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Export of MPLS Network Action (MNA) Information in IPFIX
draft-liu-opsawg-ipfix-mpls-mna-00

Document Type Active Internet-Draft (individual)
Author Yao Liu
Last updated 2025-12-23
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draft-liu-opsawg-ipfix-mpls-mna-00
OPSAWG                                                            Y. Liu
Internet-Draft                                           ZTE Corporation
Intended status: Standards Track                        23 December 2025
Expires: 26 June 2026

        Export of MPLS Network Action (MNA) Information in IPFIX
                   draft-liu-opsawg-ipfix-mpls-mna-00

Abstract

   This document introduces new IPFIX IEs for exporting MPLS Network
   Action (MNA) information in IPFIX, covering both in-stack and post-
   stack MNAs.

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 26 June 2026.

Copyright Notice

   Copyright (c) 2025 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/
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   Please review these documents carefully, as they describe your rights
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   provided without warranty as described in the Revised BSD License.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  IPFIX IEs for MNA . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  IPFIX IEs for In-Stack MNAs . . . . . . . . . . . . . . .   4
       3.1.1.  mplsMnaSubStack . . . . . . . . . . . . . . . . . . .   4
       3.1.2.  mplsMnaLseFormatB . . . . . . . . . . . . . . . . . .   4
     3.2.  IPFIX IEs for Post-Stack MNAs . . . . . . . . . . . . . .   5
       3.2.1.  mnaPostStackMplsHeaderSection . . . . . . . . . . . .   5
       3.2.2.  mnaPostStackMplsHeaderType  . . . . . . . . . . . . .   5
   4.  Operational Considerations  . . . . . . . . . . . . . . . . .   6
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   MPLS Network Actions (MNAs), as introduced in [RFC9789], are used to
   indicate actions that impact the forwarding or other processing (such
   as monitoring) of the packet along the Label Switched Path (LSP) of
   the packet and to transfer any additional data needed for these
   actions.

   Two types of MNAs solutions are defined:

   *  MNA Sub-Stack Solution/In-stack Solution: as in
      [I-D.ietf-mpls-mna-hdr], it is used to carry Network Actions and
      Ancillary Data in the MPLS label stack.  In-stack actions and
      ancillary data are contained in a Network Action Sub-Stack (NAS),
      which is recognized by a new base Special Purpose Label (bSPL).

   *  Post-Stack MNA Solution: as in [I-D.ietf-mpls-mna-ps-hdr], it is
      for carrying Network Actions and Ancillary Data after the MPLS
      label stack.  The Post-Stack MPLS Header (PSMH) consists of two
      main parts: Post-Stack MPLS Header (PSMH) Type and Post-Stack
      Network Action Encoding.

   When monitoring a traffic flow with MPLS MNA encoding, the following
   information may be required by the network operator.

   *  What's the content of the MNAs carried in the MPLS label stack ?

   *  What's the content of the MNAs carried after the MPLS label stack
      ?

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   In the existing IPFIX mechanism, mplsLabelStackSection(IE 316) can be
   used to carry a series of n octets from the MPLS label stack of a
   sampled packet, starting sectionOffset(IE 409) octets into the MPLS
   label stack, and mplsPayloadPacketSection(IE 317) carries a series of
   n octets from the MPLS payload of a sampled packet, starting
   sectionOffset(IE 409) octets into the MPLS payload.

   If mplsLabelStackSection(IE 316) and mplsPayloadPacketSection(IE 317)
   are used to carry the MNA information, additional procedures are
   required at the network analyzer to parse the
   mplsLabelStackSection or the mplsPayloadPacketSection information to
   see if there's any MNA information carried in it and what's the
   detailed MNA information.  And this would bring extra complexity in
   the network analyzer.

   This document introduces new IPFIX IEs for exporting MNA information
   in IPFIX, covering both in-stack and post-stack MNAs.

2.  Terminology

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

   This document makes use of the terms defined in [RFC7011] and
   [RFC9789].

   The following terms are used as defined in [RFC7011]:

   *  IPFIX

   *  IPFIX Information Elements

   *  Metering Process

   *  Template

   *  Collector

   *  IPFIX Device

   The following terms are used as defined in [RFC9789]:

   *  MPLS Network Action (MNA)

   *  Label Stack Entry (LSE)

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   *  Ancillary Data (AD)

   *  Network Action Sub-Stack (NAS)

   *  Post-Stack Data

3.  IPFIX IEs for MNA

   This section defines several Encapsulation Layer IEs for MPLS MNAs.
   Section 3.1 defines IEs for MNAs carried in the MPLS label stack (in-
   Stack MNA) and section 3.2 defines IEs for MNAs carried after the
   bottom of the MPLS label stack (post-Stack MNA).

3.1.  IPFIX IEs for In-Stack MNAs

3.1.1.  mplsMnaSubStack

   Name:  mplsMnaSubStack

   ElementID:  TBD1

   Description:  The MNA Sub-Stack in the MPLS label stack with the MNA
      Sub-Stack Indicator excluded.  This Information Element has a
      variable length.  Multiple mplsMnaSubStack IEs can be specified
      within a single Template since multiple MPLS Network Action Sub-
      Stacks (NASes) may appear in a label stack as described in section
      3 of [I-D.ietf-mpls-mna-hdr].

   Abstract Data Type:  octetArray

   Data Type Semantics:  default

   Additional Information:  See [I-D.ietf-mpls-mna-hdr].

   Reference:  [I-D.ietf-mpls-mna-hdr]

3.1.2.  mplsMnaLseFormatB

   Name:  mplsMnaLseFormatB

   ElementID:  TBD2

   Description:  The LSE Format B carried in the MPLS Network Action
      Sub-Stack(NAS).  As defined in section 5 of
      [I-D.ietf-mpls-mna-hdr], the second LSE in a NAS MUST be a Format
      B LSE.  This LSE contains an initial opcode plus additional fields
      that describe the NAS.  The size of this Information Element is 3
      octets.

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      If multiple mplsMnaLseFormatB Information Elements are specified
      within a single Template, then they apply to the mplsMnaSubStack
      Information Elements in order: the first mplsMnaLseFormatB applies
      to the first mplsMnaSubStack, the second to the second, and so on.
      Note that the "closest" mplsMnaLseFormatB and mplsMnaSubStack
      Information Elements within a given Template are not necessarily
      related.  If there are fewer mplsMnaLseFormatB Information
      Elements than mplsMnaSubStack Information Elements, then
      subsequent mplsMnaSubStack Information Elements have no LSE Format
      B information in this template.  If there are more
      mplsMnaLseFormatB Information Elements than the number of
      mplsMnaSubStack Information Elements, then the additional
      mplsMnaLseFormatB Information Elements are meaningless.

   Abstract Data Type:  octetArray

   Data Type Semantics:  default

   Additional Information:  See section 4.2 in [I-D.ietf-mpls-mna-hdr]
      for the definition of LSE Format B.

   Reference:  This document.

3.2.  IPFIX IEs for Post-Stack MNAs

3.2.1.  mnaPostStackMplsHeaderSection

   Name:  mnaPostStackMplsHeaderSection

   ElementID:  TBD3

   Description:  The Post-Stack MPLS Header encoded after the Bottom of
      the MPLS label stack.  This Information Element has a variable
      length.

   Abstract Data Type:  octetArray

   Data Type Semantics:  default

   Additional Information:  See section 3 of [I-D.ietf-mpls-mna-ps-hdr].

   Reference:  This document.

3.2.2.  mnaPostStackMplsHeaderType

   Name:  mnaPostStackMplsHeaderType

   ElementID:  TBD4

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   Description:  This IE carries the Post-Stack MPLS Header Type defined
      in section 3.2.1 of [I-D.ietf-mpls-mna-ps-hdr].  The Post-Stack
      MPLS Header type is the top-header for all the Post-Stack Network
      Actions that are encoded in the PSMH for each scope.  The size of
      this Information Element is 4 octets.

   Abstract Data Type:  octetArray

   Data Type Semantics:  default

   Additional Information:  See section 3.2.1 of
      [I-D.ietf-mpls-mna-ps-hdr].

   Reference:  This document.

4.  Operational Considerations

   For the in-stack MNAs, as specified in [I-D.ietf-mpls-mna-hdr], the
   presence of the MNA Sub-Stack Indicator is indicated by the MNA Sub-
   Stack Indicator which is a Base Special-Purpose MPLS Label with value
   TBA.  To generate Flow Records with the in-Stack MNA IEs included,
   the metering process MUST understand the MNA Sub-Stack Indicator.  If
   the Base Special-Purpose MPLS Label with value TBA is absent in the
   label stack, when the in-Stack MNA IEs appear in the template record,
   the corresponding field in the data record is RECOMMENDED to set to
   all zeros.

   For the post-stack MNAs, since the presence of the Post-Stack MPLS
   Header is indicated by the P-bit in the LSE Format B
   [I-D.ietf-mpls-mna-ps-hdr] which is carried in the label stack
   following the MNA Sub-Stack Indicator, the metering process MUST
   understand the MNA Sub-Stack Indicator and the P-bit in the LSE
   Format B.  Only when the P-bit is set SHOULD the metering process
   capture the post-stack MNA information after the bottom of the stack.

5.  Security Considerations

   There are no additional security considerations regarding allocation
   of these new IPFIX IEs compared to [RFC7012].

6.  IANA Considerations

   This document requests IANA to create new IEs under the "IPFIX
   Information Elements" registry [RFC7012] available at [IANA-IPFIX].

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      +------------+-------------------------------+---------------+
      | Element ID | Name                          | Reference     |
      +------------+-------------------------------+---------------+
      | TBD1       | mplsMnaSubStack               | This document |
      +------------+-------------------------------+---------------+
      | TBD2       | mplsMnaLseFormatB             | This document |
      +------------+-------------------------------+---------------+
      | TBD3       | mnaPostStackMplsHeaderSection | This document |
      +------------+-------------------------------+---------------+
      | TBD4       | mnaPostStackMplsHeaderType    | This document |
      +------------+-------------------------------+---------------+

               Table 1: IPFIX Information Elements Registry

7.  References

7.1.  Normative References

   [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-
              17, 1 December 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-mpls-
              mna-hdr-17>.

   [I-D.ietf-mpls-mna-ps-hdr]
              Rajamanickam, J., Gandhi, R., Zigler, R., Li, T., and J.
              Dong, "Post-Stack MPLS Network Action (MNA) Solution",
              Work in Progress, Internet-Draft, draft-ietf-mpls-mna-ps-
              hdr-04, 20 November 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-mpls-
              mna-ps-hdr-04>.

   [IANA-IPFIX]
              IANA, "IP Flow Information Export (IPFIX) Entities",
              <https://www.iana.org/assignments/ipfix>.

   [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>.

   [RFC7011]  Claise, B., Ed., Trammell, B., Ed., and P. Aitken,
              "Specification of the IP Flow Information Export (IPFIX)
              Protocol for the Exchange of Flow Information", STD 77,
              RFC 7011, DOI 10.17487/RFC7011, September 2013,
              <https://www.rfc-editor.org/info/rfc7011>.

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   [RFC7012]  Claise, B., Ed. and B. Trammell, Ed., "Information Model
              for IP Flow Information Export (IPFIX)", RFC 7012,
              DOI 10.17487/RFC7012, September 2013,
              <https://www.rfc-editor.org/info/rfc7012>.

   [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>.

7.2.  Informative References

   [RFC9789]  Andersson, L., Bryant, S., Bocci, M., and T. Li, "MPLS
              Network Actions (MNAs) Framework", RFC 9789,
              DOI 10.17487/RFC9789, July 2025,
              <https://www.rfc-editor.org/info/rfc9789>.

Author's Address

   Yao Liu
   ZTE Corporation
   China
   Email: liu.yao71@zte.com.cn

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