>>     <mailto:[e-mail]>>>; Carlos Pignataro (cpignata)
>>>>>>>>     >     <[e-mail] <mailto:[e-mail]>
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail] <mailto:cpignata@cisco..com>>>; Frank
>>>>>>>>     Brockners
>>>>>>>>     >     (fbrockne) <[e-mail] <mailto:[e-mail]>
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail] <mailto:[e-mail]>>>;
>>>>>>>>     >     ALEJANDRO AGUADO MARTIN
>>>>>>>>     <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail]
>>>>>>>>     <mailto:[e-mail]>>>; Shwetha
>>>>>>>>     >     Bhandari (shwethab) <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail] <mailto:[e-mail]>>>;
>>>>>>>>     Tal Mizrahi <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail]
>>>>>>>>     <mailto:[e-mail]>>>
>>>>>>>>     >     *Cc:* [e-mail] <mailto:[e-mail]> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail] <mailto:[e-mail]>>
>>>>>>>>     >     *Subject:* Re: PoT review/comments____
>>>>>>>>     >
>>>>>>>>     >     __ __
>>>>>>>>     >
>>>>>>>>     >     Hi Shwetha,____
>>>>>>>>     >
>>>>>>>>     >     __ __
>>>>>>>>     >
>>>>>>>>     >     Yes, I think it is a good idea. From your points, the second
>>>>>>>>     one is
>>>>>>>>     >     a bit confusing to me... But I do not fully remember how the
>>>>>>>>     model
>>>>>>>>     >     was structured, so I need to revise the document.____
>>>>>>>>     >
>>>>>>>>     >     __ __
>>>>>>>>     >
>>>>>>>>     >     Give me a day or two to explore again the model, and either we
>>>>>>>>     >     exchange few emails with proposals for the extension, or we can
>>>>>>>>     >     organise a quick call during next week to close a final
>>>>>>>>     proposal to
>>>>>>>>     >     share with other contributors.____
>>>>>>>>     >
>>>>>>>>     >     __ __
>>>>>>>>     >
>>>>>>>>     >     Thanks!____
>>>>>>>>     >
>>>>>>>>     >     __ __
>>>>>>>>     >
>>>>>>>>     >     Best,____
>>>>>>>>     >
>>>>>>>>     >     Alejandro____
>>>>>>>>     >
>>>>>>>>     >     __ __
>>>>>>>>     >
>>>>>>>>     >     __ __
>>>>>>>>     >
>>>>>>>>     >     El 12 de septiembre de 2019 a las 8:52:44, Shwetha Bhandari
>>>>>>>>     >     (shwethab) ([e-mail] <mailto:[e-mail]>
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail] <mailto:[e-mail]>>)
>>>>>>>>     >     escribió:____
>>>>>>>>     >
>>>>>>>>     >     Hi Alejandro, Diego,____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     Since you added extension to do OPoT, should we extend the
>>>>>>>>     model in
>>>>>>>>     >     draft-ietf-sfc-proof-of-transit to enable OPoT and any
>>>>>>>>     parameters
>>>>>>>>     >     required for it  shared masks per link. If yes my proposal
>>>>>>>>     will be
>>>>>>>>     >     to:____
>>>>>>>>     >
>>>>>>>>     >      1. Augment existing pot-profile with fields to Enable OPoT
>>>>>>>>     and a
>>>>>>>>     >         cipher scheme if needed.____
>>>>>>>>     >      2. Separate container in the model to define a map of (Node
>>>>>>>>     >         link/interface, mask) to distribute pair wise masks. For
>>>>>>>>     e.g.
>>>>>>>>     >         Node link/interface identifier can be UUID as defined in
>>>>>>>>     rfc8348
>>>>>>>>     >         Or____
>>>>>>>>     >      3. Masks can be part of pot-profile.____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     What do you think about revising the model with this?____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     Thanks,____
>>>>>>>>     >
>>>>>>>>     >     Shwetha____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     *From: *"Frank Brockners (fbrockne)" <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail] <mailto:[e-mail]>>>
>>>>>>>>     >     *Date: *Wednesday, September 11, 2019 at 2:34 PM
>>>>>>>>     >     *To: *ALEJANDRO AGUADO MARTIN
>>>>>>>>     >     <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail]
>>>>>>>>     <mailto:[e-mail]>>>, "Diego R.
>>>>>>>>     >     Lopez" <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail]
>>>>>>>>     <mailto:[e-mail]>>>, Carlos Pignataro
>>>>>>>>     >     <cpignata@cisco..com <mailto:[e-mail]
>>>>>>>>     <mailto:[e-mail]>>>, Shwetha bhandari
>>>>>>>>     >     <[e-mail] <mailto:[e-mail]>
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail] <mailto:shwethab@cisco..com>>>, Tal
>>>>>>>> Mizrahi
>>>>>>>>     >     <[e-mail] <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]
>>>>>>>> <mailto:[e-mail]>>>
>>>>>>>>     >     *Cc: *"[e-mail] <mailto:[e-mail]>
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail] <mailto:[e-mail]>>"
>>>>>>>>     >     <[e-mail] <mailto:[e-mail]>
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail] <mailto:[e-mail]>>>,
>>>>>>>>     "[e-mail] <mailto:[e-mail]> <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail] <mailto:[e-mail]>>" <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>
>>>>>>>>     >     *Subject: *RE: PoT review/comments____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     Hi Alejandro,____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     Thanks again for the review. Your comments have been
>>>>>>>>     integrated into
>>>>>>>>     >     draft-ietf-sfc-proof-of-transit-03 which just got posted.____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     Cheers, Frank____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     *From:*Frank Brockners (fbrockne)
>>>>>>>>     >     *Sent:* Montag, 27. Mai 2019 18:18
>>>>>>>>     >     *To:* ALEJANDRO AGUADO MARTIN
>>>>>>>>     >     <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail]
>>>>>>>>     <mailto:[e-mail]>>>; Diego R. Lopez
>>>>>>>>     >     <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail]
>>>>>>>>     <mailto:[e-mail]>>>; Carlos Pignataro (cpignata)
>>>>>>>>     >     <[e-mail] <mailto:[e-mail]>
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail] <mailto:cpignata@cisco..com>>>; Shwetha
>>>>>>>>     Bhandari
>>>>>>>>     >     (shwethab) <[e-mail] <mailto:[e-mail]>
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail] <mailto:[e-mail]>>>; Tal
>>>>>>>>     >     Mizrahi <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:tal.mizrahi.phd@gmail..com>
>>>>>>>>     <mailto:[e-mail]
>>>>>>>> <mailto:[e-mail]>>>
>>>>>>>>     >     *Cc:* [e-mail] <mailto:[e-mail]>
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail] <mailto:[e-mail]>>;
>>>>>>>> [e-mail] <mailto:[e-mail]> <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail] <mailto:[e-mail]>>
>>>>>>>>     >     *Subject:* RE: PoT review/comments____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     Hi Alejandro,____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     Many thanks for the comments – and sorry for the delay –
>>>>>>>>     >     unfortunately your email somehow got dropped from my todo list.
>>>>>>>>     >     Please see inline…____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     (cc’ing the list as well).____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     *From:*ALEJANDRO AGUADO MARTIN
>>>>>>>>     >     <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail]
>>>>>>>>     <mailto:[e-mail]>>>
>>>>>>>>     >     *Sent:* Montag, 15. April 2019 17:27
>>>>>>>>     >     *To:* Diego R. Lopez <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail]
>>>>>>>>     <mailto:[e-mail]>>>; Carlos Pignataro (cpignata)
>>>>>>>>     >     <[e-mail] <mailto:[e-mail]>
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail] <mailto:cpignata@cisco..com>>>; Frank
>>>>>>>>     Brockners
>>>>>>>>     >     (fbrockne) <[e-mail] <mailto:[e-mail]>
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail] <mailto:[e-mail]>>>; Shwetha
>>>>>>>>     >     Bhandari (shwethab) <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail] <mailto:[e-mail]>>>;
>>>>>>>>     Tal Mizrahi <[e-mail]
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail]>
>>>>>>>>     >     <mailto:[e-mail]
>>>>>>>>     <mailto:[e-mail]>>>
>>>>>>>>     >     *Cc:* [e-mail] <mailto:[e-mail]>
>>>>>>>> <mailto:[e-mail]>
>>>>>>>>     <mailto:[e-mail] <mailto:[e-mail]>>
>>>>>>>>     >     *Subject:* PoT review/comments____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     Dear all,____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     I gave a quick review to the PoT document. Some comments:____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     - I read “The non-constant coefficients are used to
>>>>>>>> generate the
>>>>>>>>     >     Lagrange Polynomial Constants (LPC).” As far as I
>>>>>>>>     understood, the
>>>>>>>>     >     points assigned to each node (Xi) are the ones used for
>>>>>>>>     generating
>>>>>>>>     >     the LPCi, aren’t they?____
>>>>>>>>     >
>>>>>>>>     >     */…FB: Good catch. The LPCs are of course computed using (x_i,
>>>>>>>>     >     y_i)./*____
>>>>>>>>     >
>>>>>>>>     >     - If we go for including the YANG in the current document
>>>>>>>>     (which I
>>>>>>>>     >     agree), parameters should be described before the yang
>>>>>>>>     definition,
>>>>>>>>     >     and maybe it would be helpful to have the yang tree (see the
>>>>>>>>     current
>>>>>>>>     >     version attached).____
>>>>>>>>     >
>>>>>>>>     >     */…FB: Thanks. IMHO it makes sense to keep the YANG model
>>>>>>>> in the
>>>>>>>>     >     current doc, given that the model and the description go
>>>>>>>> hand in
>>>>>>>>     >     hand. We can of course also include the yang tree to make
>>>>>>>>     reading
>>>>>>>>     >     easier. This is consistent with other documents which
>>>>>>>>     specify YANG
>>>>>>>>     >     models./*____
>>>>>>>>     >
>>>>>>>>     >     - I include in the attached file few questions about naming
>>>>>>>>     of some
>>>>>>>>     >     parameters.____
>>>>>>>>     >
>>>>>>>>     >     *//*____
>>>>>>>>     >
>>>>>>>>     >     */…FB:
>>>>>>>>     >     - naming F_i(x_i, y_i) – I agree that a better name could be
>>>>>>>>     used.
>>>>>>>>     >     The only potential concern would be that the open source
>>>>>>>>     >     implementation in OpenDaylight uses this naming – changing
>>>>>>>>     it might
>>>>>>>>     >     lead to confusion.. We can start with adding a comment to make
>>>>>>>>     >     things clearer./*____
>>>>>>>>     >
>>>>>>>>     >     *//*____
>>>>>>>>     >
>>>>>>>>     >     */- secret key – this is the constant part of the first
>>>>>>>>     polynomial
>>>>>>>>     >     which serves as the secret – and which is re-retrieved.
>>>>>>>>     Again, we
>>>>>>>>     >     can update the description to make things clearer./*____
>>>>>>>>     >
>>>>>>>>     >     *//*____
>>>>>>>>     >
>>>>>>>>     >     */- size of the random number: This is unrelated to OPOT.
>>>>>>>>     The random
>>>>>>>>     >     number is to uniquely identify a packet. There is a trade-off
>>>>>>>>     >     between the size of the random number and how often you need to
>>>>>>>>     >     re-key your system. At high speeds, the random number – which
>>>>>>>>     >     identifies a particular packet – is used up quite quickly if
>>>>>>>>     it is
>>>>>>>>     >     only 32-bit wide. See section 4
>>>>>>>>     >
>>>>>>>>         /*https://tools.ietf.org/html/draft-ietf-sfc-proof-of-transit-02#section-4____
>>>>>>>>     >
>>>>>>>>     >     *//*____
>>>>>>>>     >
>>>>>>>>     >     */- number of profiles: For a deployment which is expected
>>>>>>>>     to renew
>>>>>>>>     >     keys every now and then (e.g. you run with 32-bit random
>>>>>>>>     numbers at
>>>>>>>>     >     reasonably high speeds), you need at least 2 profiles – an
>>>>>>>>     active
>>>>>>>>     >     one and one that you can activate once you run out of random
>>>>>>>>     numbers
>>>>>>>>     >     (which is what the encapsulating node would decide).. /*____
>>>>>>>>     >
>>>>>>>>     >     - I have checked some of the existing YANG files within the
>>>>>>>>     IETF to
>>>>>>>>     >     see in which it would be helpful to include. From the (not
>>>>>>>>     so) old
>>>>>>>>     >     OpenFlow, I assume that one match is necessary (for
>>>>>>>> identify the
>>>>>>>>     >     iOAM/PoT header) whilst the source node can use any existing
>>>>>>>>     match
>>>>>>>>     >     field to identify packets where to apply the PoT scheme. In
>>>>>>>>     terms of
>>>>>>>>     >     actions, I would say that two may be required: for any node, an
>>>>>>>>     >     update-pot is necessary, while the verifier would need a
>>>>>>>>     verify-pot
>>>>>>>>     >     type of action, that would ideally either remove the header
>>>>>>>>     or drop
>>>>>>>>     >     the packet if fails (I do not know if you are thinking in more
>>>>>>>>     >     complex scenarios).____
>>>>>>>>     >
>>>>>>>>     >     *//*____
>>>>>>>>     >
>>>>>>>>     >     */…FB: From an OF perspective, that sounds feasible.. That
>>>>>>>>     said, we
>>>>>>>>     >     probably want to avoid making the spec specific to a
>>>>>>>>     technology like
>>>>>>>>     >     OF, hence would suggest that we don’t specify such a
>>>>>>>> behavior as
>>>>>>>>     >     part of this document./*____
>>>>>>>>     >
>>>>>>>>     >     *//*____
>>>>>>>>     >
>>>>>>>>     >     - For this last point, I have seen the definitions within
>>>>>>>>     >     draft-asechoud-rtgwg-qos-model-08, where matched could map
>>>>>>>>     (if I am
>>>>>>>>     >     not wrong) to classifiers/filters, and actions to actions. I
>>>>>>>>     send
>>>>>>>>     >     you the models in a zip file. In this sense the model to be
>>>>>>>>     defined
>>>>>>>>     >     in the PoT shall be an augment of the models defined in that
>>>>>>>>     >     document. I have not done a very deep revision on the model,
>>>>>>>>     but I
>>>>>>>>     >     think it could fit there. If you have check this or other
>>>>>>>>     models,
>>>>>>>>     >     let me know so I could also help.____
>>>>>>>>     >
>>>>>>>>     >     *//*____
>>>>>>>>     >
>>>>>>>>     >     */…FB: Per my note above: In order to keep POT generic and
>>>>>>>>     not link
>>>>>>>>     >     it to a particular classification mechanism, I’d prefer to
>>>>>>>>     keep the
>>>>>>>>     >     classification question as out of scope for the current
>>>>>>>>     document.
>>>>>>>>     >     That way it can also apply to technologies which come with
>>>>>>>>     their own
>>>>>>>>     >     way to classify – and which might fully decouple the tunneling
>>>>>>>>     >     aspects from the classification aspects. /*____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     Thanks a lot and sorry for such long email.____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     */..FB: Thanks again for all your comments. We’ll get them
>>>>>>>>     included
>>>>>>>>     >     in the next revision. /*____
>>>>>>>>     >
>>>>>>>>     >     *//*____
>>>>>>>>     >
>>>>>>>>     >     */Cheers, Frank/*____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     Best,____
>>>>>>>>     >
>>>>>>>>     >     Alejandro____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >     ____
>>>>>>>>     >
>>>>>>>>     >
>>>>>>>>         ------------------------------------------------------------------------
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