Extensible YANG Model for YANG-Push Notifications
draft-ietf-netconf-notif-envelope-07
| Document | Type | Active Internet-Draft (netconf WG) | |
|---|---|---|---|
| Authors | Alex Huang Feng , Pierre Francois , Thomas Graf , Benoît Claise | ||
| Last updated | 2026-10-31 | ||
| Replaces | draft-netana-netconf-notif-envelope | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | Proposed Standard | ||
| Formats | |||
| Yang Validation | 4 errors, 2 warnings | ||
| Reviews |
YANGDOCTORS Early review
(of
-05)
by Ebben Aries
Almost ready
OPSDIR Early review
(of
-03)
by Joe Clarke
Has issues
|
||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Leonardo Rodoni | ||
| Shepherd write-up | Show Last changed 2026-06-15 | ||
| IESG | IESG state | AD Evaluation::AD Followup | |
| Action Holder | |||
| Consensus boilerplate | Yes | ||
| Telechat date | (None) | ||
| Responsible AD | Mahesh Jethanandani | ||
| Send notices to | leonardo.rodoni@swisscom.com |
draft-ietf-netconf-notif-envelope-07
Network Working Group A. Huang-Feng
Internet-Draft Deutsche Telekom
Intended status: Standards Track P. Francois
Expires: 4 May 2027 INSA-Lyon
T. Graf
Swisscom
B. Claise
Everything OPS & Arrcus
31 October 2026
Extensible YANG Model for YANG-Push Notifications
draft-ietf-netconf-notif-envelope-07
Abstract
This document defines a new extensible Notification structure,
defined in YANG, for use in YANG-Push Notification messages, both for
NETCONF and RESTCONF, enabling any YANG-compatible encodings such as
XML, JSON, or CBOR. Additionally, it defines two essential
extensions: an extension to this structure supporting a hostname and
a sequence number, and an extension to the YANG-Push Notifications
supporting a timestamp characterizing the moment when the data was
observed.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 4 May 2027.
Copyright Notice
Copyright (c) 2026 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Relationship to past documents . . . . . . . . . . . . . . . 4
2.1. Relationship to RFC5277 . . . . . . . . . . . . . . . . . 5
2.2. Relationship to RFC8639 . . . . . . . . . . . . . . . . . 5
2.3. Relationship to RFC7950 . . . . . . . . . . . . . . . . . 5
2.4. Relationship to RFC7951 . . . . . . . . . . . . . . . . . 6
2.5. Relationship to RFC9254 . . . . . . . . . . . . . . . . . 6
3. Notification Envelope Model . . . . . . . . . . . . . . . . . 6
3.1. Notification Envelope Structure . . . . . . . . . . . . . 7
3.1.1. Base Notification Model . . . . . . . . . . . . . . . 7
3.1.2. Encodings of the Notification Envelope . . . . . . . 8
3.2. Extensions for the Notification Envelope . . . . . . . . 14
3.2.1. Support of Hostname and Sequencing . . . . . . . . . 14
3.3. Extensions for the YANG-Push Notifications . . . . . . . 16
3.3.1. Support of Observation Timestamp . . . . . . . . . . 17
4. Enabling the Notification Envelope . . . . . . . . . . . . . 23
5. Discovering the Support of the Notification Envelope . . . . 25
6. Operational Considerations . . . . . . . . . . . . . . . . . 26
7. YANG Modules . . . . . . . . . . . . . . . . . . . . . . . . 26
7.1. The 'ietf-yp-notification' Module . . . . . . . . . . . . 26
7.1.1. YANG 'ietf-yp-notification' Tree Diagram . . . . . . 26
7.1.2. YANG 'ietf-yp-notification' Module . . . . . . . . . 27
7.2. The 'ietf-yp-observation' Module . . . . . . . . . . . . 32
7.2.1. YANG 'ietf-yp-observation' Tree Diagram . . . . . . . 32
7.2.2. YANG 'ietf-yp-observation' Module . . . . . . . . . . 33
8. Implementation Status . . . . . . . . . . . . . . . . . . . . 36
8.1. Huawei VRP . . . . . . . . . . . . . . . . . . . . . . . 36
8.2. 6WIND VSR . . . . . . . . . . . . . . . . . . . . . . . . 36
8.3. Cisco IOS XR . . . . . . . . . . . . . . . . . . . . . . 36
9. Security Considerations . . . . . . . . . . . . . . . . . . . 36
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 38
10.1. URI . . . . . . . . . . . . . . . . . . . . . . . . . . 38
10.2. YANG module name . . . . . . . . . . . . . . . . . . . . 38
10.3. YANG SID-file . . . . . . . . . . . . . . . . . . . . . 38
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 39
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 39
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12.1. Normative References . . . . . . . . . . . . . . . . . . 39
12.2. Informative References . . . . . . . . . . . . . . . . . 41
Appendix A. .sid file . . . . . . . . . . . . . . . . . . . . . 42
Appendix B. Example extending the Notification Envelope . . . . 45
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 47
1. Introduction
YANG-Push [RFC8639] allows Publishers to send Notifications to a data
collection system. The YANG-Push Receiver decodes the message and
optionally validates the header and the content before forwarding to
the next process in the data collection system.
The Notification encoded message from YANG-Push, as defined in
Section 2.6 of [RFC8639], is currently based on the XML model from
NETCONF Event Notifications [RFC5277]. This model has the drawback
that only a single mandatory 'eventTime' leaf is defined and does not
offer a way to extend this header with new Notification metadata.
Additionally, the 'eventTime' reports "The time the event was
generated by the event source" and not the metric observation time;
the data collection system might draw the wrong conclusion in case of
a busy Publisher that delays the YANG-Push export or in case a YANG-
Push Publisher re-exports the YANG-Push message. Finally, this XML
model is only valid for XML-based environments. When messages are
encoded in other YANG encodings, such as JSON [RFC7951] or CBOR
[RFC9254], validators cannot use YANG to validate the message schema.
YANG data consumers receiving Notifications require additional
Notification metadata to understand the full context of the received
message. For example, in addition to the timestamp of when the event
was encoded, it is also important to know the timestamp when the
metrics were observed, the hostname that sourced the message, and
have sequence numbers. The hostname is required because transport-
level source information is not preserved once Notifications are
forwarded to downstream systems, and having sequence numbers at the
notification level enable operators to detect lost notifications
throughout the data processing chain. This additional Notification
metadata is also helpful in correlating the data with other sources
of Network Telemetry [RFC9232] information.
For such reasons, this document proposes the following:
* First, it provides an extensible YANG Notification header allowing
implementors and authors of Internet-Drafts to easily add new
Notification metadata to the Notification message.
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* Second, it provides the first crucial extensions enabling
operators to identify which network node publishes which YANG-Push
messages, when the events or metrics were observed on the network
node, and in which order the messages were transmitted to the
Receiver.
* And finally, it provides a way to enable and disable the
Notification Envelope globally at the Server, making the
coexistence of different YANG-Push and NETCONF Event Notification
[RFC5277] headers possible.
1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
The terms "Subscription", "Dynamic Subscription", "Configured
Subscription", "Publisher", "Receiver" and "Notification Message" are
used as defined in [RFC8639].
The term "Client" and "Server" is used as defined in [RFC6241] for
NETCONF and [RFC8040] for RESTCONF.
The terms "Implementation-time Information" and "Runtime Information"
are used as defined in [RFC9196].
In addition, this document defines the following terms:
Notification Metadata: Additional data describing the context of a
notification that is sent in each message, e.g. which node generated
the message or at which time the notification was published.
Notification Envelope: YANG structure encapsulating the payload of a
notification, allowing the inclusion of metadata.
Publisher Process: The system process responsible for publishing YANG
notification messages. With [I-D.ietf-netconf-distributed-notif], a
network node can host multiple Publisher Processes.
2. Relationship to past documents
This section shows the relationship to [RFC5277], [RFC8639],
[RFC7951] and [RFC9254].
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2.1. Relationship to RFC5277
[RFC5277] defines a mechanism for NETCONF Servers to send
Notifications to collectors. These are the key relationships between
the current document and [RFC5277]:
* This document does not change the header defined by [RFC5277] nor
update any behavior defined in [RFC5277]. Implementations of
[RFC5277] use the header defined in Section 2.2.1 of [RFC5277].
* The co-existence of the Notification model defined in [RFC5277]
and the model defined in the current document is possible. The
co-existence is discussed in Section 6.
2.2. Relationship to RFC8639
Subscribed Notifications [RFC8639] defines a mechanism on top of
[RFC5277] to stream Notifications from the Server. These are the key
relationships between the current document and [RFC8639]:
* Section 1.4 of [RFC8639] states that the solution uses the
Notification header defined in [RFC5277]. This document proposes
a new header, which Clients can enable to replace the header
defined in [RFC5277] for YANG-defined event records. When this
new header is used, YANG-defined Notifications sent via Subscribed
Notifications [RFC8639] are encoded as defined in Section 3.1.
Servers MUST continue using the [RFC5277] header for NETCONF event
streams.
* 2.4 and 2.5 of [RFC8639] defines how a Dynamic Subscription and
Configured Subscriptions are managed. This document extends the
Subscribed Notifications configuration [RFC8639] to support
enabling the new header defined in this document.
2.3. Relationship to RFC7950
[RFC7950] defines how YANG data is encoded in XML. These are the key
relationship points between the current document and [RFC7950]:
* Section 7.16.2 of [RFC7950] defines the XML encoding of YANG
Notification. This document defines a new header for such
Notifications. When a YANG-Push Publisher implements the
specifications in this document with the XML encoding, the
Notifications are encoded according to Section 3.1.2.1.
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2.4. Relationship to RFC7951
[RFC7951] defines how YANG data is encoded using JSON. These are the
key relationship points between the current document and [RFC7951]:
* [RFC7951] does not define explicitly how a YANG Notification
should be encoded using JSON encoding. This document specifies a
new header for such Notifications. When a YANG-Push Publisher
implements the specifications in this document with JSON encoding,
the Notifications are encoded according to Section 3.1.2.2.
2.5. Relationship to RFC9254
[RFC9254] defines how YANG data is encoded using CBOR. These are the
key relationship points between the current document and [RFC9254]:
* [RFC9254] does not define explicitly how a YANG Notification
should be encoded using CBOR encoding. When a YANG-Push Publisher
implements the specifications in this document in CBOR encoding,
the Notifications are encoded according to Section 3.1.2.3 in this
document.
3. Notification Envelope Model
Section 4.2.10 of [RFC7950] defines the encoding of YANG
Notifications. A Notification is defined by a 'notification'
statement in the YANG module. When a NETCONF Server sends a
Notification, it comprises two parts: a header containing
Notification metadata that encapsulates the content and the content
defined by the 'notification' statement.
In YANG 1.1 [RFC7950], the Notification header is based on the model
defined in [RFC5277] which contains a single metadata 'eventTime'
leaf. The following XML shows the example from Section 4.2.10 of
[RFC7950], using the notification namespace defined in Section 4 of
[RFC5277]:
<notification
xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
<eventTime>2007-09-01T10:00:00Z</eventTime>
<link-failure xmlns="urn:example:system">
<if-name>so-1/2/3.0</if-name>
<if-admin-status>up</if-admin-status>
<if-oper-status>down</if-oper-status>
</link-failure>
</notification>
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This document defines a new Notification header and enables extending
this header with new Notification metadata. The Notification header
and extensions in this document are to be used in YANG-Push [RFC8641]
environments and can be implemented with NETCONF [RFC6241] and
RESTCONF [RFC8040]. When enabled, this new header MUST replace all
Notifications defined in both Subscribed Notifications [RFC8639] and
YANG-Push [RFC8641] for the entire Server, for both Configured and
Dynamic Subscriptions.
The remainder of this section is structured as follows. Section 3.1
defines the Notification Envelope and how this structure is encoded
using XML, JSON, and CBOR. Section 3.2 and Section 3.3 define the
first extensions to the Notification Envelope and to the YANG-Push
Notifications, respectively.
The Notification Envelope and extensions are enabled through the
mechanism defined in Section 4. Clients can discover the support of
this header and extensions for both implementation-time and runtime
through the discovery mechanism defined in Section 5.
3.1. Notification Envelope Structure
This section defines the structure of the Notification Envelope. The
following sections define how this structure is encoded in XML, JSON
and CBOR.
3.1.1. Base Notification Model
When a YANG-Push Publisher uses the Notification model defined in
this document, the Notification is structured as follows:
* The Notification is encapsulated in a root 'envelope' container.
* The header of the Notification contains the Notification metadata
that is enabled during the configuration of the Subscription as
child nodes of the root 'envelope' container.
* The content of the Notification defined by the 'notification'
statement is encoded in the 'contents' leaf.
The following YANG tree [RFC8340] illustrates the Notification
Envelope supporting only the mandatory metadata 'event-time'. Refer
to Section 3.2 for more extensions to this header.
structure envelope:
+-- event-time yang:date-and-time
+-- contents <anydata>
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3.1.2. Encodings of the Notification Envelope
The YANG Notification can be encoded using XML
[W3C.REC-xml-20001006][RFC7951], JSON [RFC7951] and CBOR [RFC9254].
3.1.2.1. XML encoding
A YANG Notification encoded in XML is structured as a root 'envelope'
container. The namespace of this container is the namespace defined
in the YANG module 'ietf-yp-notification':
urn:ietf:params:xml:ns:yang:ietf-yp-notification
Two mandatory child nodes within the 'envelope' container are
expected, representing the event time and the Notification payload.
When other Notification metadata is enabled through configuration,
the supplementary nodes are encoded at the same level as the
mandatory 'event-time' node. The YANG nodes in the Notification
header use the XML namespace from the module that defines the nodes.
This document defines two Notification metadata. Refer to
Section 3.2 for more details.
The content of the Notification that is defined by the 'notification'
statement is encoded in the 'contents' node. The name and namespace
of this payload element are determined by the YANG module containing
the 'notification' statement representing the Notification message.
The following example shows a 'push-update' Notification defined in
the YANG module of YANG-Push [RFC8641] encoded in XML:
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<envelope xmlns="urn:ietf:params:xml:ns:yang:ietf-yp-notification">
<event-time>2024-10-10T10:59:55.32Z</event-time>
<contents>
<push-update xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push">
<id>1011</id>
<datastore-contents>
<interfaces
xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"
xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type">
<interface>
<name>eth0</name>
<type>ianaift:ethernetCsmacd</type>
<if-index>1</if-index>
<admin-status>down</admin-status>
<oper-status>down</oper-status>
<statistics>
<discontinuity-time
>2013-04-01T03:00:00+00:00</discontinuity-time>
</statistics>
</interface>
</interfaces>
</datastore-contents>
</push-update>
</contents>
</envelope>
Figure 1: XML-encoded notification
3.1.2.2. JSON Encoding
A YANG Notification encoded in JSON is structured as a root
'envelope' container. The namespace of this container is the name of
the YANG module 'ietf-yp-notification' defined in Section 7.1.2.
Two mandatory child nodes within the 'ietf-yp-notification:envelope'
container are expected, representing the event time and the
Notification payload. The 'event-time' node is defined within the
same namespace as the 'ietf-yp-notification:envelope' container.
When other Notification metadata is enabled through configuration,
the supplementary nodes are encoded at the same level as the
mandatory 'event-time' node. The YANG nodes in the Notification
header use the YANG module name from the module that defines the
nodes as its namespace. Two additional metadata are described in
this document. Refer to Section 3.2 for more details.
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The content of the Notification that is defined by the 'notification'
statement is encoded in the 'contents' node. The name and namespace
of this payload element are determined by the YANG module containing
the 'notification' statement representing the Notification message.
The following example shows a "push-update" Notification defined in
the YANG module of YANG-Push [RFC8641] encoded in JSON:
{
"ietf-yp-notification:envelope": {
"event-time": "2024-10-10T08:00:11.22Z",
"contents": {
"ietf-yang-push:push-update": {
"id": 1011,
"datastore-contents": {
"ietf-interfaces:interfaces": {
"interface": [
{
"name": "eth0",
"type": "iana-if-type:ethernetCsmacd",
"if-index": 1,
"admin-status": "up",
"oper-status": "up",
"statistics": {
"discontinuity-time": "2024-10-10T07:50:00Z"
}
}
]
}
}
}
}
}
}
Figure 2: JSON-encoded Notification
3.1.2.3. CBOR Encoding
YANG Notifications can be encoded in CBOR using Names or SIDs in
keys.
Notifications encoded using names is similar to JSON encoding as
defined in Section 3.3 of [RFC9254]. The key of the element can be
the name of the element itself or be namespace-qualified. In the
latter case, the namespace of the Notification encoded message uses
the YANG module name 'ietf-yp-notification', defined in
Section 7.1.2.
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Notification encoded using YANG-SIDs replaces the name of the keys of
the CBOR encoded message with a 63-bit unsigned integer. In this
case, the keys of the encoded data use the SID value as defined in
Section 3.2 of [RFC9254]. A SID allocation process is needed
beforehand as defined in [RFC9595].
In the Notification, two mandatory child nodes within the 'ietf-yp-
notification:envelope' container are expected, representing the event
time and the Notification payload. The 'event-time' node is defined
within the same namespace as the 'ietf-yp-notification:envelope'
container.
When other Notification metadata is enabled through configuration,
the supplementary nodes are encoded at the same level as the
mandatory 'event-time' node. The YANG nodes in the Notification
header use the YANG module name from the module that defines the
nodes as its namespace when they are encoded as names. When encoded
using YANG SIDs, the SID value assigned to the metadata node is used.
A .sid file requesting the SID values for the metadata defined in
this document can be found in Appendix A. The .sid file includes the
metadata defined in Section 3.2.
The content of the Notification that is defined by the 'notification'
statement is encoded in the 'contents' node. The name and namespace
of this payload element are determined by the YANG module containing
the 'notification' statement representing the Notification message.
Similarly, SIDs can be used as keys if they are allocated following
the process defined in [RFC9595].
Figure 3 shows a 'push-update' Notification defined in the YANG
module of YANG-Push [RFC8641] encoded in CBOR using names as keys.
The example uses the CBOR diagnostic notation as defined in
Section 3.1 of [RFC9254]:
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{
"ietf-yp-notification:envelope": {
"event-time": "2024-10-10T08:00:11.22Z",
"contents": {
"ietf-yang-push:push-update": {
"id": 1011,
"datastore-contents": {
"ietf-interfaces:interfaces": {
"interface": [
{
"name": "eth0",
"type": "iana-if-type:ethernetCsmacd",
"if-index": 1,
"admin-status": 1, / up /
"oper-status": 1, / up /
"statistics": {
"discontinuity-time": "2024-10-10T07:50:00Z"
}
}
]
}
}
}
}
}
}
Figure 3: CBOR-encoded Notification using diagnostic notation
Figure 4 shows the same Notification encoded using SIDs. The SID
values come from the ".sid" file in Appendix A: 2958 for 'envelope',
2959 for 'contents', and 2960 for 'event-time'. Per Section 3.2 of
[RFC9254], SIDs used as map keys are encoded as deltas from a
reference SID. The reference SID of the outermost map is 0, so the
key of 'envelope' is 2958. Inside the 'envelope' map, the reference
SID is 2958, so 'event-time' is encoded as 2 (2960 - 2958) and
'contents' as 1 (2959 - 2958).
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{
2958: { / envelope: 0 + 2958 /
2: "2024-10-10T08:00:11.22Z", / event-time: 2958 + 2 /
1: { / contents: 2958 + 1 /
"ietf-yang-push:push-update": {
"id": 1011,
"datastore-contents": {
"ietf-interfaces:interfaces": {
"interface": [
{
"name": "eth0",
"type": "iana-if-type:ethernetCsmacd",
"if-index": 1,
"admin-status": 1, / up /
"oper-status": 1, / up /
"statistics": {
"discontinuity-time": "2024-10-10T07:50:00Z"
}
}
]
}
}
}
}
}
}
Figure 4: CBOR-encoded Notification using YANG SIDs in CBOR
diagnostic notation
Note to the RFC-Editor: Please change the SID values from the example
Figure 4 with the ones allocated by IANA.
Note that in the example shown in Figure 4, the Notification payload
uses names as keys. These keys can also be encoded as SIDs. The
corresponding SID values must be allocated in the IANA registry,
following the procedures defined in [RFC9595]. Such a mix of SIDs
and names as keys is allowed with the 'application/yang-data+cbor'
media type without the 'id' parameter (Section 7 of [RFC9254]).
When SIDs are used throughout the Notification Envelope, they are
encoded as deltas relative to the parent node by default. The
absolute SID can also be used using the tag 47. Refer to [RFC9254]
for more details.
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3.2. Extensions for the Notification Envelope
This section describes two optional YANG nodes for the Notification
Envelope header: a 'hostname' and a 'sequence-number', which are
enabled by default when using the Notification Envelope defined in
this document. The Client discovers the support of these two
optional leafs with the mechanism defined in Section 5.
The Notification Envelope, including the metadata, results in the
following YANG tree [RFC8340].
structure envelope:
+-- event-time yang:date-and-time
+-- hostname? inet:host-name {hostname-sequence-number}?
+-- sequence-number? uint32 {hostname-sequence-number}?
+-- contents <anydata>
3.2.1. Support of Hostname and Sequencing
When YANG-Push Notification messages are forwarded from a Receiver to
another system, such as a message broker or a time series database,
the transport context is lost since it is not part of the
Notification metadata of the Notification encoded message.
Therefore, the downstream system is unable to associate the message
with the publishing process (the exporting network node), nor able to
detect message loss or reordering.
To correlate network data among different Network Telemetry planes as
described in Section 3.1 of [RFC9232] or among different YANG-Push
Subscription types as defined in Section 3.1 of [RFC8641], a
reference to the node streaming the data is needed. This is
essential for understanding the timely relationship among these
different planes and YANG-Push Subscription types.
Today, network operators work around this impediment by preserving
the transport source IP address and sequence numbers of the
publishing process. However, this implies encoding this information
in the YANG-Push Notification messages which impact the semantic
readability of the message in the downstream system.
On top of that, the transport source IP address might not represent
the management IP address by which the YANG-Push Publisher should be
known. For instance, for Configured Subscriptions, the IP address
stamped on the Notification messages is the 'source-address'
configured for the Subscription (Section 2.5 of [RFC8639]), or an
address selected by the Publisher, which might not be the management
IP address.
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To overcome these issues, this document defines an extension to the
Notification Envelope to encode a hostname and a sequence number.
This allows the downstream system to not only be able to identify
from which network node, Subscription, and time the message was
published but also, the order of the published messages.
hostname: Describes the hostname of the network node that published
the message. The hostname uniquely identifies the node within the
network.
sequence-number: Generates a sequence number for each published
message by the Publisher Process. If a network node has multiple
Publisher Processes, 'message-publisher-id' defined in Section 10
of [I-D.ietf-netconf-distributed-notif] differentiates between the
Publisher Processes. The initial number is 1 and counts up by 1
at every published Notification message until it reaches
4294967295. Then, it wraps around and restarts at 0. The value 0
is used to detect wrap arounds. When the Publisher Process
restarts, the sequence number restarts at 1.
Figure 5 provides an example of a JSON encoded, [RFC8259], 'push-
update' Notification message with 'hostname' and 'sequence-number'
included.
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{
"ietf-yp-notification:envelope": {
"event-time": "2023-03-25T08:30:11.22Z",
"hostname": "example-router.example.com",
"sequence-number": 1,
"contents": {
"ietf-yang-push:push-update": {
"id": 6666,
"datastore-contents": {
"ietf-interfaces:interfaces": {
"interface": [
{
"name": "eth0",
"type": "iana-if-type:ethernetCsmacd",
"if-index": 1,
"admin-status": "up",
"oper-status": "up",
"statistics": {
"discontinuity-time": "2023-03-25T08:20:00.00Z"
}
}
]
}
}
}
}
}
}
Figure 5: JSON Example for a 'push-update' Notification message
3.3. Extensions for the YANG-Push Notifications
This section describes two optional nodes that extend the 'push-
update' and 'push-change-update' Notifications. They do not depend
on the Notification Envelope and are sent by default when supported
(Section 4). The Client discovers the support of these two leafs
with the mechanism defined in Section 5.
This document defines the following nodes as shown in the following
YANG tree [RFC8340]. See the following sections for more details.
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module: ietf-yp-observation
augment /yp:push-update:
+--ro timestamp? yang:date-and-time
+--ro point-in-time? enumeration
augment /yp:push-change-update:
+--ro timestamp? yang:date-and-time
+--ro point-in-time? enumeration
3.3.1. Support of Observation Timestamp
To correlate network data among different Network Telemetry planes,
as described in Section 3.1 of [RFC9232], or among different YANG-
Push Subscription types, as defined in Section 3.1 of [RFC8641], a
Receiver needs a timestamp reference to align all the metrics and
events. The observation timestamp defined in this document
characterizes the moment the state change was observed or the moment
when the data was measured, so that a Receiver can correctly align
the collected data.
The delay between the YANG-Push export process and the reception of
the message at the Receiver instance can be measured using the node
'event-time' defined in Section 3.1.1. However, as the 'event-time'
node only establishes the moment when the YANG-Push Notification was
generated, the moment when such metrics were collected or the state
changes were observed cannot be measured using this timestamp. The
observation timestamp defined in this section characterizes the
moment when the metrics were observed, which enable aligning the
received metrics to the actual moment they were measured.
When the time bucket length in a time series database and the
periodic YANG-Push Subscription time are configured with the same
values, the 'event-time' of the Notification Envelope can be used for
indexing the data in the time series database. There is a variable
delay between the observation timestamp, the 'event-time', and the
'anchor-time' as described in Section 4.2 of [RFC8641]. When these
timestamps are close to the time bucket boundaries, a time bucket may
experience data collection discrepancies, e.g. 0 measurements are
aggregated into one time bucket while the next time bucket contains 2
measurements. This leads to inconsistent accounting errors in the
time series database. This problem is resolved using the observation
timestamp instead of the 'event-time' for time series database
indexation.
By extending YANG-Push Notifications with the observation timestamp
and a 'point-in-time' node, the data collection process can always
ensure it has the best available time for indexing the data. It can
therefore use unconditionally the observation timestamp node in the
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data processing chain to correctly align the metrics and events. At
the same time, the 'point-in-time' node ensures that the semantics
associated with the timestamp are not lost throughout the data
processing chain.
Besides the Subscription ID as described in Section 3.7 of [RFC8641],
the following network observation time metadata objects are part of
'push-update' and 'push-change-update' Notifications.
timestamp: States the measurement observation time for the 'push-
update' Notification in 'periodic' Subscriptions, and the
observation time of the reported state for the 'push-update' and
'push-change-update' Notifications in 'on-change' Subscriptions.
The 'point-in-time' node states which of these points in time the
timestamp characterizes.
By comparing the observation timestamp of two 'push-update'
Notifications in a periodic Subscription, the collector can deduce
the actual cadence of the measurements, and compare it with the
Subscription configuration. For a 'push-change-update'
Notification in an 'on-change' Subscription, it states the time
when the network state change was observed. For the initial
'push-update' Notification of an 'on-change' Subscription with
'sync-on-start' set to 'true', it states the point in time
described for 'initial-state' below.
point-in-time: The enumeration states at which point in time the
value of the observation timestamp was observed. Choices are:
'current-accounting' states the point in time where the metrics
are polled and observed in "periodic" Subscriptions.
'initial-state' states, for the initial 'push-update' Notification
of an 'on-change' Subscription with 'sync-on-start' set to 'true'
[RFC8641], the point in time when the reported state was last
observed to change. This point in time can precede the
establishment of the Subscription.
'state-changed' states the point in time when the state change was
observed after the Subscription was established for 'on-change'
Subscriptions.
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3.3.1.1. Usage Example
This section illustrates the usage of the 'point-in-time' node in two
different Subscriptions. Section 3.3.1.1.1 showcases a YANG-Push
Subscription monitoring the state of an interface using an 'on-
change' Subscription with 'sync-on-start' set to 'true'.
Section 3.3.1.1.2 illustrates the usage of the 'point-in-time' node
within periodic Subscriptions.
3.3.1.1.1. On-Change Subscriptions
Figure 6 illustrates the set of events that lead to the generation of
'on-change' YANG-Push Notifications. This timeline depicts the
following states and events:
* T1: At first, the operational state of the interface is "Up". The
Subscription is not configured yet at this stage and thus,
Notifications are not triggered for this state change.
* T2: After configuring an 'on-change' Subscription with 'sync-on-
start' set to 'true', the Publisher sends the initial state of the
interface. The initial state is polled based on the event having
happened at T1.
* T3: This is the moment the interface changes its operational
status to "Down".
* T4: After the interface state changes at T3, the Publisher
generates the 'on-change' Notification alerting the Receiver.
Timeline
---------------------------------------------------------------------->
| (T1) Interface | (T2) YANG-Push | (T3) Interface | (T4) YANG-Push
| state changed | "on-change" | state changed | "on-change"
| to "Up". | Subscription | to "Down". | Notification
| | with "sync-on- | | with the new
| | start" for | | interface state.
| | interface state | |
| | is established. | |
v v v v
Figure 6: Example timeline for an On-Change Subscription with
'sync-on-start'
At T2, after configuring the Subscription, the Publisher triggers a
'push-update' Notification as depicted in Figure 7. The 'event-time'
is the moment the YANG-Push process generates the Notification (T2).
The 'ietf-yp-observation:timestamp' node characterizes the moment the
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interface changed its status to "Up" (T1). T1 is the last time this
state changed, before the Subscription was established. In this
case, the 'point-in-time' node is set to 'initial-state'.
{
"ietf-yp-notification:envelope": {
"event-time": "2025-03-25T08:30:11.22Z",
"hostname": "example-router.example.com",
"sequence-number": 1,
"contents": {
"ietf-yang-push:push-update": {
"id": 2222,
"ietf-yp-observation:timestamp": "2025-03-25T08:29:30.22Z",
"ietf-yp-observation:point-in-time": "initial-state",
"datastore-contents": {
"ietf-interfaces:interfaces": {
"interface": [{
"name": "eth0",
"type": "iana-if-type:ethernetCsmacd",
"if-index": 1,
"admin-status": "up",
"oper-status": "up",
"statistics": {
"discontinuity-time": "2025-03-25T06:43:12Z"
}
}]
}
}
}
}
}
}
Figure 7: Example of 'push-update' Notification sent after the
Subscription is established.
After T3, the Publisher triggers a 'push-change-update' Notification
announcing an interface status change to the Receiver as depicted in
Figure 8. In this case, the 'ietf-yp-observation:timestamp' node
characterizes the moment the interface changed its status at T3. The
value of the 'event-time' node characterizes the moment the YANG-Push
process generated the Notification at T4.
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{
"ietf-yp-notification:envelope": {
"event-time": "2025-03-25T08:35:12.22Z",
"hostname": "example-router.example.com",
"sequence-number": 2,
"contents": {
"ietf-yang-push:push-change-update": {
"id": 2222,
"ietf-yp-observation:timestamp": "2025-03-25T08:34:05.22Z",
"ietf-yp-observation:point-in-time": "state-changed",
"datastore-changes": {
"yang-patch": {
"patch-id": "0",
"edit": [{
"edit-id": "edit_example_1",
"operation": "replace",
"target": "/ietf-interfaces:interfaces",
"value": {
"ietf-interfaces:interfaces": {
"interface": [{
"name": "eth0",
"type": "iana-if-type:ethernetCsmacd",
"if-index": 1,
"admin-status": "up",
"oper-status": "down",
"statistics": {
"discontinuity-time": "2025-03-25T06:43:12Z"
}
}]
}
}
}]
}
}
}
}
}
}
Figure 8: JSON Push Example for a push-change-update Notification
message
3.3.1.1.2. Periodic Subscriptions
In periodic Subscription, the observation time characterizes the time
when the metrics were polled from the datastore before it generates
the actual YANG-Push message.
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Figure 9 illustrates the delays associated with the generation of the
YANG-Push message. The timeline shows the following states:
* T1: This is the moment the periodic Subscription is configured to
push the operational status of the interface every N interval.
* T2: This is the moment the YANG-Push process polls the state data
and metrics from the datastore. At this stage, the Notification
is not built nor sent yet.
* T3: This is the moment the YANG-Push process generates the 'push-
update' Notification and sends it to the Receiver.
At every N interval, the process repeats the steps from T2 and T3,
first polling the datastore to retrieve the data (T2) and then
building and sending the Notification to the Receiver (T3).
Timeline
------------------------------------------------------>
| (T1) YANG-Push | (T2) YANG-Push | (T3) YANG-Push
| "periodic" | process polls | "periodic"
| Subscription | the metrics | current
| for interface | from the | accounting.
| counter is | datastore. |
| established | |
v v v
Figure 9: Example timeline for Periodic Subscription
An example of a 'push-update' Notification is illustrated in
Figure 10. This example represents a message sent at T3, after the
process built the YANG-Push Notification. The node 'event-time'
characterizes the moment the YANG-Push process generated the message
(T3). The node 'ietf-yp-observation:timestamp' establishes the
moment when the metrics were polled from the datastore (T2). For
these periodic Subscriptions, the 'point-in-time' node must be set to
'current-accounting'.
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{
"ietf-yp-notification:envelope": {
"event-time": "2023-03-25T08:30:12.25Z",
"hostname": "example-router.example.com",
"sequence-number": 1,
"contents": {
"ietf-yang-push:push-update": {
"id": 6666,
"ietf-yp-observation:timestamp": "2023-03-25T08:30:00.00Z",
"ietf-yp-observation:point-in-time": "current-accounting",
"datastore-contents": {
"ietf-interfaces:interfaces": {
"interface": [{
"name": "eth0",
"type": "iana-if-type:ethernetCsmacd",
"if-index": 1,
"admin-status": "up",
"oper-status": "up",
"statistics": {
"discontinuity-time": "2023-03-25T07:43:12Z",
"in-octets": "250"
}
}]
}
}
}
}
}
}
Figure 10: JSON Push Example for a push-update Notification message
4. Enabling the Notification Envelope
The Notification Envelope defined in this document can be enabled
either prior to or within the same NETCONF transaction that
configures the YANG-Push Subscriptions. This document augments the
'ietf-subscribed-notifications' model [RFC8639] to support the
configuration of the Notification Envelope.
When the node 'enable-notification-envelope' is enabled, all the
Notifications defined in Subscribed Notifications [RFC8639] and YANG-
Push [RFC8641] are encoded as defined in Section 3.1. If
additionally, any Notification metadata is enabled, the Notification
metadata nodes are present in the header. When the node 'enable-
notification-envelope' is disabled, Notifications are encoded as
defined in NETCONF Event Notifications [RFC5277]. The extension
defined in Section 3.2 is sent by default when (1) it is supported
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and (2) the node 'enable-notification-envelope' is enabled. The
extension defined in Section 3.3 does not depend on the Notification
Envelope: it is sent by default when it is supported, whether
'enable-notification-envelope' is enabled or disabled.
module: ietf-yp-notification
augment /sn:subscriptions:
+--rw enable-notification-envelope? boolean
+--rw metadata
When there are existing Subscriptions and a Client changes the node
'enable-notification-envelope', all existing Subscriptions MUST be
terminated. The Publisher MUST send a 'subscription-terminated'
notification, with the reason 'notification-envelope-changed' defined
in Section 7.1.2, to all the existing Subscriptions using the header
configured before the change. Any new Subscription after the change
uses the header defined by the node 'enable-notification-envelope',
i.e. encoded as Section 3.1 when enabled and as defined in [RFC5277]
if disabled.
Configured Subscriptions remain in the configuration. After the
change, the Publisher re-evaluates each Configured Subscription as if
it had just been created (Section 2.5.1 of [RFC8639]). A Configured
Subscription that passes this evaluation keeps its identifier, its
Receivers restart in the "connecting" state, and each Receiver
receives a new 'subscription-started' notification encoded with the
new header.
The container 'metadata' is intended to support optional extensions
that may be enabled on a per-extension basis. Defining explicit
configuration knobs to enable or disable these extensions is optional
and left to the extension designer. Refer to Appendix B for an
example.
Per the YANG specifications (Section 7.17 of [RFC7950]), which does
not allow making mandatory statements on augmentations, the 'enable-
notification-envelope' YANG leaf must be made optional: the
Notification metadata fields defined in Section 3.2 MUST NOT be
enabled when the Notification Envelope is not enabled.
Per-subscription support for this header was considered during the
definition of this specification, however, a network node-wide
setting was chosen to simplify network operations. In practice,
operators use YANG-Push Subscriptions in large-scale deployments
where numerous Subscriptions are created on each network node. While
per-subscription configuration provides more flexibility, maintaining
the choice of header format for each Subscription adds significant
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operational complexity when troubleshooting or migrating to a new
header format. The desire for simplifying operations led to the
definition of a global configuration knob for the Notification
Envelope.
5. Discovering the Support of the Notification Envelope
A Client can discover the support of the Notification Envelope model
through the capabilities model defined in [RFC9196]. This document
extends the 'ietf-notification-capabilities' model with:
* A container containing a leaf 'envelope', stating that the YANG
Notification can be encoded following the Notification Envelope
model.
* A container 'metadata' containing all the supported extensions to
this header. Such extensions are defined in Section 3.2.
* A leaf 'yang-push-observation-time-supported', stating that the
extension defined in Section 3.3 is supported. This leaf is
defined in the 'ietf-yp-observation' module, independently of the
Notification Envelope.
When the leafs defined in this document are supported by the Server,
the Client discovers their support with the following augmentations
in the 'ietf-notification-capabilities' module:
module: ietf-yp-notification
augment /sysc:system-capabilities/notc:subscription-capabilities:
+--ro notification-metadata
+--ro envelope? boolean
+--ro metadata
+--ro hostname-sequence-number? boolean
{hostname-sequence-number}?
module: ietf-yp-observation
augment /sysc:system-capabilities/notc:subscription-capabilities:
+--ro yang-push-observation-time-supported? boolean
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6. Operational Considerations
As stated in Section 4, the Notification Envelope defined in this
document replaces the header defined by NETCONF Event Notifications
[RFC5277] when enabled. The NETCONF Event Notifications [RFC5277]
header and the Notification Envelope defined in this document may
coexist in the same network. Since enabling or disabling the
Notification Envelope is performed on a YANG-Push Publisher basis,
Receivers must only receive Notifications in a format they support.
Operators should ensure that Receivers support the corresponding
format or that proper validation and filtering are implemented when
both formats are present in the same network.
In network devices where existing Subscriptions are active, enabling
or disabling the Notification Envelope has operational impact.
Operators should acknowledge that any existing Subscriptions will be
terminated when enabling or disabling the Notification Envelope.
Careful planning is therefore required to avoid unintended service
disruption.
7. YANG Modules
7.1. The 'ietf-yp-notification' Module
The following sections show the YANG tree and YANG module for the
'ietf-yp-notification' module. This module defines the Notification
Envelope structure, and extends the 'ietf-subscribed-notifications'
and 'ietf-notification-capabilities' modules to enable both the
configuration of the Notification Envelope and the discovery of
supported extensions. This module supports the 'hostname' and
'sequence-number' as extensions to the Notification Envelope.
7.1.1. YANG 'ietf-yp-notification' Tree Diagram
This YANG module extends 'ietf-subscribed-notifications' [RFC8639]
and 'ietf-notification-capabilities' [RFC9196] as shown in the
following YANG tree [RFC8340]:
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module: ietf-yp-notification
augment /sn:subscriptions:
+--rw enable-notification-envelope? boolean
+--rw metadata
augment /sysc:system-capabilities/notc:subscription-capabilities:
+--ro notification-metadata
+--ro envelope? boolean
+--ro metadata
+--ro hostname-sequence-number? boolean
{hostname-sequence-number}?
structure envelope:
+-- event-time yang:date-and-time
+-- hostname? inet:host-name {hostname-sequence-number}?
+-- sequence-number? uint32 {hostname-sequence-number}?
+-- contents <anydata>
7.1.2. YANG 'ietf-yp-notification' Module
The YANG module augments the module 'ietf-subscribed-notifications'
[RFC8639], augments the module "ietf-notification-capabilities"
[RFC9196] and uses 'ietf-yang-types' module [RFC9911] and 'ietf-yang-
structure-ext' module [RFC8791].
<CODE BEGINS> file "ietf-yp-notification@2026-09-25.yang"
module ietf-yp-notification {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-yp-notification";
prefix iypn;
import ietf-yang-types {
prefix yang;
reference
"RFC 9911: Common YANG Data Types";
}
import ietf-inet-types {
prefix inet;
reference
"RFC 9911: Common YANG Data Types";
}
import ietf-subscribed-notifications {
prefix sn;
reference
"RFC 8639: Subscription to YANG Notifications";
}
import ietf-system-capabilities {
prefix sysc;
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reference
"RFC 9196: YANG Modules Describing Capabilities for
Systems and Datastore Update Notifications";
}
import ietf-notification-capabilities {
prefix notc;
reference
"RFC 9196: YANG Modules Describing Capabilities for
Systems and Datastore Update Notifications";
}
import ietf-yang-structure-ext {
prefix sx;
reference
"RFC 8791: YANG Data Structure Extensions";
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <https://datatracker.ietf.org/group/netconf/>
WG List: <mailto:netconf@ietf.org>
Authors: Alex Huang Feng
<mailto:alex.huang-feng@t-systems.com>
Pierre Francois
<mailto:pierre.francois@insa-lyon.fr>
Thomas Graf
<mailto:thomas.graf@swisscom.com>
Benoit Claise
<mailto:benoit@everything-ops.net>";
description
"Defines a notification header for Subscribed Notifications
[RFC8639] and YANG-Push [RFC8641]. When this notification header
is enabled through configuration, the root container of the
notification is encoded as defined in RFC XXXX.
This module can be used to validate XML-encoded notifications
[RFC7950], JSON-encoded messages [RFC7951], and CBOR-encoded
messages [RFC9254]. Refer to Section 3.1.2 of RFC XXXX for more
details.
Copyright (c) 2026 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject to
the license terms contained in, the Revised BSD License set
forth in Section 4.c of the IETF Trust's Legal Provisions
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Relating to IETF Documents
(https://trustee.ietf.org/license-info).
All revisions of IETF and IANA published modules can be found
at the YANG Parameters registry group
(https://www.iana.org/assignments/yang-parameters).
This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
'MAY', and 'OPTIONAL' in this document are to be interpreted as
described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
they appear in all capitals, as shown here.";
revision 2026-09-25 {
description
"Initial version.";
reference
"RFC XXXX: Extensible YANG Model for YANG-Push Notifications";
}
feature hostname-sequence-number {
description
"This feature indicates that hostname and sequence numbers are
supported.";
}
identity notification-envelope-changed {
base sn:subscription-terminated-reason;
description
"The subscription was terminated because the value of
'enable-notification-envelope' was changed.";
reference
"Section 4 of RFC XXXX: Extensible YANG Model for YANG-Push
Notifications";
}
grouping notif-env-capabilities {
description
"This grouping defines the capabilities for the
notification-envelope, and the different supported metadata.";
reference
"Section 5 of RFC XXXX: Extensible YANG Model for YANG-Push
Notifications";
leaf envelope {
type boolean;
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default "true";
description
"Supports YANG-Push to use the notification-envelope. If
set to true, the publisher supports the notification
envelope. If set to false, the notification envelope is not
supported by the publisher.";
}
container metadata {
description
"Container with the supported optional metadata by the
YANG-Push publisher.";
leaf hostname-sequence-number {
if-feature "hostname-sequence-number";
type boolean;
default "false";
description
"Supports hostname and sequence-number in the YANG-Push
notifications. If set to true, the publisher supports
sending the hostname and sequence numbers within the
notification envelope. If set to false, the hostname
and sequence numbers are not supported.";
}
}
}
sx:structure envelope {
description
"This structure defines the Notification Envelope: the
notification metadata ('event-time' and, when supported,
'hostname' and 'sequence-number') and the notification
payload in 'contents'.";
reference
"Section 3 of RFC XXXX: Extensible YANG Model for YANG-Push
Notifications";
leaf event-time {
type yang:date-and-time;
mandatory true;
description
"The date and time the notification was generated by the
publisher. This is not necessarily the time at which the
reported data was observed; see Section 3.3.1 of RFC XXXX.";
}
leaf hostname {
if-feature "hostname-sequence-number";
type inet:host-name;
description
"The hostname of the network node. This value is usually
configured on the node by the administrator to identify
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the node in the network uniquely.";
}
leaf sequence-number {
if-feature "hostname-sequence-number";
type uint32;
description
"Sequence number of the published message, per publisher
process. The initial number is 1 and it counts up by 1 at
every published notification message until it reaches
4294967295. Then, it wraps around and restarts at 0. The
value 0 is used to detect wrap arounds. When the publisher
process restarts, the sequence number restarts at 1.";
}
anydata contents {
mandatory true;
description
"This contains the values defined by the 'notification'
statement unchanged.";
}
}
// Subscription container
augment "/sn:subscriptions" {
description
"This augmentation adds the configuration switches for
enabling the notification envelope and metadata.";
leaf enable-notification-envelope {
type boolean;
default "false";
description
"Enables YANG-Push to use the notification-envelope
instead of RFC 5277 defined notifications. Enabling or
disabling this leaf terminates all existing active dynamic
and configured YANG-Push subscriptions. Before terminating
each subscription, the publisher MUST send a
'subscription-terminated' notification, with the reason
'notification-envelope-changed', using the header
configuration that was in effect before the change.
Configured subscriptions are then re-evaluated and
restarted with the new header.";
reference
"Section 4 of RFC XXXX.";
}
container metadata {
description
"This container is intended to be augmented by modules
defining optional notification metadata extensions.";
reference
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"Section 4 of RFC XXXX.";
}
}
// YANG-Push Capabilities extension
augment "/sysc:system-capabilities"
+ "/notc:subscription-capabilities" {
description
"Extension to the subscription-capabilities model to enable
clients to learn whether the publisher supports the
notification-envelope";
container notification-metadata {
description
"Adds the notification metadata capabilities to subscription
capabilities.";
uses notif-env-capabilities;
}
}
}
<CODE ENDS>
7.2. The 'ietf-yp-observation' Module
The following sections show the YANG tree and YANG module for the
'ietf-yp-observation' module. This module extends the 'ietf-yang-
push' module to support sending the observation timestamp in 'push-
update' and 'push-change-update' Notifications. Additionally, it
augments the 'ietf-notification-capabilities' to enable Clients to
discover the support of observation timestamps.
7.2.1. YANG 'ietf-yp-observation' Tree Diagram
This YANG module extends 'ietf-yang-push' [RFC8641] and 'ietf-
notification-capabilities' [RFC9196] as shown in the following YANG
tree [RFC8340]:
module: ietf-yp-observation
augment /yp:push-update:
+--ro timestamp? yang:date-and-time
+--ro point-in-time? enumeration
augment /yp:push-change-update:
+--ro timestamp? yang:date-and-time
+--ro point-in-time? enumeration
augment /sysc:system-capabilities/notc:subscription-capabilities:
+--ro yang-push-observation-time-supported? boolean
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7.2.2. YANG 'ietf-yp-observation' Module
The YANG module augments the module 'ietf-yang-push' [RFC8641] and
the module 'ietf-notification-capabilities' [RFC9196].
<CODE BEGINS> file "ietf-yp-observation@2026-09-25.yang"
module ietf-yp-observation {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-yp-observation";
prefix iypo;
import ietf-yang-types {
prefix yang;
reference
"RFC 9911: Common YANG Data Types";
}
import ietf-yang-push {
prefix yp;
reference
"RFC 8641: Subscription to YANG Notifications for Datastore
Updates";
}
import ietf-system-capabilities {
prefix sysc;
reference
"RFC 9196: YANG Modules Describing Capabilities for
Systems and Datastore Update Notifications";
}
import ietf-notification-capabilities {
prefix notc;
reference
"RFC 9196: YANG Modules Describing Capabilities for
Systems and Datastore Update Notifications";
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <https://datatracker.ietf.org/group/netconf/>
WG List: <mailto:netconf@ietf.org>
Authors: Thomas Graf
<mailto:thomas.graf@swisscom.com>
Benoit Claise
<mailto:benoit@everything-ops.net>
Alex Huang Feng
<mailto:alex.huang-feng@t-systems.com>";
description
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"Defines the observation time in YANG-Push streaming update
notifications.
Copyright (c) 2026 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject to
the license terms contained in, the Revised BSD License set
forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(https://trustee.ietf.org/license-info).
All revisions of IETF and IANA published modules can be found
at the YANG Parameters registry group
(https://www.iana.org/assignments/yang-parameters).
This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices.";
revision 2026-09-25 {
description
"Initial version.";
reference
"RFC XXXX: Extensible YANG Model for YANG-Push Notifications";
}
grouping yang-push-observation {
description
"This grouping adds the observation timestamp for the
observed metrics.";
reference
"Section 3.3.1 of RFC XXXX.";
leaf timestamp {
type yang:date-and-time;
description
"The point in time at which the reported data was observed.
The 'point-in-time' leaf states which point in time this
is.";
}
leaf point-in-time {
type enumeration {
enum current-accounting {
description
"For periodic subscriptions, the point-in-time
where the metrics are being polled and observed.";
}
enum initial-state {
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description
"For the initial 'push-update' notification of an
on-change subscription with 'sync-on-start' set to
'true', the point in time when the reported state was
last observed to change. This point in time can precede
the establishment of the subscription.";
}
enum state-changed {
description
"For on-change subscriptions, the point in time when the
state change was observed after the subscription was
established.";
}
}
description
"This describes at which point in time the metrics were
observed.";
}
}
// Event notifications
augment "/yp:push-update" {
description
"This augmentation adds the observation timestamp of the
accounted metrics in the push-update notification.";
uses yang-push-observation;
}
augment "/yp:push-change-update" {
description
"This augmentation adds the observation timestamp of the
event in the push-change-update notification.";
uses yang-push-observation;
}
// Event capabilities
augment "/sysc:system-capabilities"
+ "/notc:subscription-capabilities" {
description
"Add YANG-Push notification capabilities to system-level
capability container.";
leaf yang-push-observation-time-supported {
type boolean;
default "false";
description
"Specifies whether the publisher supports exporting
observation-timestamp and point-in-time in notifications.
If set to true, the publisher supports the
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observation-timestamp and point-in-time in notifications.
If set to false, these are not supported.";
reference
"Section 3.3.1 of RFC XXXX.";
}
}
}
<CODE ENDS>
8. Implementation Status
Note to the RFC-Editor: Please remove this section before publishing.
8.1. Huawei VRP
Huawei implemented Notification Envelope encoded in JSON as described
in Section 3.2 and in push-update and push-change-update
Notifications the timestamp and point-in-time extension as described
in Section 3.3 for a YANG-Push Publisher on UDP-based Transport for
Configured Subscriptions [I-D.ietf-netconf-udp-notif] in their VRP
platform.
8.2. 6WIND VSR
6WIND implemented Notification Envelope encoded in JSON and CBOR with
Names in keys as described in Section 3.2 and in push-update and
push-change-update Notifications the timestamp and point-in-time
extension as described in Section 3.3 for a YANG-Push Publisher on
UDP-based Transport for Configured Subscriptions
[I-D.ietf-netconf-udp-notif] in their VSR platform.
8.3. Cisco IOS XR
Cisco implemented Notification Envelope encoded in JSON and CBOR with
Names in keys as described in Section 3.2 and in push-update and
push-change-update Notifications the timestamp and point-in-time
extension as described in Section 3.3 for a YANG-Push Publisher on
UDP-based Transport for Configured Subscriptions
[I-D.ietf-netconf-udp-notif] in their IOS XR platform.
9. Security Considerations
This section is modeled after the template described in Section 3.7.1
of [RFC9907].
The 'ietf-yp-notification' and 'ietf-yp-observation' YANG modules
define data models that are designed to be accessed via YANG-based
management protocols, such as NETCONF [RFC6241] and RESTCONF
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[RFC8040]. These YANG-based management protocols (1) have to use a
secure transport layer (e.g., SSH [RFC4252], TLS [RFC9846], and QUIC
[RFC9000]) and (2) have to use mutual authentication.
The Network Configuration Access Control Model (NACM) [RFC8341]
provides the means to restrict access for particular NETCONF or
RESTCONF users to a preconfigured subset of all available NETCONF or
RESTCONF protocol operations and content.
There are a number of data nodes defined in this YANG module that are
writable/creatable/deletable (i.e., "config true", which is the
default). All writable data nodes are likely to be reasonably
sensitive or vulnerable in some network environments. Write
operations (e.g., edit-config) and delete operations to these data
nodes without proper protection or authentication can have a negative
effect on network operations. The following subtrees and data nodes
have particular sensitivities/vulnerabilities:
* /sn:subscriptions/iypn:enable-notification-envelope
Changing 'enable-notification-envelope' terminates all existing
Dynamic and Configured Subscriptions on the Server (Section 4) and
changes the format of all Notifications sent to the Receivers
(Section 6). An attacker with write access to this node can
therefore interrupt all YANG-Push data collection from the network
node, and can cause Receivers that do not support the new format to
discard or misinterpret the Notifications. Access control MUST be
set so that only someone with proper access permissions has the
ability to access and modify this resource.
Some of the readable data nodes in this YANG module may be considered
sensitive or vulnerable in some network environments. It is thus
important to control read access (e.g., via get, get-config, or
Notification) to these data nodes. Specifically, the following
subtrees and data nodes have particular sensitivities/
vulnerabilities:
* /iypn:envelope/hostname
The entries in the list above will show the identity of the
originating device. Exposure of this information may assist an
attacker in mapping the network or in injecting spoofed
Notifications. Implementations SHOULD ensure that access to this
data is restricted and that Notifications are sent over secure and
authenticated channels.
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10. IANA Considerations
This document registers two URIs in the IETF XML Registry, two YANG
modules in the "YANG Module Names" registry, and a SID range in the
"IETF YANG-SID Ranges" registry.
10.1. URI
IANA is requested to register the following URIs in the "ns" registry
within the "IETF XML Registry" group [RFC3688]:
URI: urn:ietf:params:xml:ns:yang:ietf-yp-notification
Registrant Contact: The IESG
XML: N/A; the requested URI is an XML namespace.
Reference: RFC XXXX
URI: urn:ietf:params:xml:ns:yang:ietf-yp-observation
Registrant Contact: The IESG
XML: N/A; the requested URI is an XML namespace.
Reference: RFC XXXX
10.2. YANG module name
This document registers the following YANG modules in the YANG Module
Names Registry [RFC6020], within the "YANG Parameters" registry:
name: ietf-yp-notification
maintained by IANA? N
namespace: urn:ietf:params:xml:ns:yang:ietf-yp-notification
prefix: iypn
reference: RFC XXXX
name: ietf-yp-observation
maintained by IANA? N
namespace: urn:ietf:params:xml:ns:yang:ietf-yp-observation
prefix: iypo
reference: RFC XXXX
10.3. YANG SID-file
IANA is requested to allocate a SID range in the "IETF YANG-SID
Ranges" registry [RFC9595] for the 'ietf-yp-notification' module:
SID range entry point: TBD
SID range size: 50
YANG module name: ietf-yp-notification
reference: RFC XXXX
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A ".sid" file is proposed in Appendix A.
Note to the RFC-Editor:
Please replace TBD with the value allocated by IANA.
11. Acknowledgements
The authors would like to thank Paul Aitken, Per Anderson, Andy
Bierman, Carsten Bormann, Mohamed Boucadair, Tom Petch, Reshad
Rahman, Jürgen Schönwälder, Jason Sterne, Kent Watsen, Rob Wilton,
Qin Wu, Leonardo Rodoni, Ebben Aries and Mahesh Jethanandani for
their review and valuable comments.
12. References
12.1. Normative References
[I-D.ietf-netconf-distributed-notif]
Zhou, T., Zheng, G., Voit, E., Graf, T., and P. Francois,
"Subscription to Notifications in a Distributed
Architecture", Work in Progress, Internet-Draft, draft-
ietf-netconf-distributed-notif-23, 4 October 2026,
<https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
distributed-notif-23>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC5277] Chisholm, S. and H. Trevino, "NETCONF Event
Notifications", RFC 5277, DOI 10.17487/RFC5277, July 2008,
<https://www.rfc-editor.org/info/rfc5277>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
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[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
[RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG",
RFC 7951, DOI 10.17487/RFC7951, August 2016,
<https://www.rfc-editor.org/info/rfc7951>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.
[RFC8639] Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard,
E., and A. Tripathy, "Subscription to YANG Notifications",
RFC 8639, DOI 10.17487/RFC8639, September 2019,
<https://www.rfc-editor.org/info/rfc8639>.
[RFC8641] Clemm, A. and E. Voit, "Subscription to YANG Notifications
for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641,
September 2019, <https://www.rfc-editor.org/info/rfc8641>.
[RFC8791] Bierman, A., Björklund, M., and K. Watsen, "YANG Data
Structure Extensions", RFC 8791, DOI 10.17487/RFC8791,
June 2020, <https://www.rfc-editor.org/info/rfc8791>.
[RFC9196] Lengyel, B., Clemm, A., and B. Claise, "YANG Modules
Describing Capabilities for Systems and Datastore Update
Notifications", RFC 9196, DOI 10.17487/RFC9196, February
2022, <https://www.rfc-editor.org/info/rfc9196>.
[RFC9254] Veillette, M., Ed., Petrov, I., Ed., Pelov, A., Bormann,
C., and M. Richardson, "Encoding of Data Modeled with YANG
in the Concise Binary Object Representation (CBOR)",
RFC 9254, DOI 10.17487/RFC9254, July 2022,
<https://www.rfc-editor.org/info/rfc9254>.
[RFC9911] Schönwälder, J., Ed., "Common YANG Data Types", RFC 9911,
DOI 10.17487/RFC9911, December 2025,
<https://www.rfc-editor.org/info/rfc9911>.
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[W3C.REC-xml-20001006]
Bray, T., Paoli, J., Sperberg-McQueen, M., and E. Maler,
"Extensible Markup Language (XML) 1.0 (Second Edition)",
W3C, October 2000,
<https://www.w3.org/TR/2000/REC-xml-20001006>.
12.2. Informative References
[I-D.ietf-netconf-udp-notif]
Feng, A. H., Francois, P., Zhou, T., Graf, T., and P.
Lucente, "UDP-based Transport for Configured
Subscriptions", Work in Progress, Internet-Draft, draft-
ietf-netconf-udp-notif-26, 29 July 2026,
<https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
udp-notif-26>.
[RFC4252] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252,
January 2006, <https://www.rfc-editor.org/info/rfc4252>.
[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", STD 90, RFC 8259,
DOI 10.17487/RFC8259, December 2017,
<https://www.rfc-editor.org/info/rfc8259>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>.
[RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", RFC 9000,
DOI 10.17487/RFC9000, May 2021,
<https://www.rfc-editor.org/info/rfc9000>.
[RFC9232] Song, H., Qin, F., Martinez-Julia, P., Ciavaglia, L., and
A. Wang, "Network Telemetry Framework", RFC 9232,
DOI 10.17487/RFC9232, May 2022,
<https://www.rfc-editor.org/info/rfc9232>.
[RFC9595] Veillette, M., Ed., Pelov, A., Ed., Petrov, I., Ed.,
Bormann, C., and M. Richardson, "YANG Schema Item
iDentifier (YANG SID)", RFC 9595, DOI 10.17487/RFC9595,
July 2024, <https://www.rfc-editor.org/info/rfc9595>.
[RFC9846] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 9846, DOI 10.17487/RFC9846, July 2026,
<https://www.rfc-editor.org/info/rfc9846>.
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[RFC9907] Bierman, A., Boucadair, M., Ed., and Q. Wu, "Guidelines
for Authors and Reviewers of Documents Containing YANG
Data Models", BCP 216, RFC 9907, DOI 10.17487/RFC9907,
March 2026, <https://www.rfc-editor.org/info/rfc9907>.
Appendix A. .sid file
This appendix is not normative. For CBOR encoding using YANG-SIDs
identifiers, a ".sid" file is requested to IANA in Section 10.3.
The .sid file can be found in TBD2.
Note to the RFC-Editor:
1. Please replace the entry-point and SID values with the ones
allocated by IANA.
2. Please change the 'sid-file-status' to 'published' once the .sid
file is published.
3. Please remove the .sid file from the document and insert a link
in TBD2 to the .sid file reference from IANA.
<CODE BEGINS> file "ietf-yp-notification@2026-09-25.sid"
=============== NOTE: '\' line wrapping per RFC 8792 ================
{
"ietf-sid-file:sid-file": {
"module-name": "ietf-yp-notification",
"module-revision": "2026-09-25",
"sid-file-status":"unpublished",
"description": "draft-ietf-netconf-notif-envelope-07: \
Extensible YANG Model for YANG-Push Notifications",
"dependency-revision": [
{
"module-name": "ietf-yang-types",
"module-revision": "2025-12-22"
},
{
"module-name": "ietf-inet-types",
"module-revision": "2025-12-22"
},
{
"module-name": "ietf-subscribed-notifications",
"module-revision": "2019-09-09"
},
{
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"module-name": "ietf-system-capabilities",
"module-revision": "2022-02-17"
},
{
"module-name": "ietf-notification-capabilities",
"module-revision": "2022-02-17"
},
{
"module-name": "ietf-yang-structure-ext",
"module-revision": "2020-06-17"
}
],
"assignment-range": [
{
"entry-point": "2950",
"size": "50"
}
],
"item": [
{
"status":"unstable",
"namespace":"module",
"identifier":"ietf-yp-notification",
"sid":"2950"
},
{
"status":"unstable",
"namespace":"feature",
"identifier":"hostname-sequence-number",
"sid":"2951"
},
{
"status":"unstable",
"namespace":"data",
"identifier":"/ietf-subscribed-notifications:subscriptions/\
ietf-yp-notification:enable-notification-envelope",
"sid":"2952"
},
{
"status":"unstable",
"namespace":"data",
"identifier":"/ietf-subscribed-notifications:subscriptions/\
ietf-yp-notification:metadata",
"sid":"2953"
},
{
"status":"unstable",
"namespace":"data",
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"identifier":"/ietf-system-capabilities:system-capabilities/\
ietf-notification-capabilities:\
subscription-capabilities/ietf-yp-notification:\
notification-metadata",
"sid":"2954"
},
{
"status":"unstable",
"namespace":"data",
"identifier":"/ietf-system-capabilities:system-capabilities/\
ietf-notification-capabilities:\
subscription-capabilities/ietf-yp-notification:\
notification-metadata/envelope",
"sid":"2955"
},
{
"status":"unstable",
"namespace":"data",
"identifier":"/ietf-system-capabilities:system-capabilities/\
ietf-notification-capabilities:\
subscription-capabilities/ietf-yp-notification:\
notification-metadata/metadata",
"sid":"2956"
},
{
"status":"unstable",
"namespace":"data",
"identifier":"/ietf-system-capabilities:system-capabilities/\
ietf-notification-capabilities:\
subscription-capabilities/ietf-yp-notification:\
notification-metadata/metadata/hostname-sequence-number",
"sid":"2957"
},
{
"status":"unstable",
"namespace":"data",
"identifier":"/ietf-yp-notification:envelope",
"sid":"2958"
},
{
"status":"unstable",
"namespace":"data",
"identifier":"/ietf-yp-notification:envelope/contents",
"sid":"2959"
},
{
"status":"unstable",
"namespace":"data",
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"identifier":"/ietf-yp-notification:envelope/event-time",
"sid":"2960"
},
{
"status":"unstable",
"namespace":"data",
"identifier":"/ietf-yp-notification:envelope/hostname",
"sid":"2961"
},
{
"status":"unstable",
"namespace":"data",
"identifier":"/ietf-yp-notification:envelope/\
sequence-number",
"sid":"2962"
},
{
"status":"unstable",
"namespace":"identity",
"identifier":"notification-envelope-changed",
"sid":"2963"
}
]
}
}
<CODE ENDS>
Figure 11: ietf-yp-notification .sid file
Appendix B. Example extending the Notification Envelope
This appendix provides a non-normative example illustrating how an
extension to the Notification Envelope should be implemented. The
example does not define valid metadata, but serves to demonstrate how
future extensions should be specified.
Specifically, the example extends the Notification Envelope with a
metadata field named "foo". The YANG module illustrates the
necessary augmentations to both the 'ietf-yp-notification' module and
the 'ietf-notification-capabilities' module.
<CODE BEGINS> file "example-foo-extension.yang"
module example-foo-extension {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:example-foo-extension";
prefix fooext;
import ietf-subscribed-notifications {
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prefix sn;
}
import ietf-system-capabilities {
prefix sysc;
}
import ietf-notification-capabilities {
prefix notc;
}
import ietf-yang-structure-ext {
prefix sx;
}
import ietf-yp-notification {
prefix iypn;
}
description
"Defines a new 'foo' metadata for the notification envelope.";
// Extending the notification envelope header with a new
// 'foo' metadata
sx:augment-structure "/iypn:envelope" {
leaf foo {
type string;
description
"Description of the 'foo' extension.";
}
}
// Extending the notifications capabilities so that clients can
// learn whether this new extension is supported or not
augment "/sysc:system-capabilities"
+ "/notc:subscription-capabilities"
+ "/iypn:notification-metadata/iypn:metadata" {
description
"Extension to the subscription-capabilities model to enable
clients to learn whether the publisher supports the new
'foo' metadata.";
leaf foo {
type boolean;
default "false";
description
"Adds the 'foo' capability.";
}
}
// (Optional) A user can optionally add knobs for enabling and
// disabling specific metadata.
augment "/sn:subscriptions/iypn:metadata" {
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description
"A user can optionally support a configuration knob for
enabling or disabling a metadata.";
leaf foo {
type boolean;
default "false";
description
"Configuration knob for enabling and disabling the 'foo'
metadata.";
}
}
}
<CODE ENDS>
The extensions result in the following YANG tree:
module: example-foo-extension
augment /sysc:system-capabilities/notc:subscription-capabilities
/iypn:notification-metadata/iypn:metadata:
+--ro foo? boolean
augment /sn:subscriptions/iypn:metadata:
+--rw foo? boolean
augment-structure /iypn:envelope:
+-- foo? string
Authors' Addresses
Alex Huang Feng
Deutsche Telekom
Barcelona
Spain
Email: alex.huang-feng@t-systems.com
Pierre Francois
INSA-Lyon
Lyon
France
Email: pierre.francois@insa-lyon.fr
Thomas Graf
Swisscom
Binzring 17
CH-8045 Zurich
Switzerland
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Email: thomas.graf@swisscom.com
Benoit Claise
Everything OPS & Arrcus
Email: benoit@everything-ops.net
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