draft-ietf-pce-iro-update-07.txt   rfc7896.txt 
PCE Working Group D. Dhody Internet Engineering Task Force (IETF) D. Dhody
Internet-Draft Huawei Technologies Request for Comments: 7896 Huawei Technologies
Updates: 5440 (if approved) April 21, 2016 Updates: 5440 June 2016
Intended status: Standards Track Category: Standards Track
Expires: October 23, 2016 ISSN: 2070-1721
Update to Include Route Object (IRO) specification in Path Computation Update to the Include Route Object (IRO) Specification
Element communication Protocol (PCEP) in the Path Computation Element Communication Protocol (PCEP)
draft-ietf-pce-iro-update-07
Abstract Abstract
The Path Computation Element Communication Protocol (PCEP) provides The Path Computation Element Communication Protocol (PCEP) enables
for communications between a Path Computation Client (PCC) and a PCE, communications between a Path Computation Client (PCC) and a PCE, or
or between two PCEs. RFC 5440 defines the Include Route Object (IRO) between two PCEs. RFC 5440 defines the Include Route Object (IRO) to
to specify network elements to be traversed in the computed path. specify network elements to be traversed in the computed path. The
The specification did not specify if the IRO contains an ordered or specification does not specify if the IRO contains an ordered or
un-ordered list of sub-objects. During recent discussions, it was unordered list of subobjects. During recent discussions, it was
determined that there was a need to define a standard representation determined that there was a need to define a standard representation
to ensure interoperability. It was also noted that there is a to ensure interoperability. It was also noted that there is a
benefit in handling of an attribute of the IRO's sub-object, the benefit in the handling of an attribute of the IRO's subobject, the L
Loose hop bit (L bit). bit.
This document updates RFC 5440 regarding the IRO specification. This document updates RFC 5440 regarding the IRO specification.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on October 23, 2016. 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/rfc7896.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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skipping to change at page 2, line 29 skipping to change at page 2, line 34
modifications of such material outside the IETF Standards Process. modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other it for publication as an RFC or to translate it into languages other
than English. than English.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Update in the IRO specification . . . . . . . . . . . . . . . 3 2. Update in the IRO Specification . . . . . . . . . . . . . . . 3
2.1. Update to RFC 5440 . . . . . . . . . . . . . . . . . . . 3 2.1. Update to RFC 5440 . . . . . . . . . . . . . . . . . . . 3
3. Operational Considerations . . . . . . . . . . . . . . . . . 3 3. Operational Considerations . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4 4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 5. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4 5.1. Normative References . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 5.2. Informative References . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . 4 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction 1. Introduction
The Path Computation Element Communication Protocol (PCEP) provides The Path Computation Element Communication Protocol (PCEP) enables
for communications between a Path Computation Client (PCC) and a PCE, communications between a Path Computation Client (PCC) and a PCE, or
or between two PCEs. [RFC5440] defines the Include Route Object between two PCEs. [RFC5440] defines the Include Route Object (IRO)
(IRO) to specify network elements to be traversed in the computed to specify network elements to be traversed in the computed path.
path. The specification did not define if the IRO is an ordered or The specification does not specify if the IRO is an ordered or
un-ordered list of sub-objects. In addition, it defined the Loose unordered list of subobjects. In addition, it defines the L bit as
hop bit (L bit) to have no meaning within an IRO. having no meaning within an IRO.
[RFC5441] describes the use of an IRO to indicate the sequence of [RFC5441] describes the use of an IRO to indicate the sequence of
domains to be traversed during inter-domain path computation. domains to be traversed during inter-domain path computation.
During recent discussions, it was determined that there was a need to During recent discussions, it was determined that there was a need to
define a standard representation to ensure interoperability. define a standard representation to ensure interoperability.
This document updates the IRO specifications in section 7.12 of This document updates the IRO specifications in Section 7.12 of
[RFC5440]. [RFC5440].
2. Update in the IRO specification 2. Update in the IRO Specification
Section 7.12 of [RFC5440] describes the IRO as an optional object Section 7.12 of [RFC5440] describes the IRO as an optional object
used to specify a set of network elements to be traversed in the used to specify a set of network elements to be traversed in the
computed path. It stated that the Loose hop bit (L bit) in the sub- computed path. It states that the L bit in the subobject has no
object has no meaning within an IRO. It did not mention if the IRO meaning within an IRO. It does not mention if the IRO contains an
contains an ordered or un-ordered list of sub-objects. ordered or unordered list of subobjects.
2.1. Update to RFC 5440 2.1. Update to RFC 5440
Section 7.12 of [RFC5440] regarding the IRO specification is updated The IRO specification is updated to remove the last line in the
to remove the last line in the section 7.12 of [RFC5440], that states Section 7.12 of [RFC5440], which states:
:
"The L bit of such sub-object has no meaning within an IRO." "The L bit of such sub-object has no meaning within an IRO."
Further, the Section 7.12 of [RFC5440] is updated to add the Further, Section 7.12 of [RFC5440] is updated to add the following
following two statements at the end of the first paragraph. two statements at the end of the first paragraph.
- The content of an IRO is an ordered list of sub-objects - The content of an IRO is an ordered list of subobjects
representing a series of abstract nodes (refer to section 4.3.2 of representing a series of abstract nodes (refer to Section 4.3.2 of
[RFC3209]). [RFC3209]).
- The L Bit of an IRO sub-object is set based on the loose or strict - The L bit of an IRO subobject is set based on the loose or strict
hop property of the sub-object; it is set if the sub-object hop property of the subobject; it is set if the subobject
represents a loose hop. If the bit is not set, the sub-object represents a loose hop. If the bit is not set, the subobject
represents a strict hop. The interpretation of the Loose bit (L bit) represents a strict hop. The interpretation of the L bit is as
is as per section 4.3.3.1 of [RFC3209]. per Section 4.3.3.1 of [RFC3209].
3. Operational Considerations 3. Operational Considerations
Because of the lack of clarity in [RFC5440], it is possible to Because of the lack of clarity in [RFC5440], it is possible to
encounter implementations that always interpret the IRO sub-objects encounter implementations that always interpret the IRO subobjects as
as loose. When these implementations interwork with an loose. When these implementations interwork with an implementation
implementation conforming to this document, the following impact conforming to this document, the following impact might be seen:
might be seen:
o If a non-conforming (to this document) PCC sends an IRO to a o If a non-conforming (to this document) PCC sends an IRO to a
conforming (to this document) PCE, then the PCE may unexpectedly conforming (to this document) PCE, then the PCE may unexpectedly
fail to find a path (since the PCC may think of the IRO sub- fail to find a path (since the PCC may think of the IRO subobjects
objects as loose hops, but the PCE interprets them as strict as loose hops, but the PCE interprets them as strict hops).
hops).
o If a conforming PCC sends an IRO containing strict hops to a non- o If a conforming PCC sends an IRO containing strict hops to a non-
conforming PCE, then the PCE may erroneously return a path that conforming PCE, then the PCE may erroneously return a path that
does not comply with the requested strict hops (since the PCE does not comply with the requested strict hops (since the PCE
interprets them all as loose hops). The PCC may check the interprets them all as loose hops). The PCC may check the
returned path and find the issue or it may end up using an returned path and find the issue, or it may end up using an
incorrect path. incorrect path.
4. Security Considerations 4. Security Considerations
This update in the IRO specification does not introduce any new This update in the IRO specification does not introduce any new
security considerations, apart from those mentioned in [RFC5440]. security considerations, apart from those mentioned in [RFC5440].
Clarification in the supported IRO ordering or Loose hop bit handling Clarification in the supported IRO ordering or Loose hop bit handling
will not have any negative security impact. will not have any negative security impact.
It is worth noting that PCEP operates over TCP. An analysis of the It is worth noting that PCEP operates over TCP. An analysis of the
security issues for routing protocols that use TCP (including PCEP) security issues for routing protocols that use TCP (including PCEP)
is provided in [RFC6952]. is provided in [RFC6952].
5. IANA Considerations 5. References
This document makes no requests to IANA for action.
6. Acknowledgments
A special thanks to PCE chairs for guidance regarding this work.
Thanks to Francesco Fondelli for his suggestions in clarifying the L
bit usage.
Thanks to Adrian Farrel for his review and comments.
Thanks to Jonathan Hardwick for document shepherding and providing
text in Section 3.
Thanks to Deborah Brungard for her comments and being the responsible
AD.
Thanks to Peter Yee for Gen-ART review.
Thanks to Alvaro Retana for comments during the IESG review.
7. References
7.1. Normative References 5.1. Normative References
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
<http://www.rfc-editor.org/info/rfc3209>. <http://www.rfc-editor.org/info/rfc3209>.
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440, Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009, DOI 10.17487/RFC5440, March 2009,
<http://www.rfc-editor.org/info/rfc5440>. <http://www.rfc-editor.org/info/rfc5440>.
7.2. Informative References 5.2. Informative References
[RFC5441] Vasseur, JP., Ed., Zhang, R., Bitar, N., and JL. Le Roux, [RFC5441] Vasseur, JP., Ed., Zhang, R., Bitar, N., and JL. Le Roux,
"A Backward-Recursive PCE-Based Computation (BRPC) "A Backward-Recursive PCE-Based Computation (BRPC)
Procedure to Compute Shortest Constrained Inter-Domain Procedure to Compute Shortest Constrained Inter-Domain
Traffic Engineering Label Switched Paths", RFC 5441, Traffic Engineering Label Switched Paths", RFC 5441,
DOI 10.17487/RFC5441, April 2009, DOI 10.17487/RFC5441, April 2009,
<http://www.rfc-editor.org/info/rfc5441>. <http://www.rfc-editor.org/info/rfc5441>.
[RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of
BGP, LDP, PCEP, and MSDP Issues According to the Keying BGP, LDP, PCEP, and MSDP Issues According to the Keying
and Authentication for Routing Protocols (KARP) Design and Authentication for Routing Protocols (KARP) Design
Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013,
<http://www.rfc-editor.org/info/rfc6952>. <http://www.rfc-editor.org/info/rfc6952>.
Acknowledgments
A special thanks to the PCE chairs for guidance regarding this work.
Thanks to Francesco Fondelli for his suggestions in clarifying the
L bit usage.
Thanks to Adrian Farrel for his review and comments.
Thanks to Jonathan Hardwick for shepherding the document and
providing text in Section 3.
Thanks to Deborah Brungard for her comments and being the responsible
AD.
Thanks to Peter Yee for the Gen-ART review.
Thanks to Alvaro Retana for comments during the IESG review.
Author's Address Author's Address
Dhruv Dhody Dhruv Dhody
Huawei Technologies Huawei Technologies
Divyashree Techno Park, Whitefield Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560066 Bangalore, Karnataka 560066
India India
EMail: dhruv.ietf@gmail.com Email: dhruv.ietf@gmail.com
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