draft-ietf-pce-iro-update-01.txt   draft-ietf-pce-iro-update-02.txt 
PCE Working Group D. Dhody PCE Working Group D. Dhody
Internet-Draft Huawei Technologies Internet-Draft Huawei Technologies
Updates: 5440 (if approved) March 6, 2015 Updates: 5440 (if approved) May 20, 2015
Intended status: Standards Track Intended status: Standards Track
Expires: September 7, 2015 Expires: November 21, 2015
Update to Include Route Object (IRO) specification in Path Computation Update to Include Route Object (IRO) specification in Path Computation
Element communication Protocol (PCEP) Element communication Protocol (PCEP)
draft-ietf-pce-iro-update-01 draft-ietf-pce-iro-update-02
Abstract Abstract
During discussions of a document to provide a standard representation During discussions of a document to provide a standard representation
and encoding of Domain-Sequence within the Path Computation Element and encoding of Domain-Sequence within the Path Computation Element
(PCE) communication Protocol (PCEP) for communications between a Path (PCE) communication Protocol (PCEP) for communications between a Path
Computation Client (PCC) and a PCE, or between two PCEs. It was Computation Client (PCC) and a PCE, or between two PCEs, it was
determined that there was a need for clarification with respect to determined that there was a need for clarification with respect to
the ordered nature of the Include Route Object (IRO). the ordered nature of the Include Route Object (IRO).
An informal survey was conducted to determine the state of current An informal survey was conducted to determine the state of current
and planned implementation with respect to IRO ordering and handling and planned implementation with respect to IRO ordering and handling
of Loose bit (L bit). of Loose bit (L bit).
This document updates the IRO specification based on the survey This document updates the IRO specification based on the survey
conclusion and recommendation. conclusion and recommendation.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 7, 2015. This Internet-Draft will expire on November 21, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Update in IRO specification . . . . . . . . . . . . . . . . . 3 2. Update in IRO specification . . . . . . . . . . . . . . . . . 3
3. Other Considerations . . . . . . . . . . . . . . . . . . . . 4 3. Other Considerations . . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4 4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
7.1. Normative References . . . . . . . . . . . . . . . . . . 4 7.1. Normative References . . . . . . . . . . . . . . . . . . 4
7.2. Informative References . . . . . . . . . . . . . . . . . 5 7.2. Informative References . . . . . . . . . . . . . . . . . 5
Appendix A. Details of IRO survey . . . . . . . . . . . . . . . 6 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction 1. Introduction
The Path Computation Element Communication Protocol (PCEP) provides The Path Computation Element Communication Protocol (PCEP) provides
mechanisms for Path Computation Elements (PCEs) to perform path mechanisms for Path Computation Elements (PCEs) to perform path
computations in response to Path Computation Clients (PCCs) requests. computations in response to Path Computation Clients (PCCs) requests.
[RFC5440] defines the Include Route Object (IRO) to specify that the [RFC5440] defines the Include Route Object (IRO) to specify network
computed path must traverse a set of specified network elements. The elements to be traversed in the computed path. The specification did
specification did not mention if IRO is an ordered or un-ordered list not mention if IRO is an ordered or un-ordered list of sub-objects.
of sub-objects. It mentioned that the Loose bit (L bit) has no It mentioned that the Loose bit (L bit) has no meaning within an IRO.
meaning within an IRO.
[RFC5441] suggested the use of IRO to indicate the sequence of [RFC5441] suggested the use of 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 discussion of [I-D.ietf-pce-pcep-domain-sequence] it was
proposed to have a new IRO type with ordered nature, as well as
handling of Loose bit (L bit).
In order to discover the current state of affairs amongst In order to discover the current state of affairs amongst
implementations a survey of the existing and planned implementations implementations a survey of the existing and planned implementations
was conducted. This survey [I-D.dhody-pce-iro-survey] was informal was conducted. This survey [I-D.dhody-pce-iro-survey] was informal
and conducted via email. Responses were collected and anonymized by and conducted via email. Responses were collected and anonymized by
the PCE working group chair. the PCE working group chair.
This document updates the IRO specifications in [RFC5440] as per the During discussion of [I-D.ietf-pce-pcep-domain-sequence] it was
conclusion and action points presented in [I-D.dhody-pce-iro-survey]. proposed to have a new IRO type with ordered nature, as well as
handling of Loose bit (L bit); however, with the update to [RFC5440]
described in this document, no new IRO type is needed.
This document updates the IRO specifications in section 7.12 of
[RFC5440] as per the conclusion and action points presented in
[I-D.dhody-pce-iro-survey].
1.1. Requirements Language 1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2. Update in IRO specification 2. Update in IRO specification
[RFC5440] describes IRO as an optional object used to specify that Section 7.12 of [RFC5440] describes IRO as an optional object used to
the computed path MUST traverse a set of specified network elements. specify a set of network elements to be traversed in the computed
It further state that the Loose bit (L bit) of such sub-object has no path. It also states that the Loose bit (L bit) in sub-object has no
meaning within an IRO. It did not mention if IRO is an ordered or meaning within an IRO. It did not mention if IRO is an ordered or
un-ordered list of sub-objects. un-ordered list of sub-objects.
A survey of the existing and planned implementations was conducted in A survey of the existing and planned implementations was conducted in
order to discover the current state of affairs amongst order to discover the current state of affairs amongst
implementations. [I-D.dhody-pce-iro-survey] describe the implementations. [I-D.dhody-pce-iro-survey] describe the
questionnaire, results and presents some conclusions and proposed questionnaire, results and presents some conclusions and proposed
action items. More details in Appendix A. action items.
The survey suggest that most implementations construct or interpret The survey suggest that most implementations construct or interpret
IRO in an ordered fashion and consider it to be an ordered list. IRO in an ordered fashion and consider it to be an ordered list.
More than half of implementation under survey consider the IRO sub- More than half of implementation under survey consider the IRO sub-
objects as strict hops, others consider loose or support both. The objects as strict hops, others consider loose or support both. The
results shown in this survey seems to suggest that most results shown in this survey seems to suggest that most
implementations would be fine with updating [RFC5440] to specify IRO implementations would be fine with updating [RFC5440] to specify IRO
as an ordered list as well as to enable support for Loose bit (L bit) as an ordered list as well as to enable support for Loose bit (L bit)
such that both strict and loose hops could be supported in the IRO. such that both strict and loose hops could be supported in the IRO.
This document thus updates [RFC5440] regarding the IRO specification This document thus updates [RFC5440] regarding the IRO specification
making IRO as an ordered list as well as support for Loose bit (L and is intended to replace the last line in section 7.12 of
bit). [RFC5440], that states -
The content of an IRO object MUST be an ordered list of subobjects "The L bit of such sub-object has no meaning within an IRO."
representing a series of abstract nodes. An abstract node may just
be a simple abstract node comprising one node or a group of nodes for As per the update in this document, the L Bit of IRO sub-object is
example an AS (comprising of multiple hops within the AS) (refer set based on the loose or strict property of the sub-object, which is
[RFC3209] for details). Further, the loose or strict property of the set if the sub-object represents a loose hop. If the bit is not set,
subobject MUST be interpreted based on L bit, which is set if the the sub-object represents a strict hop. The interpretation of Loose
subobject represents a loose hop. If the bit is not set, the bit (L bit) is as per section 4.3.3.1 of [RFC3209].
subobject represents a strict hop. The interpretation of Loose bit
(L bit) is as per section 4.3.3.1 of [RFC3209]. Also, as per the update in this document, the content of IRO is an
ordered list of sub-objects representing a series of abstract nodes.
An abstract node could just be a simple abstract node comprising one
node or a group of nodes for example an AS (comprising of multiple
hops within the AS) (refer section 4.3.2 of [RFC3209]).
3. Other Considerations 3. Other Considerations
Based on the survey, it should be noted that most implementation Based on the survey, it should be noted that most implementation
already support the update in the IRO specification as per this already support the update in the IRO specification as per this
document. The other implementation are expected to make an update to document. The other implementation are expected to make an update to
the IRO procedures. the IRO procedures.
4. Security Considerations 4. Security Considerations
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Clarification in the supported IRO ordering or Loose bit handling Clarification in the supported IRO ordering or Loose 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], while [I-D.ietf-pce-pceps] discusses an is provided in [RFC6952], while [I-D.ietf-pce-pceps] discusses an
experimental approach to provide secure transport for PCEP. experimental approach to provide secure transport for PCEP.
5. IANA Considerations 5. IANA Considerations
This informational document makes no requests to IANA for action. This document makes no requests to IANA for action.
6. Acknowledgments 6. Acknowledgments
A special thanks to PCE chairs for guidance regarding this work. A special thanks to PCE chairs for guidance regarding this work.
Thanks to Francesco Fondelli for his suggestions in clarifying the L Thanks to Francesco Fondelli for his suggestions in clarifying the L
bit usage. bit usage.
Thanks to Adrian Farrel for his review and comments.
7. References 7. References
7.1. Normative References 7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.
[RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element [RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element
(PCE) Communication Protocol (PCEP)", RFC 5440, March (PCE) Communication Protocol (PCEP)", RFC 5440, March
2009. 2009.
7.2. Informative References 7.2. Informative References
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.
[RFC5441] Vasseur, JP., Zhang, R., Bitar, N., and JL. Le Roux, "A [RFC5441] Vasseur, JP., Zhang, R., Bitar, N., and JL. Le Roux, "A
Backward-Recursive PCE-Based Computation (BRPC) Procedure Backward-Recursive PCE-Based Computation (BRPC) Procedure
to Compute Shortest Constrained Inter-Domain Traffic to Compute Shortest Constrained Inter-Domain Traffic
Engineering Label Switched Paths", RFC 5441, April 2009. Engineering Label Switched Paths", RFC 5441, April 2009.
[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, May 2013. Guide", RFC 6952, May 2013.
[I-D.ietf-pce-pcep-domain-sequence] [I-D.ietf-pce-pcep-domain-sequence]
Dhody, D., Palle, U., and R. Casellas, "Standard Dhody, D., Palle, U., and R. Casellas, "Standard
Representation of Domain-Sequence", draft-ietf-pce-pcep- Representation of Domain-Sequence", draft-ietf-pce-pcep-
domain-sequence-07 (work in progress), December 2014. domain-sequence-08 (work in progress), April 2015.
[I-D.ietf-pce-pceps] [I-D.ietf-pce-pceps]
Lopez, D., Dios, O., Wu, W., and D. Dhody, "Secure Lopez, D., Dios, O., Wu, W., and D. Dhody, "Secure
Transport for PCEP", draft-ietf-pce-pceps-03 (work in Transport for PCEP", draft-ietf-pce-pceps-04 (work in
progress), March 2015. progress), May 2015.
[I-D.dhody-pce-iro-survey] [I-D.dhody-pce-iro-survey]
Dhody, D., "Informal Survey into Include Route Object Dhody, D., "Informal Survey into Include Route Object
(IRO) Implementations in Path Computation Element (IRO) Implementations in Path Computation Element
communication Protocol (PCEP)", draft-dhody-pce-iro- communication Protocol (PCEP)", draft-dhody-pce-iro-
survey-02 (work in progress), December 2014. survey-02 (work in progress), December 2014.
Appendix A. Details of IRO survey
During discussions of this document to provide a standard
representation and encoding of Domain-Sequence within PCEP. It was
determined that there was a need for clarification with respect to
the ordered nature of the IRO.
Since there was a proposal to have a new IRO type with ordering, as
well as handling of Loose bit, in an earlier version of this document
(refer - draft-ietf-pce-pcep-domain-sequence-05), it was deemed
necessary to conduct a survey of the existing and planned
implementations. An informal survey was conducted via email.
Responses were collected and anonymized by the PCE working group
chairs.
[I-D.dhody-pce-iro-survey] summarizes the survey questions and
captures the results. It further list some conclusions and action
points.
This document was considered as one possible venue to handle the
proposed action points.
Author's Address Author's Address
Dhruv Dhody Dhruv Dhody
Huawei Technologies Huawei Technologies
Divyashree Techno Park, Whitefield Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560037 Bangalore, Karnataka 560037
India India
EMail: dhruv.ietf@gmail.com EMail: dhruv.ietf@gmail.com
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