[core] Re: Coreconf Notifications

[Andy Bierman <[e-mail]>]

On Thu, Jul 18, 2024 at 8:56 AM Alex Huang Feng <
[e-mail]> wrote:

> Dear authors and CORE WG,
>
> I have some questions regarding how YANG notifications are encoded in CBOR.
>
> I am co-authoring draft-ahuang-netconf-notif-yang-05 where we are
> defining how NETCONF notifications are encoded in XML, JSON and CBOR.
> This definition is not explicit in JSON (RFC7951).
>
> Reading the YANG-CBOR (RFC9254) specification, the notifications are
> encoded as a “container-like” instance. This is rather a different approach
> from XML (RFC7950) and JSON (RFC7951) which to my understanding a leaf
> “eventTime” needs to be present in the notification as defined in RFC5277.
> I am wondering why YANG-CBOR defined YANG notifications differently. I
> don’t follow this WG closely but would love to hear the reasons which led
> to the wording in RFC9254. (Or if more consistency with XML and JSON is
> expected)
>
> For CORECONF, reading
> https://datatracker.ietf.org/doc/html/draft-ietf-core-comi-17#name-notify-examples,
> the notifications are also defined without the leaf defined in RFC5277 but
> still references this RFC.
>
>

YANG has the notification-stmt which only models the event part of the
notification message.
The notification message defined in RFC 5277 is a conceptual container that
has an eventTime leaf and this event part
that is modeled in YANG as child nodes.

YANG-CBOR defines the mapping to the YANG notification-stmt, not any
conceptual protocol messages
that are not defined in YANG.

Andy





> We plan to use CBOR encoding with YANG-Push (RFC8641) to reduce the size
> of the YANG-defined messages between the NETCONF server and client.
> In
> https://datatracker.ietf.org/doc/html/draft-ahuang-netconf-notif-yang-05#name-cbor-structure we
> define how we expect the CBOR message to be encoded.
> Having a similar approach to encode YANG notifications between JSON and
> CBOR ease the development of some open-source projects, such as the
> integration of YANG in the Kafka message broker.
> Here some references of such integration:
> -
> https://datatracker.ietf.org/doc/html/draft-ietf-nmop-yang-message-broker-integration-03
> -
> https://github.com/network-analytics/draft-daisy-kafka-yang-integration/blob/main/schema-registry-yangkit-integration-02.pdf
>
> Note also that we request a .sid file for YANG-SIDs for compressed CBOR
> messages in
> https://datatracker.ietf.org/doc/html/draft-ahuang-netconf-notif-yang-05#appendix-A
> .
>
> We will be onsite in Vancouver, so happy to have a live discussion
> regarding these encoding mismatches.
>
> I think the integration of YANG and CBOR into Kafka might also be of
> interest to the WG.
> Feel free to ping me back to have a discussion during the IETF week. We
> will also be present at the Hackathon Saturday and Sunday.
>
> Regards,
> Alex
>
>
>
>
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>