Subject: [sacm] Benoit Claise's Abstain on draft-ietf-sacm-requirements-16: (with COMMENT)

From: Benoit Claise <[email-masked]>
Date: Tue, 27 Jun 2017 01:58:44 -0700

Benoit Claise has entered the following ballot position for
draft-ietf-sacm-requirements-16: Abstain

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COMMENT:
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Hi Nancy,
> Hi Benoit,
> Thanks for the review and feedback.  Please see further comments below:
>
> On 6/21/17, 4:00 AM, "Benoit Claise (bclaise)" <[email-masked]> wrote:
>     ----------------------------------------------------------------------
>     COMMENT:
>     ----------------------------------------------------------------------
>
>     -     3.  The information model MUST accommodate the interoperable
>             addition of new data types and/or schemas.
>
>     I guess that you want to say: The data model MUST ...
>     See RFC 3444
> [NCW] The group actually debated “information model” vs “data model”
extensively and > decided on this language. > >     - >     Reading G-003,
G-004, G-012, it seems like you want to be able to select your >    
"transport", with your own requirements. > >     However, I guess that,
practically, you'll select a data model and the >     transport will be
obvious. MIB module => UDP IFPIX information elemeents => >     UDP/DTLS. Yeah,
the specs say SCTP/TCP, but in practice ... YANG module, either >     NETCONF
=> TCP/SSH or RESTCONF => HTTPS Not sure I believe into a single >    
transport to rules them all, where "them" is all the different data model >    
source of information. This was already my feedback during your previous >    
interim meeting (where I presented yangcatalog.org): your information model >  
  draft is basically of a mix of elements already specified in IPFIX, YANG >   
 module, MIB module. How do you consolidate all this? > [NCW] There will be
data models that are only suitable for specific transfer models > and specific
transport layers (ROLIE for example as a discovery lends itself better at > an
HTTP and not so much in MIB).  The Information model is meant to be a “raw” >
definition of elements/attributes that can them be mapped into specific data
models > (the group for instance is looking at SWID, others are looking at
netconf) etc…. > >     Same remark with "2.5 requirements for data model
operations". >     You select your data model and the data model operations are
given/specified >     already Let's say: IPFIX. From there you have a push
mechanism only (as opposed >     to pull). Let's say: YANG module. From there
you select NETCONF or NETCONF, and >     the operations are already specified.
> [NCW] In essence, that is correct. > >     - >      The SACM information
model MUST include the >         ability to discover and negotiate the use of a
particular data model >         or any data model. > >     What does it mean
"negotiate"? >     Either an end point supports a data model or it doesn't, no?
> >     Same remark for: >        DM-007  Data Model Negotiation: The
interfaces and actions in the >         data model MUST include capability
negotiation to enable discovery >         of supported and available data types
and schemas. > [NCW] In this context, “Negotiate” is the means by which two
parties can agree on the data model to be used. > The “means” could be data
model and/or transfer protocol specific….but the intent is to enable that thru
> The abstraction to allow for that should be in the Information model
definition.

>
>
>
>     - Read the following one multiple times, and I still don't understand it:
>        IM-005  Data Lifetime Management: The information model MUST provide
>         a means to allow data models to include data lifetime management.
> [NCW] It is really meant to be a means by which the consumer of the
information can know when that data may be obsoleted (updated, changed or
removed). What about trying to make the text clear(er)? > > >     - >     The
SACM information model represents an abstraction for "what" >       
information can be communicated and "how" it is to be represented and >       
shared. > >     Not sure it's aligned with RFC3444: >                   IM     
          --> conceptual/abstract model >                   |                  
 for designers and operators >        +----------+---------+ >        |        
 |         | >        DM        DM         DM     --> concrete/detailed model >
                                       for implementors > > [NCW] We really
have tried….if it isn’t clear, I am open to making it more so but > the
resulting draft and definitions come from much debate and final agreement from
the WG.

What I considered to be an easy COMMENT turned out more complicated that I
thought. I guess that we'll agree to disagree. I don't feel that this data
model/information model discussion will be resolved to my OPS-view
satisfaction. I can't support this document publication and I don't want to
spend energy to try to convince people for this COMMENT Since I don't want to
be in the way, I'll ABSTAIN.

Regards, Benoit