Allocating and Retiring Special-Purpose MPLS Labels
RFC 7274
Document | Type |
RFC - Proposed Standard
(June 2014; No errata)
Updated by RFC 9017
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|
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Authors | Kireeti Kompella , Loa Andersson , Adrian Farrel | ||
Last updated | 2018-12-20 | ||
Replaces | draft-kompella-mpls-special-purpose-labels | ||
Stream | Internet Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Reviews | |||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Ross Callon | ||
Shepherd write-up | Show (last changed 2014-01-30) | ||
IESG | IESG state | RFC 7274 (Proposed Standard) | |
Action Holders |
(None)
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||
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Alia Atlas | ||
Send notices to | (None) | ||
IANA | IANA review state | IANA OK - Actions Needed | |
IANA action state | RFC-Ed-Ack |
Internet Engineering Task Force (IETF) K. Kompella Request for Comments: 7274 Juniper Networks Updates: 3032, 3038, 3209, 3811, 4182, 4928, 5331, L. Andersson 5586, 5921, 5960, 6391, 6478, 6790 Huawei Category: Standards Track A. Farrel ISSN: 2070-1721 Juniper Networks June 2014 Allocating and Retiring Special-Purpose MPLS Labels Abstract Some MPLS labels have been allocated for specific purposes. A block of labels (0-15) has been set aside to this end; these labels are commonly called "reserved labels". They will be called "special- purpose labels" in this document. As there are only 16 of these special-purpose labels, caution is needed in the allocation of new special-purpose labels; yet, at the same time, forward progress should be allowed when one is called for. This memo defines new procedures for the allocation and retirement of special-purpose labels, as well as a method to extend the special- purpose label space and a description of how to handle extended special-purpose labels in the data plane. Finally, this memo renames the IANA registry for special-purpose labels to "Special-Purpose MPLS Label Values" and creates a new registry called the "Extended Special-Purpose MPLS Label Values" registry. This document updates a number of previous RFCs that use the term "reserved label". Specifically, this document updates RFCs 3032, 3038, 3209, 3811, 4182, 4928, 5331, 5586, 5921, 5960, 6391, 6478, and 6790. Status of This Memo 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 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7274. Kompella, et al. Standards Track [Page 1] RFC 7274 Special-Purpose MPLS Labels June 2014 Copyright Notice Copyright (c) 2014 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 (http://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 and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction ....................................................3 1.1. Conventions Used in This Document ..........................3 2. Questions .......................................................3 3. Answers .........................................................4 3.1. Extended Special-Purpose MPLS Label Values .................5 3.2. Process for Retiring Special-Purpose Labels ................6 4. Updated RFCs ....................................................7 5. IANA Considerations .............................................8 6. Security Considerations .........................................8 7. Acknowledgments .................................................9 8. References ......................................................9 8.1. Normative References .......................................9 8.2. Informative References ....................................10 Kompella, et al. Standards Track [Page 2] RFC 7274 Special-Purpose MPLS Labels June 2014 1. Introduction The MPLS Label Stack Encoding specification [RFC3032] defined four special-purpose label values (0 to 3) and set aside values 4 through 15 for future use. These labels have special significance in both the control and the data plane. Since then, three further values have been allocated (values 7, 13, and 14 in [RFC6790], [RFC5586], and [RFC3429], respectively), leaving nine unassigned values from the original space of sixteen. While the allocation of three out of the remaining twelve special- purpose label values in the space of about 12 years is not in itself a cause for concern, the scarcity of special-purpose labels is. Furthermore, many of the special-purpose labels require specialShow full document text