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<rfc xmlns:xi="http://www.w3.org/2001/XInclude" ipr="trust200902" docName="draft-yoon-ippm-collection-interval-capabilities-01" category="std" submissionType="IETF" tocInclude="true" sortRefs="true" symRefs="true" version="3">
  <!-- xml2rfc v2v3 conversion 3.33.0 -->
  <front>
    <title abbrev="PM Interval Capabilities YANG">A YANG Data Model for Performance Monitoring (PM) Interval Capabilities</title>
    <seriesInfo name="Internet-Draft" value="draft-yoon-ippm-collection-interval-capabilities-01"/>
    <author initials="B. Y." surname="Yoon" fullname="Bin Yeong Yoon">
      <organization>ETRI</organization>
      <address>
        <email>byyun@etri.re.kr</email>
      </address>
    </author>
    <author initials="Y." surname="You" fullname="Youngkil You">
      <organization>woori-net</organization>
      <address>
        <email>young@woori-net.com</email>
      </address>
    </author>
    <date year="2026" month="October" day="29"/>
    <workgroup>IPPM Working Group</workgroup>
    <keyword>performance monitoring</keyword>
    <keyword>interval capabilities</keyword>
    <keyword>capability advertisement</keyword>
    <keyword>YANG</keyword>
    <abstract>
      

<t>This document defines a YANG data model, "ietf-pm-interval-capabilities",
that enables a server to advertise which sampling and collection
intervals, measurement methods, and collection types it supports for
each performance monitoring (PM) parameter.  A client reads this
capability information before configuring PM collection, so that it
selects only values that the server can honour.  The capabilities
are advertised by augmenting the "ietf-system-capabilities" module
defined in <xref target="RFC9196"/>, so that a client discovers them at the same
well-known location used for subscription and notification
capabilities.  The model imports the "profile-names" and
"collection-type" types and the "performance-parameter" and
"measurement-method" identities from the companion PM collection
model defined in
<xref target="I-D.yoon-ippm-collection-measure"/> and mirrors its
profile-and-parameter structure, ensuring direct alignment between
capability discovery and collection configuration.  The model does
not define collection data structures or any delivery mechanism;
those are defined in the companion document.</t>
    </abstract>
    <note removeInRFC="true">
      <name>About This Document</name>
      <t>
        The latest revision of this draft can be found at <eref target="https://binyeongyoon-ietf.github.io/ietf-pm-streaming/draft-yoon-ippm-collection-interval-capabilities.html"/>.
        Status information for this document may be found at <eref target="https://datatracker.ietf.org/doc/draft-yoon-ippm-collection-interval-capabilities/"/>.
      </t>
      <t>Source for this draft and an issue tracker can be found at
        <eref target="https://github.com/binyeongyoon-ietf/ietf-pm-streaming"/>.</t>
    </note>
    <note>
      <name>Note to the RFC Editor</name>
      

<t>Please replace "RFC XXXX" with the RFC number assigned to this
document, and "RFC YYYY" with the RFC number assigned to
<xref target="I-D.yoon-ippm-collection-measure"/>, throughout this document and
in the YANG module, and remove this note.</t>
    </note>
  </front>
  <middle>
    

<section anchor="introduction">
      <name>Introduction</name>
      <t>The PM collection data model defined in
<xref target="I-D.yoon-ippm-collection-measure"/> allows a client to configure sampling
and collection intervals for performance parameters within named
parameter profiles.  The same parameter may require different intervals
depending on its type and monitoring objective, and different network
elements support different ranges and granularities of intervals.
Without a prior discovery step, a client risks configuring interval
values that the server cannot honour, leading to configuration errors or
suboptimal monitoring.</t>
      <t>This document defines a YANG data model <xref target="RFC7950"/>,
"ietf-pm-interval-capabilities", for advertising the interval
capabilities a server supports.  A client reads
this information from the operational datastore before it configures
PM collection.  The model mirrors the profile-and-parameter structure
of the companion PM collection model and reuses its
"profile-names" type and "performance-parameter" identity, so that
capability discovery aligns directly with collection configuration.</t>
      <t>In addition to interval ranges, the same discovery step advertises
which measurement methods <xref target="RFC7799"/> the server can apply to each
parameter (active, passive, or hybrid). A parameter may be
measurable by more than one method on a given network element -- for
example, delay measured either by an active probe or by a hybrid
in-band technique -- and a client needs to know the available
methods before it configures a measurement or establishes a
subscription, so that it obtains data with the intended operational
meaning. Advertising the supported methods alongside the supported
intervals lets the client make both choices in a single discovery
step, using the companion configuration model
<xref target="I-D.yoon-ippm-collection-measure"/>.</t>
      <t>The same discovery step also advertises which collection types
(counts, snapshot, and tidemarks) the server supports for each
parameter, so that a client knows which types it can enable before
it configures a parameter; a profile may also restrict a parameter to a subset of
the types, for example counts only.</t>
      <t>Rather than defining a separate top-level container, this module
augments the "system-capabilities" container of the
"ietf-system-capabilities" module defined in <xref target="RFC9196"/>.  RFC 9196
provides a placeholder structure that other modules augment to expose
YANG-related system capabilities; the companion module
"ietf-notification-capabilities" (Section 3 of <xref target="RFC9196"/>) uses the
same anchor to advertise subscription and notification capabilities.
By augmenting the same anchor, this module lets a NETCONF or RESTCONF
client discover the PM interval capabilities and the
subscription capabilities through a single, standardised query, without
prior knowledge of this module's own layout.</t>
      <t>This document does not define collection data structures, collection
types, threshold events, or any delivery mechanism.  All of those are
defined in the companion document <xref target="I-D.yoon-ippm-collection-measure"/>.</t>
      <section anchor="terminology">
        <name>Terminology</name>
        <t>The terms "client", "server", "datastore", and "operational state" are
used as defined in <xref target="RFC6241"/> and <xref target="RFC8342"/>.</t>
        <t>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 <xref target="RFC2119"/> <xref target="RFC8174"/> when, and only when, they appear in
all capitals, as shown here.</t>
      </section>
      <section anchor="relationship">
        <name>Relationship to Companion Documents</name>
        <t>The functional division between this document and
<xref target="I-D.yoon-ippm-collection-measure"/> is as follows.</t>
        <t><xref target="I-D.yoon-ippm-collection-measure"/> defines "ietf-pm-collection", which
configures PM collection and exposes the collected data.  This
document depends only on the types and identities that it imports
from that module.</t>
        <t>This document defines "ietf-pm-interval-capabilities", which covers:</t>
        <ul spacing="normal">
          <li>
            <t>Read-only advertisement of the sampling and collection interval
ranges, units, defaults, and granularity that a server supports</t>
          </li>
          <li>
            <t>Read-only advertisement of the measurement methods and collection
types that a server supports for each parameter</t>
          </li>
          <li>
            <t>Hierarchical alignment with the companion model's profile-and-
parameter structure</t>
          </li>
          <li>
            <t>Capability discovery prior to collection configuration</t>
          </li>
        </ul>
        <t>The separation of concerns is:</t>
        <ul spacing="normal">
          <li>
            <t>"What data is collected and how it is structured" is in
<xref target="I-D.yoon-ippm-collection-measure"/>.</t>
          </li>
          <li>
            <t>"Which configurations the server can support" is in this
document.</t>
          </li>
        </ul>
        <t>Specific performance parameters are defined as identities derived
from "performance-parameter" in other documents.</t>
        <t><xref target="fig-document-relationship"/> illustrates the relationship between
the two YANG modules.</t>
        <figure anchor="fig-document-relationship">
          <name>Relationship between ietf-pm-interval-capabilities and ietf-pm-collection</name>
          <artwork type="ascii-art"><![CDATA[
  +------------------------------------------+
  |     ietf-pm-interval-capabilities        |
  |         (this document)                  |
  |                                          |
  |  pm-interval-capabilities                |
  |    parameter-profile [profile-names] -+  |
  |      pm-parameter [identityref]       |  |
  |        supported-collection-types     |  |
  |        interval-relationships         |  |
  |          sampling-interval            |  |
  |            collection-interval        |  |
  +------------------------------|-----------+
                                 | imports profile-names,
                                 | performance-parameter,
                                 | measurement-method,
                                 | collection-type
                                 v
  +------------------------------------------+
  |     ietf-pm-collection                   |
  |     (companion document)                 |
  |     PM collection model                  |
  +------------------------------------------+
]]></artwork>
        </figure>
      </section>
    </section>
    <section anchor="motivation">
      <name>Motivation</name>
      <t>ITU-T G.7710 <xref target="G7710"/> does not include a clause that mandates a
capability-discovery mechanism for configurable measurement timing
parameters.  However, because sampling and collection intervals are
configurable, a client needs to know in advance which intervals a given
server can support, so that requests can be built without violating
implementation constraints.  This module provides that advertisement.</t>
      <section anchor="monitoring-objectives-require-different-intervals">
        <name>Monitoring Objectives Require Different Intervals</name>
        <t>The same PM parameter may need to be collected simultaneously at
multiple sampling and collection interval combinations, each serving
a distinct operational objective.  As illustrated by the use cases in
<xref target="I-D.yoon-ippm-collection-measure"/>, the number of lost packets counted
every second may be aggregated over a 1-minute interval for rapid fault
detection in a Network Operations Center (NOC), over a 15-minute
interval for routine maintenance monitoring, and over a 24-hour interval for daily QoS reporting -- all
three objectives active concurrently on the same parameter.  Similarly,
latency parameters may be sampled at sub-second granularity with short
collection intervals for digital twin synchronization, or at longer
intervals for AI/ML model training.</t>
        <t>A client wishing to configure all of these combinations for all
parameters in a profile must first verify that the target server
supports every required interval.  Without a capability discovery
step, the client has no way to know whether a desired combination is
valid on the specific server, and may submit configurations that the
server silently truncates, rejects, or rounds to the nearest supported
value.</t>
      </section>
      <section anchor="equipment-performance-determines-achievable-intervals">
        <name>Equipment Performance Determines Achievable Intervals</name>
        <t>Beyond monitoring objective, the processing capacity of the network
element itself directly determines which interval configurations are
feasible for a given parameter.  Network elements vary significantly
in their measurement engines and hardware resources.</t>
        <t>High-performance network elements with dedicated measurement processors
can support short minimum sampling intervals and fine-grained
collection interval steps, enabling high-resolution monitoring for
demanding use cases such as real-time fault detection, network digital
twins, and AI-driven analytics.  For example, such a device may support
a 100-millisecond sampling interval for the lost-packets parameter,
with collection intervals
as short as 1 minute and a 5-second granularity step.</t>
        <t>Lower-specification network elements, constrained by processing
resources or hardware architecture, may support only longer minimum
intervals and coarser granularity steps.  The same lost-packets parameter on
such a device might have a minimum sampling interval of 1 second and
a minimum collection interval of 15 minutes, adequate for traditional
operations and maintenance monitoring but insufficient for sub-minute
analytics.</t>
        <t><xref target="tab-equipment-classes"/> shows an example comparison for the
lost-packets parameter.</t>
        <table anchor="tab-equipment-classes">
          <name>Example interval capabilities by equipment class (lost-packets parameter)</name>
          <thead>
            <tr>
              <th align="left">Equipment class</th>
              <th align="left">Min. sampling</th>
              <th align="left">Min. collection interval</th>
              <th align="left">Granularity</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td align="left">High-performance</td>
              <td align="left">100 ms</td>
              <td align="left">1 min</td>
              <td align="left">5 s</td>
            </tr>
            <tr>
              <td align="left">Standard</td>
              <td align="left">1 s</td>
              <td align="left">1 min</td>
              <td align="left">1 min</td>
            </tr>
            <tr>
              <td align="left">Low-specification</td>
              <td align="left">1 s</td>
              <td align="left">15 min</td>
              <td align="left">15 min</td>
            </tr>
          </tbody>
        </table>
        <t>A client operating across a heterogeneous network cannot assume a
uniform interval floor and must discover the capabilities of each
network element individually.  The interval capability model enables
a client to select the highest-resolution intervals a given server
supports for each operational objective, rather than applying a
conservative lowest-common-denominator configuration across all
devices.</t>
      </section>
      <section anchor="multi-vendor-interoperability">
        <name>Multi-Vendor Interoperability</name>
        <t>Equipment from different vendors supports different ranges and
granularities of intervals, and may impose implementation-specific
constraints on the relationship between sampling and collection
intervals.  In multi-vendor networks, clients must adapt to the
capabilities of each element.  Without a discovery mechanism, clients
risk configuration failures, suboptimal monitoring, or system
instability.  A standardised capability model addresses these
challenges and enables interoperability across diverse network
environments.</t>
      </section>
    </section>
    <section anchor="structure-and-the-samplingcollection-relationship">
      <name>Structure and the Sampling/Collection Relationship</name>
      <t>The module follows a hierarchical structure that mirrors the
configuration structure of the PM collection model defined in
<xref target="I-D.yoon-ippm-collection-measure"/>,
ensuring consistency between capability discovery and actual
configuration.  It has three levels: parameter profiles (collections of
related parameters such as "example-ip-qos-15min"),
PM parameters (individual parameters identified by identities
derived from "performance-parameter"), and capabilities
(supported sampling and collection intervals, measurement methods,
and collection types for each parameter).</t>
      <t>The relationship between sampling and collection intervals is
expressed structurally by nesting collection intervals within their
corresponding sampling interval entry.</t>
      <t>For each interval, the model advertises:</t>
      <ul spacing="normal">
        <li>
          <t>min-value: minimum supported numeric value</t>
        </li>
        <li>
          <t>max-value: maximum supported numeric value</t>
        </li>
        <li>
          <t>units: list of supported time units (e.g., second, minute)</t>
        </li>
        <li>
          <t>default-value: recommended default numeric value</t>
        </li>
        <li>
          <t>default-unit: recommended default time unit</t>
        </li>
        <li>
          <t>granularity: step size; valid values must be multiples of this</t>
        </li>
      </ul>
      <t>For a collection interval, the model additionally advertises
<tt>retained-interval-count</tt>: the number of completed intervals the
server retains after they end.  This value bounds both how many
completed intervals a client may read back and, for push delivery,
how long a reporting period may be, since a reporting period may
span at most <tt>retained-interval-count</tt> collection intervals.  A
client uses it to choose a reporting period the server can honour.</t>
      <t>For each parameter, the model additionally advertises
<tt>supported-collection-types</tt>: the collection types (counts,
snapshot, tidemarks) that the server can collect for the parameter.
A client enables only the advertised collection types.  An
absent list means the server does not advertise collection-type
information for the parameter.</t>
      <t>Once a client knows the supported intervals, it can pair a single
supported sampling interval with several supported collection intervals
to serve different operational purposes for the same parameter.  The
"Use Cases" section of <xref target="I-D.yoon-ippm-collection-measure"/> gives concrete
examples of such combinations, which motivate the ranges and
granularities a server advertises here.</t>
    </section>
    <section anchor="capability-discovery-and-configuration-workflow">
      <name>Capability Discovery and Configuration Workflow</name>
      <t>A client performs the following three steps to configure PM
collection and access the collected data correctly.  Steps 2 and 3 use the companion
model defined in <xref target="I-D.yoon-ippm-collection-measure"/>; Step 1 uses the
model defined in this document.</t>
      <figure anchor="fig-workflow">
        <name>Combined Capability Discovery and Data Access Workflow</name>
        <artwork type="ascii-art"><![CDATA[
  +-----------+                        +-----------+
  |  Client   |                        |  Server   |
  | (NMS/Ctrl)|                        |   (NE)    |
  +-----+-----+                        +-----+-----+
        |                                    |
        |  Step 1: Discover intervals        |
        |  [ietf-pm-interval-capabilities]   |
        |---NETCONF get-data--------------> |
        |<--pm-interval-capabilities-------- |
        |                                    |
        |  Step 2: Configure collection      |
        |  [ietf-pm-collection]              |
        |---NETCONF edit-config-----------> |
        |<--OK------------------------------ |
        |                                    |
        |  Step 3: Access data               |
        |  [ietf-pm-collection]              |
        |                                    |
        |  Option A: Pull (polling)          |
        |---NETCONF get-data--------------> |
        |<--collected data----------------- |
        |                                    |
        |  Option B: Push (YANG-Push)        |
        |---establish-subscription--------> |
        |<--periodic-notifications---------- |
        |                                    |
]]></artwork>
      </figure>
      <t><strong>Step 1 -- Discover interval capabilities (this document).</strong>
On session establishment, the server's YANG Library <xref target="RFC8525"/> and
capability information indicate whether "ietf-pm-collection" and
"ietf-pm-interval-capabilities" are both supported.  The client
queries the "pm-interval-capabilities" container, which this module
augments into the "system-capabilities" container of
"ietf-system-capabilities" <xref target="RFC9196"/>.  Because that container is
"config false", the augmented nodes inherit "config false" and reside
in the operational datastore per the Network Management Datastore
Architecture (NMDA) <xref target="RFC8342"/>.  Querying the same anchor also returns
any subscription and notification capabilities advertised there by
"ietf-notification-capabilities" (Section 3 of <xref target="RFC9196"/>).
From it, the client retrieves the supported sampling and collection
intervals for each parameter and profile, including the minimum and
maximum values, allowed units, and granularity, together with the
supported measurement methods and collection types.  This runtime exposure
follows the model described in <xref target="RFC9196"/> for advertising capabilities
in operational state.  The same information MAY also be published as
static instance data using the format defined in <xref target="RFC9195"/>.  The
interval ranges advertised here correspond to the Measurement Timing
aspect of the Performance Metric Specification described in
Section 5.4.2 of <xref target="RFC6390"/>; this document provides the runtime
discovery of those timing constraints, which the companion model
<xref target="I-D.yoon-ippm-collection-measure"/> then applies when collection is
configured.</t>
      <t><strong>Step 2 -- Configure collection (companion document).</strong>
The client configures PM collection using "ietf-pm-collection"
<xref target="I-D.yoon-ippm-collection-measure"/>, selecting
only sampling and collection interval values, measurement methods,
and collection types that Step 1 confirmed the server supports.  This
avoids configuration errors such as an unsupported interval or
collection type being rejected during collection setup or
subscription establishment.</t>
      <t><strong>Step 3 -- Access data (companion document).</strong>
The client accesses the collected PM data, by pull-based retrieval
or push-based subscription, as specified in
<xref target="I-D.yoon-ippm-collection-measure"/>.</t>
    </section>
    <section anchor="interval-capabilities-example">
      <name>Interval Capabilities Example</name>
      <t><xref target="fig-cap-example"/> shows a NETCONF <tt>&lt;get-data&gt;</tt> request <xref target="RFC8526"/>
that retrieves, from the operational datastore, the capabilities
advertised for the "ex:lost-packets" parameter in the
"example-ip-qos-15min" profile.  The subtree filter
selects the parameter by its list keys only, so the whole entry is
returned.  The parameter is identified by "ex:lost-packets", an
example identity derived from "performance-parameter".</t>
      <figure anchor="fig-cap-example">
        <name>Interval Capabilities Discovery Request Example</name>
        <sourcecode type="xml"><![CDATA[
<rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
     message-id="301">
  <get-data
      xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-nmda"
      xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
    <datastore>ds:operational</datastore>
    <subtree-filter>
      <system-capabilities
          xmlns=
            "urn:ietf:params:xml:ns:yang:ietf-system-capabilities">
        <pm-interval-capabilities
            xmlns=
          "urn:ietf:params:xml:ns:yang:ietf-pm-interval-capabilities"
            xmlns:ex="urn:example:pm-parameters">
          <parameter-profile>
            <name>example-ip-qos-15min</name>
            <pm-parameter>
              <name>ex:lost-packets</name>
            </pm-parameter>
          </parameter-profile>
        </pm-interval-capabilities>
      </system-capabilities>
    </subtree-filter>
  </get-data>
</rpc>
]]></sourcecode>
      </figure>
      <t><xref target="fig-cap-reply"/> shows the "pm-interval-capabilities" data returned
within "system-capabilities" in the reply.</t>
      <figure anchor="fig-cap-reply">
        <name>Interval Capabilities Discovery Reply Data Example</name>
        <sourcecode type="xml"><![CDATA[
<pm-interval-capabilities
    xmlns=
  "urn:ietf:params:xml:ns:yang:ietf-pm-interval-capabilities"
    xmlns:ex="urn:example:pm-parameters">
  <parameter-profile>
    <name>example-ip-qos-15min</name>
    <pm-parameter>
      <name>ex:lost-packets</name>
      <supported-collection-types>counts</supported-collection-types>
      <interval-relationships>
        <sampling-interval>
          <id>1s</id>
          <min-value>1</min-value>
          <max-value>1</max-value>
          <units>second</units>
          <default-value>1</default-value>
          <default-unit>second</default-unit>
          <granularity>1</granularity>
          <collection-interval>
            <id>collection-range</id>
            <min-value>5</min-value>
            <max-value>1440</max-value>
            <units>minute</units>
            <default-value>15</default-value>
            <default-unit>minute</default-unit>
            <granularity>5</granularity>
            <retained-interval-count>1</retained-interval-count>
          </collection-interval>
        </sampling-interval>
      </interval-relationships>
    </pm-parameter>
  </parameter-profile>
</pm-interval-capabilities>
]]></sourcecode>
      </figure>
      <t>The reply indicates that the server supports 1-second sampling and
a collection interval range of 5 to 1440 minutes with 5-minute
granularity, with a default of 15 minutes; that it supports the
counts collection type for the parameter;
and that it retains the most recently completed collection
interval.  Using this information, the client can configure the
"ex:lost-packets" parameter in "ietf-pm-collection" with any collection interval
that is a multiple of 5 within the range 5 to 1440 minutes, and
with the counts collection type, knowing the server will
accept the configuration.</t>
      <t>When the server also advertises supported measurement methods for
the parameter, the reply additionally lists one or more
"supported-measurement-method" values (and optionally a
"default-measurement-method"), from which the client selects the
method to configure in "ietf-pm-collection".</t>
    </section>
    <section anchor="tree-diagram">
      <name>Tree Diagram</name>
      <t>The following tree diagram, using the notation defined in <xref target="RFC8340"/>,
shows the structure of the "ietf-pm-interval-capabilities" module.</t>
      <figure anchor="fig-tree">
        <name>Tree Diagram of ietf-pm-interval-capabilities</name>
        <artwork type="ascii-art"><![CDATA[
module: ietf-pm-interval-capabilities

  augment /sysc:system-capabilities:
    +--ro pm-interval-capabilities
       +--ro parameter-profile* [name]
          +--ro name            pm-co:profile-names
          +--ro pm-parameter* [name]
             +--ro name                            identityref
             +--ro supported-measurement-method*   identityref
             +--ro default-measurement-method?     identityref
             +--ro supported-collection-types*
             |       pm-co:collection-type
             +--ro interval-relationships
                +--ro sampling-interval* [id]
                   +--ro id                      string
                   +--ro min-value?              uint32
                   +--ro max-value?              uint32
                   +--ro units*                  interval-unit
                   +--ro default-value?          uint32
                   +--ro default-unit?           interval-unit
                   +--ro granularity?            uint32
                   +--ro collection-interval* [id]
                      +--ro id               string
                      +--ro min-value?       uint32
                      +--ro max-value?       uint32
                      +--ro units*           interval-unit
                      +--ro default-value?   uint32
                      +--ro default-unit?    interval-unit
                      +--ro granularity?     uint32
                      +--ro retained-interval-count?   uint32
]]></artwork>
      </figure>
    </section>
    <section anchor="yang-module">
      <name>YANG Module</name>
      <sourcecode type="yang" markers="true" name="ietf-pm-interval-capabilities@2026-10-29.yang"><![CDATA[
module ietf-pm-interval-capabilities {
  yang-version 1.1;
  namespace
    "urn:ietf:params:xml:ns:yang:ietf-pm-interval-capabilities";
  prefix pm-ic;

  import ietf-pm-collection {
    prefix pm-co;
    reference
      "RFC YYYY: A YANG Data Model for Performance Monitoring (PM)
       Collection";
  }

  import ietf-system-capabilities {
    prefix sysc;
    reference
      "RFC 9196: YANG Modules Describing Capabilities for
       Systems and Datastore Update Notifications";
  }

  organization
    "IETF IP Performance Metrics (ippm) Working Group";
  contact
    "WG Web: <https://datatracker.ietf.org/wg/ippm/>
     Editor: Bin Yeong Yoon <mailto:byyun@etri.re.kr>";
  description
    "This YANG module defines a data model for advertising
     performance monitoring (PM) interval capabilities in network
     equipment.  The module enables clients to discover which
     sampling and collection intervals, measurement methods, and
     collection types a server supports for each performance
     parameter within each parameter profile, before configuring
     PM collection.

     This module provides hierarchical interval capability
     discovery, in which collection intervals are nested within
     their corresponding sampling interval, and each parameter
     can have different interval capabilities within each
     parameter profile.

     This module imports the profile-names type, the
     performance-parameter and measurement-method identities,
     and the collection-type typedef from ietf-pm-collection and
     mirrors its profile-and-parameter structure.  It does not
     define collection data structures, collection types, or any
     delivery mechanism; those are defined in ietf-pm-collection.

     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) 2026 IETF Trust and the persons identified as
     authors of the code.  All rights reserved.

     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject
     to the license terms contained in, the Revised BSD License
     set forth in Section 4.c of the IETF Trust's Legal Provisions
     Relating to IETF Documents
     (https://trustee.ietf.org/license-info).

     This version of this YANG module is part of RFC XXXX
     (https://www.rfc-editor.org/info/rfcXXXX); see the RFC
     itself for full legal notices.";

  revision 2026-10-29 {
    description
      "Initial revision.";
    reference
      "RFC XXXX: A YANG Data Model for Performance Monitoring (PM)
       Interval Capabilities";
  }

  /*
   * TYPEDEFs
   */
  typedef interval-unit {
    type enumeration {
      enum millisecond {
        description "Time interval in milliseconds.";
      }
      enum second {
        description "Time interval in seconds.";
      }
      enum minute {
        description "Time interval in minutes.";
      }
      enum hour {
        description "Time interval in hours.";
      }
      enum day {
        description "Time interval in days.";
      }
    }
    description "Supported units for expressing time intervals.";
  }

  /*
   * GROUPINGS
   */
  grouping interval-constraints {
    description
      "Capability constraints for a single interval type,
       covering the supported range, units, default, and
       granularity.  Used for both sampling intervals and
       collection intervals.";
    leaf min-value {
      type uint32;
      description
        "Minimum supported value for this interval.";
    }
    leaf max-value {
      type uint32;
      description
        "Maximum supported value for this interval.";
    }
    leaf-list units {
      type interval-unit;
      description
        "List of supported time units for this interval.";
    }
    leaf default-value {
      type uint32;
      description
        "Default value recommended for this interval.";
    }
    leaf default-unit {
      type interval-unit;
      description
        "Default unit recommended for this interval.";
    }
    leaf granularity {
      type uint32;
      description
        "Granularity step for interval values.  Only values
         that are multiples of this granularity are supported.
         For example, if granularity is 5, valid values are
         5, 10, 15, 20, and so on.";
    }
  }

  grouping parameter-interval-capabilities {
    description
      "Capabilities for a single PM parameter within a profile.
       The structure nests collection intervals within their
       corresponding sampling interval, reflecting the
       constraints that ietf-pm-collection places on the
       relationship between the two intervals.";
    leaf name {
      type identityref {
        base pm-co:performance-parameter;
      }
      description
        "Identity of the performance parameter, derived from the
         performance-parameter base identity of
         ietf-pm-collection.  This value corresponds to the
         pm-parameter name leaf in ietf-pm-collection.";
    }
    leaf-list supported-measurement-method {
      type identityref {
        base pm-co:measurement-method;
      }
      description
        "The set of IPPM measurement methods (RFC 7799) that
         this server can apply to this parameter.  A client
         selects one of the advertised methods when configuring
         the parameter in ietf-pm-collection.  An empty or
         absent list means the server does not advertise
         measurement-method information for this parameter.";
      reference
        "RFC 7799: Active and Passive Metrics and Methods (with
         Hybrid Types In-Between)";
    }
    leaf default-measurement-method {
      type identityref {
        base pm-co:measurement-method;
      }
      description
        "The measurement method the server uses for this
         parameter when a client configures the parameter
         without selecting a method.  When present, it MUST be
         a member of supported-measurement-method.";
      reference
        "RFC 7799: Active and Passive Metrics and Methods (with
         Hybrid Types In-Between)";
    }
    leaf-list supported-collection-types {
      type pm-co:collection-type;
      description
        "The set of collection types (counts, snapshot,
         tidemarks) that this server supports for this
         parameter.  A client enables only the advertised
         collection types when configuring the parameter in
         ietf-pm-collection.  An empty or absent list means the
         server does not advertise collection-type information
         for this parameter.";
    }
    container interval-relationships {
      description
        "Hierarchical relationships between sampling and
         collection intervals for this parameter.  Each
         advertised combination of sampling and collection
         interval MUST satisfy the constraints of
         ietf-pm-collection.";
      list sampling-interval {
        key "id";
        description
          "List of supported sampling intervals and their
           compatible collection intervals.";
        leaf id {
          type string;
          description
            "Unique identifier for this sampling interval
             capability entry.";
        }
        uses interval-constraints;
        list collection-interval {
          key "id";
          description
            "List of supported collection intervals for
             this sampling interval.";
          leaf id {
            type string;
            description
              "Unique identifier for this collection
               interval capability entry.";
          }
          uses interval-constraints;
          leaf retained-interval-count {
            type uint32;
            description
              "Number of completed intervals of this collection
               interval that the server retains after they end.
               It bounds how many completed intervals a client
               may read back and, for push delivery, how long a
               reporting period may be: a reporting period may
               span at most retained-interval-count collection
               intervals.  A value of 1 means only the most
               recently completed interval is retained; 0 means
               completed intervals are not retained (each is
               delivered only as it ends).";
          }
        }
      }
    }
  }

  grouping profile-parameter-capabilities {
    description
      "Capabilities for all PM parameters within a single
       parameter profile.";
    leaf name {
      type pm-co:profile-names;
      description
        "Name of the parameter profile.  This value
         corresponds to the parameter-profile name leaf in
         ietf-pm-collection (e.g.,
         example-ip-qos-15min).";
    }
    list pm-parameter {
      key "name";
      description
        "List of PM parameters and their capabilities within
         this profile.";
      uses parameter-interval-capabilities;
    }
  }

  /*
   * AUGMENTATION OF ietf-system-capabilities (RFC 9196)
   *
   * The capabilities are advertised by augmenting the
   * "system-capabilities" container defined in RFC 9196.  This
   * places the PM interval capabilities at the same well-known
   * location at which a NETCONF/RESTCONF client discovers
   * subscription and notification capabilities
   * (ietf-notification-capabilities, RFC 9196 Section 3), so that
   * both can be retrieved in a single, standardised query.  The
   * "pm-interval-capabilities" wrapper container cleanly separates
   * this capability group from other capabilities augmented into
   * the same anchor.  All augmented nodes inherit "config false"
   * from sysc:system-capabilities and therefore reside in the
   * operational datastore.
   */
  augment "/sysc:system-capabilities" {
    description
      "Augments the system capabilities with PM interval
       capabilities, advertising the sampling and collection
       intervals, measurement methods, and collection types that
       this server supports, organised by parameter profile and
       PM parameter.";
    container pm-interval-capabilities {
      description
        "Read-only advertisement of the PM capabilities of this
         server, organised by parameter profile and PM
         parameter.  A client reads this container to determine
         which interval values, measurement methods, and
         collection types are valid before configuring PM
         collection in ietf-pm-collection.";
      list parameter-profile {
        key "name";
        description
          "List of parameter profiles and their per-parameter
           capabilities.";
        uses profile-parameter-capabilities;
      }
    }
  }
}
]]></sourcecode>
    </section>
    <section anchor="manageability-considerations">
      <name>Manageability Considerations</name>
      <t>A server SHOULD ensure that the capabilities advertised in
"pm-interval-capabilities" remain consistent with its actual ability
to honour interval configurations in "ietf-pm-collection".  If a
server's resources change dynamically (e.g., due to load), it SHOULD
update the operational datastore accordingly, and clients that have
already configured measurements using previously advertised values
SHOULD be notified through standard NETCONF or YANG-Push mechanisms.</t>
      <t>Operators SHOULD verify that the interval values configured in
"ietf-pm-collection" fall within the ranges advertised in this module
before deploying measurement configurations in production.</t>
    </section>
    <section anchor="security-considerations">
      <name>Security Considerations</name>
      <t>The YANG module defined in this document defines data nodes that are
designed to be accessed via network management protocols such as
NETCONF <xref target="RFC6241"/> or RESTCONF.  The module augments the
"system-capabilities" container of "ietf-system-capabilities"
<xref target="RFC9196"/>, which is "config false"; all nodes added by this module
therefore inherit "config false" and reside in the operational
datastore.  Following the guidance in <xref target="RFC9196"/>, this section
documents the security considerations of the augmented nodes.</t>
      <t>The lowest NETCONF layer is the secure transport layer, and the
mandatory-to-implement secure transport is Secure Shell (SSH).  The
Network Configuration Access Control Model (NACM) <xref target="RFC8341"/> provides
the means to restrict access for particular NETCONF or RESTCONF users
to a preconfigured subset of all available NETCONF or RESTCONF
protocol operations and content.</t>
      <t>Although all nodes are read-only, the capability information they
expose can reveal vendor-specific implementation details about the
equipment, such as supported interval ranges and granularities.
Operators SHOULD restrict read access to authorised management clients
to prevent unintended disclosure of device implementation
characteristics.</t>
    </section>
    <section anchor="iana-considerations">
      <name>IANA Considerations</name>
      <t>This document requests IANA to register the following URI in the
"ns" subregistry within the "IETF XML Registry" <xref target="RFC3688"/>:</t>
      <t>URI: urn:ietf:params:xml:ns:yang:ietf-pm-interval-capabilities
   Registrant Contact: The IESG.
   XML: N/A; the requested URI is an XML namespace.</t>
      <t>This document requests IANA to register the following YANG module
in the "YANG Module Names" registry <xref target="RFC6020"/>:</t>
      <t>Name:      ietf-pm-interval-capabilities
   Namespace:
     urn:ietf:params:xml:ns:yang:ietf-pm-interval-capabilities
   Prefix:    pm-ic
   Reference: RFC XXXX</t>
    </section>
  </middle>
  <back>
    <references anchor="sec-combined-references">
      <name>References</name>
      <references anchor="sec-normative-references">
        <name>Normative References</name>
        <reference anchor="RFC6020">
          <front>
            <title>YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)</title>
            <author fullname="M. Bjorklund" initials="M." role="editor" surname="Bjorklund"/>
            <date month="October" year="2010"/>
            <abstract>
              <t>YANG is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6020"/>
          <seriesInfo name="DOI" value="10.17487/RFC6020"/>
        </reference>
        <reference anchor="RFC6241">
          <front>
            <title>Network Configuration Protocol (NETCONF)</title>
            <author fullname="R. Enns" initials="R." role="editor" surname="Enns"/>
            <author fullname="M. Bjorklund" initials="M." role="editor" surname="Bjorklund"/>
            <author fullname="J. Schoenwaelder" initials="J." role="editor" surname="Schoenwaelder"/>
            <author fullname="A. Bierman" initials="A." role="editor" surname="Bierman"/>
            <date month="June" year="2011"/>
            <abstract>
              <t>The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6241"/>
          <seriesInfo name="DOI" value="10.17487/RFC6241"/>
        </reference>
        <reference anchor="RFC7950">
          <front>
            <title>The YANG 1.1 Data Modeling Language</title>
            <author fullname="M. Bjorklund" initials="M." role="editor" surname="Bjorklund"/>
            <date month="August" year="2016"/>
            <abstract>
              <t>YANG is a data modeling language used to model configuration data, state data, Remote Procedure Calls, and notifications for network management protocols. This document describes the syntax and semantics of version 1.1 of the YANG language. YANG version 1.1 is a maintenance release of the YANG language, addressing ambiguities and defects in the original specification. There are a small number of backward incompatibilities from YANG version 1. This document also specifies the YANG mappings to the Network Configuration Protocol (NETCONF).</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7950"/>
          <seriesInfo name="DOI" value="10.17487/RFC7950"/>
        </reference>
        <reference anchor="RFC8340">
          <front>
            <title>YANG Tree Diagrams</title>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <author fullname="L. Berger" initials="L." role="editor" surname="Berger"/>
            <date month="March" year="2018"/>
            <abstract>
              <t>This document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="215"/>
          <seriesInfo name="RFC" value="8340"/>
          <seriesInfo name="DOI" value="10.17487/RFC8340"/>
        </reference>
        <reference anchor="RFC8341">
          <front>
            <title>Network Configuration Access Control Model</title>
            <author fullname="A. Bierman" initials="A." surname="Bierman"/>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <date month="March" year="2018"/>
            <abstract>
              <t>The standardization of network configuration interfaces for use with the Network Configuration Protocol (NETCONF) or the RESTCONF protocol requires a structured and secure operating environment that promotes human usability and multi-vendor interoperability. There is a need for standard mechanisms to restrict NETCONF or RESTCONF protocol access for particular users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. This document defines such an access control model.</t>
              <t>This document obsoletes RFC 6536.</t>
            </abstract>
          </front>
          <seriesInfo name="STD" value="91"/>
          <seriesInfo name="RFC" value="8341"/>
          <seriesInfo name="DOI" value="10.17487/RFC8341"/>
        </reference>
        <reference anchor="RFC8342">
          <front>
            <title>Network Management Datastore Architecture (NMDA)</title>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <author fullname="J. Schoenwaelder" initials="J." surname="Schoenwaelder"/>
            <author fullname="P. Shafer" initials="P." surname="Shafer"/>
            <author fullname="K. Watsen" initials="K." surname="Watsen"/>
            <author fullname="R. Wilton" initials="R." surname="Wilton"/>
            <date month="March" year="2018"/>
            <abstract>
              <t>Datastores are a fundamental concept binding the data models written in the YANG data modeling language to network management protocols such as the Network Configuration Protocol (NETCONF) and RESTCONF. This document defines an architectural framework for datastores based on the experience gained with the initial simpler model, addressing requirements that were not well supported in the initial model. This document updates RFC 7950.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8342"/>
          <seriesInfo name="DOI" value="10.17487/RFC8342"/>
        </reference>
        <reference anchor="RFC8525">
          <front>
            <title>YANG Library</title>
            <author fullname="A. Bierman" initials="A." surname="Bierman"/>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <author fullname="J. Schoenwaelder" initials="J." surname="Schoenwaelder"/>
            <author fullname="K. Watsen" initials="K." surname="Watsen"/>
            <author fullname="R. Wilton" initials="R." surname="Wilton"/>
            <date month="March" year="2019"/>
            <abstract>
              <t>This document describes a YANG library that provides information about the YANG modules, datastores, and datastore schemas used by a network management server. Simple caching mechanisms are provided to allow clients to minimize retrieval of this information. This version of the YANG library supports the Network Management Datastore Architecture (NMDA) by listing all datastores supported by a network management server and the schema that is used by each of these datastores.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8525"/>
          <seriesInfo name="DOI" value="10.17487/RFC8525"/>
        </reference>
        <reference anchor="RFC9196">
          <front>
            <title>YANG Modules Describing Capabilities for Systems and Datastore Update Notifications</title>
            <author fullname="B. Lengyel" initials="B." surname="Lengyel"/>
            <author fullname="A. Clemm" initials="A." surname="Clemm"/>
            <author fullname="B. Claise" initials="B." surname="Claise"/>
            <date month="February" year="2022"/>
            <abstract>
              <t>This document defines two YANG modules, "ietf-system-capabilities" and "ietf-notification-capabilities".</t>
              <t>The module "ietf-system-capabilities" provides a placeholder structure that can be used to discover YANG-related system capabilities for servers. The module can be used to report capability information from the server at runtime or at implementation time by making use of the YANG instance data file format.</t>
              <t>The module "ietf-notification-capabilities" augments "ietf-system-capabilities" to specify capabilities related to "Subscription to YANG Notifications for Datastore Updates" (RFC 8641).</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="9196"/>
          <seriesInfo name="DOI" value="10.17487/RFC9196"/>
        </reference>
        <reference anchor="I-D.yoon-ippm-collection-measure">
          <front>
            <title>A YANG Data Model for Collection Measurement</title>
            <author fullname="Bin Yeong Yoon" initials="B. Y." surname="Yoon">
              <organization>ETRI</organization>
            </author>
            <author fullname="Youngkil You" initials="Y." surname="You">
              <organization>woori-net</organization>
            </author>
            <date day="5" month="July" year="2026"/>
            <abstract>
              <t>   This document specifies a YANG data model for Collection Measurement
   based on the Performance Management (PM) Collection function
   requirements defined in ITU-T G.7710.  The model processes raw
   performance data sampled at a network node and produces structured
   data that can be retrieved by clients via pull-based mechanisms or
   delivered via push-based mechanisms such as YANG-Push.  This document
   does not define new performance metrics; the base metrics are those
   of the IPPM framework, and the model specifies the collection and
   exposure of the operationally important subset identified by ITU-T
   G.7710.

              </t>
            </abstract>
          </front>
          <seriesInfo name="Internet-Draft" value="draft-yoon-ippm-collection-measure-00"/>
        </reference>
        <reference anchor="RFC2119">
          <front>
            <title>Key words for use in RFCs to Indicate Requirement Levels</title>
            <author fullname="S. Bradner" initials="S." surname="Bradner"/>
            <date month="March" year="1997"/>
            <abstract>
              <t>In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="14"/>
          <seriesInfo name="RFC" value="2119"/>
          <seriesInfo name="DOI" value="10.17487/RFC2119"/>
        </reference>
        <reference anchor="RFC8174">
          <front>
            <title>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words</title>
            <author fullname="B. Leiba" initials="B." surname="Leiba"/>
            <date month="May" year="2017"/>
            <abstract>
              <t>RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="14"/>
          <seriesInfo name="RFC" value="8174"/>
          <seriesInfo name="DOI" value="10.17487/RFC8174"/>
        </reference>
      </references>
      <references anchor="sec-informative-references">
        <name>Informative References</name>
        <reference anchor="G7710" target="https://www.itu.int/rec/T-REC-G.7710">
          <front>
            <title>Common Equipment Management Function Requirements</title>
            <author>
              <organization>ITU-T</organization>
            </author>
            <date year="2025" month="November"/>
          </front>
          <seriesInfo name="ITU-T" value="Recommendation G.7710"/>
        </reference>
        <reference anchor="RFC7799">
          <front>
            <title>Active and Passive Metrics and Methods (with Hybrid Types In-Between)</title>
            <author fullname="A. Morton" initials="A." surname="Morton"/>
            <date month="May" year="2016"/>
            <abstract>
              <t>This memo provides clear definitions for Active and Passive performance assessment. The construction of Metrics and Methods can be described as either "Active" or "Passive". Some methods may use a subset of both Active and Passive attributes, and we refer to these as "Hybrid Methods". This memo also describes multiple dimensions to help evaluate new methods as they emerge.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7799"/>
          <seriesInfo name="DOI" value="10.17487/RFC7799"/>
        </reference>
        <reference anchor="RFC6390">
          <front>
            <title>Guidelines for Considering New Performance Metric Development</title>
            <author fullname="A. Clark" initials="A." surname="Clark"/>
            <author fullname="B. Claise" initials="B." surname="Claise"/>
            <date month="October" year="2011"/>
            <abstract>
              <t>This document describes a framework and a process for developing Performance Metrics of protocols and applications transported over IETF-specified protocols. These metrics can be used to characterize traffic on live networks and services. This memo documents an Internet Best Current Practice.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="170"/>
          <seriesInfo name="RFC" value="6390"/>
          <seriesInfo name="DOI" value="10.17487/RFC6390"/>
        </reference>
        <reference anchor="RFC9195">
          <front>
            <title>A File Format for YANG Instance Data</title>
            <author fullname="B. Lengyel" initials="B." surname="Lengyel"/>
            <author fullname="B. Claise" initials="B." surname="Claise"/>
            <date month="February" year="2022"/>
            <abstract>
              <t>There is a need to document data defined in YANG models at design time, implementation time, or when a live server is unavailable. This document specifies a standard file format for YANG instance data, which follows the syntax and semantics of existing YANG models and annotates it with metadata.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="9195"/>
          <seriesInfo name="DOI" value="10.17487/RFC9195"/>
        </reference>
        <reference anchor="RFC8526">
          <front>
            <title>NETCONF Extensions to Support the Network Management Datastore Architecture</title>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <author fullname="J. Schoenwaelder" initials="J." surname="Schoenwaelder"/>
            <author fullname="P. Shafer" initials="P." surname="Shafer"/>
            <author fullname="K. Watsen" initials="K." surname="Watsen"/>
            <author fullname="R. Wilton" initials="R." surname="Wilton"/>
            <date month="March" year="2019"/>
            <abstract>
              <t>This document extends the Network Configuration Protocol (NETCONF) defined in RFC 6241 in order to support the Network Management Datastore Architecture (NMDA) defined in RFC 8342.</t>
              <t>This document updates RFCs 6241 and 7950. The update to RFC 6241 adds new and operations and augments existing,, and operations. The update to RFC 7950 requires the usage of the YANG library (described in RFC 8525) by NETCONF servers implementing the NMDA.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8526"/>
          <seriesInfo name="DOI" value="10.17487/RFC8526"/>
        </reference>
        <reference anchor="RFC3688">
          <front>
            <title>The IETF XML Registry</title>
            <author fullname="M. Mealling" initials="M." surname="Mealling"/>
            <date month="January" year="2004"/>
            <abstract>
              <t>This document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="81"/>
          <seriesInfo name="RFC" value="3688"/>
          <seriesInfo name="DOI" value="10.17487/RFC3688"/>
        </reference>
      </references>
    </references>
    <section anchor="contributors" numbered="false" toc="include" removeInRFC="false">
      <name>Contributors</name>
      <contact initials="K." surname="Lee" fullname="Kwangkoog Lee">
        <organization>KT</organization>
        <address>
          <email>kwangkoog.lee@kt.com</email>
        </address>
      </contact>
      <contact initials="J." surname="Shin" fullname="Jongyoon Shin">
        <organization>SK Telecom</organization>
        <address>
          <email>jongyoon.shin@sk.com</email>
        </address>
      </contact>
      <contact initials="S." surname="Nam" fullname="Sungyong Nam">
        <organization>LGU+</organization>
        <address>
          <email>sy.nam@lguplus.co.kr</email>
        </address>
      </contact>
    </section>
  </back>
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