Supporting In-Situ Operations, Administration, and Maintenance Direct Export Using MPLS Network Actions
draft-mb-mpls-ioam-dex-09

MPLS Working Group                                             G. Mirsky
Internet-Draft                                                  Ericsson
Intended status: Standards Track                            M. Boucadair
Expires: 24 April 2025                                            Orange
                                                                   T. Li
                                                        Juniper Networks
                                                         21 October 2024

 Supporting In-Situ Operations, Administration, and Maintenance Direct
                   Export Using MPLS Network Actions
                       draft-mb-mpls-ioam-dex-09

Abstract

   In-Situ Operations, Administration, and Maintenance (IOAM), defined
   in RFC 9197, is an on-path telemetry method to collect and transport
   the operational state and telemetry information that can be used to
   calculate various performance metrics.  IOAM Direct Export (IOAM-DEX)
   is one of the IOAM Option types, in which the operational state and
   telemetry information are collected according to the specified
   profile and exported in a manner and format defined by a local
   policy.

   MPLS Network Actions (MNA) techniques are meant to indicate actions
   to be performed on any combination of Label Switched Paths (LSPs),
   MPLS packets, and the node itself, and also to transfer data needed
   for these actions.  This document explores the on-path operational
   state, and telemetry information can be collected using IOAM-DEX
   Option in combination with MNA.

Status of This Memo

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   This Internet-Draft will expire on 24 April 2025.

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Copyright Notice

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   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions Used in this Document . . . . . . . . . . . . . .   3
     2.1.  Acronyms  . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   3.  Applicability of IOAM Option Types in an MPLS Network . . . .   3
   4.  Realization of IOAM-DEX as an MPLS Network Action . . . . . .   4
     4.1.  IOAM-DEX Format for an MPLS Network . . . . . . . . . . .   4
     4.2.  IOAM-DEX-MNA Encoding as In-Stack Data MPLS Network
           Action  . . . . . . . . . . . . . . . . . . . . . . . . .   6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
     5.1.  IOAM-DEX-MNA as an MPLS Network Action Opcode . . . . . .   7
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   8
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     8.2.  Informational References  . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   In-Situ OAM (IOAM) [RFC9197] is an on-path telemetry method to
   collect and transport the operational state and telemetry information
   that can be used to calculate various performance metrics.  Several
   IOAM Option types (e.g., Pre-allocated and Incremental) use the user
   packet to collect the operational state and telemetry information.
   Such a mechanism transports the collected information to an IOAM
   decapsulating node (typically located at the edge of the IOAM domain
   within the data packet).  IOAM Direct Export (IOAM-DEX) [RFC9326] is
   an IOAM Option type.  In IOAM-DEX, the operational state and
   telemetry information are collected according to the specified
   profile and exported in a manner and format defined by a local
   policy.  MPLS Network Actions (MNA) techniques

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   [I-D.ietf-mpls-mna-fwk] indicate actions to be performed on any
   combination of Label Switched Paths (LSPs), MPLS packets, the node
   itself, and also allow for the transfer of data needed for these
   actions.

   This document describes how MNA can be used for collecting on-path
   operational state and telemetry information using IOAM-DEX Option.
   Specifying the mechanism of exporting collected information is
   outside the scope of this document.

2.  Conventions Used in this Document

2.1.  Acronyms

   IOAM: In-Situ OAM

   IOAM-DEX: IOAM Direct Export

   IOAM-DEX-MNA: IOAM Direct Export in MPLS Network Action

   ISD: In-Stack Data

   LSP: Label Switched Path

   LSE: Label Stack Entry

   MPLS: Multiprotocol Label Switching

   MNA: MPLS Network Action

   NAI: Network Action Indicator

2.2.  Requirements Language

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

3.  Applicability of IOAM Option Types in an MPLS Network

   Pre-allocated, Incremental, and Edge-to-Edge IOAM Option types
   [RFC9197] use user packets to collect and transport the operational
   state and telemetry information.  In some environments, for example,
   data center networks, this technique is useful as the available
   bandwidth and the use of jumbo frames can accommodate the increase of
   the packet payload.  But for other use cases in which network

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   resources are closely controlled, the use of in-band channels for
   collecting and transporting the telemetry information may noticeably
   decrease the cost-efficiency of network operations.  Although the
   operational state and telemetry information are essential for network
   automation (Section 4 of [RFC8969]), its delivery is not as critical
   as user packets.  As such, collecting and transporting the
   operational state and telemetry information out-of-band using the
   management plane is a viable option for some environments.  IOAM-DEX
   [RFC9326] is used to collect IOAM data defined in [RFC9197].  The
   processing and transport of the collected information are controlled
   by a local policy which is outside the scope of this specification.
   The performance considerations discussed in Section 5 of [RFC9326]
   are applicable here.

4.  Realization of IOAM-DEX as an MPLS Network Action

4.1.  IOAM-DEX Format for an MPLS Network

   [I-D.ietf-mpls-mna-usecases] recognizes the importance of IOAM in
   MPLS networks and lists it as one of the use cases that might be
   supported using MNA techniques.  [I-D.ietf-mpls-mna-fwk] defines the
   architectural elements that compose MNA.  This document uses all the
   elements of the IOAM-DEX Option-Type format defined in [RFC9326] to
   support IOAM-DEX in an MPLS network using MPLS Network Action (MNA)
   framework [I-D.ietf-mpls-mna-fwk] and architecture as in-stack data
   (ISD) MNA [I-D.ietf-mpls-mna-hdr].  The IOAM-DEX in MNA header is
   using LSE Format D, as defined in Section 4.4 [I-D.ietf-mpls-mna-hdr]
   mapping IOAM-DEX Optin Type format [RFC9326].  In addition to the
   requirement to preserve the Bottom of Stack field, the most
   significant bit in LSE Format D is always set to 1 avoiding a
   possible mix-up of the LSE with one of the Base Special Purpose
   Labels.  The format of IOAM-DEX in MNA is shown in Figure 1.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |1|         Namespace-ID          |    Resv   |S|     Flags     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |1|            IOAM-Trace-Type-MNA            |S|O|R| Ext-Flags |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Flow ID MNA (Optional)                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                 Sequence Number MNA (Optional)                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         Figure 1: IOAM Direct Export Option Type Format in an MPLS
                          Network Action Framework

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   Where fields are defined as follows:

   *  Namespace-ID is a 16-bit identifier of the IOAM Namespace, as
      defined in [RFC9197].

   *  S is a one-bit the Bottom of Stack [RFC3032].

   *  Flags is an eight-bit field comprised of eight one-bit subfields.
      The subfields in the Flags field are allocated by IANA in IOAM DEX
      Flags registry, as defined in Section 4.2 of [RFC9326].

   *  IOAM-Trace-Type-MNA is a 22-bit field.  The interpretation of bit
      positions in the IOAM-Trace-Type-MNA is as specified in IANA's
      IOAM Trace-Type registry [IANA-IOAM-Trace-Type] from Bit 0 through
      Bit 21.

   *  O is the one-bit flag identical to the interpretation of Bit 22
      variable-length Opaque State Snapshot in IANA's IOAM Trace-Type
      registry [IANA-IOAM-Trace-Type].

   *  R (Reserved) is a one-bit flag identical to the interpretation of
      Bit 23 in IANA's IOAM Trace-Type registry [IANA-IOAM-Trace-Type].
      It MUST be zeroed on the transmission and ignored on receipt.
      Similarly to [RFC9197], it is reserved to allow for future
      extensions of the IOAM-Trace-Type-MNA bit field.

   *  The concatenation of IOAM-Trace-Type-MNA, O, and R fields,
      explained above, is identical to IOAM-Trace-Type in the
      interpretation of its bits, assigned in IANA's IOAM Trace-Type
      registry [IANA-IOAM-Trace-Type].  Also, note that the Bit 7 field,
      i.e., checksum complement, is handled as defined in [RFC9326].

   *  Ext-Flags is a six-bit field comprised of six one-bit subfields.
      The allocation of the subfields in the Ext-Flags field is
      according to Section 4.3 of [RFC9326].  The allocated flags
      indicate the presence of the optional Flow ID and/or Sequence
      Number fields in the IOAM-DEX-MNA header.  The length of the Ext-
      Flags field in IOAM-DEX Option-Type in MNA is shorter by two one-
      bit fields compared to the length of the Extension Flags field
      defined in Section 3.2 of [RFC9326].  Mapping of these two bit
      positins is for further study.  Figure 2 displays the detailed
      format of the Ext-Flags field.

   *  Optional fields, i.e., Flow ID and Sequence Number, according to
      [RFC9326], immediately follow the Reserved field used to align
      optional fields at the four-octet word boundary.  In the case of
      IOAM-DEX in MNA, such alignment can be achieved without using
      padding.

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   *  Flow ID MNA is an optional four-octet field.  The semantics of the
      Flow ID MNA field is as of the Flow ID field defined in
      Section 3.2 of [RFC9326].  The most significant bit MUST be set to
      1.  Bit 23 MUST be set according to the definition of Bottom of
      Stack field in [RFC3032].

   *  Sequence Number MNA is an optional four-octet field.  The
      semantics of the Sequence Number MNA field is as of the Sequence
      Number field defined in Section 3.2 of [RFC9326].  The most
      significant bit MUST be set to 1.  Bit 23 MUST be set according to
      the definition of Bottom of Stack field in [RFC3032].  In MPLS
      network environments where a label stack information is used for
      load-balancing flows, the 19-bit-long part of the Sequence Number
      MNA, starting from the Bit 1 position of the LSE, MUST remain
      immutable for a particular packet flow that the value of the Flow
      ID MNA field identifies.  In MPLS networks, where other load-
      balancing techniques are used, all bits of the Sequence Number MNA
      field can be variated.

    0 1 2 3 4 5
   +-+-+-+-+-+-+
   |F|S|U|U|U|U|
   +-+-+-+-+-+-+

                      Figure 2: Ext-Flags Field Format

   Where fields are defined as follows:

   *  F - one-bit flag.  When the flag is set to 1, it indicates the
      presence of the Flow ID field in the IOAM-DEX-MNA header.

   *  S - one-bit flag.  When the flag is set to 1, it indicates the
      presence of the Sequence Number field in the IOAM-DEX-MNA header.

   *  U - unassigned one-bit flag.  It MUST be zeroed on transmission
      and the value MUST be ignored upon receipt.

4.2.  IOAM-DEX-MNA Encoding as In-Stack Data MPLS Network Action

   To support the direct export of the operational state and telemetry
   information, the IOAM-DEX-MNA blob (binary large object), as shown in
   Figure 1 can be placed as part of the ISD block in an MPLS label
   stack according to the MNA encoding principles defined in
   [I-D.ietf-mpls-mna-hdr].  Using the IHS field, the IOAM-DEX-MNA can
   be performed in Hop-by-Hop, Ingress-to-Egress, or Select modes
   [I-D.ietf-mpls-mna-fwk] of collecting the operational state and
   telemetry information, as MNA Opcode (Figure 3).  Policies

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   controlling the processing of the collected operational state and
   telemetry information, and its transport are outside the scope of
   this document.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               MNA bSPL                | TC  |S|    TTL        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Opcode = TBA1 |        Data           |P|IHS|S| Res |U|  NASL |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ~                         IOAM-DEX-MNA                          ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Figure 3: An Example of IOAM-DEX Encapsulation as an MNA Opcode

   Where the enclosed elements are defined as follows:

   *  MNA bSPL is a base Special Purpose Label assigned by IANA per the
      request in [I-D.ietf-mpls-mna-hdr].

   *  S - the Bottom of Stack field [RFC3032].

   *  P, IHS, Res, U, and NASL fields are as specified in Section 4.2 of
      [I-D.ietf-mpls-mna-hdr].

   *  NASL - number of LSEs that compose the IOAM-DEX-MNA blob.

   *  Opcode is MNA-IOAM-DEX opcode (TBA1) assigned by IANA Section 5.1.

   *  IOAM-DEX-MNA - IOAM Direct Export in MPLS Network Action encoding

5.  IANA Considerations

5.1.  IOAM-DEX-MNA as an MPLS Network Action Opcode

   IANA is requested to assign an IOAM-DEX-MNA codepoint (TBA1) from its
   Network Action Opcodes registry (creation requested in
   [I-D.ietf-mpls-mna-hdr]) as specified in Table 1.

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           +========+==========================+===============+
           | Opcode |       Description        | Reference     |
           +========+==========================+===============+
           | TBA1   | IOAM-DEX as MPLS Network | This document |
           |        |     Action Indicator     |               |
           +--------+--------------------------+---------------+

              Table 1: IOAM-DEX as MPLS Network Action Opcode

6.  Security Considerations

   Security considerations discussed in [RFC9197], [RFC9326], and
   [I-D.ietf-mpls-mna-fwk] apply to this document.

7.  Acknowledgments

   The authors exxpress their sincereappreciation to Loa Andersson for
   his thorough review and thoughtful suggestion that helped in
   improving this document.

8.  References

8.1.  Normative References

   [I-D.ietf-mpls-mna-fwk]
              Andersson, L., Bryant, S., Bocci, M., and T. Li, "MPLS
              Network Actions (MNA) Framework", Work in Progress,
              Internet-Draft, draft-ietf-mpls-mna-fwk-10, 6 August 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-mpls-
              mna-fwk-10>.

   [I-D.ietf-mpls-mna-hdr]
              Rajamanickam, J., Gandhi, R., Zigler, R., Song, H., and K.
              Kompella, "MPLS Network Action (MNA) Sub-Stack Solution",
              Work in Progress, Internet-Draft, draft-ietf-mpls-mna-hdr-
              08, 30 August 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-mpls-
              mna-hdr-08>.

   [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>.

   [RFC3032]  Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
              Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
              Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001,
              <https://www.rfc-editor.org/info/rfc3032>.

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   [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., Ed., Bhandari, S., Ed., and T. Mizrahi,
              Ed., "Data Fields for In Situ Operations, Administration,
              and Maintenance (IOAM)", RFC 9197, DOI 10.17487/RFC9197,
              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 (IOAM) Direct Exporting", RFC 9326,
              DOI 10.17487/RFC9326, November 2022,
              <https://www.rfc-editor.org/info/rfc9326>.

8.2.  Informational References

   [I-D.ietf-mpls-mna-usecases]
              Saad, T., Makhijani, K., Song, H., and G. Mirsky, "Use
              Cases for MPLS Network Action Indicators and MPLS
              Ancillary Data", Work in Progress, Internet-Draft, draft-
              ietf-mpls-mna-usecases-15, 23 September 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-mpls-
              mna-usecases-15>.

   [IANA-IOAM-Trace-Type]
              IANA, "IOAM Trace-Type",
              <https://www.iana.org/assignments/ioam/ioam.xhtml#trace-
              type>.

   [RFC8969]  Wu, Q., Ed., Boucadair, M., Ed., Lopez, D., Xie, C., and
              L. Geng, "A Framework for Automating Service and Network
              Management with YANG", RFC 8969, DOI 10.17487/RFC8969,
              January 2021, <https://www.rfc-editor.org/info/rfc8969>.

Authors' Addresses

   Greg Mirsky
   Ericsson
   Email: gregimirsky@gmail.com

   Mohamed Boucadair
   Orange
   35000 Rennes
   France
   Email: mohamed.boucadair@orange.com

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   Tony Li
   Juniper Networks
   Email: tony.li@tony.li

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