Re: [CCAMP] FW: I-D Action: draft-ietf-ccamp-l1csm-yang-03.txt

Leeyoung <> Fri, 06 July 2018 21:39 UTC

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From: Leeyoung <>
To: t.petch <>, "" <>
Thread-Topic: [CCAMP] FW: I-D Action: draft-ietf-ccamp-l1csm-yang-03.txt
Date: Fri, 6 Jul 2018 21:39:44 +0000
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Subject: Re: [CCAMP] FW: I-D Action: draft-ietf-ccamp-l1csm-yang-03.txt
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Hi Tom,

Thanks for your further comment and clarification.

Please see inline for my comment.

Best regards,


-----Original Message-----
From: t.petch []
Sent: Friday, July 06, 2018 6:15 AM
To: Leeyoung <>om>;
Subject: Re: [CCAMP] FW: I-D Action: draft-ietf-ccamp-l1csm-yang-03.txt

Picking up on the MEF reference, what I mean is that the lime I-D I referenced has

   [MEF-17]   "Service OAM Requirements & Framework - Phase 1", METRO


which identifies a document to me which is my point; it is not a question of access, it is a question of identifying reliably what it is I want to access and I do not think that your current text does that.

>> Currently the relevant MEF reference (L1CS Attributes) is in the form on Working Document .  This MEF reference is about to take Last Ballot in Q3 MEF meeting in July. Once it becomes an official MEF document, we are going to update the MEF reference similar to what you show above for OAM requirements & Framework.

One more issue for the moment, on time interval again

      leaf time-interval {

        type int16;

        units seconds;

        description "a time interval (e.g., 2,419,200 seconds

                     which is 28 days)

Time intervals generally raise a number of issues that need consideration.

Should there be a default?  There should if one is in widespread, and sensible, use.  Here I do not know but think that the guidance you have in description is likely enough.

>> We can make 28 days as a default, but this need to be agreed by the WG.

Should the range be limited?  Is zero a sensible value? I tend to think of a hundred of something being the minimum for sensible statistics and

1000 as better so if we are talking about e.g.


then we are talking of hundreds or thousands of seconds so I think a minimum worth having.  Maximum? not sure; I tend to think in hours rather than days and you clearly see a month as sensible.  Needs thinking about since later reviews are likely to query this.

>> I am not expert in setting ranges for min and max for time-interval for performance monitoring. I would leave this to be discussed by the WG.

Again on a minimum value, does having a valid too low a value open up DoS attacks?  This is often called out in Security Considerations after secdir have complained about the possibility!  Again, needs considering.

>> I would leave this also to the WG discussion.

Tom Petch

----- Original Message -----

From: "Leeyoung" <<>>

To: "t.petch" <<>>; <<>>

Sent: Thursday, July 05, 2018 5:58 PM

Subject: RE: [CCAMP] FW: I-D Action: draft-ietf-ccamp-l1csm-yang-03.txt

Hi Tom,

Good to know it is getting there! Thanks for your further comments.

Please see inline for my comment.

The actual update is now frozen; so it will be done during the IETF week once the update window is re-open.



-----Original Message-----

From: t.petch []

Sent: Wednesday, July 04, 2018 4:56 AM

To: Leeyoung <<>>;<>

Subject: Re: [CCAMP] FW: I-D Action: draft-ietf-ccamp-l1csm-yang-03.txt

Getting there!


The IESG have takent to asking for something of the like of This YANG model is NDMA-compliant.

at the end of the Abstract

YL>> OK. We can add "This YANG model is NMDA-compliant."


NETCONF gets a mention but, as Security Consideratons says, RESTCONF is also an option in which case I think it should appear here (unless you think it inappropriate in which case I also think it should appear here!).

YL>> Agree.


   The terminology for describing YANG data models is found in


Nope try RFC 7950

YL>> Thanks. Agree.

YANG terminology is a mess at present.  RFC8342 has redefined some terms and not others so that draft-ietf-netconf-nmda-netconf just references

RFC8342 and says no more; that RFC does define

o client

o server

but does not define

o configuration data

o state data

o augment

o data model

o data node

I think that the best you can do for now is to reference RFC7950 and RFC6241.

YL>>  Agree. It looks like: RFC 7950 defines: client, server, data

model, data node, augment; RFC 6241 configuration data, state data.

You need a Note to the RFC Editor asking them to change the date to the date of publication in two places in both modules - by that time, there should be only the one revision clause in each module stating 'Initial Version' although up until then, you go on inserting clauses for the different versions of the I-D; I would still add the Note now.

You need reference clauses in the YANG module - having references in Section 1.4  is not enough as the YANG module has to be complete in stand alone ASCII - see how


handles this

YL>> OK. I will add that.

      leaf time-interval {

        type int16;

mmm I do not see how int16 can count up to 2,419,200 ; int64 sis seem excessive but I think that int32 is needed

YL>> Correct. Int32 would be good.


'one way severely errored second'

is the ITU-T term, then I think that you should have the ITU-T reference direct and not expect the reader to think of looking to see if it is in the MEF reference

   [MEF-L1CS] "Subscriber Layer 1 Connectivity Service Attributes",

             Working Draft (WD) v0.09 December 13, 2017.

does not enable me to locate the document;  MEF suggests MEF but I would like more; look for example at how


handles this

YL>> I still disagree with this. I try to avoid "double referencing".

Besides, there are more than 20 references from ITU-T, IEEE, ANSI and Telcordia if we were to be comprehensively referencing. I'd like to defer this issue to WG chairs. If your company is a MEF member, you should get the document from MEF wiki. If not, there should be ways to get you the MEF document as MEF initiated a liaison with IETF/CCAMP on this work.

RFC6991 is an import and so needs to be a Normative not Informative Reference for the I-D.

YL>> OK. This is fine.

I have yet to go through the YANG modules in detail but it will be a while before I have time to do that..

Tom Petch

----- Original Message -----

From: "Leeyoung" <<<>>>

To: "t.petch" <<<>>>;


Sent: Tuesday, July 03, 2018 4:01 PM

Hi Tom,

The draft has been updated yesterday. Please see


See also the attached diff file that compares versions 4 and 5.

Please see inline for my specific comment to your comment. Let us know if there are any other concerns you may have.



-----Original Message-----

From: t.petch []

Sent: Tuesday, June 26, 2018 11:31 AM

To: Leeyoung <<<>>>;<<>>

Subject: Re: [CCAMP] FW: I-D Action: draft-ietf-ccamp-l1csm-yang-03.txt

Thanks for fixing the indentation; much easier to comment on!

Two major thoughts.

First, how attached are you to l1, that is letter l followed by digit 1 ?  I know it makes sense but I also know many contexts in which that would not be allowed because the probability of confusion is so great, with the digit being read as the letter i or letter l or the letter being read as a digit  or ...  I think that this needs careful consideration; I was making mistakes reading the I-D on the comfort of a proper PC with good resolution etc (but with oldish eyes:-(

YL>> We can discuss this issue during the WG meeting in Montreal. I

don't have much preference on this.

Second, references need some work.  You identify the YANG modules as version 1.1 but have an Informative Reference - must be Normative - to YANG 1.0; confusing.  The Security Considerations are not the current one;  e.g. you should reference RESTCONF and SSH. Might I suggest looking at

draft-ietf-ccamp-mw-yang-06 ? And the section does reference RFC6241 and

RFC6536 which I cannot see in the Normative References

YL>> I think we have addressed theses references issues.

s.1    controller via a Netconf[RFC6020] interface.

No; NETCONF is not RFC6020

YL>> Corrected.

In the identity coding func you reference clauses 49, 82 and such like - these need reference clauses to the relevant specification in the YANG module.  This probably applies to most of these definitions (although one comprehensive reference to any one document would suffice).

YL>> We put the MEF reference in the YANG module as well as in the

Reference Section from which all the terms and the original references for specific clauses can be checked.

You need YANG reference clauses for

  import ietf-yang-types


  import ietf-l1-mef-service-types {

YL>> This was already done in Section 1.4. Let us know if this is what

you meant.

Likewise I recognise e.g. 'one way severely errored second' as a technical term of the ITU-T; if that is what you intend, then these all need a reference to the current ITU-T Recommendation.  If not, more explanation is needed

YL>> It is indeed ITU-T term. The MEF document referenced has the

original ITU-T references.

You need YANG reference clauses for

  import ietf-yang-types


  import ietf-l1-mef-service-types {

YL>> I think this is the same comment as above.

Besides this,

- the running footing tells me that this is valid until 2028.

YL>> I am not sure which one you are pointing. If this is not fixed with

the revision, please let us know which one you are referring to.

-s 1.4 references [This I-D]

Suggest RFC XXXX (and add a note up front to the RFC Editor asking them to replace XXXX with the number assigned to the RFC)

YL>> We corrected. See Section 1.4 for this.

-  grouping protocol-coding-optical_interface {

    description  "describes <p,c,o>";

p c o are not expanded in the YANG module - they need to be

YL>> We added description for each term.

-  grouping subscriber-l1vc-sls-service-attribute {


      "The value of the Subscriber L1VC SLS (Service Level

        Specification) Service Attribute expressed in a 3-tuple

        of the form.";

leaves me asking what form does the 3-tuple take?

YL>> We added comment that the 3-tuple is <p,c,o>.

-      leaf time-interval {

        type int64;

        units seconds;

        description "a time interval (e.g., 1 month) ...

int64 is a lot of seconds and anyway cannot be used to express a month since a month is a number of different lengths.  If a month is a sensible time (seems long to me) then change it to 28 day and give the value for 28 day in second and perhaps provide a default as that.  And how about a range limiting this to something sensible (lest a typo sets it to 2028 years)

YL>> We added an example with 28 days and changed int64 to int 16.

-      leaf subscriber-l1vc-ep-id-1 { type string;

        description "subscriber end point ID";  }

      leaf subscriber-l1vc-ep-id-2 { type string;

        description "subscriber end point ID"; Spot the difference - I can't!

YL>> we added "subscriber end point ID for one end" and "subscriber end

point ID for the other end" to differentiate these two terms.

-  container l1cs

This is the sort of identifier I expect to be frequently misspelt!

YL>>  I would stick to this for now until we have discussion in the f2f


Enough for now

Tom Petch

----- Original Message -----

From: "t.petch"


To: "Leeyoung"



Sent: Saturday, June 23, 2018 9:07 PM

Subject: Re: [CCAMP] FW: I-D Action: draft-ietf-ccamp-l1csm-yang-03.txt

> Young


> The most significant comment, for me, is the one about the


> there came a point where I gave up trying to follow the I-D because it

> was so hard, so fix that and likely more comments will follow:-)


> Tom Petch


> ----- Original Message -----

> From: "Leeyoung"


> To:


> Sent: Thursday, June 21, 2018 11:43 PM


> > Hi WG,

> >

> > This revision had some error in the date field in the yang model. So

> it is corrected; Tom's comments will be incorporated in the next


> (04).

> >

> > Thanks,

> > Young

> >

> > -----Original Message-----

> > From: CCAMP [] On Behalf Of


> > Sent: Thursday, June 21, 2018 5:35 PM

> > To:<<mailto:i-d-announce@i<>>>

> > Cc:<<<><>>>

> > Subject: [CCAMP] I-D Action: draft-ietf-ccamp-l1csm-yang-03.txt

> >

> >

> > A New Internet-Draft is available from the on-line Internet-Drafts

> directories.

> > This draft is a work item of the Common Control and Measurement


> WG of the IETF.

> >

> >         Title           : A Yang Data Model for L1 Connectivity

> Service Model (L1CSM)

> >         Authors         : G. Fioccola

> >                           K. Lee

> >                           Y. Lee

> >                           D. Dhody

> >                           D. Ceccarelli

> > Filename        : draft-ietf-ccamp-l1csm-yang-03.txt

> > Pages           : 24

> > Date            : 2018-06-21

> >

> > Abstract:

> >    This document provides a YANG data model for Layer 1 Connectivity

> >    Service Model (L1CSM).

> >

> >

> >

> >

> > The IETF datatracker status page for this draft is:

> >

> >

> > There are also htmlized versions available at:

> >

> >

> >

> > A diff from the previous version is available at:

> >

> >

> >

> > Please note that it may take a couple of minutes from the time of

> submission until the htmlized version and diff are available at


> >

> > Internet-Drafts are also available by anonymous FTP at:

> >

> >

> > _______________________________________________

> > CCAMP mailing list

> ><<<><>>>

> >

> >

> > _______________________________________________

> > CCAMP mailing list

> ><<<><>>>

> >


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