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MPLS Data Plane Encapsulation for In Situ OAM Data
draft-gandhi-mpls-ioam-10

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This is an older version of an Internet-Draft whose latest revision state is "Active".
Authors Rakesh Gandhi , Frank Brockners , Bin Wen , Bruno Decraene , Haoyu Song
Last updated 2023-03-10
Replaces draft-gandhi-mpls-ioam-sr
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draft-gandhi-mpls-ioam-10
MPLS Working Group                                        R. Gandhi, Ed.
Internet-Draft                                              F. Brockners
Intended status: Standards Track                     Cisco Systems, Inc.
Expires: 11 September 2023                                        B. Wen
                                                                 Comcast
                                                             B. Decraene
                                                                  Orange
                                                                 H. Song
                                                  Futurewei Technologies
                                                           10 March 2023

           MPLS Data Plane Encapsulation for In Situ OAM Data
                       draft-gandhi-mpls-ioam-10

Abstract

   In Situ Operations, Administration, and Maintenance (IOAM) is used
   for recording and collecting operational and telemetry information
   while the packet traverses a path between two points in the network.
   This document defines how IOAM data fields are transported with MPLS
   data plane encapsulation using MPLS Network Action (MNA).

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Internet-Drafts are draft documents valid for a maximum of six months
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   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 11 September 2023.

Copyright Notice

   Copyright (c) 2023 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.

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   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Requirement Language  . . . . . . . . . . . . . . . . . .   3
     2.2.  Abbreviations . . . . . . . . . . . . . . . . . . . . . .   3
   3.  MPLS Extensions for IOAM Data Fields  . . . . . . . . . . . .   4
     3.1.  Post-Stack Network Action for IOAM  . . . . . . . . . . .   4
     3.2.  MNA Sub-Stack for IOAM Post-Stack Network Action  . . . .   6
   4.  Edge-To-Edge IOAM Network Action  . . . . . . . . . . . . . .   7
     4.1.  MNA Sub-Stack for Edge-To-Edge IOAM . . . . . . . . . . .   7
     4.2.  Procedure for Edge-To-Edge IOAM Network Action  . . . . .   8
   5.  Hop-By-Hop IOAM Network Action  . . . . . . . . . . . . . . .   8
     5.1.  MNA Sub-Stack for Hop-By-Hop IOAM . . . . . . . . . . . .   9
     5.2.  Procedure for Hop-By-Hop IOAM Network Action  . . . . . .   9
     5.3.  Hop-By-Hop and Edge-To-Edge IOAM Network Actions  . . . .  10
   6.  Select IOAM Network Action  . . . . . . . . . . . . . . . . .  10
   7.  Considerations for IOAM . . . . . . . . . . . . . . . . . . .  10
     7.1.  Considerations for ECMP . . . . . . . . . . . . . . . . .  10
     7.2.  Node Capability . . . . . . . . . . . . . . . . . . . . .  11
     7.3.  Nested MPLS Encapsulation . . . . . . . . . . . . . . . .  11
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  12
     10.2.  Informative References . . . . . . . . . . . . . . . . .  12
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  13
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   In Situ Operations, Administration, and Maintenance (IOAM) is used
   for recording and collecting operational and telemetry information
   while the packet traverses a path between two points in the network.
   The term "in-situ" refers to the fact that the IOAM data fields are
   added to the data packets rather than being sent within the probe
   packets specifically dedicated to OAM.  The IOAM data fields are
   defined in [RFC9197].  The IOAM data fields are further updated in
   [RFC9326] for direct export use-cases.

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   This document defines how IOAM data fields are transported with MPLS
   data plane encapsulations using MPLS Network Action (MNA).

   [I-D.ietf-mpls-mna-hdr] defines mechanisms for carrying MNA Sub-Stack
   (NAS) above the Bottom of the label stack (BOS) and
   [I-D.jags-mpls-ps-mna-hdr] defines mechanisms for carrying Post-Stack
   Network Actions in MPLS packets after the Bottom of the label stack.
   This document uses these two mechanisms and describes the procedures
   for carrying IOAM data fields in an MPLS packet.

2.  Conventions

2.1.  Requirement Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119] [RFC8174]
   when, and only when, they appear in all capitals, as shown here.

2.2.  Abbreviations

   The MPLS Network Action (MNA) terminology defined in
   [I-D.ietf-mpls-mna-hdr] are used in this document.

   Abbreviations used in this document:

   ECMP  Equal Cost Multi-Path

   E2E  Edge-To-Edge

   HBH  Hop-By-Hop

   IHS  Ingress-To-Egress (I2E), Hop-By-Hop (HBH) or Select Scope

   IOAM  In Situ Operations, Administration, and Maintenance

   MPLS  Multiprotocol Label Switching

   MNA  MPLS Network Action

   NAI  Network Action Indicator

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   NASL  Network Action Sub-Stack Length

   OAM  Operations, Administration, and Maintenance

   POT  Proof-of-Transit

3.  MPLS Extensions for IOAM Data Fields

3.1.  Post-Stack Network Action for IOAM

   The Post-Stack Network Action for IOAM is defined using the
   specification from [I-D.jags-mpls-ps-mna-hdr].

   The Post-Stack Network Action encoding contains IOAM Post-Stack
   Network Action Opcode (value TBA2 allocated by IANA), length in
   number of 4-Octet units, and IOAM Option-Type with IOAM-Data-Fields
   in ancillary data as shown in Figure 1.  The IOAM-Data-Fields MUST
   follow the definitions corresponding to their IOAM-Option-Types
   (e.g., see Section 4.4 of [RFC9197] and Section 3 of [RFC9326]).

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   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
   |N N N N|Version| PS-MNA-LEN    | TYPE = POST-STACK-MNA         | TH
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|<-+
   |PS-NA-OP=IOAM| BLOCK-NUMBER  |IOAM-OPT-TYPE|R|R|R| IOAM-HDR-LEN|  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  I
   |                                                               |  O
   |                                                               |  A
   ~   IOAM Option and Data Space [RFC9197] [RFC9326]              ~  M
   |                                                               |  |
   |                                                               |  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
   .                                                               .
   .                                                               .
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
   |PS-NA-OP=IOAM| BLOCK-NUMBER  |IOAM-OPT-TYPE|R|R|R| IOAM-HDR-LEN|  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  I
   |                                                               |  O
   |                                                               |  A
   ~   IOAM Option and Data Space [RFC9197] [RFC9326]              ~  M
   |                                                               |  |
   |                                                               |  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
   |                                                               |
   |                                                               |
   ~                 Optional Payload + Padding                    ~
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         Figure 1: Post-Stack Network Action with IOAM Data Fields

   The 4-Octet Top Header is added with the following fields in the the
   Post-Stack Network Action as defined in [I-D.jags-mpls-ps-mna-hdr]

   NNNN:  The first 4-bit (value TBA3 allocated by IANA) as defined in
     [I-D.jags-mpls-ps-mna-hdr].  As specified in
     [I-D.jags-mpls-ps-mna-hdr], the NNNN value can be 0001b for Generic
     Associated Channel (G-ACH) [RFC5586].

   PS-MNA-LEN:  Length of the Post-Stack Network Action Stack in the
     packet in 4-Octet units including the Top Header.

   TYPE:  TYPE is defined for POST-STACK-MNA (value TBA4 allocated by

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     IANA) in [I-D.jags-mpls-ps-mna-hdr].  As specified in
     [I-D.jags-mpls-ps-mna-hdr], the POST-STACK-MNA Type can be a
     Generic Associated Channel (G-ACH) Type [RFC5586] (value TBA5
     allocated by IANA).

   An IOAM-Data-Field is added in the Post-Stack Network Action
   containing the following fields:

   IOAM-OPT-TYPE:  7-bit field defining the IOAM Option-Type, as defined
     in the "IOAM Option-Type Registry" specified in [RFC9197] and
     [RFC9326]).

   IOAM-HDR-LEN:  7-bit unsigned integer.  Length of the IOAM Data-
     Fields in 4-Octet units.

   IOAM Option and Data Space:  IOAM-Data-Fields as specified by the
     IOAM-OPT-Type field.  IOAM-Data-Fields are defined corresponding to
     the IOAM-Option-Type (e.g., see Section 4.4 of [RFC9197] and
     Section 3 of [RFC9326].

   BLOCK-NUMBER:  The Block Number can be used to aggregate the IOAM
     data collected in data plane, e.g., to compute measurement metrics
     for each block of a data flow.  It is also used to correlate the
     IOAM data on different nodes.

3.2.  MNA Sub-Stack for IOAM Post-Stack Network Action

   The P flag defined in [I-D.jags-mpls-ps-mna-hdr] is used to indicate
   the presence of Post-Stack Network Action and Ancillary Data.

   A Post-Stack Network Action Indicator (P flag) MUST be set to "1" to
   indicate the presence of the Post-Stack Network Action with IOAM-
   Data-Fields in the Post-Stack Network Action (after the Bottom of the
   Stack).

   The IHS scope field defined in [I-D.ietf-mpls-mna-hdr] is used to
   indicate that E2E or HBH or Select processing is required for the
   Post-Stack Network Action and Ancillary Data.

   If both edge and intermediate nodes need to process the IOAM data
   fields then IHS scope MUST be set to "HBH, value 0x1".  If only edge
   nodes need to process the IOAM data fields then IHS scope MUST be set
   to "I2E, value 0x0".  The HBH scope allows to skip the IOAM data
   processing on the intermediate nodes i.e., avoids the need to parse
   all IOAM-Data-Fields to detect the HBH option type.

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   The MNA Label used in this document is a Base Special Purpose Label
   (bSPL value TBA1 to be allocated by IANA), which is also called
   Network Action Sub-Stack Indicator [I-D.ietf-mpls-mna-hdr].

   Opcode 2 is used to carry the Flag-Based Network Action Indicators
   (NAIs) in the Ancillary Data field [I-D.ietf-mpls-mna-hdr].  The
   Flag-Based Network Action Indicators is set to 0x0 to indicate that
   no Network Action other than the Post-Stack Network Action(s) is
   required for the packet.

   The U Flag for Unknown Action Handling is specified in
   [I-D.ietf-mpls-mna-hdr].

   The Network Action Sub-Stack Length (NASL) is set to 0 if no
   additional Label Stack Entry (LSE) is added after the LSE carrying
   the P Flag.

4.  Edge-To-Edge IOAM Network Action

4.1.  MNA Sub-Stack for Edge-To-Edge IOAM

   The IHS scope is set to "I2E, value 0x0" to indicate the scope of E2E
   IOAM-Data-Fields in the MPLS Sub-Stack as shown in Figure 2.  Note
   that there may be additional Network Action (NA) LSEs added in the
   MNA Sub-Stack and NASL is updated based on the number of LSEs after
   the LSE with P flag.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |  Label                                | TC  |S|  TTL          |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    .                                                               .
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |  MNA Label (bSPL value TBA1)          | TC  |S|  TTL          |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |  Opcode=2   | Flag-Based NAIs         |1|E2E|S| Res |U|NASL=0 |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    .                                                               .
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                Packet as shown in Figure 1                    |
    .                                                               .
    +---------------------------------------------------------------+

                Figure 2: Example MNA Sub-Stack for E2E IOAM

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   The E2E IOAM-Data-Fields carry the Option-Type(s) that require
   processing on the encapsulating and decapsulating nodes only.  The
   IOAM Option-Type carried can be IOAM Edge-To-Edge Option-Type (value
   3) defined in [RFC9197] as well as Direct Export (DEX) Option-Type
   (value 4) defined in [RFC9326].  The E2E IOAM-Data-Fields SHOULD NOT
   carry any IOAM Option-Type that require IOAM processing on the
   intermediate nodes as it will not be processed by them since IHS
   scope is set to "I2E, value 0x0".

4.2.  Procedure for Edge-To-Edge IOAM Network Action

   The E2E IOAM Network Action procedure is summarized as following:

   *  The encapsulating node inserts an MNA Sub-Stack with the MNA Label
      (bSPL value TBA1) with the Post-Stack Network Action Indicator (P
      flag) set to "1" and IHS scope set to "I2E, value 0x0" and one or
      more IOAM-Data-Fields in the Post-Stack Network Action in the MPLS
      packet.

   *  The intermediate nodes do not process IOAM-Data-Fields.

   *  The penultimate node MUST NOT remove the MNA Sub-Stack from the
      MPLS header so that the MNA Sub-Stack is received at the
      decapsulating node.

   *  The decapsulating node MAY punt the IOAM data from the packet with
      the receive timestamp to the slow path for IOAM-Data-Fields
      processing.  The receive timestamp is required by the various E2E
      OAM use-cases, including streaming telemetry.  Note that the
      packet is not necessarily punted to the control-plane.

   *  The decapsulating node processes the IOAM-Data-Fields using the
      procedures defined in [RFC9197].  An example of IOAM processing is
      to export the IOAM-Data-Fields, send IOAM-Data-Fields via
      streaming telemetry, etc.

   *  The decapsulating node MUST remove the Post-Stack Network Action
      with IOAM-Data-Fields from the received packet.  The decapsulated
      packet is forwarded downstream or terminated locally similar to
      the regular data packets.

5.  Hop-By-Hop IOAM Network Action

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5.1.  MNA Sub-Stack for Hop-By-Hop IOAM

   The IHS scope is set to "HBH, value 0x1" to indicate the scope of HBH
   IOAM-Data-Fields in the MNA Sub-Stack as shown in Figure 3.  Note
   that there may be additional Network Action (NA) LSEs added in the
   MNA Sub-Stack and NASL is updated based on the number of LSEs after
   the LSE with P flag.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |  Label                                | TC  |S|  TTL          |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    .                                                               .
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |  MNA Label (bSPL value TBA1)          | TC  |S|  TTL          |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |  Opcode=2   | Flag-Based NAIs         |1|HBH|S| Res |U|NASL=0 |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    .                                                               .
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                Packet as shown in Figure 1                    |
    .                                                               .
    +---------------------------------------------------------------+

                Figure 3: Example MNA Sub-Stack for HBH IOAM

   The HBH IOAM-Data-Fields carry the Option-Type(s) that require
   processing at the intermediate and/or encapsulating and decapsulating
   nodes.  The IOAM Option-Type carried can be IOAM Pre-allocated Trace
   Option-Type (value 0), IOAM Incremental Trace Option-Type (value 1)
   and IOAM Proof of Transit (POT) Option-Type (value 2), and Edge-To-
   Edge Option-Type (value 3) defined in [RFC9197] as well as Direct
   Export (DEX) Option-Type (value 4) defined in [RFC9326].

5.2.  Procedure for Hop-By-Hop IOAM Network Action

   The Hop-By-Hop IOAM Network Action procedure is summarized as
   following:

   *  The encapsulating node inserts an MNA Sub-Stack containing MNA
      Label (bSPL value TBA1) with the Post-Stack Network Action
      Indicator (P flag) set to "1" and IHS scope set to "HBH, value
      0x1" and one or more IOAM-Data-Fields in the Post-Stack Network
      Action in the MPLS packet.

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   *  The intermediate node enabled with HBH IOAM function processes the
      data packet including the IOAM-Data-Fields as defined in [RFC9197]
      and [RFC9326] when the node recognizes the HBH scope in the MNA
      Sub-Stack.

   *  The intermediate node MAY punt the IOAM data from the packet with
      the receive timestamp to the slow path for IOAM-Data-Fields
      processing when the node recognizes the HBH scope.  The receive
      timestamp is required by the various HBH OAM use-cases, including
      streaming telemetry.  Note that the packet is not necessarily
      punted to the control-plane.

   *  The intermediate node forwards the data packet downstream.

   *  The processing on the penultimate node is same as E2E case.

   *  The processing on the decapsulating node is same as E2E case.

5.3.  Hop-By-Hop and Edge-To-Edge IOAM Network Actions

   Both HBH and E2E IOAM NAs may be added in an MNA Sub-Stack.  In this
   case, the HBH IOAM NAs MUST be added after the BOS and before the E2E
   IOAM NAs.  When an intermediate node that processes the HBH IOAM NAs,
   encounters the first E2E IOAM NA, it will stop processing of the E2E
   NA.

6.  Select IOAM Network Action

   The procedure for carrying the IOAM NAs for Select Scope is the same
   as HBH Scope IOAM except the IHS scope is set to "Select, value 0x2".
   In this case, only the select nodes will process the IOAM-Data-
   Fields.

7.  Considerations for IOAM

7.1.  Considerations for ECMP

   The encapsulating node needs to make sure the IOAM-Data-Fields do not
   start with a well-known IP Version Number (e.g. 0x4 for IPv4 and 0x6
   for IPv6) as that can alter the hashing function for ECMP that uses
   the IP header.  This is achieved by using the first nibble NNNN in
   the Top Header with a different IP Version Number (value TBA3 to be
   allocated by IANA or 0001b for G-ACH) after the MPLS label stack.

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7.2.  Node Capability

   The decapsulating node that has to remove the IOAM-Data-Fields and
   perform the IOAM function may not be capable of supporting it.  The
   encapsulating node needs to know if the decapsulating node can
   support the IOAM function.  The signaling extension for this
   capability exchange is outside the scope of this document.

   The intermediate node that is not capable of supporting the IOAM
   functions defined in this document, can simply skip the IOAM
   processing.

   The node that does not recognize the MNA Label received at the top of
   the label stack will drop the packet.

7.3.  Nested MPLS Encapsulation

   When a packet is received with MPLS Encapsulated IOAM Network Action,
   the nested MPLS encapsulating node that supports a different IOAM
   Network Action, the node MUST add a new MNA Label with Sub-Stack with
   the supported IOAM Post-Stack Network Action as part of the new MPLS
   encapsulation.

8.  Security Considerations

   The security considerations of IOAM in general are discussed in
   [RFC9197] and apply to the procedure defined in this document.

   IOAM is considered a "per domain" feature, where one or several
   operators decide on configuring IOAM according to their needs.  IOAM
   is intended for deployment in limited domains [RFC8799].  As such, it
   assumes that a node involved in IOAM operation has previously
   verified the integrity of the path.  Still, operators need to
   properly secure the IOAM domain to avoid malicious configuration and
   use, which could include injecting malicious IOAM packets into the
   domain.

9.  IANA Considerations

   The PS-NA-OPCODE for IOAM is allocated from the "Post-Stack Network
   Action" registry.

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              +=======+======+=============+===============+
              | Value | Name | Description |   Reference   |
              +=======+======+=============+===============+
              | TBA2  | IOAM | In Situ OAM | This document |
              +-------+------+-------------+---------------+

                Table 1: Post-Stack Network Action Opcode

10.  References

10.1.  Normative References

   [I-D.ietf-mpls-mna-hdr]
              Rajamanickam, J., Ed., Gandhi, R., Ed., Zigler, R., Ed.,
              Song, H., Ed., and K. Kompella, Ed., "MPLS Network Action
              Sub-Stack Solution", Work in Progress, Internet-Draft,
              draft-ietf-mpls-mna-hdr-01, March 2023,
              <https://www.ietf.org/archive/id/draft-ietf-mpls-mna-hdr-
              01.txt>.

   [I-D.jags-mpls-ps-mna-hdr]
              Rajamanickam, J., Ed., Gandhi, R., Ed., Zigler, R., Li,
              T., and J. Dong, "Post-Stack MPLS Network Action (MNA)
              Solution", Work in Progress, Internet-Draft, draft-jags-
              mpls-ps-mna-hdr-00, March 2023,
              <https://www.ietf.org/archive/id/draft-jags-mpls-ps-mna-
              hdr-00.txt>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC9197]  Brockners, F., Bhandari, S., and T. Mizrahi, "Data Fields
              for In Situ Operations, Administration, and Maintenance",
              RFC 9197, May 2022,
              <https://www.rfc-editor.org/info/rfc9197>.

   [RFC9326]  Song, H., Gafni, B., Brockners, F., Bhandari, S., and T.
              Mizrahi, "In Situ Operations, Administration, and
              Maintenance OAM Direct Exporting", RFC 9326, November
              2022, <https://www.rfc-editor.org/info/rfc9326>.

10.2.  Informative References

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   [RFC8799]  Carpenter, B. and B. Liu, "Limited Domains and Internet
              Protocols", RFC 8799, DOI 10.17487/RFC8799, July 2020,
              <https://www.rfc-editor.org/info/rfc8799>.

Acknowledgements

   The authors would like to thank Patrick Khordoc, Sagar Soni, Shwetha
   Bhandari, Clarence Filsfils, and Vengada Prasad Govindan for the
   discussions on IOAM.  The authors would also like to thank Tarek
   Saad, Loa Andersson, Greg Mirsky, Stewart Bryant, Xiao Min, Jaganbabu
   Rajamanickam, and Cheng Li for providing many useful comments.  The
   authors would also like to thank Mach Chen, Andrew Malis, Matthew
   Bocci, and Nick Delregno for the MPLS-RT reviews of the early version
   of the draft.

Contributors

   The following people have substantially contributed to this document:

   Zafar Ali
   Cisco Systems, Inc.
   Email: zali@cisco.com

   Voitek Kozak
   Comcast
   Email: Voitek_Kozak@comcast.com

Authors' Addresses

   Rakesh Gandhi (editor)
   Cisco Systems, Inc.
   Canada
   Email: rgandhi@cisco.com

   Frank Brockners
   Cisco Systems, Inc.
   Hansaallee 249, 3rd Floor
   DUESSELDORF, NORDRHEIN-WESTFALEN 40549
   Germany
   Email: fbrockne@cisco.com

   Bin Wen
   Comcast
   Email: Bin_Wen@cable.comcast.com

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   Bruno Decraene
   Orange
   Email: bruno.decraene@orange.com

   Haoyu Song
   Futurewei Technologies
   United States of America
   Email: haoyu.song@futurewei.com

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