IANA has created "Protocol in the Segment ID Sub-TLV" and "Protocol in Label Stack Sub-TLV of Downstream Detailed Mapping TLV" registries under the "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" registry. RFC 8287 defines the code points for Open Shortest Path First (OSPF) and Intermediate System to Intermediate System (IS-IS) protocols. This document specifies the code point to be used in the Segment ID sub-TLV and Downstream Detailed Mapping (DDMAP) TLV when the Interior Gateway Protocol (IGP) is OSPFv3. This document also updates RFC 8287 by clarifying that the existing "OSPF" code point is to be used only to indicate OSPFv2 and by defining the behavior when the Segment ID sub-TLV indicates the use of IPv6.

This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc9214.

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IANA has created the "Protocol in the Segment ID Sub-TLV" registry and "Protocol in Label Stack Sub-TLV of Downstream Detailed Mapping TLV" registries under the "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" registry [IANA-MPLS-LSP-PING]. [RFC 8287] defines the code points for OSPF and IS-IS. "OSPF for IPv6" [RFC 5340] describes OSPF version 3 (OSPFv3) to support IPv6. "Support of Address Families in OSPFv3" [RFC 5838] describes the mechanism to support multiple address families (AFs) in OSPFv3. Accordingly, OSPFv3 may be used to advertise IPv6 and IPv4 prefixes. This document specifies the code point to be used in the Segment ID sub-TLV (Types 34, 35, and 36) and in the Downstream Detailed Mapping (DDMAP) TLV when the IGP is OSPFv3. This document also updates "Label Switched Path (LSP) Ping/Traceroute for Segment Routing (SR) IGP-Prefix and IGP-Adjacency Segment Identifiers (SIDs) with MPLS Data Planes" [RFC 8287] by clarifying that the existing "OSPF" code point is to be used only to indicate OSPFv2 and by defining the behavior when the Segment ID sub-TLV indicates the use of IPv6.

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 [RFC 2119] [RFC 8174] when, and only when, they appear in all capitals, as shown here.

This document uses the terminology defined in "Segment Routing Architecture" [RFC 8402], "Detecting Multiprotocol Label Switched (MPLS) Data-Plane Failures" [RFC 8029], and "Label Switched Path (LSP) Ping/Traceroute for Segment Routing (SR) IGP-Prefix and IGP-Adjacency Segment Identifiers (SIDs) with MPLS Data Planes" [RFC 8287], and so the readers are expected to be familiar with the same.

When the protocol field of the Segment ID sub-TLV of Type 34 (IPv4 IGP-Prefix Segment ID), Type 35 (IPv6 IGP-Prefix Segment ID), and Type 36 (IGP-Adjacency Segment ID) is set to 3, the responder MUST perform the Forwarding Equivalence Class (FEC) validation using OSPFv3 as the IGP. The initiator MUST NOT set the protocol field of the Segment ID sub-TLV Type 35 and Type 36 as OSPF (value 1) as OSPFv2 is not compatible with the use of IPv6 addresses indicated by this sub-TLV. When the protocol field in the received Segment ID sub-TLV Type 35 and Type 36 is OSPF (value 1), the responder MAY treat the protocol value as "Any IGP Protocol" (value 0) according to step 4a of Section 7.4 of RFC 8287. This allows the responder to support legacy implementations that use value 1 to indicate OSPFv3.

The protocol field of the DDMAP TLV in an echo reply is set to 7 when OSPFv3 is used to distribute the label carried in the Downstream Label field.

Section 5 of RFC 8287 defines the code point for OSPF to be used in the Protocol field of the Segment ID sub-TLV. Section 6 of RFC 8287 defines the code point for OSPF to be used in the Protocol field of the DDMAP TLV. This document updates [RFC 8287] by specifying that the "OSPF" code points SHOULD be used only for OSPFv2.

IANA has assigned a new code point from the "Protocol in the Segment ID Sub-TLV" registry under the "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" registry as follows: Table 1 IANA has added a note for the existing entry for code point 1 (OSPF): "To be used for OSPFv2 only".

IANA has assigned a new code point for OSPFv3 from "Protocol in Label Stack Sub-TLV of Downstream Detailed Mapping TLV" registry under the "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" registry as follows: Table 2 IANA has added a note for the existing codepoint 5 (OSPF): "To be used for OSPFv2 only".

This document updates [RFC 8287] and does not introduce any additional security considerations. See [RFC 8029] to see generic security considerations about the MPLS LSP Ping.

[IANA-MPLS-LSP-PING]

IANA, "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters",
<https://www.iana.org/assignments/mpls-lsp-ping-parameters>.

[RFC2119]

S. Bradner, "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>.

[RFC5340]

R. Coltun, D. Ferguson, J. Moy, and A. Lindem, "OSPF for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
<https://www.rfc-editor.org/info/rfc5340>.

[RFC5838]

A. Lindem, S. Mirtorabi, A. Roy, M. Barnes, and R. Aggarwal, "Support of Address Families in OSPFv3", RFC 5838, DOI 10.17487/RFC5838, April 2010,
<https://www.rfc-editor.org/info/rfc5838>.

[RFC8029]

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

[RFC8174]

B. Leiba, "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>.

[RFC8287]

N. Kumar, C. Pignataro, G. Swallow, N. Akiya, S. Kini, and M. Chen, "Label Switched Path (LSP) Ping/Traceroute for Segment Routing (SR) IGP-Prefix and IGP-Adjacency Segment Identifiers (SIDs) with MPLS Data Planes", RFC 8287, DOI 10.17487/RFC8287, December 2017,
<https://www.rfc-editor.org/info/rfc8287>.

[RFC8402]

C. Filsfils, S. Previdi, L. Ginsberg, B. Decraene, S. Litkowski, and R. Shakir, "Segment Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, July 2018,
<https://www.rfc-editor.org/info/rfc8402>.

The authors would like to thank Les Ginsberg, Zafar Ali, Loa Andersson, Andrew Molotchko, Deborah Brungard, Acee Lindem, and Adrian Farrel for their review and suggestions. The authors also would like to thank Christer Holmberg, Tero Kivinen, Matthew Bocci, Tom Petch, and Martin Vigoureux for their review comments.

Nagendra Kumar Nainar

Carlos Pignataro

Mustapha Aissaoui