MPLS Working Group                                               L. Gong
Internet-Draft                                              China Mobile
Intended status: Standards Track                                  C. Lin
Expires: 3 September 2026                           New H3C Technologies
                                                            2 March 2026

 Operations, Administration and Maintenance (OAM) for Network Resource
                    Partition (NRP) in MPLS Network
                    draft-gong-mpls-nrp-oam-mpls-02

Abstract

   A Network Resource Partition (NRP) represents a subset of network
   resources and associated policies within the underlay network.

   This document describes the implementation of the Operations,
   Administration, and Maintenance (OAM) mechanism for NRPs in MPLS
   networks.  By extending existing OAM mechanisms such as ping,
   traceroute, the proposed solution enables comprehensive NRP support
   in MPLS networks.

Status of This Memo

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

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   This Internet-Draft will expire on 3 September 2026.

Copyright Notice

   Copyright (c) 2026 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.
   Please review these documents carefully, as they describe your rights

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   and restrictions with respect to this document.  Code Components
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   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  OAM Mechanisms  . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  MPLS PING . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  MPLS TRACEROUTE . . . . . . . . . . . . . . . . . . . . . . .   5
   5.  UseCase . . . . . . . . . . . . . . . . . . . . . . . . . . .   6
     5.1.  MPLS PING . . . . . . . . . . . . . . . . . . . . . . . .   6
     5.2.  MPLS TRACEROUTE . . . . . . . . . . . . . . . . . . . . .   7
   6.  Security Consideration  . . . . . . . . . . . . . . . . . . .   8
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   [RFC9543] provides the definition of IETF network slice for use
   within the IETF and discusses the general framework for requesting
   and operating IETF Network Slices, their characteristics, and the
   necessary system components and interfaces.  It also introduces the
   concept Network Resource Partition (NRP), which is a subset of the
   resources and associated policies in the underlay network.

   Using OAM tools enables real-time monitoring of the operational
   status of network slices, allowing for quick detection and
   localization of faults.  When a node or link within a network slice
   experiences a failure, OAM tools can promptly issue alerts, assisting
   network administrators in taking swift corrective action to minimize
   service downtime.  Therefore, the use of OAM tools in an NRP network
   is crucial for ensuring the availability and performance of network
   slice resources.  This not only enhances user experience but also
   improves the overall efficiency and stability of the network.

   Existing OAM tools typically include Ping, Traceroute.  [RFC8029]
   describes how to Detect MPLS Data-Plane Failures in MPLS networks.

   This document continues to employ these existing OAM mechanisms to
   monitor Data-Plane NRP resources Failures.

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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
   [RFC2119] (Bradner, S., "Key words for use in RFCs to Indicate
   Requirement Levels", BCP 14, RFC 2119, March 1997) and [RFC8174]
   (Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key
   Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017).

1.2.  Terminology

   The key terms used in this document are defined below.

   Network Resource Partition (NRP): a subset of the network resources
   and associated policies on each of a connected set of links in the
   underlay network.  This term is defined in [RFC9543].

   IETF Network Slice: The realization of the service in the provider's
   network achieved by partitioning network resources and by applying
   certain tools and techniques within the network.  This term is
   defined in [RFC9543].

2.  OAM Mechanisms

   [RFC8029] describes how to detect MPLS data-plane failures in MPLS
   networks.

   To support NRP OAM, the initiator of an OAM operation (e.g., ping or
   traceroute) MUST include the NRP Identifier (NRP-ID) in the data
   plane of the probe packets.  The method for carrying the NRP-ID in
   the data plane is outside the scope of this document; it is assumed
   that the underlay network provides a mechanism to associate a packet
   with a specific NRP (e.g., through a dedicated label, a traffic
   class, or a slice identifier).

   Intermediate equipment and OAM End Points need to check the NRP
   resources when receiving OAM packets with an NRP-ID.  If the resource
   check fails, the node shall respond with an MPLS Echo Reply carrying
   an appropriate error code (see Section 7)

3.  MPLS PING

   When performing an MPLS PING operation, the initiator sends an MPLS
   Echo request.  To support probing of NRP resources, the NRP-ID MUST
   be carried in the data plane (e.g., via a dedicated label or other
   encoding).  The MPLS Echo request is forwarded along the LSP towards
   the destination.

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   The intermediate node processes the MPLS Echo Request, looks up the
   forwarding table, obtains the Downstream information, and checks the
   NRP to the Downstream.  If NRP are not available, it responds with a
   MPLS Echo Reply, indicating the Error as "NRP resources unavailable".
   If this node does not recognize the NRP ID or has not allocated
   resources for this NRP, it returns "NRP unknown or not supported".

   According to [RFC8029], an MPLS Echo Request is designed to be
   processed in the control plane of transit nodes and the egress node,
   triggered by mechanisms such as the Router Alert Option, the MPLS
   Router Alert label, or TTL expiration.  This document does not alter
   that fundamental behavior.  The newly added error codes apply only to
   scenarios where the packet is processed in the control plane.

      1） MPLS Echo Request with NRP
      --------------------->
                 2） Check NRP
                    MPLS Echo Reply Reponse Error
      <-----------

                           3） MPLS Echo Reply
      <----------------------
      +--+      +--+      +--+
      |N1+------|N2+------|N3+
      +--+      +--+      +--+

                        Figure 1: MPLS PING for NRP

   Process of MPLS PING for NRP:

   1) The initiator of the MPLS Echo Request includes the NRP-ID in the
   data layer when sending the MPLS PING request.

   2) The intermediate node processes the MPLS Echo Request, looks up
   the forwarding table, obtains the Downstream information, and checks
   the NRP to the Downstream.  If NRP are not available, it responds
   with a MPLS Echo Reply, indicating the Error as "NRP resources
   unavailable".  If this node does not recognize the NRP ID or has not
   allocated resources for this NRP, it returns "NRP unknown or not
   supported".

     For MPLS networks, it is necessary to extend the Return Codes
     carried in the MPLS Echo Reply(IANA 7).

   3) If the check passes, the End Point will respond with a normal MPLS
   Echo Reply.

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4.  MPLS TRACEROUTE

   When performing a MPLS TRACEROUTE operation, the TRACEROUTE initiator
   sends MPLS Echo request packets toward the destination node by
   incrementally increasing the TTL value.  To support the probing of
   NRP resources, NRP information is carried in the data layer.  Each
   intermediate node, when forwarding the MPLS Echo request, looks up
   the forwarding table to obtain the Downstream information and
   performs NRP check for the next hop.  If the resources are
   unavailable, the node responds with an MPLS Echo Reply with error
   message indicating "NRP resource unavailability".  If this node does
   not recognize the NRP ID or has not allocated resources for this NRP,
   it returns "NRP unknown or not supported".  The packets used for MPLS
   TRACEROUTE are the same as those used for MPLS PING.  When NRP
   resources are unavailable, the error codes used are also identical to
   those used in MPLS PING operations

   1）           MPLS Echo Request with NRP-ID
      ------------>
                 2） MPLS Echo Reply
      <-----------
      3） MPLS Echo Request with NRP-ID
      --------------------->

                          4） MPLS Echo Reply
      <--------------------
      +--+      +--+      +--+
      |N1+------|N2+------|N3+
      +--+      +--+      +--+

                     Figure 2: MPLS Traceroute for NRP

   Process of MPLS Traceroute for NRP:

   1) The initiator of the MPLS Echo request includes the NRP-ID in the
   data layer when sending the Traceroute request.

     The MPLS Echo Request with TTL 1 to n increase.

   2) The intermediate node looks up the forwarding table to obtain the
   Downstream information and performs NRP check for the Downstream when
   processing a MPLS Echo Request.  If they are not available, it
   responds with a MPLS Echo Reply, indicating the Error as "NRP
   resources unavailable".  If this node does not recognize the NRP ID
   or has not allocated resources for this NRP, it returns "NRP unknown
   or not supported".  The error code for expansion should be the same
   as MPLS PING.

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   3) If the check passes, the process proceeds with a normal MPLS
   Traceroute, performing hop-by-hop detection of the path to the End
   Point until the Traceroute process is completed, and the detection
   results are outputted.

5.  UseCase

  +-------------------------| N100 |--------------------------------+
     |                                                                 |
     |  ======NRP-1===== NRP-1 ------ NRP-1======NRP-1-----   ======   |
        ||N1||-----||N2||------| N3 |------||N4||-----| N5 |---||N7||
        ||  ||-----||  ||------|    |------||  ||-----|    |---||  ||
        ======NRP-2===== NRP-2 ------ NRP-2======NRP-2------   ======
           |            |                      |                  |
        ---+--          | NRP-1 ------ NRP-1   |                --+---
        |CE 1|          +-------| N6 |---------+                |CE 2|
        ------            NRP-2 |    | NRP-2                    ------
                                ------

                      Figure 3: NRP Network Diagram

   In the reference topology of Figure 3:

   *  Node j has an IPv4 loopback address 192.168.j.1/32.

   *  A label at node j is 1j000 (e.g., node 2 uses label 12000).

   *  Node N100 is a controller.

   Two NRPs are defined: - NRP-1 (ID=1) and NRP-2 (ID=2).  Different
   links and nodes may participate in different NRPs as shown.

   The following subsections illustrate MPLS ping and traceroute
   operations with NRP support.

5.1.  MPLS PING

   Example 1: Successful MPLS ping through NRP-1.

      ping 15000 via label-stack 12000, 14000, NRP-ID: 1, Ret NRP-ID: 2

   Sending 5, 100-byte MPLS Echos to 192.168.5.1, timeout is 2 seconds:

   !!!!!

   Success rate is 100 percent (5/5), round-trip min/avg/max = 0.625
   /0.749/0.931 ms

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   Example 2: MPLS ping failure due to NRP resource unavailability.

      ping 15000 via label-stack 12000, 14000, NRP-ID: 1, Ret NRP-ID: 2

   Reply to request 2 (1 ms) from 192.168.2.1.  Return Code: 'NA'

   Reply to request 3 (1 ms) from 192.168.2.1.  Return Code: 'NA'

   Reply to request 4 (1 ms) from 192.168.2.1.  Return Code: 'NA'

   Reply to request 5 (1 ms) from 192.168.2.1.  Return Code: 'NA'

   Success rate is 0 percent (0/5), round-trip min/avg/max = 1/1/1 ms

   In the above examples: - 'NA' indicates "NRP resources unavailable".
   These codes are placeholders for the IANA-assigned values (see
   Section 7).

5.2.  MPLS TRACEROUTE

   Example 1: Successful MPLS traceroute through NRP-1.

      traceroute 15000 via label-stack 12000, 14000, NRP-ID: 1, Ret-NRP-
      ID: 2

   Tracing the route to 15000

    TTL   Replier        Time    Type      Downstream

    0                            Ingress   192.168.2.1/[12000]
    1     192.168.2.1     1 ms   Transit   192.168.4.1/[14000]
    2     192.168.4.1     1 ms   Transit   192.168.5.1/[15000]
    3     192.168.5.1     1 ms   Egress

   Example 2: MPLS traceroute failure due to NRP resource
   unavailability.

 > traceroute 15000 via label-stack 12000, 14000, NRP-ID: 1, Ret-NRP-    ID: 2

   Tracing the route to 15000

    TTL   Replier      Time   Type      Downstream

    0                         Ingress   192.168.2.1/[12000]

    1     192.168.2.1  1 ms   Transit   192.168.4.1/[14000] Return[NA]

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6.  Security Consideration

   This document does not impose any additional security challenges
   beyond those described in [RFC4884], [RFC4443], [RFC0792], [RFC8754],
   and [RFC8986].  The inclusion of an NRP-ID in OAM packets does not
   introduce new vulnerabilities, as the NRP-ID is used only within the
   trusted domain of a network provider.  Operators should ensure that
   OAM packets are adequately protected (e.g., by filtering at network
   boundaries) to prevent unauthorized injection or disclosure of
   network slice information.

7.  IANA Considerations

   IANA is requested to allocate two new Return Codes in the "Multi-
   Protocol Label Switching (MPLS) Label Switched Path (LSP) Ping
   Parameters" registry, sub-registry "Return Codes".

   The following values are proposed (specific code points to be
   assigned by IANA):

     Value    Meaning
     -----    -------
     TBD1     NRP unknown/not supported
     TBD2     NRP resource unavailable

   The code "NRP unknown/not supported" indicates that the egress LSR
   does not recognize the NRP-ID or the NRP is not provisioned on that
   node.  The code "NRP resource unavailable" indicates that the NRP is
   recognized but the required resources (e.g., bandwidth, queue) are
   not currently available.

8.  Normative References

   [RFC8029]  Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N.,
              Aldrin, S., and M. Chen, "Detecting Multiprotocol Label
              Switched (MPLS) Data-Plane Failures", RFC 8029,
              DOI 10.17487/RFC8029, March 2017,
              <https://www.rfc-editor.org/rfc/rfc8029>.

   [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/rfc/rfc9543>.

Authors' Addresses

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   Liyan Gong
   China Mobile
   China
   Email: gongliyan@chinamobile.com

   Changwang Lin
   New H3C Technologies
   China
   Email: linchangwang.04414@h3c.com

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