Internet DRAFT - draft-ietf-pce-pcep-exp-codepoints
draft-ietf-pce-pcep-exp-codepoints
PCE Working Group D. Dhody
Internet-Draft Huawei Technologies
Updates: 5440 (if approved) D. King
Intended status: Standards Track Lancaster University
Expires: July 14, 2018 A. Farrel
Juniper Networks
January 10, 2018
Experimental Codepoint Allocation for the Path Computation Element
communication Protocol (PCEP)
draft-ietf-pce-pcep-exp-codepoints-05
Abstract
IANA assigns values to the Path Computation Element (PCE)
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 code points as
assigned for Experimental Use.
Status of This Memo
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This Internet-Draft will expire on July 14, 2018.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. PCEP Messages . . . . . . . . . . . . . . . . . . . . . . . . 3
3. PCEP Objects . . . . . . . . . . . . . . . . . . . . . . . . 3
4. PCEP TLVs . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Handling of Unknown Experimentation . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6.1. New PCEP Messages . . . . . . . . . . . . . . . . . . . . 4
6.2. New PCEP Objects . . . . . . . . . . . . . . . . . . . . 4
6.3. New PCEP TLVs . . . . . . . . . . . . . . . . . . . . . . 5
7. Security Considerations . . . . . . . . . . . . . . . . . . . 5
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 5
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
9.1. Normative References . . . . . . . . . . . . . . . . . . 6
9.2. Informative References . . . . . . . . . . . . . . . . . 6
Appendix A. Other PCEP Registries . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
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 Clients (PCCs)
requests.
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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 code points,
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 won't collide not only with existing codepoints but
any future allocation.
This document updates [RFC5440] by changing the allocation policies
for these three registries to mark some of the code points as
assigned for Experimental Use. As stated in [RFC3692], experiments
using these code points are not intended to be used in general
deployments and due care must be taken to ensure that two experiments
with the same code points are not run in the same environment. See
[RFC3692] for further discussion of the use of experimental
codepoints.
2. 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.
3. 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.
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4. 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, would react as per section 6.9 of
[RFC5440] by sending a PCErr message with Error-value=2 (capability
not supported).
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 (PCUpd) Request message).
As per section 7.1 of [RFC5440], unknown experimental PCEP TLV would
be ignored.
6. IANA Considerations
IANA maintains the "Path Computation Element Protocol (PCEP) Numbers"
at <http://www.iana.org/assignments/pcep>.
6.1. New PCEP Messages
Within this registry IANA maintains a sub-registry for PCEP Messages
(see PCEP Messages at <http://www.iana.org/assignments/pcep>).
IANA is requested to change the registration procedure for this
registry to read as follows:
0-251 IETF Review
252-255 Experimental Use
IANA is also requested to mark the values 252-255 in the registry
accordingly.
6.2. New PCEP Objects
Within this registry IANA maintains a sub-registry for PCEP Objects
(see PCEP Objects at <http://www.iana.org/assignments/pcep>).
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IANA is requested to change the registration procedure for this
registry to read as follows:
0-247 IETF Review
248-255 Experimental Use
IANA is also requested to mark the values 248-255 in the registry
accordingly.
6.3. New PCEP TLVs
Within this registry IANA maintains a sub-registry for PCEP TLVs (see
PCEP TLV Type Indicators at <http://www.iana.org/assignments/pcep>).
IANA is requested to change the registration procedure for this
registry to read as follows:
0-65503 IETF Review
65504-65535 Experimental Use
IANA is also requested to mark 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 code points
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 code points needs to consider the security
aspects of the experimental extensions. [RFC6709] provide various
design considerations for protocol extensions (including those
designated as experimental).
8. 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.
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Thanks Brian Carpenter for the GENART review. Thanks Ben Niven-
Jenkins and Scott Bradner for RTGDIR and OPSDIR reviews respectively.
9. References
9.1. 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>.
9.2. 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>.
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[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 code point 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 code point in another
PCEP sub-registry, it can implement the same function using a new
experimental object or TLV instead.
Authors' Addresses
Dhruv Dhody
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560066
India
EMail: dhruv.ietf@gmail.com
Daniel King
Lancaster University
UK
EMail: d.king@lancaster.ac.uk
Adrian Farrel
Juniper Networks
UK
EMail: afarrel@juniper.net
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