IANA Registry and Processing Recommendations for the First Nibble Following a Label Stack

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Publisher: IETF
Doc Type: Standard
Pages: 15
Abstract: This document creates a new IANA registry (called the "Post-Stack First Nibble" registry) for the first nibble (4-bit field) immediately following an MPLS label stack. Furthermore, this document presents some requirements for registering new values and making the processing of MPLS packets easier and more robust. The relationship between the IANA "Post-Stack First Nibble" registry and the "IP Version Numbers" registry (RFC 2780) is described in this document. This document updates RFC 4928 by deprecating the heuristic method for identifying the type of packet encapsulated in MPLS.
Publication Date: 2025-07-01
Status Note: Proposed Standard
DOI: 10.17487/RFC9790
Link: https://doi.org/10.17487/RFC9790
Author(s): Kireeti Kompella
Stewart Bryant
Matthew Bocci
Greg Mirsky
Loa Andersson
Jie Dong
Keyword(s): Load Balancing

Latest version of IETF RFC 9790

Document Versions — IETF RFC 9790

▶ IETF RFC 9790 (2025-07-01)

THIS DOC [ACTIVE] [LATEST VERSION]

Normative Reference(s)

IETF RFC 791 [Active*]
IETF RFC 2119 [Active*]
IETF RFC 2780 [Active*]
IETF RFC 3032 [Active*]
IETF RFC 4385 [Active*]
IETF RFC 4928 [Active*]
IETF RFC 5462 [Active*]
IETF RFC 6391 [Active*]
IETF RFC 6790 [Active*]
IETF RFC 8174 [Active*]
IETF RFC 8200 [Active*]
RFC8296 — RFC8296 EXTERNAL
IETF RFC 8469 [Active*]
RFC8964 — RFC8964 EXTERNAL
RFC9789 — RFC9789 EXTERNAL

Bibliographic Reference(s)

IETF.draft-ietf-mpls-mna-ps-hdr-01 — I-D.ietf-mpls-mna-ps-hdr EXTERNAL
IETF RFC 4446 [Active*]
IETF RFC 4761 [Active*]
RFC4762 — 10 EXTERNAL
IETF RFC 5586 [Active*]
IETF RFC 7274 [Active*]
RFC7432 — RFC7432 EXTERNAL
IETF RFC 8126 [Active*]
RFC8300 — RFC8300 EXTERNAL
RFC9546 — RFC9546 EXTERNAL

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<span class="citation"><cite>IETF RFC 9790</cite>, IANA Registry and Processing Recommendations for the First Nibble Following a Label Stack. Available at <a href="https://doi.org/10.17487/RFC9790" target="_blank" rel="noopener">https://doi.org/10.17487/RFC9790</a></span>

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IETF RFC 9790, IANA Registry and Processing Recommendations for the First Nibble Following a Label Stack
doi: 10.17487/RFC9790
url: https://doi.org/10.17487/RFC9790

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<li>
<cite id="bib-rfc9790">IETF RFC 9790</cite>, IANA Registry and Processing Recommendations for the First Nibble Following a Label Stack
<span class="doi">10.17487/RFC9790</span>
</li>