MPLS Working Group                                          L. Andersson
Internet-Draft                                  Bronze Dragon Consulting
Updates: 8029, 8611 (if approved)                                M. Chen
Intended status: Standards Track                      Huawei Techologies
Expires: September 6, October 18, 2020                                   C. Pignataro
                                                           Cisco Systems
                                                                 T. Saad
                                                        Juniper Networks
                                                           March 5,
                                                          April 16, 2020

               Updating the IANA MPLS LSP Ping Parameters
             draft-ietf-mpls-lsp-ping-registries-update-01
             draft-ietf-mpls-lsp-ping-registries-update-02

Abstract

   This document updates RFC 8029 and RFC 8611 that both define IANA
   registries for MPLS LSP Ping.  It also updates the language that is
   used to define the procedures for responses are sent when an unkwon
   or errored code point is found.  The updates are mostly for clarification
   and to align this registry name space with recent developments.. developments.

Status of This Memo

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   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on September 6, October 18, 2020.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirement Language  . . . . . . . . . . . . . . . . . .   3
   2.  Updating the Message Types, Reply Mode and Return Codes
       Registries  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Updating the TLV and sub-TLV registries . . . . . . . . . . .   4
     3.1.  General principles the LSP Ping TLV and sub-TLV
           registries  . . . . . . . . . . . . . . . . . . . . . . .   5   4
       3.1.1.  Unrecognized Experimental and Private TLVs and sub-
               TLVs  . . . . . . . . . . . . . . . . . . . . . . . .   6   5
     3.2.  Changes to the LSP Ping registries Registries  . . . . . . . . . . .   6   5
       3.2.1.  Common changes Changes to the TLV and sub-TLV registries Registries  . .   6   5
   4.  Text chages/updates Chages/Updates to related Related RFCs . . . . . . . . . . . . .   7   6
     4.1.  Text changes Changes to RFC 8029  . . . . . . . . . . . . . . . .   7
       4.1.1.  Comments to this changes to RFC 8029  . . . . . . . .   8   6
     4.2.  Text changes Changes to RFC 8611  . . . . . . . . . . . . . . . .   8
       4.2.1.  Comments to this changes to RFC 8611  . . . . . . . .   9   7
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   9   8
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9   8
     6.1.  New  Updates of Message Type, Reply Mode and Return Codes registries    9
           Registries  . . . . . . . . . . . . . . . . . . . . . . .   8
     6.2.  Common Registration Procedures for TLVs and sub-TLVs  . .  10   9
     6.3.  IANA assignments Assignments for TLVs and sub-TLVs  . . . . . . . . .  11   9
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  12  10
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  13  11
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  13  11
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  14  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15  13

1.  Introduction

   When RFC 8029 [RFC8029] was published it contained among other things updates to the
   "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs)
   Ping Parameters" IANA name space [IANA-LSP-PING].

   RFC 8611 [RFC8611] updated the LSP Ping IANA registries to match RFC
   8029, but the registrations can be
   8029.  This document further clarified clarifies the entries in those
   registries and their makes the definitions more precise.

   This document updates RFC 8029 [[RFC8029] and RFC 8611 [RFC8611] by
   updating two groups of registries. registries as follows:

   First the registries for Message Types [IANA-MT], Reply Modes
   [IANA-RM] and Return Codes [IANA-RC]. [IANA-RC] are updated.  The changes to
   these registries are minor.

   Second, this document updates the TLV and sub-TLV registries.

   o  TLVs [IANA-TLV-reg]

   o  Sub-TLVs for TLVs 1, 16 and 21 [IANA-Sub-1-16-21]

   o  Sub-TLVs for TLV 6 [IANA-Sub-6]

   o  Sub-TLVs for TLV 11 [IANA-Sub-11]

   o  Sub-TLVs for TLV 20 [IANA-Sub-20]

   o  Sub-TLVs for TLV 23 [IANA-Sub-23]

   o  Sub-TLVs for TLV 27 [IANA-Sub-27]

   The registry for sub-TLVs for TLV 9 [IANA-Sub-9] is not updated.

   Third, some code points (TLVs and sub-TLVs) are "mandatory" and
   "optional".  Contrary to how other RFCs use these words, indicating
   that it is mandatory or optional to include the code points in a
   message, RFC 8029 use the words to indicate that an acction might or
   might nt be nesesary.  The words "mandatory and "optional" are
   dropped and the text is changed to focus on what should be doen.

1.1.  Requirement 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.

2.  Updating the Message Types, Reply Mode and Return Codes Registries

   The following changes are made to the Message Types, Reply Modes and
   Return Codes [IANA-MT] registries.

   o  In the listing of assignments the term "Vendor Private Use" is
      changed to "Private Use"

   o  a small set of code points (4 code points) for experimental use Experimental Use is
      added, actually they are take from
      added by reducing the range for "Private Use".

   o  the registration procedure "Specification Required" is changed to
      "RFC Required" and the note "Experimental RFC needed" is removed

   o  In the listing of assignments the term "Vendor Private Use" is
      changed to "Private Use"

   o  the registration procedures "Private Use" and "Experimental Use"
      are added to the table of registration procedures

   o  A note "Not to be assigned" is added for the registration
      procedures "Private Use" and "Experimental Use"

   o  In the list that capture the assignment status, the fields that
      are reserved, i.e.  0, Private Use and Experimental Use are
      clearly marked.

      *  In the Return Codes [IANA-RC] registry the code point "0"
         already been assigned.  This assignment is not changed and this
         registry will not have the "0" value "Reserved".

   The new Registration Procedures layout and the new assignments for
   these registries will be found in Section 6.1.

3.  Updating the TLV and sub-TLV registries

   When a new

3.1.  General principles the LSP Ping sub-TLV registry were created by RFC 8611
   [RFC8611] this registry "Sub-TLVs for TLV Type 6" [IANA-Sub-6] was
   set up following the intentions of RFC 8029.

   The registry for "Sub-TLVs for TLV Type 6" will serve as a model to
   change/update the rest of the TLV and sub-TLV registries in this name
   space.

   The registration procedures in the current registry for "Sub-TLVs for
   TLV Type 6" looks like this (2019-06-20).  This will be used as a
   base-line and some additions/changes will be made as captured in the
   Appendixes:

   +-------------+-------------------+---------------------------------+
   | Range       | Registration      | Note                            |
   |             | Procedures        |                                 |
   +-------------+-------------------+---------------------------------+
   | 0-16383     | Standards Action  | This range is for mandatory     |
   |             |                   | TLVs or for optional TLVs that  |
   |             |                   | require an error message if not |
   |             |                   | recognized.                     |
   | 16384-31743 | RFC Required      | This range is for mandatory     |
   |             |                   | TLVs or for optional TLVs that  |
   |             |                   | require an error message if not |
   |             |                   | recognized.                     |
   | 31744-32767 | Private Use       | Not to be assigned              |
   | 32768-49161 | Standards Action  | This range is for optional TLVs |
   |             |                   | that can be silently dropped if |
   |             |                   | not recognized.                 |
   | 49162-64511 | RFC Required      | This range is for optional TLVs |
   |             |                   | that can be silently dropped if |
   |             |                   | not recognized.                 |
   | 64512-65535 | Private Use       | Not to be assigned              |
   +-------------+-------------------+---------------------------------+

              Sub-TLVs for TLV Type 6 Registration Procedures

   This document adds small ranges of code points for Experimental Use
   to this registry and to registries listed in Section 6.2.

   All registries will be changed to reflect the same model.

3.1.  General principles the LSP Ping TLV and TLV and sub-TLV registries

   The following principles are valid for all the LSP Ping TLV and sub-
   TLV IANA registries

   o  all mandatory TLVs and sub-TLVs requires with a response if typ in the are not
      recognized

   o  some optional TLVs and sub-TLVs requires the range 0-32767 require
      a response if the they are not recognized

   o  some optional  all TLVs and sub-TLVs in the range 32768-65535 may be silently
      dropped if the are not recognized

   The range of each TLV and sub-TLV registry is divided into to wto
   blocks, one with a range from 0 to 49161 32767 for TLVs and sub-TLVs that
   require a response if not recognized.  Another block in the range
   from 49161 32768 to 65535, this block is for TLVs and sub-TLVs that may be
   silently dropped if not recognized.

   Each of the blocks have has code point spaces with the following
   registration procedures:

   o  Standards Action

   o  RFC Required

   o  Experimental Use
   o  Private Use

   The exact defintion of registration procedures for IANA registries
   are found in [RFC8126]

3.1.1.  Unrecognized Experimental and Private TLVs and sub-TLVs

   Unrecognized TLVs and sub-TLVs for Expereimetal USe and Privagte Use
   are handled as any other unrecognised TLV or sub-TLV.

   o  If the unrecognized TLV or sub-TLV is from the Experimental Use
      range (37144-37147) or from the Private Use range (31748-32767) a
      the Return Code of 2 ("One or more of the TLVs was not
      understood") will be sent in the echo response.

   o  If the unrecognized TLV or sub-TLV is from the Experimental Use
      range (64512-64515) or from the Private Use range (64515-65535)
      the TLVs SHOULD be silently ignored.

   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 experiment or
   the private network.  The statement above relates to how standard
   compliant implementations will treat the unrecognized TLVs and sub-
   TLVs from these ranges.

3.2.  Changes to the LSP Ping registries Registries

   This section lists the changes to each MPLS LSP Ping Registry, in Registry.
   Section 6.1, Section 6.2 and Section 6.3 set out how the changes are detailed and
   it is shown what new versions
   of the IANA registry version of registries should look, together with the registration
   procedures and assignments would look like.
   procedures.

3.2.1.  Common changes Changes to the TLV and sub-TLV registries Registries

   The following changes are made to the TLV and sub-TLV registries.

   o  the registration procedures "Private Use" and "Experimental Use"
      are added to the table of registration procedures

   o  two small set sets of code points (2 times 4 code points) for
      experimental use is added, actually they are take from the range
      for "Private Use".

   o  the registration procedure "Specification Required" is changed to
      "RFC Required" and the note "Experimental RFC needed" is removed

   o  In the listing of assignements the term "Vendor Private Use" is
      changed to "Private Use"

   o  In the listing of assignments the range for "Experimental Use" is
      added

   o  the registration procedures "Private Use" and "Experimental Use"
      are added to the table of registration procedures

   o  A note "Not to be assigned" is added for the registration
      procedures "Experimental Use" and "Private Use"

   o  In the list that capture assignment status, the fields that are
      reserved, i.e.  0, Experimental Use and Private Use are clearly
      marked.

   The new Registration Procedures description and the new assignments
   for these registries will be found in Section 6.2 and Section 6.3.

4.  Text chages/updates Chages/Updates to related Related RFCs

   Some referenced RFCs are using the concept "mandatory TLVs" and
   "mandatory sub-TLVs" to indicate that if a TLV or sub-TLV of the
   range 0-16383 or 16384-31743 is present in a message but not
   understood, error message need to be sent in response.

   Since other RFCs are using "mandatory TLVs" and "mandatory sub-TLVs"
   to indicate TLVs and sub-TLVs ths that must be present in a message, we
   want to discontinue the use of "mandatory" to indicate TLVs and sub-
   TLVs that requires an error message in response if not understood.
   The changes to the RFCs below are intended to align with this
   practice.

4.1.  Text changes Changes to RFC 8029

   In section

   Mandatory and optional is used in this way on page 14 and 15 in
   Section 3 of RFC 8029 says: 8029.

   The text in those two paragraphs are now changed to:

      TLV and sub-TLV Types less than 32768 (i.e., with the high-order
      bit equal to 0) are mandatory TLVs and sub-TLVs that MUST either be
      supported by an implementation or result in the Return Code of 2
      ("One or more of the TLVs was not understood") being sent in the
      echo response.

      Types greater than or equal to 32768 (i.e., with the high-order
      bit equal to 1) are optional TLVs that SHOULD be ignored if the

      An implementation that does not understand or support them.

   This text is nows changed to: a received
      TLV and or sub-TLV Types less with Type greater than or equal to 32768 (i.e.,
      with the high-order bit equal to 0) are TLVs 1) SHOULD ignore and sub-TLVs that MUST either be
      supported by step over
      the TLV or sub-TLV, however an implementation or result in the MAY send an echo
      response with Return Code of 2 ("One or more of the TLVs was not
      understood") being sent as it would have doen if the high order bit had been
      clear.

   In Section 3.8 of RFC 8029 "mandatory" is used in the same way.  The
   first two paragaraphs of this section ar now changed to read:

      The following TLV is a TLV that MAY be included in an echo reply
      to inform the sender of an echo response.

      TLV and sub-TLV request icluding TLVs or sub-TLVs
      Types greater than or equal to 32768 (i.e., with the high-order
      bit equal to 1) are TLVs and sub-TLVs that SHOULD
      be ignored if iether nor supported by the implementation does not understand or support
      them.

4.1.1.  Comments to this changes to RFC 8029

   1.  RFC 8029 is a Standard Tracks RFC.  Ranges 0-16383 and
       32768-49161 are assigned by Standards Action.  Ranges 31744-32767
      parsed and 49162-64511 are assigned by RFC Required, as specified e.g.
       in Section 6.2 found to be in this doucument.

   2. error.

      The text is change in two ways

          First, Value field contains the ambigous use of "mandatory" and "optional" is
          removed,

          Second, it is clarified TLVs, including sub-TLVs, that both un-supported or not
          recognized TLVs and sub-TLVs will generate an error message in
          the Echo Reply message.

   3.  The name of the TLV used in the Echo Reply message is "TLV were
      not
       understood", however it applies equally to understood, encoded as sub-TLVs.  If a sub-
       TLV is not understood or supported, the entire TLV that includes
       the sub-TLV is returned.

4.2.  Text changes Changes to RFC 8611

   RFC 8611 defines a sub-TLV registry - "Sub-TLVs for TLV Type 6".  The
   allocation policies for this registry is described in Section 3 of
   this document.

   The "Sub-TLVs for TLV Type 6" registry is now updated to align with
   changes defined in this document.

   The registration procedurs procedures for the "Sub-TLVs for TLV Type 6"
   registry will now be like this:

   +-------------+-------------------+---------------------------------+
   | Range       | Registration      | Note                            |
   |             | Procedures        |                                 |
   +-------------+-------------------+---------------------------------+
   | 0-16383     | Standards Action  | This range is for sub-TLVs that |
   |             |                   | require an error message if not |
   |             |                   | recognized.                     |
   | 16384-31743 | RFC Required      | This range is for sub-TLVs that |
   |             |                   | require an error message if not |
   |             |                   | recognized.                     |
   | 31744-32767 | Private Use       | Not to be assigned              |
   | 32768-49161 | Standards Action  | This range is for sub-TLVs that |
   |             |                   | can be silently dropped if not  |
   |             |                   | recognized.                     |
   | 49162-64511 | RFC Required      | This range is for sub-TLVs that |
   |             |                   | can be silently dropped if not  |
   |             |                   | recognized.                     |
   | 64512-65535 | Private Use       | Not to be assigned              |
   +-------------+-------------------+---------------------------------+

              Sub-TLVs for TLV Type 6 Registration Procedures

4.2.1.  Comments to this changes to RFC 8611

   While it is true that the same rules apply to sub-TLVs and TLVs when
   it comes tu return am error message if a TLV or sub-TLV is not
   recognized.  In the case if the registry for "Sub-TLVs for TLV Type 6
   Registration Procedures" ir only includes sub-TLVs.

   The changes described in this section aligns RFC 8611 with the
   changes/updates described in the rest of this document.

5.  Security Considerations

   This document only updates IANA registries, some 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 is requested to update the LSP Ping name space as described in
   this document and documented in the Appendixies. document.

6.1.  New  Updates of Message Type, Reply Mode and Return Codes registries Registries

   This section details the updated registration procedures for and
   allocations for: Message Type, Reply Mode and Return Codes
   registries.

   +---------+--------------------+------------------------------------+
   | Range   | Registration       | Note                               |
   |         | Procedures         |                                    |
   +---------+--------------------+------------------------------------+
   | 0-191   | Standards Action   |                                    |
   | 192-247 | RFC Required       |                                    |
   | 248-251 | Experimental Use   | Not to be assigned                 |
   | 252-255 | Private Use        | Not to be assigned                 |
   +---------+--------------------+------------------------------------+

                    New common registration procedures

   +---------+---------------------------------+-----------------------+
   | Value   | Meaning                         | Reference             |
   +---------+---------------------------------+-----------------------+
   | 0       | Reserved                        | This document         |
   | 1-247   | No changes to the existing      |                       |
   |         | assignments                     |                       |
   | 248-251 | Reserved for Experimental Use   | This document         |
   | 252-255 | Reserved for Private Use        | [RFC8029]             |
   +---------+---------------------------------+-----------------------+

   Common Assignments for the Message Types, Reply Mode and Return Code
                                registries

   Note that for the Return Code registry the assignment for code point
   zero has been previously assigned, it is not changed but will remain:

   +-------+----------------------------------+------------------------+
   | Value | Meaning                          | Reference              |
   +-------+----------------------------------+------------------------+
   | 0     | No return code                   | [RFC8029]              |
   +-------+----------------------------------+------------------------+

          Assignment for code point 0 in the Return Code registry

6.2.  Common Registration Procedures for TLVs and sub-TLVs

   This section describes the new registration procedures for the TLV
   and sub-TLV registries.  The registry for sub-TLV 9 ([IANA-Sub-9] is
   not changed.

   +-------------+-------------------+---------------------------------+
   | Range       | Registration      | Note                            |
   |             | Procedures        |                                 |
   +-------------+-------------------+---------------------------------+
   | 0-16383     | Standards Action  | This range is for TLVs that     |
   |             |                   | require an error message if not |
   |             |                   | recognized.                     |
   | 16384-31743 | RFC Required      | This range is for TLVs that     |
   |             |                   | require an error message if not |
   |             |                   | recognized.                     |
   | 37144-37147 | Experimental Use  | Not to be assigned              |
   | 31748-32767 | Private Use       | Not to be assigned              |
   | 32768-49161 | Standards Action  | This range is for TLVs that can |
   |             |                   | be silently dropped if not      |
   |             |                   | recognized.                     |
   | 49162-64511 | RFC Required      | This range is for TLVs that can |
   |             |                   | be silently dropped if not      |
   |             |                   | recognized.                     |
   | 64512-64515 | Experimental Use  | Not to be assigned              |
   | 64515-65535 | Private Use       | Not to be assigned              |
   +-------------+-------------------+---------------------------------+

                  TLV and sub-TLV Registration Procedures

6.3.  IANA assignments Assignments for TLVs and sub-TLVs

   The two tables in this section describes the updated IANA assignments
   for the TLV and sub-TLV registries.  The registry for sub-TLV 9
   ([IANA-Sub-9] is not changed.

   +-------------+-------------------+------------------+--------------+
   | Type        | TLV name          | Reference        | sub-TLV      |
   |             |                   |                  | registry     |
   +-------------+-------------------+------------------+--------------+
   | 0           | Reserved          | This document    |              |
   | 1-31743     | [any]             | No changes to    | [any]        |
   |             |                   | the current      |              |
   |             |                   | registry         |              |
   | 37144-37147 | Reserved for      | This document    | NA           |
   |             | Experimental Use  |                  |              |
   | 31748-32767 | Reserved for      | This document    | NA           |
   |             | Private Use       |                  |              |
   | 32768-64511 | [any]             | No changes to    | [any]        |
   |             |                   | the current      |              |
   |             |                   | registry.        |              |
   | 64512-64515 | Reserved for      | This document    | NA           |
   |             | Experimental Use  |                  |              |
   | 64515-65535 | Reserved for      | This document    | NA           |
   |             | Private Use       |                  |              |
   +-------------+-------------------+------------------+--------------+

                              TLV Assignments

   Updated Sub-TLV assignments

   +-------------+-------------------------------+---------------------+
   | Type        | TLV name                      | Reference           |
   +-------------+-------------------------------+---------------------+
   | 0           | Reserved                      | This document       |
   | 1-31743     | [any]                         | No changes to the   |
   |             |                               | current registry    |
   | 37144-37147 | Reserved for Experimental Use | This document       |
   | 31748-32767 | Reserved for Private Use      | This document       |
   | 32768-64511 | [any]                         | No changes to the   |
   |             |                               | current registry.   |
   | 64512-64515 | Reserved for Experimental Use | This document       |
   | 64515-65535 | Reserved for Private Use      | This document       |
   +-------------+-------------------------------+---------------------+

                            Sub-TLV Assignments

7.  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 Micelle Cotton who very patiently
   worked with us to determine how our registries could and should be
   updated.

8.  References

8.1.  Normative References

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

   [IANA-MT]  "Message Types", <https://www.iana.org/assignments/mpls-
              lsp-ping-parameters/mpls-lsp-ping-
              parameters.xhtml#message-types>.

   [IANA-RC]  "Return Codes", <https://www.iana.org/assignments/mpls-
              lsp-ping-parameters/#return-codes>.

   [IANA-RM]  "Reply Modes", <https://www.iana.org/assignments/mpls-lsp-
              ping-parameters/#reply-modes>.

   [IANA-Sub-1-16-21]
              "Sub-TLVs for TLV Types 1, 16, and 21",
              <https://www.iana.org/assignments/https://www.iana.org/
              assignments/mpls-lsp-ping-parameters/mpls-lsp-ping-
              parameters.xhtml#sub-tlv-1-16-21>.

   [IANA-Sub-11]
              "Sub-TLVs for TLV Type 11",
              <https://www.iana.org/assignments/mpls-lsp-ping-
              parameters/mpls-lsp-ping-parameters/mpls-lsp-ping-
              parameters.xhtml#sub-tlv-11>.

   [IANA-Sub-20]
              "Sub-TLVs for TLV Type 20",
              <https://www.iana.org/assignments/mpls-lsp-ping-
              parameters/mpls-lsp-ping-parameters/mpls-lsp-ping-
              parameters.xhtml#sub-tlv-20>.

   [IANA-Sub-23]
              "Sub-TLVs for TLV Type 23",
              <https://www.iana.org/assignments/mpls-lsp-ping-
              parameters/mpls-lsp-ping-parameters/mpls-lsp-ping-
              parameters.xhtml#sub-tlv-23>.

   [IANA-Sub-27]
              "Sub-TLVs for TLV Type 27",
              <https://www.iana.org/assignments/mpls-lsp-ping-
              parameters/mpls-lsp-ping-parameters/mpls-lsp-ping-
              parameters.xhtml#sub-tlv-27>.

   [IANA-Sub-6]
              "Sub-TLVs for TLV Type 6",
              <https://www.iana.org/assignments/mpls-lsp-ping-
              parameters/mpls-lsp-ping-parameters/mpls-lsp-ping-
              parameters.xhtml#sub-tlv-6>.

   [IANA-TLV-reg]
              "TLVs", <https://www.iana.org/assignments/mpls-lsp-ping-
              parameters/mpls-lsp-ping-parameters.xhtml#tlvs>.

   [RFC2119]  Bradner, S., "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>.

   [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/RFC8029, March 2017,
              <https://www.rfc-editor.org/info/rfc8029>.

   [RFC8174]  Leiba, B., "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>.

   [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/RFC8611,
              June 2019, <https://www.rfc-editor.org/info/rfc8611>.

8.2.  Informative References

   [IANA-Sub-9]
              "Sub-TLVs for TLV Type 9",
              <https://www.iana.org/assignments/mpls-lsp-ping-
              parameters/mpls-lsp-ping-parameters/mpls-lsp-ping-
              parameters.xhtml#sub-tlv-9>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

Authors' Addresses

   Loa Andersson
   Bronze Dragon Consulting

   Email: loa@pi.nu

   Mach Chen
   Huawei Techologies

   Email: mach.chen@huawei.com

   Carlos Pignataro
   Cisco Systems

   Email: cpignata@cisco.com

   Tarek Saad
   Juniper Networks

   Email: tsaad@juniper.net