RFC 9041: Updating the MPLS Label Switched Paths (LSPs) Ping Parameters IANA Registry
- L. Andersson,
- M. Chen,
- C. Pignataro,
- T. Saad
Abstract
This document updates RFCs 8029 and 8611, both of which define IANA registries for MPLS Label Switched Path (LSP) Ping. In particular, the registration procedure "Private Use" (previously known as "Vendor Private Use") has been changed to "First Come First Served" for the TLV and sub-TLV registries.¶
It also updates the description of the procedures for the responses sent when an unknown or erroneous code point is found. The updates are to clarify and align this namespace with recent developments, e.g., aligning terminology with RFC 8126 instead of the now obsoleted RFC 5226 (both titled "Guidelines for Writing an IANA Considerations Section in RFCs").¶
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 7841.¶
Information about the current status of this document, any
errata, and how to provide feedback on it may be obtained at
https://
Copyright Notice
Copyright (c) 2021 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://
1. Introduction
There were a number of reasons to start the work that has led to this document, e.g.,¶
Over time, there have been attempts to administrativel
[RFC8029] contains updates to the "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" IANA namespace [IANA-LSP-PING].¶
[RFC8611] created LSP Ping IANA registries that match [RFC8126]. This document further clarifies the entries in those registries and makes the definitions more precise.¶
This document updates [RFC8029] and [RFC8611] by updating two groups of registries as follows:¶
First, the "Message Types" [IANA-MT], "Reply Modes" [IANA-RM], and "Return Codes" [IANA-RC] registries are updated. The changes to these registries are minor.¶
Second, this document updates the TLV and sub-TLV registries listed below:¶
It should be noted that [RFC8029] was published before [RFC8126] and uses outdated terminology for some registration procedures, e.g., "Vendor Private Use". [RFC8611] was published after [RFC8126] and uses its recommended terminology, e.g., "Private Use". However, now both "Vendor Private Use" and "Private Use" have been removed and replaced with "First Come First Served" (FCFS) code points.¶
One reason to change from code points allocated by Vendor Private Use or Private Use is that such code points are allowed in production networks. Theoretically, it is possible that two vendors might use the same code point value with different meanings. If such a code is ever deployed in the same network, this could cause protocol issues that would be hard to debug.¶
With FCFS code points, this will not happen. Vendors that have existing code using Vendor Private Use or Private Use code points should register those code points as FCFS code points as soon as this document is published as an RFC.¶
The "Sub-TLVs for TLV Type 9" subregistry is not updated.¶
Third, according to [RFC8029], some code points (TLVs and sub-TLVs) are called "mandatory" or "optional". Contrary to how other RFCs use these words, indicating that it is mandatory or optional to include the code points in a message, [RFC8029] uses these words to indicate that an action might or might not be mandatory. This document updates [RFC8029] to drop the words "mandatory" and "optional", and the text is changed to focus on what should be done.¶
1.1. Requirements Language
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.¶
1.2. Terminology
This section lists terms that are used when discussing the hierarchy of IANA registries (Section 1.2.1), and abbreviations used in IANA registries are updated in this document (Section 1.2.2).¶
1.2.1. Terminology Used in This Document
Terms related to IANA registries are used as follows in this document:¶
- Namespace
- A namespace is a top-level registry. An example could be "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" [IANA-LSP-PING]. A namespace is most often a container for registries that hold code points that share some affinity.¶
- Registry
- An IANA registry holds code points and lists the registration procedures and allocation for these code points. One example would be the "TLVs" registry [IANA-TLV-reg].¶
- Subregistry
- A subregistry is used when a
code point, or a set of code points allocated in a single registry, needs
"sub
-code -points" scoped by the code point or the set of code points. An example of a subregistry that holds code points for more than one TLV is "Sub-TLVs for TLV Types 1, 16, and 21" [IANA-Sub-1-16-21].¶
1.2.2. Abbreviations
This section lists abbreviations used in the unchanged part of the registries updated by this document. These abbreviations were originally expanded in the document defining the registries. They are listed here following the requirement to expand any abbreviation that is not well known. All these abbreviations are from the "Return Codes" registry [IANA-RC].¶
2. Updating the Message Types, Reply Modes, and Return Codes Registries
The following changes have been made to the "Message Types" [IANA-MT], "Reply Modes" [IANA-RM], and "Return Codes" [IANA-RC] registries.¶
The new registration procedures, the registry layouts, and the new assignments for these registries are found in Section 6.1.¶
3. Updating the TLV and Sub-TLV Registries
3.1. General Principles for the LSP Ping TLV and Sub-TLV Registries
The following principles apply to the processing of any TLV from any of the LSP Ping TLV and sub-TLV IANA registries.¶
Each of the blocks has code point spaces with the following registration procedures:¶
The exact definitions of these procedures are found in [RFC8126].¶
3.1.1. Unrecognized Experimental Use TLVs and Sub-TLVs
Unrecognized TLVs and sub-TLVs in the Experimental Use and FCFS ranges are handled as any other unrecognized TLV or sub-TLV.¶
The IETF does not prescribe how recognized or unrecognized Experimental Use
and Private Use TLVs and sub-TLVs are
handled in experimental or private networks; that is up to the agency running
the experimental or the private network. The statement above describes how
standards
3.3. Changes to the LSP Ping Registries
This section lists the changes to each MPLS LSP Ping TLV and sub-TLV registry. Sections 6.2.1 to 6.2.7 describe how the new versions of the IANA registries should look, together with the registration procedures for each registry.¶
The new registration procedure descriptions and the new assignments for these registries are used to model the changed MPLS LSP Ping registries; see Section 6.¶
3.3.1. Changes Common to the TLV and Sub-TLV Registries
The following changes are made to the TLV and sub-TLV registries.¶
4. Updates to Related RFCs
Some referenced RFCs use the concept "mandatory TLVs" and "mandatory sub-TLVs" to indicate that, if a TLV or sub-TLV of the range 0-32767 in a message is not understood, an error message needs to be sent in response.¶
The same RFCs use "optional TLVs" and "optional sub-TLVs" to mean TLVs or sub-TLVs that can be silently ignored if not recognized.¶
Since other RFCs use "mandatory TLVs" and "mandatory sub-TLVs" to indicate TLVs and sub-TLVs that must be present in a message, we want to discontinue the use of "mandatory" to indicate TLVs and sub-TLVs that require an error message in response if not understood. The changes to the RFCs below align with this practice.¶
4.1. Updates to RFC 8029
"Mandatory" and "optional" are used to indicate whether a response is needed if a TLV or sub-TLV is not understood in Section 3 of "Detecting Multiprotocol Label Switched (MPLS) Data-Plane Failures" [RFC8611].¶
The text in those two paragraphs is now updated to the following:¶
TLV and sub-TLV types less than 32768 (i.e., with the high-order bit equal to 0) are TLVs and sub-TLVs that MUST either be supported by an implementation or result in a Return Code of 2 ("One or more of the TLVs was not understood") being sent in the echo response.¶
An implementation that does not understand or support a received TLV or sub-TLV with a type greater than or equal to 32768 (i.e., with the high-order bit equal to 1) SHOULD ignore and step over the TLV or sub-TLV; however, an implementation MAY send an echo response with a Return Code of 2 ("One or more of the TLVs was not understood") as it would have done if the high-order bit had been clear.¶
In Section 3.8 of [RFC8029], "mandatory" is used in the same way. The first two paragraphs of this section are now updated to read as follows:¶
The following TLV is a TLV that MAY be included in an echo reply to inform the sender of an echo request that includes TLV or sub-TLV Types less than 32768 (i.e., with the high-order bit equal to 0) that are either not supported by the implementation or parsed and found to be in error.¶
The Value field uses sub-TLVs to encode the received TLVs and sub-TLVs that were not understood.¶
4.2. Updates to RFC 8611
Section 13.4.1 of "Label Switched Path (LSP) Ping and Traceroute Multipath Support for Link Aggregation Group (LAG) Interfaces" [RFC8611] defines "Sub-TLVs for TLV Type 6" [IANA-Sub-6].¶
The "Sub-TLVs for TLV Type 6" registry has been updated to align with changes defined in this document.¶
Section 13.4.1 of [RFC8611] is now updated as follows:¶
Section 13.4.1 Sub-TLVs for TLV Type 6¶
IANA has created a new subregistry, "Sub-TLVs for TLV Type 6", [IANA-Sub-6]
under the "TLVs" registry [IANA-TLV-reg]
of the "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" namespace
[lsp
The "Sub-TLVs for TLV Type 6" subregistry is now updated to align with changes defined in this document.¶
5. Security Considerations
This document updates IANA registries. It also updates terminology used to define, and clarifies the terminology related to, the code points in the registries. The document does not change how the code points in the registries are used. This should not create any new threats.¶
However, the updated terminology and the clarifications improve security because it makes it more likely that implementations will be consistent and harder to attack.¶
6. IANA Considerations
IANA has updated the "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" namespace [IANA-LSP-PING] as described in this document.¶
See Section 1.2.1 of "Terminology Used in This Document" to see how "namespace", "registry", and "subregistry" are used in this document.¶
In other parts of this document, the commonality of the changes to the LSP Ping registries has been the focus. For the IANA Considerations, each changed registry has been described in its own right.¶
The following registries and subregistries have been changed:¶
This document has been listed as an additional reference for each of the registries described in Sections 6.1 and 6.2.¶
6.1. Updates by IANA to the Message Types, Reply Modes, and Return Codes Registries
This section details the updated registration procedures and allocations for the "Message Types", "Reply Modes", and "Return Codes" registries.¶
6.1.1. Updates to the Message Types Registry
These are the changes to the "Message Types" registry specified in this document:¶
The registration procedures after the changes listed above for the "Message Types" registry are shown in the table below:¶
The updated assignments for the "Message Types" registry appear as follows:¶
6.1.2. Updates to the Reply Modes Registry
These are the changes to the "Reply Modes" registry specified in this document:¶
The registration procedures after the changes for the "Reply Modes" registry are shown in the table below:¶
The updated assignments for the "Reply Modes" registry are as follows:¶
6.1.3. Updates to the Return Codes Registry
These are the changes to the "Return Codes" registry specified in this document:¶
The registration procedures after the changes for the "Return Codes" registry are shown in the table below:¶
The updated assignments for the "Return Codes" registry are as follows:¶
- Note 1:
- Notes [1] and [2] for code points 5, 6, and 14 point to footnotes in the "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" namespace. The footnotes are not changed by this document.¶
- Note 2:
- <RSC> stands for "Return Subcode" and is explained in Section 3.1 of [RFC8029].¶
6.2. Updates to the TLV and Sub-TLV Registries
The updates to the TLV and the sub-TLV registries are mostly the same; however, the "Sub-TLVs for TLV Type 9" [IANA-Sub-9] registry has not been updated.¶
Note that when a field in an assignment table says "EQ", it means that there is no change from the existing field in the "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" namespace [IANA-LSP-PING].¶
6.2.1. Updates to the TLVs Registry
This section describes the new registration procedures and the assignments for the "TLVs" registry [IANA-TLV-reg] that are based on them.¶
The registration procedures have been changed, as follows, for the "TLVs" registry.¶
The registration procedures for the "TLVs" registry [IANA-TLV-reg] after the changes listed above are shown in the table below:¶
The updated assignments for this registry appear as follows:¶
Note that when a field in an assignment table says "EQ", it means that there was no change from the existing field in the "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" namespace [IANA-LSP-PING].¶
6.2.2. Updates to the Registry for Sub-TLVs for TLV Types 1, 16, and 21
This section describes the new registration procedures and the assignments for the "Sub-TLVs for TLV Types 1, 16, and 21" [IANA-Sub-1-16-21] subregistry that are based on them.¶
The registration procedures for the "Sub-TLVs for TLV Types 1, 16, and 21" [IANA-Sub-1-16-21] subregistry appear as follows after the changes listed above:¶
6.2.3. Updates to the Registry for Sub-TLVs for TLV Type 6
This section describes the new registration procedures and the assignments for the "Sub-TLVs for TLV Type 6" [IANA-Sub-6] subregistry that are based on them.¶
The registration procedures for the "Sub-TLVs for TLV Type 6" [IANA-Sub-6] subregistry after the changes listed above are shown in the table below:¶
6.2.4. Updates to the Registry for Sub-TLVs for TLV Type 11
This section describes the new registration procedures and the assignments for the "Sub-TLVs for TLV Type 11" [IANA-Sub-11] subregistry that are based on them.¶
The registration procedures for the "Sub-TLVs for TLV Type 11" [IANA-Sub-11] subregistry after the changes listed above are shown in the table below:¶
6.2.5. Updates to the Registry for Sub-TLVs for TLV Type 20
This section describes the new registration procedures and the assignments for the "Sub-TLVs for TLV Type 20" [IANA-Sub-20] subregistry that are based on them.¶
The registration procedures for the "Sub-TLVs for TLV Type 20" [IANA-Sub-20] subregistry after the changes listed above are shown in the table below:¶
6.2.6. Updates to the Registry for Sub-TLVs for TLV Type 23
This section describes the new registration procedures and the assignments for the "Sub-TLVs for TLV Type 23" [IANA-Sub-23] subregistry that are based on them.¶
The registration procedures for the "Sub-TLVs for TLV Type 23" [IANA-Sub-23] subregistry after the changes listed above are shown in the table below:¶
6.2.7. Updates to the Registry for Sub-TLVs for TLV Type 27
This section describes the new registration procedures and the assignments for the "Sub-TLVs for TLV Type 27" [IANA-Sub-27] subregistry that are based on them.¶
The registration procedures for the "Sub-TLVs for TLV Type 27" [IANA-Sub-27] subregistry after the changes listed above are shown in the table below:¶
7. References
7.1. Normative References
- [IANA-LSP-PING]
-
IANA, "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters", <https://
www >..iana .org /assignments /mpls -lsp -ping -parameters - [IANA-MT]
-
IANA, "Message Types", <https://
www >..iana .org /assignments /mpls -lsp -ping -parameters / - [IANA-RC]
-
IANA, "Return Codes", <https://
www >..iana .org /assignments /mpls -lsp -ping -parameters / - [IANA-RM]
-
IANA, "Reply Modes", <https://
www >..iana .org /assignments /mpls -lsp -ping -parameters / - [IANA
-Sub -1 -16 -21] -
IANA, "Sub-TLVs for TLV Types 1, 16, and 21", <https://
www >..iana .org /assignments /mpls -lsp -ping -parameters / - [IANA-Sub-11]
-
IANA, "Sub-TLVs for TLV Type 11", <https://
www >..iana .org /assignments /mpls -lsp -ping -parameters / - [IANA-Sub-20]
-
IANA, "Sub-TLVs for TLV Type 20", <https://
www >..iana .org /assignments /mpls -lsp -ping -parameters / - [IANA-Sub-23]
-
IANA, "Sub-TLVs for TLV Type 23", <https://
www >..iana .org /assignments /mpls -lsp -ping -parameters / - [IANA-Sub-27]
-
IANA, "Sub-TLVs for TLV Type 27", <https://
www >..iana .org /assignments /mpls -lsp -ping -parameters / - [IANA-Sub-6]
-
IANA, "Sub-TLVs for TLV Type 6", <https://
www >..iana .org /assignments /mpls -lsp -ping -parameters / - [IANA-TLV-reg]
-
IANA, "TLVs", <https://
www >..iana .org /assignments /mpls -lsp -ping -parameters / - [RFC2119]
-
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10
.17487 , , <https:///RFC2119 www >..rfc -editor .org /info /rfc2119 - [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 , , <https:///RFC8029 www >..rfc -editor .org /info /rfc8029 - [RFC8126]
-
Cotton, M., Leiba, B., and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10
.17487 , , <https:///RFC8126 www >..rfc -editor .org /info /rfc8126 - [RFC8174]
-
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10
.17487 , , <https:///RFC8174 www >..rfc -editor .org /info /rfc8174 - [RFC8611]
-
Akiya, N., Swallow, G., Litkowski, S., Decraene, B., Drake, J., and M. Chen, "Label Switched Path (LSP) Ping and Traceroute Multipath Support for Link Aggregation Group (LAG) Interfaces", RFC 8611, DOI 10
.17487 , , <https:///RFC8611 www >..rfc -editor .org /info /rfc8611
7.2. Informative References
- [IANA-Sub-9]
-
IANA, "Sub-TLVs for TLV Type 9", <https://
www >..iana .org /assignments /mpls -lsp -ping -parameters / - [lsp
-ping -Namespace] -
IANA, "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters", <https://
www >..iana .org /assignments /mpls -lsp -ping -parameters / - [RFC7110]
-
Chen, M., Cao, W., Ning, S., Jounay, F., and S. Delord, "Return Path Specified Label Switched Path (LSP) Ping", RFC 7110, DOI 10
.17487 , , <https:///RFC7110 www >..rfc -editor .org /info /rfc7110 - [RFC7555]
-
Swallow, G., Lim, V., and S. Aldrin, "Proxy MPLS Echo Request", RFC 7555, DOI 10
.17487 , , <https:///RFC7555 www >..rfc -editor .org /info /rfc7555 - [RFC7743]
-
Luo, J., Ed., Jin, L., Ed., Nadeau, T., Ed., and G. Swallow, Ed., "Relayed Echo Reply Mechanism for Label Switched Path (LSP) Ping", RFC 7743, DOI 10
.17487 , , <https:///RFC7743 www >..rfc -editor .org /info /rfc7743 - [RFC7759]
-
Bellagamba, E., Mirsky, G., Andersson, L., Skoldstrom, P., Ward, D., and J. Drake, "Configuration of Proactive Operations, Administration, and Maintenance (OAM) Functions for MPLS-Based Transport Networks Using Label Switched Path (LSP) Ping", RFC 7759, DOI 10
.17487 , , <https:///RFC7759 www >..rfc -editor .org /info /rfc7759 - [RFC8287]
-
Kumar, N., Ed., Pignataro, C., Ed., Swallow, G., Akiya, N., Kini, S., 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 , , <https:///RFC8287 www >..rfc -editor .org /info /rfc8287
Acknowledgements
The authors wish to thank Adrian Farrel, who both made very useful comments and agreed to serve as the Document Shepherd.¶
The authors also wish to thank Michelle Cotton and Amanda Baber, who very patiently worked with us to determine how our registries could and should be updated.¶
The authors thank Donald Eastlake 3rd and Tom Petch for their careful and detailed review.¶