MPLS Working Group X. Min Internet-Draft ZTE Corp. Intended status: Standards Track G. Mirsky Expires: 27 July 2026 Ericsson L. Andersson Bronze Dragon Consulting 23 January 2026 LSP Ping/Traceroute for Enabled In-situ OAM Capabilities draft-ietf-mpls-lsp-ping-ioam-conf-state-01 Abstract This document describes the application of the mechanism of discovering In-situ OAM (IOAM) capabilities, described in RFC 9359 "Echo Request/Reply for Enabled In Situ OAM (IOAM) Capabilities", in MPLS networks. The MPLS Node IOAM Information Query functionality uses the MPLS echo request/reply messages, allowing the IOAM encapsulating node to discover the enabled IOAM capabilities of each IOAM transit and IOAM decapsulating node. 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/. 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 27 July 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 Min, et al. Expires 27 July 2026 [Page 1] Internet-Draft LSP Ping for IOAM Capabilities January 2026 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 Used in This Document . . . . . . . . . . . . . . 3 3. IOAM Capabilities Query TLV . . . . . . . . . . . . . . . . . 3 3.1. Examples of the IOAM Capabilities Query . . . . . . . . . 4 4. IOAM Capabilities Response TLV . . . . . . . . . . . . . . . 4 4.1. IOAM Capabilities Sub-TLVs . . . . . . . . . . . . . . . 5 4.2. Examples of IOAM Capabilities Response TLV . . . . . . . 6 5. Return Code Field Processing . . . . . . . . . . . . . . . . 8 6. Operational Considerations . . . . . . . . . . . . . . . . . 9 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 7.1. TLV assigments . . . . . . . . . . . . . . . . . . . . . 9 7.2. New Sub-TLV registry . . . . . . . . . . . . . . . . . . 10 7.3. Return Code assignment . . . . . . . . . . . . . . . . . 11 8. Security Considerations . . . . . . . . . . . . . . . . . . . 11 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 10.1. Normative References . . . . . . . . . . . . . . . . . . 12 10.2. Informative References . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 1. Introduction MPLS encapsulation for In-situ OAM (IOAM) data is defined in [I-D.ietf-mpls-mna-ioam], which utilizes MPLS Network Actions (MNA) techniques ([RFC9789]) to carry IOAM data fields ([RFC9197], [RFC9326]) in MPLS packets. As specified in [RFC9359], the echo request/reply can be used by the IOAM encapsulating node to discover the enabled IOAM capabilities at IOAM transit and decapsulating nodes. [RFC8029] defines a probe message called "MPLS echo request", and a response message called "MPLS echo reply" for returning the result of the probe. This document describes the MPLS Node IOAM Information Query functionality, which uses the MPLS echo request/reply messages, allowing the IOAM encapsulating node to discover the enabled IOAM capabilities of each IOAM transit and IOAM decapsulating node. Min, et al. Expires 27 July 2026 [Page 2] Internet-Draft LSP Ping for IOAM Capabilities January 2026 [RFC8029] specifies "ping" and "traceroute" modes. In "ping" mode, the ingress LSR sends a single MPLS echo request with the TTL in the outermost label stack entry set to 255. The MPLS echo request is intended to reach the end of the path and only the egress LSR is expected to respond with the MPLS echo reply. In "traceroute" mode, the ingress LSR transmits a sequence of MPLS echo requests with the TTL value being set in successive probe packets to 1, 2, and so on. Using TTL expiration as the exception mechanism, each LSR is expected to respond by transmitting an MPLS echo reply. In an MPLS network, the ingress LSR may also act as the IOAM encapsulating node. In such a case, a transit LSR acts as the IOAM transit node, and the egress LSR acts as the IOAM decapsulating node. Usually, the trace option of IOAM data is needed, the IOAM encapsulating node requires to query the enabled IOAM capabilities of each IOAM transit and decapsulating node, then the "traceroute" mode can be used. In case that only the edge to edge option of IOAM data is needed, the IOAM encapsulating node requires to query the enabled IOAM Capabilities of only the IOAM decapsulating node, then the "ping" mode can be used. The mechanism specified in this document applies to both point-to- point (P2P) MPLS LSP and point-to-multipoint (P2MP) MPLS LSP. 2. Conventions Used in This Document 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. IOAM Capabilities Query TLV The IOAM Capabilities Query TLV presented in Figure 1 is carried as a TLV of the MPLS Echo Request message: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM Capa. Query Type (TBA1) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . . List of IOAM Namespace-IDs . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: IOAM Capabilities Query TLV Min, et al. Expires 27 July 2026 [Page 3] Internet-Draft LSP Ping for IOAM Capabilities January 2026 Type: Indicates the IOAM Capabilities Query TLV. The value is TBA1. Length: The length of the TLV's Value field in octets. The Value field is a List of IOAM Namespace-IDs, which is also called IOAM Capabilities Query Container Payload in Section 3.1 of [RFC9359]. 3.1. Examples of the IOAM Capabilities Query The format of an IOAM Capabilities Query can vary from deployment to deployment. In a deployment where only the default Namespace-ID is used, the IOAM Capabilities Query is depicted as the following: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM Capa. Query Type (TBA1) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID | Zero-padded | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: IOAM Capabilities Query of the Default IOAM Namespace In a deployment where two Namespace-IDs (Namespace-ID1 and Namespace- ID2) are used, the IOAM Capabilities Query is depicted as the following: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM Capa. Query Type (TBA1) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID1 | Namespace-ID2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: IOAM Capabilities Query of the Two IOAM Namespaces 4. IOAM Capabilities Response TLV The IOAM Capabilities Response TLV presented in Figure 4 is carried as a TLV of the MPLS Echo Reply message: Min, et al. Expires 27 July 2026 [Page 4] Internet-Draft LSP Ping for IOAM Capabilities January 2026 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |IOAM Capa. Response Type (TBA2)| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . . List of IOAM Capabilities Sub-TLVs . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4: IOAM Capabilities Response TLV Type: Indicates the IOAM Capabilities Response TLV. The value is TBA2. Length: The length of the TLV's Value field in octets. The Value field is a List of IOAM Capabilities Objects, which is also called IOAM Capabilities Response Container Payload in Section 3.2 of [RFC9359]. Each IOAM Capabilities Object is encoded in a sub-TLV format. 4.1. IOAM Capabilities Sub-TLVs All IOAM Capabilities sub-TLVs (aka Objects) are encapsulated in an IOAM Capabilities Response TLV of an MPLS Echo Reply message. Each IOAM Capabilities sub-TLV has the following format: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM Capa. Sub-type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . . IOAM Capabilities Object Payload . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5: IOAM Capabilities Sub-TLV Sub-type: Indicates the IOAM Capabilities sub-TLVs. The values are listed as the following: Min, et al. Expires 27 July 2026 [Page 5] Internet-Draft LSP Ping for IOAM Capabilities January 2026 Value Sub-type Name ----- ----------- 1 IOAM Pre-allocated Tracing Capabilities Object 2 IOAM Proof of Transit Capabilities Object 3 IOAM Edge-to-Edge Capabilities Object 4 IOAM DEX Capabilities Object 5 IOAM End-of-Domain Object Length: The length of the sub-TLV's Value field in octets. The Value field of the IOAM Capabilities sub-TLV is the IOAM Capabilities Object Payload, which is defined in Sections 3.2.1, 3.2.3, 3.2.4, 3.2.5, and 3.2.6 of [RFC9359]. 4.2. Examples of IOAM Capabilities Response TLV The format of an IOAM Capabilities Response can vary from deployment to deployment. In a deployment where only the default Namespace-ID is used, the IOAM Pre-allocated Tracing Capabilities and IOAM Proof of Transit Capabilities are enabled at an IOAM transit node, if that IOAM transit node received an MPLS echo request containing IOAM Capabilities Query TLV, then the IOAM Capabilities Response TLV contained in an MPLS echo reply is depicted as the following: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |IOAM Capa. Response Type (TBA2)| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM Capa. Sub-type (1) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM-Trace-Type | Reserved |W| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID | Ingress_MTU | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ingress_if_id (short or wide format) ...... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM Capa. Sub-type (2) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID | IOAM-POT-Type |SoP| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 6: Example 1 of IOAM Capabilities Response TLV Min, et al. Expires 27 July 2026 [Page 6] Internet-Draft LSP Ping for IOAM Capabilities January 2026 In a deployment where two Namespace-IDs (Namespace-ID1 and Namespace- ID2) are used, for both Namespace-ID1 and Namespace-ID2 the IOAM Pre- allocated Tracing Capabilities and IOAM Proof of Transit Capabilities are enabled at an IOAM transit node, if that IOAM transit node received an MPLS echo request containing IOAM Capabilities Query TLV, then the IOAM Capabilities Response TLV contained in an MPLS echo reply is depicted as the following: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |IOAM Capa. Response Type (TBA2)| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM Capa. Sub-type (1) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM-Trace-Type | Reserved |W| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID1 | Ingress_MTU | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ingress_if_id (short or wide format) ...... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM Capa. Sub-type (2) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID1 | IOAM-POT-Type |SoP| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM Capa. Sub-type (1) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM-Trace-Type | Reserved |W| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID2 | Ingress_MTU | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ingress_if_id (short or wide format) ...... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM Capa. Sub-type (2) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID2 | IOAM-POT-Type |SoP| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7: Example 2 of IOAM Capabilities Response TLV Note that multiple sub-TLVs with the same sub-type may be present in an IOAM Capabilities Response TLV, as long as the Namespace-IDs in these sub-TLVs are all different. In a deployment where only the default Namespace-ID is used, the IOAM Pre-allocated Tracing Capabilities, IOAM Proof of Transit Capabilities and IOAM Edge-to-Edge Capabilities are enabled at the IOAM decapsulating node, if that IOAM decapsulating node received an Min, et al. Expires 27 July 2026 [Page 7] Internet-Draft LSP Ping for IOAM Capabilities January 2026 MPLS echo request containing IOAM Capabilities Query TLV, then the IOAM Capabilities Response TLV contained in an MPLS echo reply is depicted as the following: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |IOAM Capa. Response Type (TBA2)| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM Capa. Sub-type (1) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM-Trace-Type | Reserved |W| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID | Ingress_MTU | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ingress_if_id (short or wide format) ...... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM Capa. Sub-type (2) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID | IOAM-POT-Type |SoP| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM Capa. Sub-type (3) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID | IOAM-E2E-Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |TSF| Reserved | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 8: Example 3 of IOAM Capabilities Response TLV 5. Return Code Field Processing The Return Code field in the MPLS echo reply MUST be set to (TBA3) No Matched Namespace-ID if any of the following conditions apply: * The IOAM Capabilities Query TLV does not include any Namespace-ID. * None of the contained list of IOAM Namespace-IDs is recognized. * None of the contained list of IOAM Namespace-IDs is enabled. Min, et al. Expires 27 July 2026 [Page 8] Internet-Draft LSP Ping for IOAM Capabilities January 2026 6. Operational Considerations Section 4 of [RFC9359] provides an operational guide on how to use echo request/reply for discovering enabled IOAM capabilities at network nodes, which applies to this document as well. Specifically, if only the IOAM Edge-to-Edge Option-Type is enabled for an MPLS LSP, then LSP Ping in "ping" mode would be operated, which means the LSP ingress node would send a single MPLS echo request to the LSP egress node for discovering its IOAM Edge-to-Edge Capabilities; if other IOAM Option-Type than the Edge-to-Edge Option-Type is enabled for an MPLS LSP, e.g., the IOAM Pre-allocated Trace Option-Type is enabled for an MPLS LSP, then LSP Ping in "traceroute" mode would be operated, which means the LSP ingress node would send a sequence of MPLS echo requests with TTL equal to 1, 2, 3, and so on, until the LSP ingress node receives an MPLS echo reply sent by the LSP egress node. Considering the IOAM function is resource-consuming, in an MPLS network with high number LSPs, usually not all the LSPs are IOAM enabled, in that case, the LSP Ping mechanism for IOAM capabilities discovery would be executed only with the IOAM-enabled LSPs. 7. IANA Considerations This document does request that IANA assigns two new TLVs, and new sub-TLV registry for one of the new TLVs, 5 sub-TLVs to initially populate this registry and a new return code (TBA3). 7.1. TLV assigments IANA is requested to assign two new TLVs (TBA1 and TBA2) from the "TLV" registry in the "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" registry group. The TLVs' values should be assigned from the range of TLVs that require an error message if the TLV is not recognized. If possible the two lowest free values should be used for these TLVs. +======+=========================+===============+==================+ | Type | TLV Name | Reference | Sub-TLV Registry | +======+=========================+===============+==================+ | TBA1 | IOAM Capabilities Query | This | No Sub-TLVs | | | | document | | +------+-------------------------+---------------+------------------+ | TBA2 | IOAM Capabilities | This | Table 3 | | | Response | document | | +------+-------------------------+---------------+------------------+ Table 1: New TLVs Min, et al. Expires 27 July 2026 [Page 9] Internet-Draft LSP Ping for IOAM Capabilities January 2026 7.2. New Sub-TLV registry A new sub-TLV registry should be created for the TLV TBA2 created in Section 6.1. The registration procedures for this sub-TLV registry shall be: +=============+==============+=====================================+ | Range | Registration | Note | | | Procedure | | +=============+==============+=====================================+ | 0-16383 | Standards | This range is for TLVs that require | | | Action | an error message if not recognized. | | | | ([RFC9041], Section 3.1) | +-------------+--------------+-------------------------------------+ | 16384-31739 | RFC Required | This range is for TLVs that require | | | | an error message if not recognized. | | | | ([RFC9041], Section 3.1) | +-------------+--------------+-------------------------------------+ | 31740-31743 | Experimental | Reserved, not to be assigned. This | | | Use | range is for TLVs that require an | | | | error message if not recognized. | | | | ([RFC9041], Section 3.1) | +-------------+--------------+-------------------------------------+ | 31744-32767 | First Come | This range is for TLVs that require | | | First Served | an error message if not recognized. | | | | ([RFC9041], Section 3.1) | +-------------+--------------+-------------------------------------+ | 32768-49161 | Standards | This range is for TLVs that can be | | | Action | silently dropped if not recognized. | +-------------+--------------+-------------------------------------+ | 49162-64507 | RFC Required | This range is for TLVs that can be | | | | silently dropped if not recognized. | +-------------+--------------+-------------------------------------+ | 64508-64511 | Experimental | Reserved, not to be assigned. This | | | Use | range is for TLVs that can be | | | | silently dropped if not recognized. | +-------------+--------------+-------------------------------------+ | 64512-65535 | First Come | This range is for TLVs that can be | | | First Served | silently dropped if not recognized. | +-------------+--------------+-------------------------------------+ Table 2: Sub-TLV Registration Procedures This sub-TLV registry should initially be populated with the following values. Min, et al. Expires 27 July 2026 [Page 10] Internet-Draft LSP Ping for IOAM Capabilities January 2026 +==========+============================+===============+=========+ | Sub-Type | Sub-TLV name | Reference | Comment | +==========+============================+===============+=========+ | 0 | Reserved | This document | | +----------+----------------------------+---------------+---------+ | 1 | IOAM Pre-allocated Tracing | This document | | | | Capabilities Object | | | +----------+----------------------------+---------------+---------+ | 2 | IOAM Proof of Transit | This document | | | | Capabilities Object | | | +----------+----------------------------+---------------+---------+ | 3 | IOAM Edge-to-Edge | This document | | | | Capabilities Object | | | +----------+----------------------------+---------------+---------+ | 4 | IOAM DEX Capabilities | This document | | | | Object | | | +----------+----------------------------+---------------+---------+ | 5 | IOAM End-of-Domain Object | This document | | +----------+----------------------------+---------------+---------+ Table 3: New Sub-TLV Registry for TLV TBA2 7.3. Return Code assignment IANA is requested to assign a new Return Code from the "Return Code" registry in the "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" registry group as follows: +=======+=========================+===============+ | Value | Meaning | Reference | +=======+=========================+===============+ | TBA3 | No Matched Namespace-ID | This document | +-------+-------------------------+---------------+ Table 4: New Return Code 8. Security Considerations Security issues discussed in [RFC8029] and [RFC9359] apply to this document. This document recommends that the network operators establish policies that restrict access to MPLS Node IOAM Information Query functionality. In order to enforce these policies, nodes that support MPLS Node IOAM Information Query functionality are RECOMMENDED to support the following configuration options: Min, et al. Expires 27 July 2026 [Page 11] Internet-Draft LSP Ping for IOAM Capabilities January 2026 * Enable/disable MPLS Node IOAM Information Query functionality. By default, MPLS Node IOAM Information Query functionality is disabled. * Define enabled Namespace-IDs. By default, all Namespace-IDs except the default one (i.e., Namespace-ID 0x0000) are disabled. While applying the MPLS Node IOAM Information Query to P2MP MPLS LSP, since a single MPLS echo request may trigger multiple echo replies, there are scaling concerns and some mitigation measures, e.g., containing the Echo Jitter TLV in the MPLS echo request, as being specified in [RFC6425], MAY be applied. 9. Acknowledgements The authors would like to acknowledge Tarek Saad for his comments on the idea of using LSP Ping for MPLS IOAM Capabilities Discovery. The authors would like to acknowledge Adrian Farrel for his insightful review and comments. 10. References 10.1. Normative References [I-D.ietf-mpls-mna-ioam] Gandhi, R., Mirsky, G., Li, T., Song, H., and B. Wen, "Supporting In Situ Operations, Administration and Maintenance Using MPLS Network Actions", Work in Progress, Internet-Draft, draft-ietf-mpls-mna-ioam-04, 20 November 2025, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC6425] Saxena, S., Ed., Swallow, G., Ali, Z., Farrel, A., Yasukawa, S., and T. Nadeau, "Detecting Data-Plane Failures in Point-to-Multipoint MPLS - Extensions to LSP Ping", RFC 6425, DOI 10.17487/RFC6425, November 2011, . Min, et al. Expires 27 July 2026 [Page 12] Internet-Draft LSP Ping for IOAM Capabilities January 2026 [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, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC9041] Andersson, L., Chen, M., Pignataro, C., and T. Saad, "Updating the MPLS Label Switched Paths (LSPs) Ping Parameters IANA Registry", RFC 9041, DOI 10.17487/RFC9041, July 2021, . [RFC9359] Min, X., Mirsky, G., and L. Bo, "Echo Request/Reply for Enabled In Situ OAM (IOAM) Capabilities", RFC 9359, DOI 10.17487/RFC9359, April 2023, . 10.2. Informative References [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, . [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, . [RFC9789] Andersson, L., Bryant, S., Bocci, M., and T. Li, "MPLS Network Actions (MNAs) Framework", RFC 9789, DOI 10.17487/RFC9789, July 2025, . Authors' Addresses Xiao Min ZTE Corp. Nanjing China Phone: +86 18061680168 Email: xiao.min2@zte.com.cn Min, et al. Expires 27 July 2026 [Page 13] Internet-Draft LSP Ping for IOAM Capabilities January 2026 Greg Mirsky Ericsson United States of America Email: gregimirsky@gmail.com Loa Andersson Bronze Dragon Consulting Sweden Email: loa@pi.nu Min, et al. Expires 27 July 2026 [Page 14]