Subject: [netmod] I-D Action: draft-ietf-netmod-revised-datastores-02.txt

From: [email-masked]
Date: Thu, 11 May 2017 13:09:35 -0700

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the NETCONF Data Modeling Language of the IETF.

        Title           : Network Management Datastore Architecture
        Authors         : Martin Bjorklund
                          Juergen Schoenwaelder
                          Phil Shafer
                          Kent Watsen
                          Rob Wilton
	Filename        : draft-ietf-netmod-revised-datastores-02.txt
	Pages           : 34
	Date            : 2017-05-11

Abstract:
   Datastores are a fundamental concept binding the data models written
   in the YANG data modeling language to network management protocols
   such as NETCONF and RESTCONF.  This document defines an architectural
   framework for datastores based on the experience gained with the
   initial simpler model, addressing requirements that were not well
   supported in the initial model.

The IETF datatracker status page for this draft is:
https://datatracker.ietf.org/doc/draft-ietf-netmod-revised-datastores/

There are also htmlized versions available at:
https://tools.ietf.org/html/draft-ietf-netmod-revised-datastores-02
https://datatracker.ietf.org/doc/html/draft-ietf-netmod-revised-datastores-02

A diff from the previous version is available at:
https://www.ietf.org/rfcdiff?url2=draft-ietf-netmod-revised-datastores-02

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---

From: Martin Bjorklund <[email-masked]>
Date: Thu, 11 May 2017 22:22:13 +0200 (CEST)

Hi,

This version addresses the comments on the ML, and contains some
reworked terminiology in order to be consistent.  Further, all open
issues are resolved.  We have also removed the Appendicies that
previously were included as placeholders for text that will go into
other documents.

>From the authors' point of view, this version is ready for WG LC.

/martin

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---

From: Andy Bierman <[email-masked]>
Date: Fri, 12 May 2017 11:11:53 -0700

Hi,

I think the remnant configuration text needs clarification.
I thought the whole point of the operational datastore for config=true
nodes was to
provide the intended and applied values using the exact same
instance-identifier.

NC/RC/YANG does not allow the old operational value and new operational
value to
exist in the same datastore.  Once the server has the new value to report,
it will overwrite
the old value.

Perhaps you mean other instances will be considered old, but the RD
solution has no way to
correlate the new instances to the old ones. Therefore, YANG validation may
fail on the operational
datastore while updates are being applied. I think the draft should make
this more clear.

Andy

---

From: Phil Shafer <[email-masked]>
Date: Fri, 12 May 2017 17:21:47 -0400

>provide the intended and applied values using the exact same

Instance names are the same.  Remnant configuration is data that
remains in operational use (and is reported in <operational>) after
it has been removed from <intended>.  This is typically the brief
period during implementation of the incoming data.  The text says:

  - remnant configuration: Configuration that remains part of the
    applied configuration for a period of time after it has been removed
    from the intended configuration or dynamic configuration.  The time
    period may be minimal, or may last until all resources used by the
    newly-deleted configuration (e.g., network connections, memory
    allocations, file handles) have been deallocated.

There's also text in the "The Operational State Datastore" section
(quoted below).  What is needed to make it more clear?

>exist in the same datastore.  Once the server has the new value to report,

<operational> should report the currently in use values, even when
that differs from <intended>.  The draft currently says:

  As a result of remnant configuration, the semantic constraints defined
  in the data model cannot be relied upon for <operational>, since the
  system may have remnant configuration whose constraints were valid
  with the previous configuration and that are not valid with the
  current configuration.  Since constraints on "config false" nodes may
  refer to "config true" nodes, remnant configuration may force the
  violation of those constraints.  The constraints that may not hold
  include "when", "must", "min-elements", and "max-elements".  Note that
  syntactic constraints cannot be violated, including hierarchical
  organization, identifiers, and type-based constraints.

>datastore while updates are being applied. I think the draft should make

Yes, <operational> will be have circumstances where it's contents
will not be valid.  It's better that the box provide accurate data
than provide valid data that is not accurate.  So we say that while
syntactic constraints cannot be violated, semantic constraints can
be.

Thanks,
 Phil