draft-tgraf-opsawg-ipfix-inband-telemetry-00.xml

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<rfc category="std" docName="draft-tgraf-opsawg-ipfix-inband-telemetry-00"
     ipr="trust200902">
  <front>
    <title abbrev="Export of Forwarding Path Delay in IPFIX">Export of
    Forwarding Path Delay in IPFIX</title>

    <author fullname="Thomas Graf" initials="T" surname="Graf">
      <organization>Swisscom</organization>

      <address>
        <postal>
          <street>Binzring 17</street>

          <city>Zurich</city>

          <code>8045</code>

          <country>Switzerland</country>
        </postal>

        <email>thomas.graf@swisscom.com</email>
      </address>
    </author>

    <author fullname="Benoit Claise" initials="B" surname="Claise">
      <organization>Huawei</organization>

      <address>
        <email>benoit.claise@huawei.com</email>
      </address>
    </author>

    <author fullname="Alex Huang Feng" initials="A." surname="Huang Feng">
      <organization>INSA-Lyon</organization>

      <address>
        <postal>
          <street/>

          <city>Lyon</city>

          <region/>

          <code/>

          <country>France</country>
        </postal>

        <phone/>

        <facsimile/>

        <email>alex.huang-feng@insa-lyon.fr</email>

        <uri/>
      </address>
    </author>

    <date day="8" month="July" year="2022"/>

    <abstract>
      <t>This document introduces new IP Flow Information Export (IPFIX)
      information elements to expose the Inband Telemetry measured forwarding
      path delay in passport and postcard mode on the transit and
      decapsulation nodes.</t>
    </abstract>
  </front>

  <middle>
    <section anchor="Introduction" title="Introduction">
      <t>With Inband Telemetry, defined in <xref
      target="I-D.ietf-ippm-ioam-deployment">In-situ OAM</xref>, <xref
      target="I-D.filsfils-spring-path-tracing">Path Tracing</xref> and <xref
      target="I-D.song-opsawg-ifit-framework">In-situ Flow Information
      Telemetry</xref>, the path delay between two endpoints is measured by
      inserting a timestamp in the packet.</t>

      <t>Inband Telemetry can be distinguished between two modes. Passport
      mode where only the last hop in the forwarding path of the Inband
      Telemetry domain exposes all the metrics and postcard mode where the
      transit nodes also expose metrics. In both modes the forwarding path is
      exposed thus allowing to determine how much delay has been accumulated
      hop by hop.</t>

      <t>This document defines eight new IPFIX Information Elements (IEs) with
      their four corresponding entries in the performance metrics registry to
      expose the forwarding path delay on the transit and decapsulation
      nodes.</t>

      <t>The delay is measured by calculating the difference between the
      timestamp imposed with Inband Telemetry in the packet at the
      encapsulation node and the timestamp exported in the IPFIX flow record
      from the transit and decapsulation nodes. Depending on the IE, the
      lowest, highest or the sum of measured delay is being exported.</t>
    </section>

    <section anchor="ip-ow-delay-hybridtype1-passive-reg-entries"
             title="IP One-Way Delay Hybrid Type I Passive Registry Entries">
      <t>This section specifies four Registry Entries for the Hybrid Type I
      Passive assessment of IP One-Way Delay.</t>

      <t>All column entries besides the ID, Name, Description, and Output
      Reference Method categories are the same; thus, this section defines
      four closely related Registry Entries. As a result, IANA has assigned
      corresponding URLs to each of the four Named Metrics.</t>

      <section numbered="true" title="Summary">
        <t>This category includes multiple indexes to the Registry Entry: the
        element ID and Metric Name.</t>

        <section title="ID (Identifier)">
          <t>&lt;insert a numeric Identifier, an integer, TBD&gt;</t>
        </section>

        <section title="Name">
          <t>IANA has allocated the numeric Identifiers TBD1-4 for the four
          Named Metric Entries in this section</t>
        </section>

        <section title="Name">
          <t>TBD1: OWDelay_HybridType1_Passive_IP_RFCTBD_Seconds_Mean</t>

          <t>TBD2: OWDelay_HybridType1_Passive_IP_RFCTBD_Seconds_Min</t>

          <t>TBD3: OWDelay_HybridType1_Passive_IP_RFCTBD_Seconds_Max</t>

          <t>TBD4: OWDelay_HybridType1_Passive_IP_RFCTBD_Seconds_Sum</t>
        </section>

        <section title="URI">
          <t>URL: <eref
          target="https://www.iana.org/assignments/performance-metrics/OWDelay_HybridType1_Passive_IP_RFCTBD_Seconds_Mean"/></t>

          <t>URL: <eref
          target="https://www.iana.org/assignments/performance-metrics/OWDelay_HybridType1_Passive_IP_RFCTBD_Seconds_Min"/></t>

          <t>URL: <eref
          target="https://www.iana.org/assignments/performance-metrics/OWDelay_HybridType1_Passive_IP_RFCTBD_Seconds_Max"/></t>

          <t>URL: <eref
          target="https://www.iana.org/assignments/performance-metrics/OWDelay_HybridType1_Passive_IP_RFCTBD_Seconds_Sum"/></t>
        </section>
      </section>

      <section title="Description">
        <t>This metric assesses the one-way delay of IP packets constituting a
        single connection, exchanged between two hosts. We consider the
        measurement of one-way delay based on a single Observation Point (OP)
        <xref target="RFC7011"/> somewhere in the network. The output is the
        one-way delay for all successfully exchanged packets expressed as the
        &lt;statistic&gt; of their conditional delay distribution, where
        &lt;statistic&gt; is one of:</t>

        <t><list style="symbols">
            <t>Mean</t>

            <t>Min</t>

            <t>Max</t>

            <t>Sum</t>
          </list></t>
      </section>

      <section title="Change Controller">
        <t>IETF</t>
      </section>

      <section title="Version of Registry Format">
        <t>1.0</t>
      </section>
    </section>

    <section title="Metric Definition">
      <t>This category includes columns to prompt the entry of all necessary
      details related to the metric definition, including the immutable
      document reference and values of input factors, called "Fixed
      Parameters".</t>

      <section title="Reference Definition">
        <t>Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton, Ed., "A
        One-Way Delay Metric for IP Performance Metrics (IPPM)", STD 81, RFC
        7679, DOI 10.17487/RFC7679, January 2016,
        &lt;https://www.rfc-editor.org/info/rfc7679&gt;. <xref
        target="RFC7679"/></t>

        <t>Morton, A. and E. Stephan, "Spatial Composition of Metrics", RFC
        6049, DOI 10.17487/RFC6049, January 2011,
        &lt;https://www.rfc-editor.org/info/rfc6049&gt;. <xref
        target="RFC6049"/></t>

        <t>Section 3.4 of <xref target="RFC7679"/> provides the reference
        definition of the singleton (single value) one-way delay metric.
        Section 4.4 of <xref target="RFC7679"/> provides the reference
        definition expanded to cover a multi-value sample. Note that terms
        such as "singleton" and "sample" are defined in section 2 of <xref
        target="RFC2330"/>.</t>

        <t>With the OP <xref target="RFC7011"/> typically located between the
        hosts participating in the IP connection, the one-way delay metric
        requires one individual measurement between the OP and sourcing host,
        such that the Spatial Composition <xref target="RFC6049"/> of the
        measurements yields a one-way delay singleton.</t>
      </section>

      <section title="Fixed Parameters">
        <t><figure>
            <preamble>Traffic Filters:</preamble>

            <artwork><![CDATA[
 IPv4 header values:
   DSCP: Set to 0

 IPv6 header values:
   DSCP: Set to 0
   Hop Count: Set to 255
   Flow Label: Set to 0
   Extension Headers: None
          ]]></artwork>
          </figure></t>
      </section>
    </section>

    <section title="Method of Measurement">
      <t>This category includes columns for references to relevant sections of
      the RFC(s) and any supplemental information needed to ensure an
      unambiguous method for implementations.</t>

      <section title="Reference Methods">
        <t>The foundational methodology for this metric is defined in section
        4 of <xref target="RFC7323"/> using the Timestamps option with
        modifications that allow application at a mid-path OP <xref
        target="RFC7011"/>.</t>

        <t>The Traffic Filter at the OP is configured to observe a single IP
        connection.</t>
      </section>

      <section title="Packet Stream Generation">
        <t>N/A</t>
      </section>

      <section title="Traffic Filtering (Observation) Details">
        <t>The Fixed Parameters above give a portion of the Traffic Filter.
        Other aspects will be supplied as Runtime Parameters (below).</t>
      </section>

      <section title="Sampling Distribution">
        <t>This metric requires a partial sample of all packets that qualify
        according to the Traffic Filter criteria.</t>
      </section>

      <section title="Runtime Parameters and Data Format">
        <t>Runtime Parameters are input factors that must be determined,
        configured into the measurement system, and reported with the results
        for the context to be complete.</t>

        <t><list style="hanging">
            <t hangText="Src:">The IP address of the host in the host A Role
            (format ipv4&nbhy;address-no-zone value for IPv4 or
            ipv6-address-no-zone value for IPv6; see section 4 of <xref
            target="RFC6991"/>.</t>

            <t hangText="Dst:">The IP address of the host in the host B Role
            (format ipv4&nbhy;address-no-zone value for IPv4 or
            ipv6-address-no-zone value for IPv6; see section 4 of <xref
            target="RFC6991"/>.</t>

            <t hangText="TTL or Hop Limit:">Set at desired value.</t>

            <t hangText="DSCP:">Set at desired value.</t>

            <t hangText="IPv6 Flow Label:">Set at desired value.</t>

            <t hangText="Timestamp:">The timestamp when the packet is being
            received at IOAM encapsulation node. Format depends on Inband
            Telemetry implementation. For IOAM, Section 4.4.1 of <xref
            target="RFC9197"/> describes what kind of timestamps are
            supported. Section 4.4.2.3 and 4.4.2.4 describe where the
            timestamp is being inserted. For Path Tracing, Section 4.1 of
            <xref target="I-D.filsfils-spring-path-tracing"/> describes what
            kind of timestamps are supported. Section 9.2 describe the SRH
            path tracing TLV where the timestamp is being inserted.</t>
          </list></t>
      </section>

      <section title="Roles">
        <t><list style="hanging">
            <t hangText="host A:">Launches the IP packet to open the
            connection. The Role of "host A" is synonymous with the IP address
            used at host A.</t>

            <t hangText="host B:">Receives the IP packet to open the
            connection. The Role of "host B" is synonymous with the IP address
            used at host B.</t>

            <t hangText="Encapsulation Node:">Receives the IP packet to open
            the connection and encapsulates the timestamp into the packet. The
            Role of "Encapsulation Node" is synonymous with the timestamp
            inserted in the packet.</t>

            <t hangText="Transit Node:">Receives the IP packet to open the
            connection and measures the delay between the timestamp in the
            packet and the timestamp when the packet was received.</t>

            <t hangText="Decapsulation Node:">Receives the IP packet to open
            the connection and measures the delay between the timestamp in the
            packet and the timestamp when the packet was received and removes
            the IOAM header from the packet.</t>
          </list></t>
      </section>
    </section>

    <section title="Output">
      <t>This category specifies all details of the output of measurements
      using the metric.</t>

      <section title="Type">
        <t>OWDelay Types are discussed in the subsections below.</t>
      </section>

      <section title="Reference Definition">
        <t>For all output types:</t>

        <t><list style="hanging">
            <t hangText="OWDelay_HybridType1_Passive_IP:">The one-trip delay
            of one IP packet is a Singleton</t>
          </list></t>

        <t>For each &lt;statistic&gt;, Singleton one of the following
        subsections applies.</t>

        <section title="Mean">
          <t>The mean SHALL be calculated using the conditional distribution
          of all packets with a finite value of one-way delay (undefined
          delays are excluded) -- a single value, as follows:</t>

          <t>See section 4.1 of <xref target="RFC3393"/> for details on the
          conditional distribution to exclude undefined values of delay, and
          see section 5 of <xref target="RFC6703"/> for background on this
          analysis choice.</t>

          <t>See section 4.2.2 of <xref target="RFC6049"/> for details on
          calculating this statistic; see also section 4.2.3 of <xref
          target="RFC6049"/>.</t>

          <t><list style="hanging">
              <t hangText="Mean:">The time value of the result is expressed in
              units of seconds, as a positive value of type decimal64 with
              fraction digits = 9 (see section 9.3 of <xref
              target="RFC6020"/>) with a resolution of
              0.000000001&nbsp;seconds (1.0 ns), and with lossless conversion
              to/from the 64-bit NTP timestamp as per section 6 of <xref
              target="RFC5905"/>.</t>
            </list></t>
        </section>

        <section title="Min">
          <t>The minimum SHALL be calculated using the conditional
          distribution of all packets with a finite value of one-way delay
          (undefined delays are excluded) -- a single value, as follows:</t>

          <t>See section 4.1 of <xref target="RFC3393"/> for details on the
          conditional distribution to exclude undefined values of delay, and
          see section 5 of <xref target="RFC6703"/> for background on this
          analysis choice.</t>

          <t>See section 4.3.2 of <xref target="RFC6049"/> for details on
          calculating this statistic; see also section 4.3.3 of <xref
          target="RFC6049"/>.</t>

          <t><list style="hanging">
              <t hangText="Min:">The time value of the result is expressed in
              units of seconds, as a positive value of type decimal64 with
              fraction digits = 9 (see section 9.3 of <xref
              target="RFC6020"/>) with a resolution of
              0.000000001&nbsp;seconds (1.0 ns), and with lossless conversion
              to/from the 64-bit NTP timestamp as per section 6 of <xref
              target="RFC5905"/>.</t>
            </list></t>
        </section>

        <section title="Max">
          <t>The maximum SHALL be calculated using the conditional
          distribution of all packets with a finite value of one-way delay
          (undefined delays are excluded) -- a single value, as follows:</t>

          <t>See section 4.1 of <xref target="RFC3393"/> for details on the
          conditional distribution to exclude undefined values of delay, and
          see section 5 of <xref target="RFC6703"/> for background on this
          analysis choice.</t>

          <t>See section 4.3.2 of <xref target="RFC6049"/> for a closely
          related method for calculating this statistic; see also section
          4.3.3 of <xref target="RFC6049"/>. The formula is as follows:</t>

          <t><figure>
              <artwork><![CDATA[ 
 Max = (FiniteDelay[j])
 such that for some index, j, where 1 <= j <= N
 FiniteDelay[j] >= FiniteDelay[n] for all n
         ]]></artwork>
            </figure></t>

          <t><list style="hanging">
              <t hangText="Max:">The time value of the result is expressed in
              units of seconds, as a positive value of type decimal64 with
              fraction digits = 9 (see section 9.3 of <xref
              target="RFC6020"/>) with a resolution of
              0.000000001&nbsp;seconds (1.0 ns), and with lossless conversion
              to/from the 64-bit NTP timestamp as per section 6 of <xref
              target="RFC5905"/>.</t>
            </list></t>
        </section>

        <section title="Sum">
          <t>The sum SHALL be calculated using the conditional distribution of
          all packets with a finite value of one-way delay (undefined delays
          are excluded) -- a single value, as follows:</t>

          <t>See section 4.1 of <xref target="RFC3393"/> for details on the
          conditional distribution to exclude undefined values of delay, and
          see section 5 of <xref target="RFC6703"/> for background on this
          analysis choice.</t>

          <t>See section 4.3.5 of <xref target="RFC6049"/> for details on
          calculating this statistic. However in this case FiniteDelay or
          MaxDelay MAY be used.</t>

          <t><list style="hanging">
              <t hangText="Sum:">The time value of the result is expressed in
              units of seconds, as a positive value of type decimal64 with
              fraction digits = 9 (see section 9.3 of <xref
              target="RFC6020"/>) with a resolution of
              0.000000001&nbsp;seconds (1.0 ns), and with lossless conversion
              to/from the 64-bit NTP timestamp as per section 6 of <xref
              target="RFC5905"/>.</t>
            </list></t>
        </section>

        <section title="Metric Units">
          <t>The &lt;statistic&gt; of one-way delay is expressed in seconds,
          where &lt;statistic&gt; is one of:</t>

          <t><list style="symbols">
              <t>Mean</t>

              <t>Min</t>

              <t>Max</t>

              <t>Sum</t>
            </list></t>

          <t>The one-way delay of the IP connection singleton is expressed in
          seconds.</t>
        </section>

        <section title="Calibration">
          <t>Passive Measurements at an OP could be calibrated against an
          Active Measurement at host A where the Active Measurement represents
          the ground truth.</t>
        </section>
      </section>

      <section title="Administrative Items">
        <section title="Status">
          <t>Current</t>
        </section>

        <section title="Requester">
          <t>This RFC</t>
        </section>

        <section title="Revision">
          <t>1.0</t>
        </section>

        <section title="Revision Date">
          <t>RFC Date</t>
        </section>
      </section>

      <section title="Comments and Remarks">
        <t>None</t>
      </section>
    </section>

    <section anchor="IE" title="IPFIX Information Elements">
      <t>This section defines and describes the new IPFIX IEs.<list
          style="hanging">
          <t hangText="PathDelayMeanDeltaMicroseconds"><vspace
          blankLines="0"/> 16-bit unsigned integer that identifies the mean
          path delay.</t>

          <t hangText="PathDelayMeanDeltaNanoseconds"><vspace blankLines="0"/>
          32-bit unsigned integer that identifies the mean path delay.</t>

          <t hangText="PathDelayMinDeltaMicroseconds"><vspace blankLines="0"/>
          16-bit unsigned integer that identifies the lowest path delay.</t>

          <t hangText="PathDelayMinDeltaNanoseconds"><vspace blankLines="0"/>
          32-bit unsigned integer that identifies the lowest path delay.</t>

          <t hangText="PathDelayMaxDeltaMicroseconds"><vspace blankLines="0"/>
          16-bit unsigned integer that identifies the highest path delay.</t>

          <t hangText="PathDelayMaxDeltaNanoseconds"><vspace blankLines="0"/>
          32-bit unsigned integer that identifies the highest path delay.</t>

          <t hangText="PathDelaySumDeltaMicroseconds"><vspace blankLines="0"/>
          32-bit unsigned integer that identifies the sum of the path
          delay.</t>

          <t hangText="PathDelaySumDeltaNanoseconds"><vspace blankLines="0"/>
          64-bit unsigned integer that identifies the sum of the path
          delay.</t>
        </list></t>
    </section>

    <section anchor="Use-Cases" title="Use Cases">
      <t>The measured forwarding path delay can be aggregated with Flow
      Aggregation as defined in <xref target="RFC7015"/> to the following
      device and control-plane dimensions to determine:</t>

      <t><list style="symbols">
          <t>With node id and egressInterface(IE14), on which node which
          logical egress interfaces have been contributing to how much
          delay.</t>

          <t>With node id and egressPhysicalInterface(253), on which node
          which physical egress interfaces have been contributing to how much
          delay.</t>

          <t>With ipNextHopIPv4Address(IE15) or ipNextHopIPv6Address(IE62),
          the forwarding path to which next-hop IP contributed to how much
          delay.</t>

          <t>With mplsTopLabelIPv4Address(IE47) or srhActiveSegmentIPv6 from
          <xref target="I-D.tgraf-opsawg-ipfix-srv6-srh"/>, the forwarding
          path to which MPLS top label IPv4 address or SRv6 active segment
          contributed to how much delay.</t>

          <t>BGP communities are often used for setting a path priority or
          service selection. With bgpDestinationExtendedCommunityList(488) or
          bgpDestinationCommunityList(485) or
          bgpDestinationLargeCommunityList(491) which group of prefixes
          accumulated at which node how much delay.</t>

          <t>With destinationIPv4Address(13), destinationTransportPort(11),
          protocolIdentifier (4) and sourceIPv4Address(IE8), the forwarding
          path delay on each node from each IPv4 source address to a specific
          application in the network.</t>
        </list></t>
    </section>

    <section anchor="IANA" title="IANA Considerations">
      <t>This document requests IANA to create new IEs (see table 1) and
      assign the following initial code points.</t>

      <t><figure>
          <artwork><![CDATA[
     +-------+--------------------------------+
     |Element|              Name              |
     |   ID  |                                |
     +-------+--------------------------------+
     | TBD5  | PathDelayMeanDeltaMicroseconds |
     |       |                                |
     +-------+--------------------------------+
     | TBD6  | PathDelayMeanDeltaNanoseconds  |
     |       |                                |     
     +-------+--------------------------------+
     | TBD7  | PathDelayMinDeltaMicroseconds  |
     |       |                                |
     +-------+--------------------------------+
     | TBD8  | PathDelayMinDeltaNanoseconds   |
     |       |                                |
     +-------+--------------------------------+
     | TBD9  | PathDelayMaxDeltaMicroseconds  |
     |       |                                |
     +-------+--------------------------------+
     | TBD10 | PathDelayMaxDeltaNanoseconds   |
     |       |                                |
     +-------+--------------------------------+
     | TBD11 | PathDelaySumDeltaMicroseconds  |
     |       |                                |
     +-------+--------------------------------+
     | TBD12 | PathDelaySumDeltaNanoseconds   |
     |       |                                |
     +-------+--------------------------------+
  Table 1: Creates IEs in the "IPFIX Information Elements" registry
       ]]></artwork>
        </figure></t>

      <t>Note to the RFC-Editor:</t>

      <t><list style="symbols">
          <t>Please replace TBD5 - TBD12 with the values allocated by IANA</t>

          <t>Please replace the [RFC-to-be] with the RFC number assigned to
          this document</t>
        </list></t>

      <section anchor="IANAPathDelayMeanDeltaMicroseconds"
               title="PathDelayMeanDeltaMicroseconds">
        <t>Name: PathDelayMeanDeltaMicroseconds <vspace blankLines="0"/>
        ElementID: TBD5 <vspace blankLines="0"/> Description: This Information
        Element identifies the mean path delay in microseconds. <vspace
        blankLines="0"/> Abstract Data Type: unsigned16 <vspace
        blankLines="0"/> Data Type Semantics: OctedDelta <vspace
        blankLines="0"/> Reference: [RFC-to-be], xxx</t>
      </section>

      <section anchor="IANAPathDelayMeanDeltaNanoseconds"
               title="PathDelayMeanDeltaNanoseconds">
        <t>Name: PathDelayMeanDeltaNanoseconds <vspace blankLines="0"/>
        ElementID: TBD6 <vspace blankLines="0"/> Description: This Information
        Element identifies the mean path delay in nanoseconds. <vspace
        blankLines="0"/> Abstract Data Type: unsigned32 <vspace
        blankLines="0"/> Data Type Semantics: OctedDelta <vspace
        blankLines="0"/> Reference: [RFC-to-be], xxx</t>
      </section>

      <section anchor="IANAPathDelayMinDeltaMicroseconds"
               title="PathDelayMinDeltaMicroseconds">
        <t>Name: PathDelayMinDeltaMicroseconds <vspace blankLines="0"/>
        ElementID: TBD7 <vspace blankLines="0"/> Description: This Information
        Element identifies the lowest path delay in microseconds. <vspace
        blankLines="0"/> Abstract Data Type: unsigned16 <vspace
        blankLines="0"/> Data Type Semantics: OctedDelta <vspace
        blankLines="0"/> Reference: [RFC-to-be], xxx</t>
      </section>

      <section anchor="IANAPathDelayMinDeltaNanoseconds"
               title="PathDelayMinDeltaNanoseconds">
        <t>Name: PathDelayMinDeltaNanoseconds <vspace blankLines="0"/>
        ElementID: TBD8 <vspace blankLines="0"/> Description: This Information
        Element identifies the lowest path delay in nanoseconds. <vspace
        blankLines="0"/> Abstract Data Type: unsigned32 <vspace
        blankLines="0"/> Data Type Semantics: OctedDelta <vspace
        blankLines="0"/> Reference: [RFC-to-be], xxx</t>
      </section>

      <section anchor="IANAPathDelayMaxDeltaMicroseconds"
               title="PathDelayMaxDeltaMicroseconds">
        <t>Name: PathDelayMaxDeltaMicroseconds <vspace blankLines="0"/>
        ElementID: TBD9 <vspace blankLines="0"/> Description: This Information
        Element identifies the highest path delay in microseconds. <vspace
        blankLines="0"/> Abstract Data Type: unsigned16 <vspace
        blankLines="0"/> Data Type Semantics: OctedDelta <vspace
        blankLines="0"/> Reference: [RFC-to-be], xxx</t>
      </section>

      <section anchor="IANAPathDelayMaxDeltaNanoseconds"
               title="PathDelayMaxDeltaNanoseconds">
        <t>Name: PathDelayMaxDeltaNanoseconds <vspace blankLines="0"/>
        ElementID: TBD10 <vspace blankLines="0"/> Description: This
        Information Element identifies the highest path delay in nanoseconds.
        <vspace blankLines="0"/> Abstract Data Type: unsigned32 <vspace
        blankLines="0"/> Data Type Semantics: OctedDelta <vspace
        blankLines="0"/> Reference: [RFC-to-be], xxx</t>
      </section>

      <section anchor="IANAPathDelaySumDeltaMicroseconds"
               title="PathDelaySumDeltaMicroseconds">
        <t>Name: PathDelaySumDeltaMicroseconds <vspace blankLines="0"/>
        ElementID: TBD11 <vspace blankLines="0"/> Description: This
        Information Element identifies the sum of the path delay in
        microseconds. <vspace blankLines="0"/> Abstract Data Type: unsigned32
        <vspace blankLines="0"/> Data Type Semantics: OctedDelta <vspace
        blankLines="0"/> Reference: [RFC-to-be], xxx</t>
      </section>

      <section anchor="IANAPathDelaySumDeltaNanoseconds"
               title="PathDelaySumDeltaNanoseconds">
        <t>Name: PathDelaySumDeltaNanoseconds <vspace blankLines="0"/>
        ElementID: TBD12 <vspace blankLines="0"/> Description: This
        Information Element identifies the sum of the path delay in
        nanoseconds. <vspace blankLines="0"/> Abstract Data Type: unsigned64
        <vspace blankLines="0"/> Data Type Semantics: OctedDelta <vspace
        blankLines="0"/> Reference: [RFC-to-be], xxx</t>
      </section>
    </section>

    <section anchor="Operational" title="Operational Considerations">
      <section anchor="OpsTimeAccuracy" title="Time Accuracy">
        <t>The same recommendation as defined in section 4.5 of <xref
        target="RFC5153"/> for IPFIX applies in terms of clock precision to
        this document as well.</t>
      </section>

      <section anchor="OpsMeanDelay" title="Mean Delay">
        <t>The mean (average) path delay can be calculated by dividing the
        PathDelaySumDeltaMicroseconds(TBD5) or
        PathDelaySumDeltaNanoseconds(TBD6) by the packetDeltaCount(2) at the
        IPFIX data collection.</t>
      </section>

      <section anchor="OpsIoamPackTimestamps" title="IOAM Packet Time Stamps">
        <t>For IOAM, Section 4.4.1 of <xref target="RFC9197"/> describes what
        kind of timestamps are supported. Section 4.4.2.3 and 4.4.2.4 describe
        where the timestamp is being inserted.</t>

        <t>For Path Tracing, Section 4.1 of <xref
        target="I-D.filsfils-spring-path-tracing"/> describes what kind of
        timestamps are supported. Section 9.2 describe the SRH path tracing
        TLV where the timestamp is being inserted.</t>
      </section>
    </section>

    <section anchor="Security" title="Security Considerations">
      <t>There are no significant extra security considerations regarding the
      allocation of these new IPFIX IEs compared to <xref
      target="RFC7012"/>.</t>
    </section>

    <section anchor="Acknowledgements" title="Acknowledgements">
      <t>The authors would like to thank xxx for their review and valuable
      comments.</t>
    </section>
  </middle>

  <back>
    <references title="Normative References">
      <?rfc include='reference.RFC.7012'?>
    </references>

    <references title="Informative References">
      <?rfc include='reference.I-D.ietf-ippm-ioam-deployment'?>

      <?rfc include='reference.I-D.filsfils-spring-path-tracing'?>

      <?rfc include='reference.I-D.song-opsawg-ifit-framework'?>

      <?rfc include='reference.RFC.7011'?>

      <?rfc include='reference.RFC.7679'?>

      <?rfc include='reference.RFC.6049'?>

      <?rfc include='reference.RFC.2330'?>

      <?rfc include='reference.RFC.7323'?>

      <?rfc include='reference.RFC.6991'?>

      <?rfc include='reference.RFC.3393'?>

      <?rfc include='reference.RFC.6703'?>

      <?rfc include='reference.RFC.6020'?>

      <?rfc include='reference.RFC.5905'?>

      <?rfc include='reference.I-D.tgraf-opsawg-ipfix-srv6-srh'?>

      <?rfc include='reference.RFC.5153'?>

      <?rfc include='reference.RFC.7015'?>

      <?rfc include='reference.RFC.9197'?>
    </references>
  </back>
</rfc>