Re: [i2rs] Kathleen Moriarty's No Objection on draft-ietf-i2rs-yang-l3-topology-08: (with COMMENT)

[Giles Heron <[e-mail]>]

Hi Alia,

> On 25 Jan 2017, at 13:35, Alia Atlas <[e-mail]> wrote:
> 
> Could one of you who are saying that a writable topology model can appear in the regular configuration data-store please explain:
> 
> How does validation at reboot work when there is dependency on learned topology data that isn't yet available?

um - it can’t? (or I don’t think it can).    But why would you have a writeable topology depend on learned topology data?  Or am I totally misunderstanding your question?

At any rate I’m only thinking of writeable topology in the context of inventory (so stuff that is configured rather than learned from a dynamic protocol) and perhaps intent (so, for example a point-to-point circuit could be expressed in a “service” model as a pair of nodes connected by a pair of unidirectional links with bandwidth parameters etc. - which the network-facing OSS would create by configuring a PWE between the two nodes).

> I'd prefer more technology discussion of the nuances.  This one has been an active topic of discussion for at least 2 years, so I'm hopeful that you all have well thought out answers.

I’m afraid I’ve not followed I2RS closely enough.  When the WG was set up I hoped it would define an ephemeral data store, define that YANG-modelled data could be carried over various transports/encodings (and perhaps define a binary-encoded protocol over an asynchronous transport as an example of such), and then shut itself down.   It has taken a very different path so to a great extent I have disengaged (but remained subscribed to the list).  I only got suck(er)ed into this thread because Juergen mentioned ODL.

I’m not saying that the discussions over traceability, priority, security etc. are wrong but I see them as being largely orthogonal to the issue of ephemeral vs persistent config and to the selection of transport/protocol used to access the NE (just as I see the topology models themselves as being general rather than I2RS-specific).

Giles

> Regards,
> Alia
> 
> On Wed, Jan 25, 2017 at 7:27 AM, Lou Berger <[e-mail] <mailto:[e-mail]>> wrote:
> 
> Sue,
> 
> In short, I'm going to agree with Benoit - but for slightly different
> reasons as I also co-chair TEAS, a group that is basing some of its
> work on I2RS developed models.
> 
> As a WG chair, I have always viewed the models being developed by I2RS
> as typical models that are generally useful, and being defined by I2RS
> simply because they were ahead of other groups that might otherwise
> define the models -- and I view this as a fine thing that has benefit
> for YANG users and other WGs. As TEAS chair, this is what lead me to
> ensure that the models being defined in TEAS built on the I2RS YANG
> modules vs their original path of redefining parallel function.
> 
> As part of my view of the I2RS models being generally applicable to uses
> beyond I2RS together with I2RS choosing YANG for modeling ephemeral
> data, I have always expected that the I2RS WG would at some (perhaps as
> part of the I2RS protocol definition) define how any YANG model can be
> used to support I2RS. This view certainly lead me to conclude that
> having the I2RS models move forward, just like any other YANG model,
> makes sense and would benefit the other models and WGs that reference
> this core work. This view also allows for the relationship to the
> revised-data store work, as well as the specification of which data
> store(s) I2RS uses, to be separately defined -- and to not gate
> publication of these models. This separate specification would be
> the location for any I2RS-specific transport and security considers,
> so such would not belong in the generally reusable models developed
> by I2RS.
> 
> Essentially, As NETMOD co-chair, I concluded that the revised data
> store work provided the direction on how ephemeral would be supported
> in a general YANG context and, therefore, the major open issue / gating
> impediment to progressing I2RS models had been removed and publication
> of these models were unblocked. This also motivated my comments in the
> related discussions at the last meeting.
> 
> If my understanding/view is correct, i.e., that the topology models are
> just like any other YANG model, then I think publication can and
> should proceed (with the appropriate text for a typical YANG model). If
> I misunderstood something, and the models produced by I2RS are limited
> to ephemeral representations/data stores as well as specific YANG
> transport protocols -- then as TEAS chair, I have to hit reset on the
> TEAS topology work, and as NETMOD chair I think the NETMOD WG needs to
> discuss what it means for a YANG model to be protocol/datastore
> specific and if any guidelines or other new NTEMOD documents are need
> to support such.
> 
> Less importantly, as I2RS participant, I'd also ask for the documents
> to be sent back to the WG for a new last call once the documents
> are updated to reflect their narrow scope -- as I bet I'm not the only
> person who viewed this work applicable to non-ephemeral uses.
> 
> I hope this helps.
> 
> Lou
> 
> 
> On January 24, 2017 11:56:32 AM "Susan Hares" <[e-mail] <mailto:[e-mail]>> wrote:
> 
> > To: Martin:
> >
> > You have a reasonable request. If the NETMOD WG Chairs confirm their
> > decision to make I2RS Yang Modules part of the Control Plane Datastore then
> > as shepherd/WG-chair I will recommend these get added to the draft.
> >
> > Note to authors :
> >
> > As we wait for the NETMOD WG Chairs and Benoit to deliver the decision on
> > Config/Control Plane datastore, the authors should work on:  Basic Yang
> > security considerations and the other I2RS Yang Module information.
> >
> > Sue Hares (Shepherd)
> > -----Original Message-----
> > From: Martin Bjorklund [mailto:[e-mail] <mailto:[e-mail]>]
> > Sent: Tuesday, January 24, 2017 10:39 AM
> > To: [e-mail] <mailto:[e-mail]>
> > Cc: [e-mail] <mailto:[e-mail]>; [e-mail] <mailto:[e-mail]>;
> > [e-mail] <mailto:[e-mail]>; [e-mail] <mailto:[e-mail]>; [e-mail] <mailto:[e-mail]>;
> > [e-mail] <mailto:[e-mail]>; [e-mail] <mailto:[e-mail]>; [e-mail] <mailto:[e-mail]>;
> > [e-mail] <mailto:[e-mail]>
> > Subject: Re: [i2rs] Kathleen Moriarty's No Objection on
> > draft-ietf-i2rs-yang-l3-topology-08: (with COMMENT)
> >
> > "Susan Hares" <[e-mail] <mailto:[e-mail]>> wrote:
> >> Martin:
> >>
> >>
> >>
> >> I'm sorry if misunderstood your comments regarding the
> >> draft-ietf-netmod-revised-datastores-00.txt.  The reason the answer is
> >> unclear is that it depends on the context of the question.
> >>
> >>
> >>
> >> .         If you ask if the pre-standardization I2RS Yang Topology models
> >> (basic and L3)  implemented are part of the configuration data store,
> >> the answer is yes - AFAIK.
> >
> > This is not my question.
> >
> >> .         If you ask if the WG LC Topology models are approved to be part
> > of
> >> the configuration data store, my understanding was no.   I2RS WG was to
> >> abide by the decision of NETMOD WG on which data store I2RS modules
> >> were placed in.
> >
> > Yes, this is my question.  And my concern is that even if your understanding
> > is that they are not designed to be part of the configuration datastores,
> > this fact is not mentioned in the drafts.
> >
> >> If you are concerned the implementation varies from the standardized,
> > please
> >> express this to Benoit Claise.   Based on your comments on my email
> > thread,
> >> I will be brief in my answers today.
> >
> > This is not my concern.
> >
> >
> > /martin
> >
> >
> >
> >>
> >>
> >>
> >> Sue
> >>
> >>
> >>
> >>
> >>
> >> -----Original Message-----
> >> From: Martin Bjorklund [mailto:[e-mail] <mailto:[e-mail]>]
> >> Sent: Tuesday, January 24, 2017 7:35 AM
> >> To: [e-mail] <mailto:[e-mail]>
> >> Cc: [e-mail] <mailto:[e-mail]>; [e-mail] <mailto:[e-mail]>;
> >> [e-mail] <mailto:[e-mail]>; [e-mail] <mailto:[e-mail]>;
> >> [e-mail] <mailto:[e-mail]>; [e-mail] <mailto:[e-mail]>; [e-mail] <mailto:[e-mail]>;
> >> [e-mail] <mailto:[e-mail]>; [e-mail] <mailto:[e-mail]>
> >> Subject: Re: [i2rs] Kathleen Moriarty's No Objection on
> >> draft-ietf-i2rs-yang-l3-topology-08: (with COMMENT)
> >>
> >>
> >>
> >> "Susan Hares" < <mailto:[e-mail] <mailto:[e-mail]>> [e-mail] <mailto:[e-mail]>> wrote:
> >>
> >> > Martin:
> >>
> >> >
> >>
> >> > Your statement "One problem is that relying on the solution in
> >>
> >> > draft-ietf-netmod-revised-datastores-00 is a bit premature - in
> >> > fact,
> >>
> >> > that document does not yet provide any details at all on the I2RS
> >>
> >> > ephemeral data store." This statement is not what I understood from
> >> > IETF
> >> 98 or the netmod
> >>
> >> > ADs.   I guess your objection to this data model falls into Benoit
> > Claise
> >>
> >> > (AD) and the NETMOD folks to answer.
> >>
> >>
> >>
> >> Why do you think that I have any objection to
> >> draft-ietf-netmod-revised-datastores-00.  Please re-read what I wrote.
> >>
> >>
> >>
> >> My objection regards your statement:
> >>
> >>
> >>
> >>    1) I2RS Data models do not utilize the configuration data store,
> >>
> >>
> >>
> >> If this is true it needs to be clarified in the document.
> >>
> >>
> >>
> >> After all these emails back and forth, it is still not clear whether
> >> this statement is true or not.
> >>
> >>
> >>
> >>
> >>
> >> /martin
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> >
> >>
> >> > Sue Hares
> >>
> >> >
> >>
> >> > -----Original Message-----
> >>
> >> > From: i2rs [ <mailto:[e-mail] <mailto:[e-mail]>>
> >> > mailto:[e-mail] <mailto:[e-mail]>]
> >> On Behalf Of Martin
> >>
> >> > Bjorklund
> >>
> >> > Sent: Monday, January 23, 2017 5:26 PM
> >>
> >> > To:  <mailto:[e-mail] <mailto:[e-mail]>> [e-mail] <mailto:[e-mail]>
> >>
> >> > Cc:  <mailto:[e-mail] <mailto:[e-mail]>> [e-mail] <mailto:[e-mail]>;
> >> <mailto:[e-mail] <mailto:[e-mail]>>
> >> [e-mail] <mailto:[e-mail]>;
> >>
> >> >  <mailto:[e-mail] <mailto:[e-mail]>>
> >> [e-mail] <mailto:[e-mail]>;  <mailto:[e-mail] <mailto:[e-mail]>>
> >> [e-mail] <mailto:[e-mail]>;
> >>
> >> >  <mailto:[e-mail] <mailto:[e-mail]>> [e-mail] <mailto:[e-mail]>;
> >> <mailto:[e-mail] <mailto:[e-mail]>>
> >> [e-mail] <mailto:[e-mail]>; <mailto:[e-mail] <mailto:[e-mail]>> [e-mail] <mailto:[e-mail]>
> >>
> >> > Subject: Re: [i2rs] Kathleen Moriarty's No Objection on
> >>
> >> > draft-ietf-i2rs-yang-l3-topology-08: (with COMMENT)
> >>
> >> >
> >>
> >> > "Susan Hares" < <mailto:[e-mail] <mailto:[e-mail]>> [e-mail] <mailto:[e-mail]>> wrote:
> >>
> >> > > Robert and Martin:
> >>
> >> > >
> >>
> >> > > I agree with Robert that the current implementations of the ODL
> >>
> >> > > topology models are handled as part of the configuration data
> >> > > store
> >>
> >> > > with
> >>
> >> > ephemeral
> >>
> >> > > state.   I will point out that these implementation are pre-standards
> >>
> >> > > implementations of the I2RS YANG Data model.
> >>
> >> > >
> >>
> >> > > While standardizing the topology data models, the I2RS WG have
> >> > > been
> >>
> >> > > asked to align with the
> >> > > draft-ietf-netmod-revised-datastores-00.txt
> >>
> >> > > NETMOD WG document.  This NETMOD WG document moves the I2RS
> >>
> >> > > ephemeral data
> >>
> >> > store from
> >>
> >> > > configuration data store to a Control Plane data store.   If we follow
> >>
> >> > this
> >>
> >> > > draft, the I2RS Topology models are part of the I2RS ephemeral
> >> > > data
> >> store.
> >>
> >> > > If you disagree with the placement of the Topology data models,
> >>
> >> > > please indicate this to the NETMOD WG and to Benoit.  Could you
> >>
> >> > > propose a way that you would see the ephemeral state working with
> >>
> >> > > the configuration data
> >>
> >> > store
> >>
> >> > > to the NETMOD WG?
> >>
> >> > >
> >>
> >> > > Quite frankly, I feel a bit of whip-lash on this topic.   NETMOD WG
> > asks
> >>
> >> > for
> >>
> >> > > Control Plane Data store.  You ask for configuration data store
> >>
> >> > > (which was the I2RS initial proposal).
> >>
> >> >
> >>
> >> > Not really; I ask for clarification.
> >>
> >> >
> >>
> >> > > It is possible for either one to work for I2RS
> >>
> >> > > Topology models - if the right details are taken care of.   How do we
> >> make
> >>
> >> > > progress on choosing one method so we can write the I2RS Topology
> >>
> >> > > Models security considerations.?
> >>
> >> >
> >>
> >> > One problem is that relying on the solution in
> >>
> >> > draft-ietf-netmod-revised-datastores-00 is a bit premature - in
> >> > fact,
> >>
> >> > that document does not yet provide any details at all on the I2RS
> >>
> >> > ephemeral datastore.
> >>
> >> >
> >>
> >> > So I see two alternatives.  Either wait with these documents, or
> >>
> >> > publish them with their datamodels as is (i.e., no new additional
> >>
> >> > notes), for the existing protocols and architecure.  This would
> >> > allow
> >>
> >> > them to be implemented just like any other YANG data model.  This
> >>
> >> > would mean that the normal YANG security considerations guidelines
> >> > should
> >> be followed.
> >>
> >> >
> >>
> >> >
> >>
> >> >
> >>
> >> > /martin
> >>
> >> >
> >>
> >> > >
> >>
> >> > > Sue
> >>
> >> > >
> >>
> >> > > -----Original Message-----
> >>
> >> > > From: Robert Varga [ <mailto:[e-mail] <mailto:[e-mail]>> mailto:[e-mail] <mailto:[e-mail]>]
> >>
> >> > > Sent: Monday, January 23, 2017 4:11 PM
> >>
> >> > > To: Martin Bjorklund;  <mailto:[e-mail] <mailto:[e-mail]>> [e-mail] <mailto:[e-mail]>
> >>
> >> > > Cc:  <mailto:[e-mail] <mailto:[e-mail]>> [e-mail] <mailto:[e-mail]>;
> >> <mailto:[e-mail] <mailto:[e-mail]>>
> >> [e-mail] <mailto:[e-mail]>;
> >>
> >> > >  <mailto:[e-mail] <mailto:[e-mail]>>
> >> [e-mail] <mailto:[e-mail]>;  <mailto:[e-mail] <mailto:[e-mail]>>
> >> [e-mail] <mailto:[e-mail]>;
> >>
> >> > >  <mailto:[e-mail] <mailto:[e-mail]>>
> >> [e-mail] <mailto:[e-mail]>;  <mailto:[e-mail] <mailto:[e-mail]>>
> >> [e-mail] <mailto:[e-mail]>
> >>
> >> > > Subject: Re: [i2rs] Kathleen Moriarty's No Objection on
> >>
> >> > > draft-ietf-i2rs-yang-l3-topology-08: (with COMMENT)
> >>
> >> > >
> >>
> >> > > On 01/23/2017 09:26 PM, Martin Bjorklund wrote:
> >>
> >> > > >> I'm pulling your questions to the top of this email.
> >>
> >> > > >>
> >>
> >> > > >>
> >>
> >> > > >>
> >>
> >> > > >> Question 1: Ok.  Just to make sure I understand this correctly
> >> > > >> -
> >>
> >> > > >> these topology models are intended to be I2RS-specific, and
> >> > > >> they
> >>
> >> > > >> cannot be used for any other purpose.  If anyone needs a
> >> > > >> general
> >>
> >> > > >> topology model outside of the I2RS protocol, they will have to
> >>
> >> > > >> design their own model.  Is this correct?
> >>
> >> > > >>
> >>
> >> > > >>
> >>
> >> > > >>
> >>
> >> > > >> Response 1:  Not really.
> >>
> >> > > > Ok, so are you saying that the models are in fact generic, and
> >> > > > can
> >>
> >> > > > be used outside of I2RS?  I.e., they *can* be used with the
> >> > > > normal
> >>
> >> > > > configuration datastores?
> >>
> >> > > >
> >>
> >> > >
> >>
> >> > > From implementation experience, yes, they can be used for storing
> >>
> >> > > configuration. OpenDaylight uses (an ancient predecessor of)
> >>
> >> > > yang-network-topo to store configure details about devices in its
> >>
> >> > > managed networks.
> >>
> >> > >
> >>
> >> > > Regards,
> >>
> >> > > Robert
> >>
> >> > >
> >>
> >> > >
> >>
> >> >
> >>
> >> > _______________________________________________
> >>
> >> > i2rs mailing list
> >>
> >> >  <mailto:[e-mail] <mailto:[e-mail]>> [e-mail] <mailto:[e-mail]>
> >>
> >> >  <https://www.ietf.org/mailman/listinfo/i2rs <https://www.ietf.org/mailman/listinfo/i2rs>>
> >> https://www.ietf.org/mailman/listinfo/i2rs <https://www.ietf.org/mailman/listinfo/i2rs>
> >>
> >> >
> >>
> >
> >
> 
> 
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