Re: [netconf] [Technical Errata Reported] RFC6243 (7426)

["Rob Wilton (rwilton)" <[e-mail]>]

Hi Andy, Dylan,

I don’t think that the proposed text is quite right, but there might be something worth clarifying here.

I.e., I believe that I understand what section 2.3.1 is meaning, but it doesn’t define what to do for default values that haven’t been explicit set by the client.  I.e., arguably, it looks servers are free to choose whether to include or not include data nodes with a default value that haven’t been set by the client (which I don’t think is the intent).  Note, the logically equivalent section in 3.3 is more explicit that they MUST NOT be reported:

<quote>
3.3<https://www.rfc-editor.org/rfc/rfc6243#section-3.3>.  'explicit' Retrieval Mode

   When data is retrieved with a <with-defaults> parameter equal to
   'explicit', a data node that was set by a client to its schema
   default value MUST be reported.  A conceptual data node that would be
   set by the server to the schema default value MUST NOT be reported.
   Non-configuration data nodes containing the schema default value MUST
   be reported.
<end quote>

Hence, I’m wondering whether section 2.3.1 should take this sentence from section 3.3:  “A conceptual data node that would be
   set by the server to the schema default value MUST NOT be reported.”, i.e., actually read something like:

<proposed>

2.3.1<https://www.rfc-editor.org/rfc/rfc6243#section-2.3.1>.  'explicit' Basic Mode Retrieval



   When data is retrieved from a server using the 'explicit' basic mode,

   and the <with-defaults> parameter is not present, data nodes MUST be

   reported if explicitly set by the client, even if they contain the

   schema default value.  A conceptual data node that would be set by

   the server to the schema default value MUST NOT be reported.

   Non-configuration data nodes containing the schema default value MUST

   be reported.
<end proposed>

Dylan, is this what you were trying to clarify?  Andy, does this change your opinion?

Thanks,
Rob



From: Andy Bierman <[e-mail]>
Sent: 18 April 2023 17:18
To: RFC Errata System <[e-mail]>
Cc: [e-mail]; [e-mail]; Rob Wilton (rwilton) <[e-mail]>; [e-mail]; [e-mail]; [e-mail]; [e-mail]
Subject: Re: [Technical Errata Reported] RFC6243 (7426)

Hi,

This Errata should be rejected.
The intent in section 2.3.1 is that all explicitly set data is returned.
The proposed new text does not reflect this intent.

There is a subtle difference between a server using the YANG default value because no instance exists
and a server creating an instance that equals the YANG default value.  The server implementation
needs to distinguish between them. The "create" and "delete" edit operations are impacted by this distinction.


Andy


On Tue, Apr 18, 2023 at 5:35 AM RFC Errata System <[e-mail]<mailto:[e-mail]>> wrote:
The following errata report has been submitted for RFC6243,
"With-defaults Capability for NETCONF".

--------------------------------------
You may review the report below and at:
https://www.rfc-editor.org/errata/eid7426

--------------------------------------
Type: Technical
Reported by: Dylan Sadoun <[e-mail]<mailto:[e-mail]>>

Section: 2.3.1

Original Text
-------------
When data is retrieved from a server using the 'explicit' basic mode, and the <with-defaults> parameter is not present, data nodes MUST be reported if explicitly set by the client, even if they contain the schema default value. Non-configuration data nodes containing the schema default value MUST be reported.

Corrected Text
--------------
When data is retrieved from a server using the 'explicit' basic mode, and the <with-defaults> parameter is not present, data nodes MUST be reported if explicitly set. This means that data nodes containing the schema default value MUST be reported if set by a NETCONF client, but MUST NOT be reported if set by the NETCONF server. Data nodes set by the NETCONF server to values other than their schema default values MUST be reported. Non-configuration data nodes containing the schema default value MUST be reported.

Notes
-----
The RFC defines "Explicitly set data" for the sole purpose of defining the explicit retrieval mode. This definition is clear about when data set by the server should be considered "explicitly set" i.e. when not set to the schema default value. However, the 2.3.1 and 3.3 sections are ambiguous and prone to misunderstanding, as they only emphasise the "set by the client" case, which leads to think that data set by the server to a value different from its schema default value should not be reported.
This erratum is for the 2.3.1 section.

Instructions:
-------------
This erratum is currently posted as "Reported". If necessary, please
use "Reply All" to discuss whether it should be verified or
rejected. When a decision is reached, the verifying party
can log in to change the status and edit the report, if necessary.

--------------------------------------
RFC6243 (draft-ietf-netconf-with-defaults-14)
--------------------------------------
Title               : With-defaults Capability for NETCONF
Publication Date    : June 2011
Author(s)           : A. Bierman, B. Lengyel
Category            : PROPOSED STANDARD
Source              : Network Configuration
Area                : Operations and Management
Stream              : IETF
Verifying Party     : IESG