Internet DRAFT - draft-claise-opsawg-collected-data-manifest
draft-claise-opsawg-collected-data-manifest
OPSAWG B. Claise
Internet-Draft J. Quilbeuf
Intended status: Standards Track Huawei
Expires: 11 September 2023 D. Lopez
I. Dominguez
Telefonica I+D
T. Graf
Swisscom
10 March 2023
A Data Manifest for Contextualized Telemetry Data
draft-claise-opsawg-collected-data-manifest-06
Abstract
Network elements use Model-driven Telemetry, and in particular YANG-
Push, to continuously stream information, including both counters and
state information. This document documents the metadata that ensure
that the collected data can be interpreted correctly. This document
specifies the Data Manifest, composed of two YANG data models (the
Platform Manifest and the Data Collection Manifest.) The Data
Manifest must be streamed and stored along with the data, up to the
collection and analytics system in order to keep the collected data
fully exploitable by the data scientists.
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 11 September 2023.
Copyright Notice
Copyright (c) 2023 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 . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.1. Network Analytics . . . . . . . . . . . . . . . . . . 4
1.1.2. New Device Onboarding . . . . . . . . . . . . . . . . 5
1.1.3. Data Mesh Principles in Networking . . . . . . . . . 5
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
3. Platform Manifest . . . . . . . . . . . . . . . . . . . . . . 6
3.1. Overview of the Model . . . . . . . . . . . . . . . . . . 6
3.2. YANG module ietf-platform-manifest . . . . . . . . . . . 8
4. Data Collection Manifest . . . . . . . . . . . . . . . . . . 14
4.1. Overview of the Model . . . . . . . . . . . . . . . . . . 14
4.2. YANG module ietf-data-collection-manifest . . . . . . . . 16
5. Data Manifest and the Collected Data . . . . . . . . . . . . 23
5.1. Collecting the Data Manifest . . . . . . . . . . . . . . 23
5.2. Mapping Collected Data to the Data Manifest . . . . . . . 24
5.3. Operational Considerations . . . . . . . . . . . . . . . 24
6. Security Considerations . . . . . . . . . . . . . . . . . . . 25
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 25
9. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 25
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
10.1. Normative References . . . . . . . . . . . . . . . . . . 26
10.2. Informative References . . . . . . . . . . . . . . . . . 26
Appendix A. Example of use based on MDT . . . . . . . . . . . . 27
Appendix B. Changes between revisions . . . . . . . . . . . . . 29
Appendix C. YANG module ietf-yang-push-modif . . . . . . . . . . 31
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 48
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 48
1. Introduction
Network elements use Model-driven Telemetry (MDT), and in particular
YANG-Push [RFC8641], to continuously stream information, including
both counters and state information.
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This document specifies what needs to be kept as metadata (i.e., the
Data Manifest) to ensure that the collected data can still be
interpreted correctly throughout the collection and network analytics
toolchain. When streaming YANG-structured data with YANG-Push
[RFC8641], there is a semantic definition in the corresponding YANG
module definition. This is the semantic information for the
collected objects: While this semantic is absolutely required to
correctly decode and interpret the data, understanding the network
element and collection environment contexts information is equally
important to interpret the data.
This document proposes the Data Manifest, which is composed of two
YANG data models, namely, the Platform Manifest and the Data
Collection Manifest, in order to keep the collected data exploitable
by the data scientists.
The Platform Manifest contains information characterizing the
platform streaming the telemetry information, while the the Data
Collection Manifest contains the required information to characterize
how and when the telemetry information was metered.
The two proposed YANG modules in the Data Manifest do not expose many
new information but rather define what should be exposed by a
platform streaming telemetry. Some related YANG modules have been
specified to retrieve the platform capabilities:
* The IETF YANG Library [RFC8525].
* YANG Modules Describing Capabilities for Systems and Datastore
Update Notifications [RFC9196] for the platform capabilities
regarding the production and export of telemetry data.
* [I-D.claise-netconf-metadata-for-collection], which is based on
the previous draft to define the optimal settings to stream
specific items (i.e., per path).
These related YANG modules are important to discover the capabilities
before applying the telemetry configuration (such as on-change).
Some of their content is part of the context for the streamed data.
We first present the module for the Platform Manifest in Section 3
and then the module for the Data Collection Manifest in Section 4.
The full Data Manifest is obtained by combining these two modules.
We explain in Section 5 how the Data Manifest can be retrieved and
how collected data is mapped to the Data Manifest.
1.1. Use Cases
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1.1.1. Network Analytics
Streamed information from network elements is used for network
analytics, incident detections, and in the end closed-loop
automation. This streamed data can be stored in a database
(sometimes called a big data lake) for further analysis.
As an example, a database could store a time series representing the
evolution of a specific counter collected from a network element.
When analyzing the data, the network operator/data scientist must
understand the context information for these data:
* This object definition in the YANG model.
* The network element specific vendor, platform, and OS.
* The collection parameters.
Characterizing the source used for producing the data (vendor,
platform, and OS) is useful to complement the data. As an example,
knowing the exact data source software specification might reveal a
particularity in the observed data, explained by a specific bug, a
specific bug fix, or simply a particular specific behavior. This is
also necessary to ensure the reliability of the collected data. On
top of that, in particular for YANG-Push [RFC8641], it is crucial to
know the set of YANG modules supported by the platform, along with
their deviations. In some cases, there might even be some backwards
incompatible changes in native modules between one OS version to the
next one. This information is captured by the proposed Platform
Manifest.
From a collection parameters point of view, the data scientists
analyzing the collected data must know that the counter was requested
from the network element as on-change or at specific cadence.
Indeed, an on-change collection explains why there is a single value
as opposed to a time series. In case of periodic collection, this
exact cadence might not be observable in the time series. Indeed,
this time series might report some values as 0 or might even omit
some values. The reason for this behavior might be diverse: the
network element was under stress, with a too small observation
period, compared to the minimum-observed-period
[I-D.claise-netconf-metadata-for-collection]. Again, knowing the
conditions under which the counter was collected and streamed (along
with the platform details) help drawing the right conclusions. As an
example, taking into account the value of 0 might lead to a wrong
conclusion that the counter dropped to zero. This document specifies
the Data Collection Manifest, which contains the required information
to characterize how and when the telemetry information was metered.
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The goal of the current document is to define what needs to be kept
as metadata (i.e., the Data Manifest) to ensure that the collected
data can still be interpreted correctly.
1.1.2. New Device Onboarding
When a new device is onboarded, operators must make sure that the new
device streams data with YANG-Push, that the telemetry data is the
right ones, and that the data is correctly ingested in the collection
system, and finally that the data can be analyzed (compared with
other similar devices). For the last point, the Data Manifiest,
which must be linked to the data up to the collection and analytics
system, contains all the relevant information.
1.1.3. Data Mesh Principles in Networking
The concept behind the data mesh https://www.datamesh-
architecture.com/ are:
* Principle of Domain Ownership: Architecturally and
organizationally align business, technology, and analytical data,
following the line of responsibility. Here, the Data Mesh
principles adopt the boundary of bounded context to individual
data products where each domain is responsible for (and owns) its
data and models.
* Principle of Data as a Product: The "Domain" owners are
responsible to provide the data in useful way (discoverable
through a catalog, addressable with a permanent and unique
address, understandable with well defined semantics, trustworthy
and truthful, self-describing for easy consumption, interoperable
by supporting standards, secure, self-contained, etc.) and should
treat consumers of that data as customers. It requires and relies
on the "Domain Ownership" principle.
* Principle of Self-serve Data Platform: This fosters the sharing of
cross-domain data in order to create extra value.
* Principle of Federated Computational Governance: Describes the
operating model and approach to establishing global policies
across a mesh of data products.
The most relevant concept for this document is the "Data as a
Product" principle. The Data Manifest fulfills this principle as the
two YANG data models, Platform Manifest and the Data Collection
Manifest, along with the data, provide all the necessary information
in a self-describing way for easy consumption.
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2. 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.
Data Manifest: all the necessary data required to interpret the
telemetry information.
Platform Manifest: part of the Data Manifest that completely
characterizes the platform producing the telemetry information
Data Collection Manifest: part of the Data Manifest that completely
characterizes how and when the telemetry information was metered.
3. Platform Manifest
3.1. Overview of the Model
Figure 1 contains the YANG tree diagram [RFC8340] of the ietf-
platform-manifest module.
module: ietf-platform-manifest
+--ro platforms
+--ro platform* [id]
+--ro id string
+--ro name? string
+--ro vendor? string
+--ro vendor-pen? uint32
+--ro software-version? string
+--ro software-flavor? string
+--ro os-version? string
+--ro os-type? string
+--ro yang-push-streams
| +--ro stream* [name]
| +--ro name string
| +--ro description? string
+--ro yang-library
+--ro module-set* [name]
| +--ro name string
| +--ro module* [name]
| | +--ro name yang:yang-identifier
| | +--ro revision? revision-identifier
| | +--ro namespace inet:uri
| | +--ro location* inet:uri
| | +--ro submodule* [name]
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| | | +--ro name yang:yang-identifier
| | | +--ro revision? revision-identifier
| | | +--ro location* inet:uri
| | | +--ro revision-label? rev:revision-label
| | +--ro feature* yang:yang-identifier
| | +--ro deviation* -> ../../module/name
| | +--ro revision-label? rev:revision-label
| +--ro import-only-module* [name revision]
| +--ro name yang:yang-identifier
| +--ro revision union
| +--ro namespace inet:uri
| +--ro location* inet:uri
| +--ro submodule* [name]
| | +--ro name yang:yang-identifier
| | +--ro revision? revision-identifier
| | +--ro location* inet:uri
| | +--ro revision-label? rev:revision-label
| +--ro revision-label? rev:revision-label
+--ro schema* [name]
| +--ro name string
| +--ro module-set*
| | -> ../../module-set/name
| +--ro deprecated-nodes-implemented? boolean
| +--ro obsolete-nodes-absent? boolean
+--ro datastore* [name]
+--ro name ds:datastore-ref
+--ro schema -> ../../schema/name
Figure 1: YANG tree diagram for ietf-platform-manifest module
The YANG module actually contains a list of Platform Manifests (in
'platforms/platform'), indexed by the identifier of the platform.
That identifier should be defined by the network manager so that each
platform has a unique id. As an example, the identifier could be the
'sysname' from the ietf-notification module presented in
[I-D.tgraf-netconf-notif-sequencing]. The scope of this module is
the scope of the data collection, i.e. a given network, therefore it
contains a collection of Platform Manifests, as opposed to the device
scope, which would contain a single Platform Manifest.
The Platform Manifest is identified by a set of parameters ('name',
'software-version', 'software-flavor', 'os-version', 'os-type') that
are aligned with the YANG Catalog www.yangcatalog.org
[I-D.clacla-netmod-model-catalog] so that the YANG Catalog could be
used to retrieve the YANG modules a posteriori. The vendor of the
platform can be identified via its name 'vendor' or its PEN number
'vendor-pen', as described in [RFC9371].
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In order to provide information for yang-push subscriptions based on
streams, the Platform Manifest specifies the streams available on the
platform within the 'yang-push-streams' container. That container is
similar to the one from the ietf-subscribed-notifications module, and
the Data Collection Manifest uses it to refer to streams used by
subscriptions.
The Platform Manifest also includes the contents of the YANG Library
[RFC8525]. That module set is particularly useful to define the
paths, as they are based on module names. Similarly, this module
defines the available datastores, which can be referred to from the
Data Manifest, if necessary. If supported by the platform, fetching
metrics from a specific datastore could enable some specific use
cases: monitoring configuration before it is committed, comparing
between the configuration and operational datastore.
3.2. YANG module ietf-platform-manifest
<CODE BEGINS> file "ietf-platform-manifest@2023-03-08.yang"
module ietf-platform-manifest {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-platform-manifest";
prefix p-mf;
import ietf-yang-library {
prefix yanglib;
reference
"RFC8525: YANG Library";
}
import ietf-yang-revisions {
prefix rev;
reference
"XXXX: Updated YANG Module Revision Handling";
}
organization
"IETF OPSAWG (Network Configuration) Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/opsawg/>
WG List: <mailto:opsawg@ietf.org>
Author: Benoit Claise <mailto:benoit.claise@huawei.com>
Author: Jean Quilbeuf <mailto:jean.quilbeuf@huawei.com>
Author: Diego R. Lopez <diego.r.lopez@telefonica.com>
Author: Ignacio Dominguez
<ignacio.dominguezmartinez@telefonica.com>
Author: Thomas Grapf <thomas.graf@swisscom.com>";
description
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"This module describes the platform information to be used as
context of data collection from a given network element. The
contents of this model must be streamed along with the data
streamed from the network element so that the platform context
of the data collection can be retrieved later.
The data content of this model should not change except on
upgrade or patching of the device.
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.
Copyright (c) 2022 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).
This version of this YANG module is part of RFC XXXX; see the
RFC itself for full legal notices. ";
revision 2023-03-08 {
description
"Initial revision";
reference
"RFC xxxx: Title to be completed";
}
// This is a copy-paste of the augments from the module
// ietf-yang-library-revisions.
// We just changed the path to which the data is added
augment "/p-mf:platforms/p-mf:platform/p-mf:yang-library"
+ "/p-mf:module-set/p-mf:module" {
description
"Add a revision label to module information";
leaf revision-label {
type rev:revision-label;
description
"The revision label associated with this module revision.
The label MUST match the rev:revision-label value in the
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specific revision of the module loaded in this module-set.";
reference
"XXXX: Updated YANG Module Revision Handling;
Section 5.2.1, Advertising revision-label";
}
}
augment "/p-mf:platforms/p-mf:platform/p-mf:yang-library/"
+ "p-mf:module-set/p-mf:module/p-mf:submodule" {
description
"Add a revision label to submodule information";
leaf revision-label {
type rev:revision-label;
description
"The revision label associated with this submodule revision.
The label MUST match the rev:revision-label value in the
specific revision of the submodule included by the module
loaded in this module-set.";
reference
"XXXX: Updated YANG Module Revision Handling;
Section 5.2.1, Advertising revision-label";
}
}
augment
"/p-mf:platforms/p-mf:platform/p-mf:yang-library/p-mf:module-set/"
+ "p-mf:import-only-module" {
description
"Add a revision label to module information";
leaf revision-label {
type rev:revision-label;
description
"The revision label associated with this module revision.
The label MUST match the rev:revision-label value in the
specific revision of the module included in this module-set.";
reference
"XXXX: Updated YANG Module Revision Handling;
Section 5.2.1, Advertising revision-label";
}
}
augment
"/p-mf:platforms/p-mf:platform/p-mf:yang-library/p-mf:module-set/"
+ "p-mf:import-only-module/p-mf:submodule" {
description
"Add a revision label to submodule information";
leaf revision-label {
type rev:revision-label;
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description
"The revision label associated with this submodule revision.
The label MUST match the rev:label value in the specific
revision of the submodule included by the
import-only-module loaded in this module-set.";
reference
"XXXX: Updated YANG Module Revision Handling;
Section 5.2.1, Advertising revision-label";
}
}
augment "/p-mf:platforms/p-mf:platform/p-mf:yang-library"
+ "/p-mf:schema" {
description
"Augmentations to the ietf-yang-library module to indicate how
deprecated and obsoleted nodes are handled for each datastore
schema supported by the server.";
leaf deprecated-nodes-implemented {
type boolean;
description
"If set to true, this leaf indicates that all schema nodes with
a status 'deprecated' are implemented
equivalently as if they had status 'current'; otherwise
deviations MUST be used to explicitly remove deprecated
nodes from the schema. If this leaf is absent or set to false,
then the behavior is unspecified.";
reference
"XXXX: Updated YANG Module Revision Handling;
Section 5.2.2, Reporting how deprecated and obsolete nodes
are handled";
}
leaf obsolete-nodes-absent {
type boolean;
description
"If set to true, this leaf indicates that the server does not
implement any status 'obsolete' schema nodes. If this leaf is
absent or set to false, then the behaviour is unspecified.";
reference
"XXXX: Updated YANG Module Revision Handling;
Section 5.2.2, Reporting how deprecated and obsolete nodes
are handled";
}
}
container platforms {
config false;
description
"Top container including all platforms in scope. If this model is
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hosted on a single device, it should contain a single entry in
the list. At the network level, it should contain an entry for
every monitored platform.";
list platform {
key "id";
description
"Contains information about the platform that allows to identify
and understand the individual data collection information. ";
leaf id {
type string;
description
"Identifies a given platform on the network, for instance the
sysname of the plaftorm. The id has to be unique on the
network.";
}
leaf name {
type string;
description
"Model of the platform from which data is collected.";
}
leaf vendor {
type string;
description
"Organization that implements that platform.";
}
leaf vendor-pen {
type uint32;
description
"Vendor''s registered Private Enterprise Number as
described in RFC9371";
}
leaf software-version {
type string;
description
"Name of the version of software. With respect to most network
device appliances, this will be the operating system version.
But for other YANG module implementation, this would be a
version of appliance software. Ultimately, this should
correspond to a version string that will be recognizable by
the consumers of the platform.";
}
leaf software-flavor {
type string;
description
"A variation of a specific version where YANG model support
may be different. Depending on the vendor, this could be a
license, additional software component, or a feature set.";
}
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leaf os-version {
type string;
description
"Version of the operating system using this module. This is
primarily useful if the software implementing the module is
an application that requires a specific operating system
version.";
}
leaf os-type {
type string;
description
"Type of the operating system using this module. This is
primarily useful if the software implementing the module is
an application that requires a specific operating system
type.";
}
container yang-push-streams {
// copied from "streams" container of
// ietf-subscribed-notifications
config false;
description
"Contains information on the built-in event streams provided
by the platform.";
list stream {
key "name";
description
"Identifies the built-in event streams that are supported by
the publisher.";
leaf name {
type string;
description
"A handle for a system-provided event stream made up of a
sequential set of event records, each of which is
characterized by its own domain and semantics.";
}
leaf description {
type string;
description
"A description of the event stream, including such
information as the type of event records that are
available in this event stream.";
}
}
}
container yang-library {
description
"The YANG library of the device specifying the modules
available in each of the datastores.";
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uses yanglib:yang-library-parameters;
}
}
}
}
<CODE ENDS>
4. Data Collection Manifest
4.1. Overview of the Model
Figure 2 contains the YANG tree diagram [RFC8340] of the ietf-data-
collection-manifest module.
module: ietf-data-collection-manifest
+--ro data-collections
+--ro data-collection* [platform-id]
+--ro platform-id
| -> /p-mf:platforms/platform/id
+--ro yang-push-subscriptions
+--ro subscription* [id]
+--ro id
| sn:subscription-id
+--ro (target)
| +--:(stream)
| | +--ro stream leafref
| | +--ro (filter-spec)?
| | +--:(stream-subtree-filter)
| | | +--ro stream-subtree-filter? <anydata>
| | | {subtree}?
| | +--:(stream-xpath-filter)
| | +--ro stream-xpath-filter?
| | yang:xpath1.0 {xpath}?
| +--:(datastore)
| +--ro datastore leafref
| +--ro (datastore-filter-spec)?
| +--:(datastore-subtree-filter)
| | +--ro datastore-subtree-filter? <anydata>
| | {sn:subtree}?
| +--:(datastore-xpath-filter)
| +--ro datastore-xpath-filter?
| yang:xpath1.0 {sn:xpath}?
+--ro transport?
| sn:transport
+--ro encoding?
| sn:encoding
+--ro purpose? string
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+--ro dscp? inet:dscp
| {dscp}?
+--ro weighting? uint8
| {qos}?
+--ro dependency?
| subscription-id {qos}?
+--ro (update-trigger)?
| +--:(periodic)
| | +--ro periodic!
| | +--ro period centiseconds
| | +--ro anchor-time? yang:date-and-time
| +--:(on-change) {on-change}?
| +--ro on-change!
| +--ro dampening-period? centiseconds
+--ro current-period?
| yp:centiseconds
+--ro receivers
+--ro receiver* [name]
+--ro name string
+--ro sent-event-records?
| yang:zero-based-counter64
+--ro excluded-event-records?
| yang:zero-based-counter64
+--ro state enumeration
Figure 2: YANG tree diagram for ietf-data-collection-manifest module
The 'data-collections' container contains the information related to
each YANG-Push subscription. As for the Platform Manifest, these
subscriptions are indexed by the platform id, so that all
subscriptions in the network can be represented in the module.
The YANG-Push collection is organized in subscriptions, the
parameters for such a subscription are specified in [RFC8639] and
[RFC8641]. The list of subscription from a given platform is stored
in '/data-collection/data-collection/yang-push-subscriptions/
subscription'. Subscription metadata are the bulk of the Data
Collection Manifest, they are heavily based on the two RFCs above.
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The 'target' choice specify the selected contents for the
subscription. We did not include the target with a reference to a
common filter as stored in 'filters' in ietf-subscribed-notfications.
The rationale for this choice is that otherwise we would need to
store these filters in the Platform Manifest, which could cause
changes in that manifest more often than needed. If a stream based
subscription is used [RFC8639], the stream must exist in the 'yang-
push-streams' container of Platform Manifest, which is modelled as a
leafref in our module. If a datastore based subscription is used
[RFC8641], the datastore must exist in the 'yang-library' container
of the Platform Manifest, which is modelled by a leafref as well.
We also included 'transport', 'encoding' and 'purpose' as in ietf-
subscribed-notification, but without the feature switches as we are
not concerned about using this module for configuration.
We also included the 'dscp', 'weighting' and 'dependency' as in ietf-
subscribed-notification, again without the feature switches. This
information might be useful to understand why the collection is
failing or less frequent than expected for a given subscription.
The 'update-trigger' choice from ietf-yang-push is included as well,
as it is crucial to understand the frequency at which notifications
should arrive.
The only new content is the 'current-period', which might differ from
the requested period (when in periodic collection mode) if the
platform implements a mechanism to increase the collection period
when it is overloaded.
Finally, we also included the state of the receivers for that
subscription, as in ietf-subscribed-notifications.
This information is crucial to understand the collected values. For
instance, the 'on-change' trigger, if used, might remove a lot of
messages from the database because values are sent only when there is
a change.
4.2. YANG module ietf-data-collection-manifest
<CODE BEGINS> file "ietf-data-collection-manifest@2023-03-08.yang"
module ietf-data-collection-manifest {
yang-version 1.1;
namespace
"urn:ietf:params:xml:ns:yang:ietf-data-collection-manifest";
prefix d-mf;
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import ietf-platform-manifest {
prefix p-mf;
reference
"RFC XXXX: Title to be completed";
}
import ietf-subscribed-notifications {
prefix sn;
reference
"RFC 8639: A YANG Data Model for Subscriptions to
Event Notifications";
}
import ietf-yang-push-modif {
prefix yp;
reference
"RFC 8641: Subscriptions to YANG Datastores. TODO fix and
used original version. This import is a modified version so that
it compiles.";
}
import ietf-yang-types {
prefix yang;
reference
"RFC 6991: Common YANG Data Types";
}
organization
"IETF OPSAWG (Network Configuration) Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/opsawg/>
WG List: <mailto:opsawg@ietf.org>
Author: Benoit Claise <mailto:benoit.claise@huawei.com>
Author: Jean Quilbeuf <mailto:jean.quilbeuf@huawei.com>
Author: Diego R. Lopez <diego.r.lopez@telefonica.com>
Author: Ignacio Dominguez
<ignacio.dominguezmartinez@telefonica.com>
Author: Thomas Grapf <thomas.graf@swisscom.com>";
description
"This module describes the context of data collection from a
given network element. The contents of this model must be
streamed along with the data streamed from the network
element so that the context of the data collection can
be retrieved later.
This module must be completed with
ietf-platform-manifest
to capture the whole context of a data collection session.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL',
'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED',
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'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.
Copyright (c) 2022 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).
This version of this YANG module is part of RFC XXXX; see the
RFC itself for full legal notices. ";
revision 2023-03-08 {
description
"Initial revision";
reference
"RFC xxxx: Title to be completed";
}
container data-collections {
config false;
description
"Contains the configuration and statistics for the collected data,
per node in the network.";
list data-collection {
key "platform-id";
description
"Defines the information for each collected object";
leaf platform-id {
type leafref {
path "/p-mf:platforms/p-mf:platform/p-mf:id";
}
description
"Id of the platform collecting the data. This id is the same
as the one in the platform manifest.";
}
container yang-push-subscriptions {
/*
* Copy-pasting here some of the contents of the "subscriptions"
* container from ietf-subscribed notification.
*/
description
"Contains the list of currently active subscriptions, i.e.,
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subscriptions that are currently in effect, used for
subscription management and monitoring purposes. This
includes subscriptions that have been set up via
RPC primitives as well as subscriptions that have been
established via configuration.";
list subscription {
key "id";
description
"The identity and specific parameters of a subscription.
Subscriptions in this list can be created using a control
channel or RPC or can be established through configuration.
If the 'kill-subscription' RPC or configuration operations
are used to delete a subscription, a
'subscription-terminated' message is sent to any active or
suspended receivers.";
leaf id {
type sn:subscription-id;
description
"Identifier of a subscription; unique in a given
publisher.";
}
choice target {
mandatory true;
description
"Identifies the source of information against which a
subscription is being applied as well as specifics on the
subset of information desired from that source.";
case stream {
description
"An event stream filter can be applied to a
subscription. That filter should always be fully
included in the Data Collection manifest, i.e. common
filters need to be added here.";
leaf stream {
type leafref {
path "/p-mf:platforms"
+ "/p-mf:platform[p-mf:id=current()/../../.."
+ "/platform-id]/p-mf:yang-push-streams"
+ "/p-mf:stream/p-mf:name";
}
mandatory true;
description
"Indicates the event stream to be considered for
this subscription.";
}
uses sn:stream-filter-elements;
}
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case datastore {
description
"Yang-push subscription from a datastore.
That filter should always be fully included in the
Data Collection manifest, i.e. common filters need
to be added here.";
leaf datastore {
type leafref {
path "/p-mf:platforms"
+ "/p-mf:platform[p-mf:id=current()/../../.."
+ "/platform-id]/p-mf:yang-library"
+ "/p-mf:datastore/p-mf:name";
}
mandatory true;
description
"Datastore from which to retrieve data.";
}
uses yp:selection-filter-types;
}
}
leaf transport {
type sn:transport;
description
"For a configured subscription, this leaf specifies the
transport used to deliver messages destined for all
receivers of that subscription.";
}
leaf encoding {
type sn:encoding;
description
"The type of encoding for notification messages. For a
dynamic subscription, if not included as part of an
'establish-subscription' RPC, the encoding will be
populated with the encoding used by that RPC. For a
configured subscription, if not explicitly configured,
the encoding will be the default encoding for an
underlying transport.";
}
leaf purpose {
type string;
description
"Open text allowing a configuring entity to embed the
originator or other specifics of this subscription.";
}
uses sn:update-qos;
uses yp:update-policy-modifiable;
leaf current-period {
when '../periodic';
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type yp:centiseconds;
description
"Period during two succesive data collections, in the
current state. Might differ from the configured period
when the plaftorm might increase the period
automatically when it is overloaded.";
}
container receivers {
description
"Set of receivers in a subscription.";
list receiver {
key "name";
min-elements 1;
description
"A host intended as a recipient for the notification
messages of a subscription. For configured
subscriptions, transport-specific network parameters
(or a leafref to those parameters) may be augmented to
a specific receiver in this list.";
leaf name {
type string;
description
"Identifies a unique receiver for a subscription.";
}
leaf sent-event-records {
type yang:zero-based-counter64;
config false;
description
"The number of event records sent to the receiver.
The count is initialized when a dynamic subscription
is established or when a configured receiver
transitions to the 'valid' state.";
}
leaf excluded-event-records {
type yang:zero-based-counter64;
config false;
description
"The number of event records explicitly removed via
either an event stream filter or an access control
filter so that they are not passed to a receiver.
This count is set to zero each time
'sent-event-records' is initialized.";
}
leaf state {
type enumeration {
enum active {
value 1;
description
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"The receiver is currently being sent any
applicable notification messages for the
subscription.";
}
enum suspended {
value 2;
description
"The receiver state is 'suspended', so the
publisher is currently unable to provide
notification messages for the subscription.";
}
enum connecting {
value 3;
description
"A subscription has been configured, but a
'subscription-started' subscription state change
notification needs to be successfully received
before notification messages are sent. ";
}
enum disconnected {
value 4;
description
"A subscription has failed to send a
'subscription-started' state change to the
receiver. Additional connection attempts are not
currently being made.";
}
}
config false;
mandatory true;
description
"Specifies the state of a subscription from the
perspective of a particular receiver. With this
information, it is possible to determine whether a
publisher is currently generating notification
messages intended for that receiver.";
}
}
}
}
}
// we could augment here with other kind of collection items
}
}
}
<CODE ENDS>
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5. Data Manifest and the Collected Data
5.1. Collecting the Data Manifest
The Data Manifest MUST be streamed and stored along with the
collected data. In case the collected data are moved to a different
place (typically a database), the Data Manifest MUST follow the
collected data. This can render the collected data unusable if that
context is lost, for instance when the data is stored without the
relevant information. The Data Manifest MUST be updated when the
Data Manifest information changes, for example, when a router is
upgraded, when a new telemetry subscription is configured, or when
the telemetry subscription parameters change. The Data Manifest can
itself be considered as a time series, and stored in a similar
fashion to the collected data.
The collected data should be mapped to the Data Manifest. Since the
Data Manifest will not change as frequently as the collected data
itself, it makes sense to map several data to the same Data Manifest.
Somehow, the collected data must include a metadata pointing to the
corresponding Data Manifest. In case of Data Manifest change, the
system should keep the mapping between the data collected so far and
the old Data Manifest, and not assume that the latest Data Manifest
is valid for the entire time series.
The Platform Manifest is likely to remain the same until the platform
is updated. Thus, the Platform Manifest only needs to be collected
once per streaming session and updated after a platform reboot.
As this draft specifically focuses on giving context on data
collected via streamed telemetry, we can assume that a streaming
telemetry system is available. Retrieving the Data Collection
Manifest and Platform Manifest can be done either by reusing that
streaming telemetry system (in-band) or using another system (out-of-
band), for instance by adding headers or saving manifests into a YANG
instance file [RFC9195].
We propose to reuse the existing telemetry system (in-band approach)
in order to lower the efforts for implementing this draft. To enable
a platform supporting streaming telemetry to also support the Data
Manifest, it is sufficient that this platform supports the models
from Section 3 and Section 4. Recall that each type of manifest has
its own rough frequency update, i.e. at reboot for the Platform
Manifest and at new subscription or CPU load variation for the Data
Collection Manifest. The Data Manifest MUST be streamed with the
YANG-Push on-change feature [RFC8641] (also called event-driven
telemetry).
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5.2. Mapping Collected Data to the Data Manifest
With YANG-push, each notification sent by the device is part of a
subscription, which is also one of the YANG keys used to retrieve the
Data Manifest, the other key being the platform ID. In order to
enable a posteriori retrieval of the Data Manifest associated to a
datapoint, the collector must:
* Keep the subscription id and platform id in the metadata of the
collected values
* Collect as well the Data Manifest for the subscription associated
to the datapoint.
With this information, to retrieve the Data Manifest from the
datapoint, the following happens:
* The subscription id and platform id are retrieved from the
datapoint metadata
* The Data Manifest for that datapoint is obtained by using the
values above as keys.
We don’t focus on the timing aspect as storing both the data and
their manifest in a time series database will allow the data
scientists to look for the Data Manifest corresponding to the
timestamp of the datapoint. In that scenario, the reliability of the
collection of the Data Manifest is the same as the reliability of the
data collection itself, since the Data Manifest is like any other
data.
5.3. Operational Considerations
It is expected that the Data Manifest is streamed directly from the
network equipment, along with YANG-Push [RFC8641] data. However, if
the network element streaming telemetry does not support yet the YANG
modules from the Data Manifest specified in this document, the
telemetry collector could populate the Data Manifest from available
information collected from the platform. However, this option
requires efforts on the telemetry collector side, as the information
gathered in the Data Manifest proposed in this document could be
scattered among various standard and vendor- specific YANG modules
[RFC8199], that depend on the platform.
That Data Manifest should be kept and available even if the source
platform is not accessible (from the collection system), or if the
platform has been updated (new operating system or new
configuration). The Platform Manifest is "pretty" stable and should
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change only when the platform is updated or patched. On the other
hand, the Data Collection Manifest is likely to change each time a
new YANG-Push subscription [RFC8641] is requested and might even
change if the platform load increases and collection periods are
updated. To separate these two parts, we enclose each of them in its
own module.
6. Security Considerations
As we are reusing an existing telemetry system, the security
considerations lies with the new content divulged in the new
manifests. Appropriate access control must be associated to the
corresponding leafs and containers.
7. IANA Considerations
This document includes no request to IANA.
8. Contributors
9. Open Issues
* Do we want to handle the absence of values, i.e. add information
about missed collection or errors in the collection context ? It
could also explain why some values are missing. On the other
hand, this might also be out scope.
* Regarding the inclusion of ietf-yang-library in our module, do we
want to include as well the changes from ietf-yang-library-
revisions? What if other information are present in the yang-
library from the platform? Should we use a YANG mount to capture
them as well (they would not be captured with our use of the main
yang-library grouping). Similarly, the ietf-data-collection-
manifest.yang includes many lines of copy-pasting from ietf-yang-
push.yang and ietf-subscribed-notifications.yang since we want to
include the information from these modules. Reusing groupings is
not suitable as some leafrefs are pointing to nodes that are not
at the same location in our network level module. Maybe we need
to find a solution (deviations + some kind of schema mount?) maybe
we can live with similar modules since they have common nodes but
different purposes?
* Henk: how does this interact with SBOM effort?
* Eliot: important to give integrity of the information a lot of
thought. Threat model to be considered.
10. References
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10.1. Normative References
[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>.
[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>.
[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>.
[RFC8525] Bierman, A., Bjorklund, M., Schoenwaelder, J., Watsen, K.,
and R. Wilton, "YANG Library", RFC 8525,
DOI 10.17487/RFC8525, March 2019,
<https://www.rfc-editor.org/info/rfc8525>.
[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>.
[RFC9195] Lengyel, B. and B. Claise, "A File Format for YANG
Instance Data", RFC 9195, DOI 10.17487/RFC9195, February
2022, <https://www.rfc-editor.org/info/rfc9195>.
10.2. Informative References
[I-D.clacla-netmod-model-catalog]
Clarke, J. and B. Claise, "YANG module for
yangcatalog.org", Work in Progress, Internet-Draft, draft-
clacla-netmod-model-catalog-03, 3 April 2018,
<https://datatracker.ietf.org/doc/html/draft-clacla-
netmod-model-catalog-03>.
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[I-D.claise-netconf-metadata-for-collection]
Claise, B., Nayyar, M., and A. R. Sesani, "Per-Node
Capabilities for Optimum Operational Data Collection",
Work in Progress, Internet-Draft, draft-claise-netconf-
metadata-for-collection-02, 12 July 2021,
<https://datatracker.ietf.org/doc/html/draft-claise-
netconf-metadata-for-collection-02>.
[I-D.tgraf-netconf-notif-sequencing]
Graf, T., Quilbeuf, J., and A. H. Feng, "Support of
Hostname and Sequencing in YANG Notifications", Work in
Progress, Internet-Draft, draft-tgraf-netconf-notif-
sequencing-00, 4 March 2023,
<https://datatracker.ietf.org/doc/html/draft-tgraf-
netconf-notif-sequencing-00>.
[RFC8199] Bogdanovic, D., Claise, B., and C. Moberg, "YANG Module
Classification", RFC 8199, DOI 10.17487/RFC8199, July
2017, <https://www.rfc-editor.org/info/rfc8199>.
[RFC8343] Bjorklund, M., "A YANG Data Model for Interface
Management", RFC 8343, DOI 10.17487/RFC8343, March 2018,
<https://www.rfc-editor.org/info/rfc8343>.
[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>.
[RFC9371] Baber, A. and P. Hoffman, "Registration Procedures for
Private Enterprise Numbers (PENs)", RFC 9371,
DOI 10.17487/RFC9371, March 2023,
<https://www.rfc-editor.org/info/rfc9371>.
Appendix A. Example of use based on MDT
In this example, the goal is to collect the administrative status and
number of received bytes for the interfaces of a fictional ACME
device, and store the result in a Influx database. The metrics are
collected via YANG-Push, which is configured by specifying their
XPaths and when they should be collected (periodically or on-change).
More precisely, we want collect "ietf-
interfaces:interfaces/interface/enabled" on every change and "ietf-
interfaces:interfaces/interface/statistics/in-octets" every 100
milliseconds. The paths here are referring to the YANG module from
[RFC8343]. The configuration of YANG push is out of scope for this
document. Since they don’t have the same trigger, each of the path
must be collected in its own subscription.
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+------------+ +----------+
| MDT | | Influx |
| Collector |--------------> | DB |
+------------+ +----------+
^
|
|
+---------+
| Device |
+---------+
Figure 3: Example of collection from a device to Influx DB
In the scenario from Figure 3, the collector receives YANG-push from
the device and stores it into InfluxDB. We first present a version
without data manifest and then how to enrich it with the data
manifest.
In InfluxDB, a datapoint is specified by giving the name of the
measurement, zero or more key value entries named tags, one or more
named values called fields and the timestamp for the datapoint. In
our case a measurement could be "admin-status". The tags, whose aim
to identify a particular instance of the measurement could be the
name of the device and the name of the interface. The fields contain
the values to store. InfluxDb defines a textual notation, named line
protocol, to represent one datapoint per line. We use this line
protocol in Figure 4 and Figure 6 to represent the way data could be
fed to InfluxDB, omitting the timestamp for readability. See
https://docs.influxdata.com/influxdb/cloud/reference/syntax/line-
protocol/ for more details.
Without the data manifest, the YANG-push collector is likely to store
something similar to Figure 4 in InfluxDB. In that case, only the
value is stored, without any way to know how the value was obtained.
admin_status,device="PE1",interface="gig1" val=T
sent_bytes,device="PE1",interface="gig1" val=1234
Figure 4: Storing datapoints without data manifest
A possibility for keeping the data manifest with the data is to store
it directly into InfluxDB. In that case, the collector can subscribe
to the data exported by the module presented in this draft and store
it inside influxDB. For the Platform Manifest, assuming the platform
ID is "PE1", the collector subscribes to the path "ietf-platform-
manifest:platforms/platform[id=PE1]". For the Data Collection
Manifest, assuming the subscription id is 42, the collector
subscribes to the path "ietf-data-collection-manifest:data-
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collections/data-collection[platform-id="PE1"]/yang-push-
subscriptions/subscription[id=42]". The data, for instance
serialized in JSON, can be stored in InfluxDB as shown in Figure 5
where "<platform-manifest>" and "<data-manifest>" represent the
contents of respectively the Platform Manifest and the Data
Collection Manifest.
platform-manifest,device="PE1" val=<plaftorm-manifest>
collection-data-manifest,device="PE1",subId=42 val=<data-manifest>
Figure 5: Storing data manifest
In our example, The link between a collected datapoint and the
corresponding Platform Manifest is done via the common "device" tag.
In order to link a datapoint with the corresponding Data Collection
Manifest, the collector can add fields to specify where the Data
Collection Manifest is located for that specific datapoint. For
instance, the same datapoints as in Figure 4 could be stored as in
Figure 6.
admin_status,device="PE1",interface="gig1" val=T,subId=42
sent_bytes,device="PE1",interface="gig1" val=1234,subId=43
Figure 6: Storing datapoints with data manifest
In our simple example, from the "admin_status" datapoint, one can
retrieve the corresponding Platform Manifest by looking at the last
value for the "platform-manifest" measurement with the same value for
the "device" tag. From the "admin-status" datapoint, one can
retrieve the corresponding Data Collection Manifest by looking at the
last value for the "data-manifest" measurement with tags "device" and
"subId" matching respectively with the tag "device" and the field
"subId" of the measurement.
Appendix B. Changes between revisions
v05 -> v06
Remove YANG packages
Switch YANG models from device view to network view
Add PEN number to identify vendors
Intro rewritten with uses cases
Added an "Operational Considerations" section
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Switch from MDT to YANG-push
v04 -> v05
First version of example scenario
Updated affiliation
Updated YANG module names to ietf-platform-manifest and ietf-data-
collection-manifest
Unify used terms as defined in the terminology section
Replaced 'device' with 'platform'
Split Section 5 into two sections for better readibility
v03 -> v04
Fix xym error
Moved terminology after introduction
Clarified the role of the module
v02 -> v03
Add when clause in YANG model
Fix validation errors on YANG modules
Augment YANG library to handle semantic versioning
v01 -> v02
Alignment with YANGCatalog YANG module: name, vendor
Clarify the use of YANG instance file
Editorial improvements
v00 -> v01
Adding more into data platform: yang packages, whole yanglib
module to specify datastores
Setting the right type for periods: int64 -> uint64
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Specify the origin datastore for mdt subscription
Set both models to config false
Applying text comments from Mohamed Boucadair
Adding an example of data-manifest file
Adding rationale for reusing telemetry system for collection of
the manifests
Export manifest with on change telemetry as opposed to YANG
instance file
v00
Initial version
Appendix C. YANG module ietf-yang-push-modif
This section is only here to ensure that the draft passes without
compilations error. It should be removed as soon as we can fix the
issue.
<CODE BEGINS> file "ietf-yang-push-modif@2023-03-08.yang"
module ietf-yang-push-modif {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-yang-push-modif";
prefix yp;
import ietf-yang-types {
prefix yang;
reference
"RFC 6991: Common YANG Data Types";
}
import ietf-subscribed-notifications {
prefix sn;
reference
"RFC 8639: Subscription to YANG Notifications";
}
import ietf-datastores {
prefix ds;
reference
"RFC 8342: Network Management Datastore Architecture (NMDA)";
}
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import ietf-restconf {
prefix rc;
reference
"RFC 8040: RESTCONF Protocol";
}
import ietf-yang-patch {
prefix ypatch;
reference
"RFC 8072: YANG Patch Media Type";
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <https:/datatracker.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>
Author: Alexander Clemm
<mailto:ludwig@clemm.org>
Author: Eric Voit
<mailto:evoit@cisco.com>";
description
"This module contains YANG specifications for YANG-Push.
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.
Copyright (c) 2019 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 Simplified 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).
This version of this YANG module is part of RFC 8641; see the
RFC itself for full legal notices.";
revision 2023-03-08 {
description
"Hack so that ietf-data-collection-manifest compiles.";
reference
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"RFC 8641: Subscriptions to YANG Datastores";
}
revision 2019-09-09 {
description
"Initial revision.";
reference
"RFC 8641: Subscriptions to YANG Datastores";
}
/*
* FEATURES
*/
feature on-change {
description
"This feature indicates that on-change triggered subscriptions
are supported.";
}
/*
* IDENTITIES
*/
/* Error type identities for datastore subscription */
identity resync-subscription-error {
description
"Problem found while attempting to fulfill a
'resync-subscription' RPC request.";
}
identity cant-exclude {
base sn:establish-subscription-error;
description
"Unable to remove the set of 'excluded-change' parameters.
This means that the publisher is unable to restrict
'push-change-update' notifications to just the change types
requested for this subscription.";
}
identity datastore-not-subscribable {
base sn:establish-subscription-error;
base sn:subscription-terminated-reason;
description
"This is not a subscribable datastore.";
}
identity no-such-subscription-resync {
base resync-subscription-error;
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description
"The referenced subscription doesn't exist. This may be as a
result of a nonexistent subscription ID, an ID that belongs to
another subscriber, or an ID for a configured subscription.";
}
identity on-change-unsupported {
base sn:establish-subscription-error;
description
"On-change is not supported for any objects that are
selectable by this filter.";
}
identity on-change-sync-unsupported {
base sn:establish-subscription-error;
description
"Neither 'sync-on-start' nor resynchronization is supported for
this subscription. This error will be used for two reasons:
(1) if an 'establish-subscription' RPC includes
'sync-on-start' but the publisher can't support sending a
'push-update' for this subscription for reasons other than
'on-change-unsupported' or 'sync-too-big'
(2) if the 'resync-subscription' RPC is invoked for either an
existing periodic subscription or an on-change subscription
that can't support resynchronization.";
}
identity period-unsupported {
base sn:establish-subscription-error;
base sn:modify-subscription-error;
base sn:subscription-suspended-reason;
description
"The requested time period or 'dampening-period' is too short.
This can be for both periodic and on-change subscriptions
(with or without dampening). Hints suggesting alternative
periods may be returned as supplemental information.";
}
identity update-too-big {
base sn:establish-subscription-error;
base sn:modify-subscription-error;
base sn:subscription-suspended-reason;
description
"Periodic or on-change push update data trees exceed a maximum
size limit. Hints on the estimated size of what was too big
may be returned as supplemental information.";
}
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identity sync-too-big {
base sn:establish-subscription-error;
base sn:modify-subscription-error;
base resync-subscription-error;
base sn:subscription-suspended-reason;
description
"The 'sync-on-start' or resynchronization data tree exceeds a
maximum size limit. Hints on the estimated size of what was
too big may be returned as supplemental information.";
}
identity unchanging-selection {
base sn:establish-subscription-error;
base sn:modify-subscription-error;
base sn:subscription-terminated-reason;
description
"The selection filter is unlikely to ever select data tree
nodes. This means that based on the subscriber's current
access rights, the publisher recognizes that the selection
filter is unlikely to ever select data tree nodes that change.
Examples for this might be that the node or subtree doesn't
exist, read access is not permitted for a receiver, or static
objects that only change at reboot have been chosen.";
}
/*
* TYPE DEFINITIONS
*/
typedef change-type {
type enumeration {
enum create {
description
"A change that refers to the creation of a new
datastore node.";
}
enum delete {
description
"A change that refers to the deletion of a
datastore node.";
}
enum insert {
description
"A change that refers to the insertion of a new
user-ordered datastore node.";
}
enum move {
description
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"A change that refers to a reordering of the target
datastore node.";
}
enum replace {
description
"A change that refers to a replacement of the target
datastore node's value.";
}
}
description
"Specifies different types of datastore changes.
This type is based on the edit operations defined for
YANG Patch, with the difference that it is valid for a
receiver to process an update record that performs a
'create' operation on a datastore node the receiver believes
exists or to process a delete on a datastore node the
receiver believes is missing.";
reference
"RFC 8072: YANG Patch Media Type, Section 2.5";
}
typedef selection-filter-ref {
type leafref {
path "/sn:filters/yp:selection-filter/yp:filter-id";
}
description
"This type is used to reference a selection filter.";
}
typedef centiseconds {
type uint32;
description
"A period of time, measured in units of 0.01 seconds.";
}
/*
* GROUP DEFINITIONS
*/
grouping datastore-criteria {
description
"A grouping to define criteria for which selected objects from
a targeted datastore should be included in push updates.";
leaf datastore {
type identityref {
base ds:datastore;
}
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mandatory true;
description
"Datastore from which to retrieve data.";
}
uses selection-filter-objects;
}
grouping selection-filter-types {
description
"This grouping defines the types of selectors for objects
from a datastore.";
choice datastore-filter-spec {
description
"The content filter specification for this request.";
anydata datastore-subtree-filter {
if-feature "sn:subtree";
description
"This parameter identifies the portions of the
target datastore to retrieve.";
reference
"RFC 6241: Network Configuration Protocol (NETCONF),
Section 6";
}
leaf datastore-xpath-filter {
if-feature "sn:xpath";
type yang:xpath1.0;
description
"This parameter contains an XPath expression identifying
the portions of the target datastore to retrieve.
If the expression returns a node set, all nodes in the
node set are selected by the filter. Otherwise, if the
expression does not return a node set, the filter
doesn't select any nodes.
The expression is evaluated in the following XPath
context:
o The set of namespace declarations is the set of prefix
and namespace pairs for all YANG modules implemented
by the server, where the prefix is the YANG module
name and the namespace is as defined by the
'namespace' statement in the YANG module.
If the leaf is encoded in XML, all namespace
declarations in scope on the 'stream-xpath-filter'
leaf element are added to the set of namespace
declarations. If a prefix found in the XML is
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already present in the set of namespace declarations,
the namespace in the XML is used.
o The set of variable bindings is empty.
o The function library is comprised of the core
function library and the XPath functions defined in
Section 10 in RFC 7950.
o The context node is the root node of the target
datastore.";
reference
"XML Path Language (XPath) Version 1.0
(https://www.w3.org/TR/1999/REC-xpath-19991116)
RFC 7950: The YANG 1.1 Data Modeling Language,
Section 10";
}
}
}
grouping selection-filter-objects {
description
"This grouping defines a selector for objects from a
datastore.";
choice selection-filter {
description
"The source of the selection filter applied to the
subscription. This will either (1) come referenced from a
global list or (2) be provided in the subscription itself.";
case by-reference {
description
"Incorporates a filter that has been configured
separately.";
leaf selection-filter-ref {
type selection-filter-ref;
mandatory true;
description
"References an existing selection filter that is to be
applied to the subscription.";
}
}
case within-subscription {
description
"A local definition allows a filter to have the same
lifecycle as the subscription.";
uses selection-filter-types;
}
}
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}
grouping update-policy-modifiable {
description
"This grouping describes the datastore-specific subscription
conditions that can be changed during the lifetime of the
subscription.";
choice update-trigger {
description
"Defines necessary conditions for sending an event record to
the subscriber.";
case periodic {
container periodic {
presence "indicates a periodic subscription";
description
"The publisher is requested to periodically notify the
receiver regarding the current values of the datastore
as defined by the selection filter.";
leaf period {
type centiseconds;
mandatory true;
description
"Duration of time that should occur between periodic
push updates, in units of 0.01 seconds.";
}
leaf anchor-time {
type yang:date-and-time;
description
"Designates a timestamp before or after which a series
of periodic push updates are determined. The next
update will take place at a point in time that is a
multiple of a period from the 'anchor-time'.
For example, for an 'anchor-time' that is set for the
top of a particular minute and a period interval of a
minute, updates will be sent at the top of every
minute that this subscription is active.";
}
}
}
case on-change {
if-feature "on-change";
container on-change {
presence "indicates an on-change subscription";
description
"The publisher is requested to notify the receiver
regarding changes in values in the datastore subset as
defined by a selection filter.";
leaf dampening-period {
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type centiseconds;
default "0";
description
"Specifies the minimum interval between the assembly of
successive update records for a single receiver of a
subscription. Whenever subscribed objects change and
a dampening-period interval (which may be zero) has
elapsed since the previous update record creation for
a receiver, any subscribed objects and properties
that have changed since the previous update record
will have their current values marshalled and placed
in a new update record.";
}
}
}
}
}
grouping update-policy {
description
"This grouping describes the datastore-specific subscription
conditions of a subscription.";
uses update-policy-modifiable {
augment "update-trigger/on-change/on-change" {
description
"Includes objects that are not modifiable once a
subscription is established.";
leaf sync-on-start {
type boolean;
default "true";
description
"When this object is set to 'false', (1) it restricts an
on-change subscription from sending 'push-update'
notifications and (2) pushing a full selection per the
terms of the selection filter MUST NOT be done for
this subscription. Only updates about changes
(i.e., only 'push-change-update' notifications)
are sent. When set to 'true' (the default behavior),
in order to facilitate a receiver's synchronization,
a full update is sent, via a 'push-update' notification,
when the subscription starts. After that,
'push-change-update' notifications are exclusively sent,
unless the publisher chooses to resync the subscription
via a new 'push-update' notification.";
}
leaf-list excluded-change {
type change-type;
description
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"Used to restrict which changes trigger an update. For
example, if a 'replace' operation is excluded, only the
creation and deletion of objects are reported.";
}
}
}
}
grouping hints {
description
"Parameters associated with an error for a subscription
made upon a datastore.";
leaf period-hint {
type centiseconds;
description
"Returned when the requested time period is too short. This
hint can assert a viable period for either a periodic push
cadence or an on-change dampening interval.";
}
leaf filter-failure-hint {
type string;
description
"Information describing where and/or why a provided filter
was unsupportable for a subscription.";
}
leaf object-count-estimate {
type uint32;
description
"If there are too many objects that could potentially be
returned by the selection filter, this identifies the
estimate of the number of objects that the filter would
potentially pass.";
}
leaf object-count-limit {
type uint32;
description
"If there are too many objects that could be returned by
the selection filter, this identifies the upper limit of
the publisher's ability to service this subscription.";
}
leaf kilobytes-estimate {
type uint32;
description
"If the returned information could be beyond the capacity
of the publisher, this would identify the estimated
data size that could result from this selection filter.";
}
leaf kilobytes-limit {
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type uint32;
description
"If the returned information would be beyond the capacity
of the publisher, this identifies the upper limit of the
publisher's ability to service this subscription.";
}
}
/*
* RPCs
*/
rpc resync-subscription {
if-feature "on-change";
description
"This RPC allows a subscriber of an active on-change
subscription to request a full push of objects.
A successful invocation results in a 'push-update' of all
datastore nodes that the subscriber is permitted to access.
This RPC can only be invoked on the same session on which the
subscription is currently active. In the case of an error, a
'resync-subscription-error' is sent as part of an error
response.";
input {
leaf id {
type sn:subscription-id;
mandatory true;
description
"Identifier of the subscription that is to be resynced.";
}
}
}
/*
* NOTIFICATIONS
*/
notification push-update {
description
"This notification contains a push update that in turn contains
data subscribed to via a subscription. In the case of a
periodic subscription, this notification is sent for periodic
updates. It can also be used for synchronization updates of
an on-change subscription. This notification shall only be
sent to receivers of a subscription. It does not constitute
a general-purpose notification that would be subscribable as
part of the NETCONF event stream by any receiver.";
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anydata datastore-contents {
description
"This contains the updated data. It constitutes a snapshot
at the time of update of the set of data that has been
subscribed to. The snapshot corresponds to the same
snapshot that would be returned in a corresponding 'get'
operation with the same selection filter parameters
applied.";
}
leaf id {
type sn:subscription-id;
description
"This references the subscription that drove the
notification to be sent.";
}
leaf incomplete-update {
type empty;
description
"This is a flag that indicates that not all datastore
nodes subscribed to are included with this update. In
other words, the publisher has failed to fulfill its full
subscription obligations and, despite its best efforts, is
providing an incomplete set of objects.";
}
}
notification push-change-update {
if-feature "on-change";
description
"This notification contains an on-change push update. This
notification shall only be sent to the receivers of a
subscription. It does not constitute a general-purpose
notification that would be subscribable as part of the
NETCONF event stream by any receiver.";
leaf id {
type sn:subscription-id;
description
"This references the subscription that drove the
notification to be sent.";
}
container datastore-changes {
description
"This contains the set of datastore changes of the target
datastore, starting at the time of the previous update, per
the terms of the subscription.";
uses ypatch:yang-patch;
}
leaf incomplete-update {
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type empty;
description
"The presence of this object indicates that not all changes
that have occurred since the last update are included with
this update. In other words, the publisher has failed to
fulfill its full subscription obligations -- for example,
in cases where it was not able to keep up with a burst of
changes.";
}
}
augment "/sn:establish-subscription/sn:input" {
description
"This augmentation adds additional subscription parameters
that apply specifically to datastore updates to RPC input.";
uses update-policy;
}
augment "/sn:establish-subscription/sn:input/sn:target" {
description
"This augmentation adds the datastore as a valid target
for the subscription to RPC input.";
case datastore {
description
"Information specifying the parameters of a request for a
datastore subscription.";
uses datastore-criteria;
}
}
augment "/sn:modify-subscription/sn:input" {
description
"This augmentation adds additional subscription parameters
specific to datastore updates.";
uses update-policy-modifiable;
}
augment "/sn:modify-subscription/sn:input/sn:target" {
description
"This augmentation adds the datastore as a valid target
for the subscription to RPC input.";
case datastore {
description
"Information specifying the parameters of a request for a
datastore subscription.";
uses datastore-criteria;
}
}
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augment "/sn:subscription-started" {
description
"This augmentation adds datastore-specific objects to
the notification that a subscription has started.";
uses update-policy;
}
augment "/sn:subscription-started/sn:target" {
description
"This augmentation allows the datastore to be included as
part of the notification that a subscription has started.";
case datastore {
uses datastore-criteria {
refine "selection-filter/within-subscription" {
description
"Specifies the selection filter and where it originated
from. If the 'selection-filter-ref' is populated, the
filter in the subscription came from the 'filters'
container. Otherwise, it is populated in-line as part
of the subscription itself.";
}
}
}
}
augment "/sn:subscription-modified" {
description
"This augmentation adds datastore-specific objects to
the notification that a subscription has been modified.";
uses update-policy;
}
augment "/sn:subscription-modified/sn:target" {
description
"This augmentation allows the datastore to be included as
part of the notification that a subscription has been
modified.";
case datastore {
uses datastore-criteria {
refine "selection-filter/within-subscription" {
description
"Specifies the selection filter and where it originated
from. If the 'selection-filter-ref' is populated, the
filter in the subscription came from the 'filters'
container. Otherwise, it is populated in-line as part
of the subscription itself.";
}
}
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}
}
/*
* DATA NODES
*/
augment "/sn:filters" {
description
"This augmentation allows the datastore to be included as part
of the selection-filtering criteria for a subscription.";
list selection-filter {
key "filter-id";
description
"A list of preconfigured filters that can be applied
to datastore subscriptions.";
leaf filter-id {
type string;
description
"An identifier to differentiate between selection
filters.";
}
uses selection-filter-types;
}
}
augment "/sn:subscriptions/sn:subscription" {
when 'yp:datastore';
description
"This augmentation adds objects to a subscription that are
specific to a datastore subscription, i.e., a subscription to
a stream of datastore node updates.";
uses update-policy;
}
augment "/sn:subscriptions/sn:subscription/sn:target" {
description
"This augmentation allows the datastore to be included as
part of the selection-filtering criteria for a subscription.";
case datastore {
uses datastore-criteria;
}
}
rc:yang-data resync-subscription-error {
container resync-subscription-error {
description
"If a 'resync-subscription' RPC fails, the subscription is
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not resynced and the RPC error response MUST indicate the
reason for this failure. This yang-data MAY be inserted as
structured data in a subscription's RPC error response
to indicate the reason for the failure.";
leaf reason {
type identityref {
base resync-subscription-error;
}
mandatory true;
description
"Indicates the reason why the publisher has declined a
request for subscription resynchronization.";
}
uses hints;
}
}
rc:yang-data establish-subscription-datastore-error-info {
container establish-subscription-datastore-error-info {
description
"If any 'establish-subscription' RPC parameters are
unsupportable against the datastore, a subscription is not
created and the RPC error response MUST indicate the reason
why the subscription failed to be created. This yang-data
MAY be inserted as structured data in a subscription's
RPC error response to indicate the reason for the failure.
This yang-data MUST be inserted if hints are to be provided
back to the subscriber.";
leaf reason {
type identityref {
base sn:establish-subscription-error;
}
description
"Indicates the reason why the subscription has failed to
be created to a targeted datastore.";
}
uses hints;
}
}
rc:yang-data modify-subscription-datastore-error-info {
container modify-subscription-datastore-error-info {
description
"This yang-data MAY be provided as part of a subscription's
RPC error response when there is a failure of a
'modify-subscription' RPC that has been made against a
datastore. This yang-data MUST be used if hints are to be
provided back to the subscriber.";
leaf reason {
type identityref {
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base sn:modify-subscription-error;
}
description
"Indicates the reason why the subscription has failed to
be modified.";
}
uses hints;
}
}
}
<CODE ENDS>
Acknowledgements
Thanks to Mohamed Boucadair and Tianran Zhou for their reviews and
comments.
Authors' Addresses
Benoit Claise
Huawei
Email: benoit.claise@huawei.com
Jean Quilbeuf
Huawei
Email: jean.quilbeuf@huawei.com
Diego R. Lopez
Telefonica I+D
Don Ramon de la Cruz, 82
Madrid 28006
Spain
Email: diego.r.lopez@telefonica.com
Ignacio Dominguez
Telefonica I+D
Ronda de la Comunicacion, S/N
Madrid 28050
Spain
Email: ignacio.dominguezmartinez@telefonica.com
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Thomas Graf
Swisscom
Binzring 17
CH-8045 Zurich
Switzerland
Email: thomas.graf@swisscom.com
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