



MPLS Working Group                                                 T. Li
Internet-Draft                                              V. P. Beeram
Intended status: Standards Track                                     HPE
Expires: 26 June 2026                                           J. Drake
                                                                        
                                                                 T. Saad
                                                           Cisco Systems
                                                               I. Meilik
                                                                Broadcom
                                                        23 December 2025


      MPLS Network Actions for Network Resource Partition Selector
                  draft-ietf-mpls-mna-nrp-selector-03

Abstract

   An IETF Network Slice service provides connectivity coupled with a
   set of network resource commitments and is expressed in terms of one
   or more connectivity constructs.  A Network Resource Partition (NRP)
   is a collection of resources identified in the underlay network to
   support IETF Network Slice services.  A Slice-Flow Aggregate refers
   to the set of traffic streams from one or more connectivity
   constructs belonging to one or more IETF Network Slices that are
   mapped to a specific NRP and provide the same forwarding treatment.
   The packets associated with a Slice-Flow Aggregate may carry a
   marking in the packet's network layer header to identify this
   association and this marking is referred to as NRP Selector.  The NRP
   Selector is used to map the packet to the associated NRP and provide
   the corresponding forwarding treatment to the packet.

   MPLS Network Actions (MNA) technologies are used to indicate actions
   for Label Switched Paths (LSPs) and/or MPLS packets and to transfer
   data needed for these actions.  This document discusses options for
   using MPLS Network Actions (MNAs) to carry the NRP Selector in MPLS
   packets.

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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.





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   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   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
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   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
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   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   4
   2.  MPLS Network Actions  . . . . . . . . . . . . . . . . . . . .   4
     2.1.  13-bit NRP Selector (NRPS13) Action . . . . . . . . . . .   4
     2.2.  20-bit NRP Selector (NRPS20) Action . . . . . . . . . . .   4
     2.3.  20-bit Entropy and NRP Selector (ENRPS20) Action  . . . .   5
     2.4.  Top-most NRPS Action  . . . . . . . . . . . . . . . . . .   6
     2.5.  Unknown NRPS  . . . . . . . . . . . . . . . . . . . . . .   6
   3.  Deployment Considerations . . . . . . . . . . . . . . . . . .   6
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
     4.1.  13-bit NRP Selector Action  . . . . . . . . . . . . . . .   6
     4.2.  20-bit NRP Selector Action  . . . . . . . . . . . . . . .   7
     4.3.  20-bit Entropy and NRP Selector Action  . . . . . . . . .   7
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   6.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .   7
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9









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1.  Introduction

   An IETF Network Slice [RFC9543] service provides connectivity coupled
   with a set of specific commitments of network resources between a
   number of endpoints over a shared underlay network.  The IETF Network
   Slice service is expressed in terms of one or more connectivity
   constructs.  A Network Resource Partition (NRP) [RFC9543] is a
   collection of resources identified in the underlay network to support
   IETF Network Slice services (or any other services that need logical
   network structures with required characteristics to be created).  An
   NRP Policy is a policy construct that enables instantiation of
   mechanisms in support of service specific control and data plane
   behaviors on select topological elements associated with the NRP.
   This is also discussed in [I-D.ietf-teas-ns-ip-mpls].

   A Slice-Flow Aggregate refers to the set of traffic streams from one
   or more connectivity constructs belonging to one or more IETF Network
   Slices that are mapped to a specific NRP and are provided the same
   forwarding treatment.  The NRP policy dictates the identification of
   the flow aggregate that the packet belongs to and the corresponding
   forwarding treatment that needs to be applied to the packet.  The
   packets associated with a Slice-Flow Aggregate may carry a marking in
   the packet's network layer header to identify this association and
   this marking is referred to as NRP Selector (NRPS).
   [I-D.ietf-teas-ns-ip-mpls] discusses a few options for carrying the
   NRP Selector in MPLS packets, including overloading the semantics of
   forwarding/service labels and using a dedicated identifier field.

   [I-D.ietf-mpls-mna-fwk] specifies an architectural framework for the
   MPLS Network Actions (MNA) technologies.  MNA technologies are used
   to indicate actions for Label Switched Paths (LSPs) and/or MPLS
   packets and to transfer data needed for these actions.  The MNA
   architecture can facilitate carrying the dedicated identifier based
   NRP Selector in the MPLS label stack.  This document discusses a few
   options for using MPLS network actions to carry the NRP Selector.
   The proposed encodings are compliant with the MNA header encoding
   formats defined in [I-D.ietf-mpls-mna-hdr].

   The reader is expected to be familiar with terminology specified in
   [I-D.ietf-mpls-mna-fwk] and MNA header encoding formats defined in
   [I-D.ietf-mpls-mna-hdr].










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1.1.  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.  These words may also appear in this
   document in lower case as plain English words, absent their normative
   meanings.

2.  MPLS Network Actions

2.1.  13-bit NRP Selector (NRPS13) Action

   The format of the 13-bit NRP Selector (NRPS13) Action (when encoded
   in the second label stack entry in the Network Action Sub-Stack) is:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Opcode=TBA1 |           NRPS          |R|IHS|S|  NASL |U| NAL |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   *  Name: 13-bit NRP Selector (NRPS13) Action

   *  Network Action Indication: The NRPS13 Action indication is opcode
      TBA1.

   *  Scope: The NRPS13 Action is valid in all scopes.

   *  In-Stack Data: The NRPS13 Action carries 13 bits of ancillary
      data.  The NRPS is encoded in the 13 bits.  The packet carrying
      the NRPS13 action should be given the forwarding treatment
      specified by the associated NRP policy.

   *  LSE Format: B.  The Network Action Length (NAL) field MUST be
      transmitted as zero.

   *  Post-Stack Data: None.

2.2.  20-bit NRP Selector (NRPS20) Action

   The format of the 20-bit NRP Selector (NRPS20) Action is:








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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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Opcode=TBA2 |             NRPS              |S|  NRPS |U| NAL |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   *  Name: 20-bit NRP Selector (NRPS20) Action

   *  Network Action Indication: The NRPS20 Action indication is opcode
      TBA2.

   *  Scope: The NRPS20 Action is valid in all scopes.

   *  In-Stack Data: The NRPS20 Action carries 20 bits of ancillary
      data.  The NRPS is encoded in the 20 bits.  The packet carrying
      the NRPS20 action should be given the forwarding treatment
      specified by the associated NRP policy.

   *  LSE Format: C.  The Network Action Length (NAL) field MUST be
      transmitted as zero.

   *  Post-Stack Data: None.

2.3.  20-bit Entropy and NRP Selector (ENRPS20) Action

   The format of the 20-bit Entropy and NRP Selector (ENRPS20) Action
   is:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Opcode=TBA3 |        Entropy        | NRPS  |S|  NRPS |U| NAL |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   *  Name: 20-bit Entropy and NRP Selector (ENRPS20) Action

   *  Network Action Indication: The ENRPS20 Action indication is opcode
      TBA3.

   *  Scope: The ENRPS20 Action is valid in all scopes.

   *  In-Stack Data: The ENRPS20 Action carries 20 bits of ancillary
      data.  The most significant 12 bits of ancillary data is the
      Entropy Value.  The least significant 8 bits of ancillary data is
      the NRPS.  The Entropy Value has semantics consistent with the
      Entropy Label [RFC6790].  While the RFC 6790 Entropy Label has
      some restrictions to avoid collisions with the reserved label
      space (0-15) [RFC3032], those restrictions are not necessary for



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      the Entropy Value and do not apply.  The packet carrying the
      ENRPS20 action should be given the forwarding treatment specified
      by the associated NRP policy.

   *  LSE Format: C.  The Network Action Length (NAL) field MUST be
      transmitted as zero.

   *  Post-Stack Data: None.

2.4.  Top-most NRPS Action

   Multiple NRPS Actions may be encoded in a single packet.  An
   implementation MUST use only the top-most NRPS Action to determine
   the packet's forwarding treatment.  An implementation that finds a
   subsequent opcode of any of the three NRPS Actions in the label stack
   MUST ignore it.  The specific scenarios where multiple NRPS Actions
   are present in the label stack are outside the scope of this
   document.

2.5.  Unknown NRPS

   An NRP-capable node MUST drop a packet by default if the encoded NRPS
   cannot be mapped to a known NRP.  This requirement MAY be overridden
   by an operator-specified policy, the specification of which is
   outside the scope of this document.

3.  Deployment Considerations

   The choice of the number of bits to encode an NRP Selector is a
   network-wide deployment decision.  This decision may be constrained
   by implementations.

   The choice of which Action to use when the NRP Selector could fit in
   multiple Actions, is open, but it is RECOMMENDED to use NRPS13 where
   possible unless Entropy is also to be carried and it is possible to
   use ENSRP20.

4.  IANA Considerations

4.1.  13-bit NRP Selector Action

   This document requests that IANA allocate a codepoint (TBA1) from the
   "Multiprotocol Label Switching Architecture (MPLS)"/"MPLS Network
   Actions Parameters"/"Network Action Opcodes" registry for the 13-bit
   NRP Selector Action.  The allocation should reference this document.






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4.2.  20-bit NRP Selector Action

   This document requests that IANA allocate a codepoint (TBA2) from the
   "Multiprotocol Label Switching Architecture (MPLS)"/"MPLS Network
   Actions Parameters"/"Network Action Opcodes" registry for the 20-bit
   NRP Selector Action.  The allocation should reference this document.

4.3.  20-bit Entropy and NRP Selector Action

   This document requests that IANA allocate a codepoint (TBA3) from the
   "Multiprotocol Label Switching Architecture (MPLS)"/"MPLS Network
   Actions Parameters"/"Network Action Opcodes" registry for the 20-bit
   Entropy and NRP Selector Action.  The allocation should reference
   this document.

5.  Security Considerations

   The forwarding plane is insecure.  If an adversary can affect the
   forwarding plane, then they can inject data, remove data, corrupt
   data, or modify data.  MNA additionally allows an adversary to make
   packets perform arbitrary network actions.

   Link-level security mechanisms can help mitigate some on-link
   attacks, but does nothing to preclude hostile nodes.

6.  Contributors

   The following individuals contributed to this document:

   Colby Barth
   Juniper Networks
   Email: cbarth@juniper.net

   Srihari R.  Sangli
   Juniper Networks
   Email: ssangli@juniper.net

   Chandra Ramachandran
   Juniper Networks
   Email: csekar@juniper.net

   Kireeti Kompella
   Juniper Networks
   Email: kireeti@juniper.net

7.  References

7.1.  Normative References



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   [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>.

   [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>.

   [RFC6790]  Kompella, K., Drake, J., Amante, S., Henderickx, W., and
              L. Yong, "The Use of Entropy Labels in MPLS Forwarding",
              RFC 6790, DOI 10.17487/RFC6790, November 2012,
              <https://www.rfc-editor.org/info/rfc6790>.

   [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

   [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-15, 27 December
              2024, <https://datatracker.ietf.org/doc/html/draft-ietf-
              mpls-mna-fwk-15>.

   [RFC9543]  Farrel, A., Ed., Drake, J., Ed., Rokui, R., Homma, S.,
              Makhijani, K., Contreras, L., and J. Tantsura, "A
              Framework for Network Slices in Networks Built from IETF
              Technologies", RFC 9543, DOI 10.17487/RFC9543, March 2024,
              <https://www.rfc-editor.org/info/rfc9543>.










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   [I-D.ietf-teas-ns-ip-mpls]
              Saad, T., Beeram, V. P., Dong, J., Halpern, J. M., and S.
              Peng, "Realizing Network Slices in IP/MPLS Networks", Work
              in Progress, Internet-Draft, draft-ietf-teas-ns-ip-mpls-
              06, 20 October 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-teas-ns-
              ip-mpls-06>.

Authors' Addresses

   Tony Li
   HPE
   1701 E Mossy Oaks Rd.
   Spring, TX 77389
   United States
   Email: tony.li@tony.li


   Vishnu Pavan Beeram
   HPE
   1701 E Mossy Oaks Rd.
   Spring, TX 77389
   United States
   Email: vbeeram@juniper.net


   John Drake
   Email: je_drake@yahoo.com


   Tarek Saad
   Cisco Systems
   Email: tsaad.net@gmail.com


   Israel Meilik
   Broadcom
   Email: israel.meilik@broadcom.com













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