Extensible YANG Model for YANG-Push Notifications

YANG-Push 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 , is currently based on the XML model from NETCONF Event Notifications . 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 or CBOR , 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 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.
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 these extensions globally at the Server, making the coexistence of different YANG-Push and NETCONF Event Notification possible.

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 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 . The term "Client" and "Server" is used as defined in for NETCONF and for RESTCONF. The terms "Implementation-time Information" and "Runtime Information" are used as defined in . 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.

This section shows the relationship to , , and .

defines a mechanism for NETCONF Servers to send Notifications to collectors. These are the key relationships between the current document and :

This document does not change the header defined by nor update any behavior defined in . Implementations of use the header defined in Section 2.2.1 of .
The co-existence of the Notification model defined in and the model defined in the current document is possible. The co-existence is discussed in .

Subscribed Notifications defines a mechanism on top of to stream Notifications from the Server. These are the key relationships between the current document and :

states that the solution uses the Notification header defined in . This document proposes a new header, which Clients can enable to replace the header defined in for YANG-defined event records. When this new header is used, YANG-defined Notifications sent via Subscribed Notifications are encoded as defined in . Servers MUST continue using the header for NETCONF event streams.
and of defines how a Dynamic Subscription and Configured Subscriptions are managed. This document extends the Subscribed Notifications configuration to support enabling the new header defined in this document.

defines how YANG data is encoded in XML. These are the key relationship points between the current document and :

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 .

defines how YANG data is encoded using JSON. These are the key relationship points between the current document and :

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 .

defines how YANG data is encoded using CBOR. These are the key relationship points between the current document and :

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 in this document.

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 , the Notification header is based on the model defined in which contains a single metadata 'eventTime' leaf. An example extracted from is shown in the following XML: 2007-09-01T10:00:00Z

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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 environments and can be implemented with NETCONF and RESTCONF . When enabled, this new header MUST replace all Notifications defined in both Subscribed Notifications and YANG-Push for the entire Server, for both Configured and Dynamic Subscriptions. The remainder of this section is structured as follows. defines the Notification Envelope and how this structure is encoded using XML, JSON, and CBOR. and defines the first Notification extensions to both the Notification Envelope and the YANG-Push header. The Notification Envelope and extensions are enabled through the mechanism defined in . Clients can discover the support of this header and extensions for both implementation-time and runtime through the discovery mechanism defined in .

This section defines the structure of the Notification Envelope. The following sections define how this structure is encoded in XML, JSON and CBOR.

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 illustrates the Notification Envelope supporting only the mandatory metadata 'event-time'. Refer to for more extensions to this header. ]]>

The YANG Notification can be encoded using XML , JSON and CBOR .

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': 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 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 encoded in XML:

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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 . 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 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 encoded in JSON:

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 . 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 . 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 . A SID allocation process is needed beforehand as defined in . 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 . The .sid file includes the metadata defined in . 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 . shows a 'push-update' Notification defined in the YANG module of YANG-Push encoded in CBOR using names as keys. The example uses the CBOR diagnostic notation as defined in :

shows the same Notification encoded using SIDs:

Note to the RFC-Editor: Please change the SID values from the example with the ones allocated by IANA. Note that in the example shown in , 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 . 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 for more details.

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 . The Notification Envelope, including the metadata, results in the following YANG tree . ]]>

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 or among different YANG-Push Subscription types as defined in , 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. In other terms, the 'source-host' , which is the "Address of the remote host for the session" might not be the management IP address. 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 unique sequence number for each published message by the Publisher process. 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.

provides an example of a JSON encoded, , 'push-update' Notification message with 'hostname' and 'sequence-number' included.

This section described two optional 'push-update' and 'push-change-update' Notification header extensions which are enabled by default when using the Notification Envelope defined in this document. The Client discovers the support of these two leafs with the mechanism defined in . This document defines the following Notification metadata as shown in the following YANG tree . See the following sections for more details.

To correlate network data among different Network Telemetry planes, as described in , or among different YANG-Push Subscription types, as defined in , 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 . However, as the 'event-time' node only establishes the moment when the YANG-Push message was crafted and sent, 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 NETCONF Notification message header 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 . 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 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 , 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 for the 'push-change-update' Notification in 'on-change' Subscriptions. 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. In case of an 'on-change' Subscription it states the time when the network state change was observed.
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 the initial point in time when the Subscription was established and the state was observed for 'on-change sync on start' Subscriptions. 'state-changed' states the point in time when the state change was observed after the Subscription was established for 'on-change' and 'on-change sync on start' Subscriptions.

This section illustrates the usage of the 'point-in-time' node in two different Subscriptions. showcases a YANG-Push Subscription monitoring the state of an interface using an 'on-change sync on start' Subscription. illustrates the usage of the 'point-in-time' node within periodic Subscriptions.

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 supporting 'sync on start', 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.

After T3, the Publisher triggers a 'push-change-update' Notification announcing an interface status change to the Receiver as depicted in . 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.

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. 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).

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-notification' model to support the configuration of the Notification Envelope. When the node 'enable-notification-envelope' is enabled, all the Notifications defined in Subscribed Notification and YANG-Push are encoded as defined in . 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 . Both extensions defined in and are sent by default when (1) they are supported and (2) the node 'enable-notification-envelope' is enabled. 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 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 when enabled and as defined in if disabled. 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 for an example. Per the YANG specifications (), which does not allow making mandatory statements on augmentations, the 'enable-notification-envelope' YANG leaf must be made optional: the metadata fields 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 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.

A Client can discover the support of the Notification Envelope model through the capabilities model defined in . 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. Extensions are defined in and .

When the leafs defined in this document are supported by the Server, the Client discovers the presence of new metadata with the following augmentations in the 'ietf-notification-capabilities' module:

As stated in , the Notification Envelope defined in this document replaces the header defined by NETCONF Event Notifications when enabled. The NETCONF Event Notifications 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.

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.

This YANG module extends 'ietf-subscribed-notifications' and 'ietf-notification-capabilities' as shown in the following YANG tree : ]]>

The YANG module augments the module 'ietf-subscribed-notifications' , augments the module "ietf-notification-capabilities" and uses 'ietf-yang-types' module and 'ietf-yang-structure-ext' module . WG List: Authors: Alex Huang Feng Pierre Francois Thomas Graf Benoit Claise "; 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 RFCXXX. 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) 2025 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. 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 2025-12-24 { 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."; } grouping notif-env-capabilities { description "This grouping defines the capabilities for the notification-envelope defined in RFC XXXX and the different supported metadata."; leaf envelope { type boolean; default "true"; description "Supports YANG-Push to use the notification-envelope as defined in RFC XXXX. 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 as defined in the YANG-Push notification-envelope in RFC XXXX. 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 { leaf event-time { type yang:date-and-time; mandatory true; description "The date and time the event was generated by the network node."; } 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 the node in the network uniquely."; } leaf sequence-number { if-feature "hostname-sequence-number"; type yang:counter32; description "Unique sequence number for each published message by the publisher process. 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."; } anydata contents { 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 defined in RFC XXXX. Enabling or disabling this leaf terminates all existing active dynamic and configured YANG-Push subscriptions. The publisher MUST send a 'subscription-terminated' notification to all the existing active subscriptions using the header configured before the change, then the subscription is terminated. Refer to Section 4 of RFC XXXX for more details."; } container metadata { description "Container for configuring optional metadata. Refer to Section 4 of RFC XXXX for more details."; } } // 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; } } } ]]>

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.

This YANG module extends 'ietf-yang-push' and 'ietf-notification-capabilities' as shown in the following YANG tree :

The YANG module augments the module 'ietf-yang-push' , augments the module 'ietf-system-capabilities' . WG List: Authors: Thomas Graf Benoit Claise Alex Huang Feng "; description "Defines YANG-Push event notification header with the observation time in streaming update notifications. Copyright (c) 2025 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 2025-12-24 { 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."; leaf timestamp { type yang:date-and-time; description "This is the time when the metrics were observed."; } 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 { description "For 'on-change sync on start' subscriptions, the initial point in time when the subscription was established and the state was observed."; } enum state-changed { description "For 'on-change sync on start' 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 iypo: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 iypo: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, publisher supports. If set to false, the observation-timestamp is not supported."; reference "RFC XXXX: Extensible YANG Model for YANG-Push Notifications"; } } } ]]>

Note to the RFC-Editor: Please remove this section before publishing.

Huawei implemented in push-update and push-change-update Notifications the timestamp and point-in-time extension as described in for a YANG-Push Publisher on UDP-based Transport for Configured Subscriptions in their VRP platform.

6WIND implemented in push-update and push-change-update Notifications the timestamp and point-in-time extension as described in for a YANG-Push Publisher on UDP-based Transport for Configured Subscriptions in their VSR platform.

Cisco implemented in push-update and push-change-update Notifications the timestamp and point-in-time extension as described in for a YANG-Push Publisher on UDP-based Transport for Configured Subscriptions in their IOS XR platform.

This section uses the template described in . 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 and RESTCONF . These YANG-based management protocols (1) have to use a secure transport layer (e.g., SSH , TLS , and QUIC ) and (2) have to use mutual authentication. The Network Configuration Access Control Model (NACM) 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

The entries in the list above will show whether the mechanism defined in this document is enabled. 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.

This document describes the URI used for the IETF XML Registry and registers a new YANG module name.

IANA is requested to add this document as a reference in the following URI's in the IETF XML Registry.

This document registers the following YANG modules in the YANG Module Names Registry, within the "YANG Parameters" registry:

IANA is requested to register a new ".sid" file in the "IETF YANG SID Registry": A ".sid" file is proposed in . Note to the RFC-Editor: Please replace TBD with the value allocated by IANA.

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 and Qin Wu for their review and valuable comments.

Extensible Markup Language (XML) 1.0 (Second Edition) W3C

This appendix is not normative. For CBOR encoding using YANG-SIDs identifiers, a ".sid" file is requested to IANA in . 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.

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. The extensions result in the following YANG tree: