Internet Engineering Task Force (IETF)                          D. Dhody
Request for Comments: 8356                           Huawei Technologies
Updates: 5440                                                    D. King
Category: Standards Track                           Lancaster University
ISSN: 2070-1721                                                A. Farrel
                                                       Juniper Networks
                                                             March 2018


                Experimental Codepoint Allocation for
      the Path Computation Element Communication Protocol (PCEP)

Abstract

  IANA assigns values to the Path Computation Element Communication
  Protocol (PCEP) parameters (messages, objects, TLVs).  IANA
  established a top-level registry to contain all PCEP codepoints and
  sub-registries.  This top-level registry contains sub-registries for
  PCEP message, object, and TLV types.  The allocation policy for each
  of these sub-registries is IETF Review.

  This document updates RFC 5440 by changing the allocation policies
  for these three registries to mark some of the codepoints as assigned
  for Experimental Use.

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://www.rfc-editor.org/info/rfc8356.













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Copyright Notice

  Copyright (c) 2018 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://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.

  This document may contain material from IETF Documents or IETF
  Contributions published or made publicly available before November
  10, 2008.  The person(s) controlling the copyright in some of this
  material may not have granted the IETF Trust the right to allow
  modifications of such material outside the IETF Standards Process.
  Without obtaining an adequate license from the person(s) controlling
  the copyright in such materials, this document may not be modified
  outside the IETF Standards Process, and derivative works of it may
  not be created outside the IETF Standards Process, except to format
  it for publication as an RFC or to translate it into languages other
  than English.

Table of Contents

  1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
  2.  Experimental PCEP Messages  . . . . . . . . . . . . . . . . .   3
  3.  Experimental PCEP Objects . . . . . . . . . . . . . . . . . .   4
  4.  Experimental PCEP TLVs  . . . . . . . . . . . . . . . . . . .   4
  5.  Handling of Unknown Experimentation . . . . . . . . . . . . .   4
  6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
    6.1.  PCEP Messages . . . . . . . . . . . . . . . . . . . . . .   4
    6.2.  PCEP Objects  . . . . . . . . . . . . . . . . . . . . . .   5
    6.3.  PCEP TLVs . . . . . . . . . . . . . . . . . . . . . . . .   5
  7.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
  8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
    8.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
    8.2.  Informative References  . . . . . . . . . . . . . . . . .   6
  Appendix A.  Other PCEP Registries  . . . . . . . . . . . . . . .   7
  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   7
  Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7






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1.  Introduction

  The Path Computation Element Communication Protocol (PCEP) [RFC5440]
  provides mechanisms for Path Computation Elements (PCEs) to perform
  path computations in response to Path Computation Client (PCC)
  requests.

  Further, in order to support use cases described in [RFC8051],
  [RFC8231] specifies a set of extensions to PCEP to enable stateful
  control of MPLS-TE and GMPLS LSPs via PCEP.  [RFC8281] describes the
  setup, maintenance, and teardown of PCE-initiated LSPs under the
  stateful PCE model.

  In Section 9 of [RFC5440], IANA assigns values to the PCEP protocol
  parameters (messages, objects, TLVs).  IANA established a top-level
  registry to contain all PCEP codepoints and sub-registries.  This
  top-level registry contains sub-registries for PCEP message, object
  and TLV types.  The allocation policy for each of these sub-
  registries is IETF Review [RFC8126].  Also, early allocation
  [RFC7120] provides some latitude for allocation of these codepoints
  but is reserved for features that are considered appropriately
  stable.

  Recently, there have been rapid advancements in PCE technology, which
  has created an enhanced need to experiment with PCEP.  It is often
  necessary to use some sort of number or constant in order to actually
  test or experiment with the new function, even when testing in a
  closed environment.  In order to run experiments, it is important
  that the value not collide with existing codepoints or any future
  allocations.

  This document updates [RFC5440] by changing the allocation policies
  for these three registries to mark some of the codepoints as assigned
  for Experimental Use.  As stated in [RFC3692], experiments using
  these codepoints are not intended to be used in general deployments,
  and due care must be taken to ensure that two experiments using the
  same codepoints are not run in the same environment.  See [RFC3692]
  for further discussion of the use of experimental codepoints (also
  referred to as "experimental and testing numbers").

2.  Experimental PCEP Messages

  PCEP message types are in the range 0 to 255.  This document sets
  aside message types 252-255 for experimentation as described in
  Section 6.1.






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3.  Experimental PCEP Objects

  PCEP objects are identified by values in the range 0 to 255.  This
  document sets aside object identifiers 248-255 for experimentation as
  described in Section 6.2.

4.  Experimental PCEP TLVs

  PCEP TLV type codes are in the range 0 to 65535.  This document sets
  aside object identifiers 65504-65535 for experimentation as described
  in Section 6.2.

5.  Handling of Unknown Experimentation

  A PCEP implementation that receives an experimental PCEP message that
  it does not recognize reacts by sending a PCErr message with
  Error-Type=2 (capability not supported) per Section 6.9 of [RFC5440].

  If a PCEP speaker does not understand or support an experimental
  object, then the way it handles this situation depends on the message
  type.  For example, a PCE handles an unknown object in the Path
  Computation Request (PCReq) message according to the rules of
  [RFC5440].  Message-specific behavior may be specified (e.g.,
  [RFC8231] defines rules for a PCC to handle an unknown object in a
  Path Computation LSP Update Request (PCUpd) message).

  As per Section 7.1 of [RFC5440], an unknown experimental PCEP TLV
  would be ignored.

6.  IANA Considerations

  IANA maintains the "Path Computation Element Protocol (PCEP) Numbers"
  registry at <http://www.iana.org/assignments/pcep>.

6.1.  PCEP Messages

  Within the PCEP Numbers registry, IANA maintains the "PCEP Messages"
  sub-registry.

  IANA has changed the registration procedure for this registry to read
  as follows:

     0-251   IETF Review
     252-255 Experimental Use

  IANA has also marked the values 252-255 in the registry accordingly.





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6.2.  PCEP Objects

  Within the PCEP Numbers registry, IANA maintains the "PCEP Objects"
  sub-registry.

  IANA has changed the registration procedure for this registry to read
  as follows:

     0-247   IETF Review
     248-255 Experimental Use

  IANA has also marked the values 248-255 in the registry accordingly,
  and Object-Types 0-15 have been marked for Experimental Use.

6.3.  PCEP TLVs

  Within the PCEP Numbers registry, IANA maintains the "PCEP TLV Type
  Indicators" sub-registry.

  IANA has changed the registration procedure for this registry to read
  as follows:

     0-65503     IETF Review
     65504-65535 Experimental Use

  IANA has also marked the values 65504-65535 in the registry
  accordingly.

7.  Security Considerations

  This document does not introduce any new security considerations to
  the existing protocol.  Refer to [RFC5440] for further details of the
  specific security measures.

  [RFC3692] asserts that the existence of experimental codepoints
  introduce no new security considerations.  However, implementations
  accepting experimental codepoints need to take care in how they parse
  and process the messages, objects, and TLVs in case they come,
  accidentally, from another experiment.  Further, an implementation
  accepting experimental codepoints needs to consider the security
  aspects of the experimental extensions.  [RFC6709] provides various
  design considerations for protocol extensions (including those
  designated as experimental).








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8.  References

8.1.  Normative References

  [RFC3692]  Narten, T., "Assigning Experimental and Testing Numbers
             Considered Useful", BCP 82, RFC 3692,
             DOI 10.17487/RFC3692, January 2004,
             <https://www.rfc-editor.org/info/rfc3692>.

  [RFC5440]  Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
             Element (PCE) Communication Protocol (PCEP)", RFC 5440,
             DOI 10.17487/RFC5440, March 2009,
             <https://www.rfc-editor.org/info/rfc5440>.

  [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>.

  [RFC8231]  Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
             Computation Element Communication Protocol (PCEP)
             Extensions for Stateful PCE", RFC 8231,
             DOI 10.17487/RFC8231, September 2017,
             <https://www.rfc-editor.org/info/rfc8231>.

  [RFC8281]  Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path
             Computation Element Communication Protocol (PCEP)
             Extensions for PCE-Initiated LSP Setup in a Stateful PCE
             Model", RFC 8281, DOI 10.17487/RFC8281, December 2017,
             <https://www.rfc-editor.org/info/rfc8281>.

8.2.  Informative References

  [RFC6709]  Carpenter, B., Aboba, B., Ed., and S. Cheshire, "Design
             Considerations for Protocol Extensions", RFC 6709,
             DOI 10.17487/RFC6709, September 2012,
             <https://www.rfc-editor.org/info/rfc6709>.

  [RFC7120]  Cotton, M., "Early IANA Allocation of Standards Track Code
             Points", BCP 100, RFC 7120, DOI 10.17487/RFC7120, January
             2014, <https://www.rfc-editor.org/info/rfc7120>.

  [RFC8051]  Zhang, X., Ed. and I. Minei, Ed., "Applicability of a
             Stateful Path Computation Element (PCE)", RFC 8051,
             DOI 10.17487/RFC8051, January 2017,
             <https://www.rfc-editor.org/info/rfc8051>.





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Appendix A.  Other PCEP Registries

  Based on feedback from the PCE WG, it was decided to allocate an
  Experimental codepoint range only in the message, object, and TLV
  sub-registries.  The justification for this decision is that, if an
  experiment finds that it wants to use a new codepoint in another PCEP
  sub-registry, it can implement the same function using a new
  experimental object or TLV instead.

Acknowledgments

  The authors would like to thank Ramon Casellas, Jeff Tantsura, Julien
  Meuric, Lou Berger, Michael Shroff, and Andrew Dolganow for their
  feedback and suggestions.

  We would like to thank Jonathan Hardwick for shepherding this
  document and providing comments with text suggestions.

  Thanks to Brian Carpenter for the GENART review.  Thanks to Ben
  Niven-Jenkins and Scott Bradner for RTGDIR and OPSDIR reviews
  respectively.

Authors' Addresses

  Dhruv Dhody
  Huawei Technologies
  Divyashree Techno Park, Whitefield
  Bangalore, Karnataka  560066
  India

  EMail: [email protected]


  Daniel King
  Lancaster University
  United Kingdom

  EMail: [email protected]


  Adrian Farrel
  Juniper Networks
  United Kingdom

  EMail: [email protected]






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