OSPFv3 Code Point for MPLS LSP Ping

Introduction 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 . defines the code points for OSPF and IS-IS. "OSPF for IPv6" describes OSPF version 3 (OSPFv3) to support IPv6. "Support of Address Families in OSPFv3" 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" 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.

Requirements Notation 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 when, and only when, they appear in all capitals, as shown here.

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

OSPFv3 Protocol in Segment ID Sub-TLVs 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 . This allows the responder to support legacy implementations that use value 1 to indicate OSPFv3.

OSPFv3 Protocol in Downstream Detailed Mapping TLV 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.

Update to RFC 8287 - OSPFv2 Protocol in Segment ID and DDMAP Sub-TLVs defines the code point for OSPF to be used in the Protocol field of the Segment ID sub-TLV. defines the code point for OSPF to be used in the Protocol field of the DDMAP TLV. This document updates by specifying that the "OSPF" code points SHOULD be used only for OSPFv2.

IANA Considerations

Protocol in the Segment ID Sub-TLV 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:

Value	Meaning	Reference
3	OSPFv3	RFC 9214

IANA has added a note for the existing entry for code point 1 (OSPF): "To be used for OSPFv2 only".

Protocol in Label Stack Sub-TLV of Downstream Detailed Mapping TLV 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:

Value	Meaning	Reference
7	OSPFv3	RFC 9214

IANA has added a note for the existing codepoint 5 (OSPF): "To be used for OSPFv2 only".

Security Considerations This document updates and does not introduce any additional security considerations. See to see generic security considerations about the MPLS LSP Ping.

Normative References Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters IANA

Acknowledgements The authors would like to thank , , , , , , and for their review and suggestions. The authors also would like to thank , , , , and for their review comments.