draft-ietf-pce-brpc-08.txt   draft-ietf-pce-brpc-09.txt 
Networking Working Group JP. Vasseur, Ed. Networking Working Group JP. Vasseur, Ed.
Internet-Draft Cisco Systems, Inc Internet-Draft Cisco Systems, Inc
Intended status: Standards Track R. Zhang Intended status: Standards Track R. Zhang
Expires: October 2, 2008 BT Infonet Expires: October 16, 2008 BT Infonet
N. Bitar N. Bitar
Verizon Verizon
JL. Le Roux JL. Le Roux
France Telecom France Telecom
March 31, 2008 April 14, 2008
A Backward Recursive PCE-based Computation (BRPC) Procedure To Compute A Backward Recursive PCE-based Computation (BRPC) Procedure To Compute
Shortest Constrained Inter-domain Traffic Engineering Label Switched Shortest Constrained Inter-domain Traffic Engineering Label Switched
Paths Paths
draft-ietf-pce-brpc-08.txt draft-ietf-pce-brpc-09.txt
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
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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."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
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This Internet-Draft will expire on October 2, 2008. This Internet-Draft will expire on October 16, 2008.
Abstract Abstract
The ability to compute shortest constrained Traffic Engineering Label The ability to compute shortest constrained Traffic Engineering Label
Switched Paths (TE LSPs) in Multiprotocol Label Switching (MPLS) and Switched Paths (TE LSPs) in Multiprotocol Label Switching (MPLS) and
Generalized MPLS (GMPLS) networks across multiple domains (where a Generalized MPLS (GMPLS) networks across multiple domains (where a
domain is a collection of network elements within a common sphere of domain is a collection of network elements within a common sphere of
address management or path computational responsibility such as an address management or path computational responsibility such as an
IGP area or an Autonomous Systems) has been identified as a key IGP area or an Autonomous Systems) has been identified as a key
requirement. This document specifies a procedure relying on the use requirement. This document specifies a procedure relying on the use
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. General Assumptions . . . . . . . . . . . . . . . . . . . . . 5 3. General Assumptions . . . . . . . . . . . . . . . . . . . . . 5
4. BRPC Procedure . . . . . . . . . . . . . . . . . . . . . . . . 6 4. BRPC Procedure . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Domain Path Selection . . . . . . . . . . . . . . . . . . 7 4.1. Domain Path Selection . . . . . . . . . . . . . . . . . . 7
4.2. Mode of Operation . . . . . . . . . . . . . . . . . . . . 7 4.2. Mode of Operation . . . . . . . . . . . . . . . . . . . . 7
5. PCEP Protocol Extensions . . . . . . . . . . . . . . . . . . . 9 5. PCEP Protocol Extensions . . . . . . . . . . . . . . . . . . . 9
6. VSPT Encoding . . . . . . . . . . . . . . . . . . . . . . . . 9 6. VSPT Encoding . . . . . . . . . . . . . . . . . . . . . . . . 10
7. Inter-AS TE Links . . . . . . . . . . . . . . . . . . . . . . 10 7. Inter-AS TE Links . . . . . . . . . . . . . . . . . . . . . . 10
8. Usage In Conjunction With Per-domain Path Computation . . . . 11 8. Usage In Conjunction With Per-domain Path Computation . . . . 11
9. BRPC Procedure Completion Failure . . . . . . . . . . . . . . 11 9. BRPC Procedure Completion Failure . . . . . . . . . . . . . . 11
10. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 11 10. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 12
10.1. Diverse end-to-end path computation . . . . . . . . . . . 12 10.1. Diverse end-to-end path computation . . . . . . . . . . . 12
10.2. Path Optimality . . . . . . . . . . . . . . . . . . . . . 12 10.2. Path Optimality . . . . . . . . . . . . . . . . . . . . . 12
11. Reoptimization Of An Inter-domain TE LSP . . . . . . . . . . . 12 11. Reoptimization Of An Inter-domain TE LSP . . . . . . . . . . . 13
12. Path Computation Failure . . . . . . . . . . . . . . . . . . . 13 12. Path Computation Failure . . . . . . . . . . . . . . . . . . . 13
13. Metric Normalization . . . . . . . . . . . . . . . . . . . . . 13 13. Metric Normalization . . . . . . . . . . . . . . . . . . . . . 13
14. Manageability Considerations . . . . . . . . . . . . . . . . . 13 14. Manageability Considerations . . . . . . . . . . . . . . . . . 14
14.1. Control of Function And Policy . . . . . . . . . . . . . . 13 14.1. Control of Function And Policy . . . . . . . . . . . . . . 14
14.2. Information And Data Models . . . . . . . . . . . . . . . 14 14.2. Information And Data Models . . . . . . . . . . . . . . . 14
14.3. Liveness Detection and Monitoring . . . . . . . . . . . . 14 14.3. Liveness Detection and Monitoring . . . . . . . . . . . . 14
14.4. Verifying Correct Operation . . . . . . . . . . . . . . . 14 14.4. Verifying Correct Operation . . . . . . . . . . . . . . . 14
14.5. Requirements on Other Protocols and Functional 14.5. Requirements on Other Protocols and Functional
Components . . . . . . . . . . . . . . . . . . . . . . . . 14 Components . . . . . . . . . . . . . . . . . . . . . . . . 15
14.6. Impact on Network Operation . . . . . . . . . . . . . . . 14 14.6. Impact on Network Operation . . . . . . . . . . . . . . . 15
14.7. Path Computation Chain Monitoring . . . . . . . . . . . . 15 14.7. Path Computation Chain Monitoring . . . . . . . . . . . . 15
15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
15.1. New Flag Of The RP Object . . . . . . . . . . . . . . . . 15 15.1. New Flag Of The RP Object . . . . . . . . . . . . . . . . 15
15.2. New Error-Type And Error-Value . . . . . . . . . . . . . . 15 15.2. New Error-Type And Error-Value . . . . . . . . . . . . . . 15
15.3. New Flag Of The NO-PATH-VECTOR TLV . . . . . . . . . . . . 15 15.3. New Flag Of The NO-PATH-VECTOR TLV . . . . . . . . . . . . 16
16. Security Considerations . . . . . . . . . . . . . . . . . . . 16 16. Security Considerations . . . . . . . . . . . . . . . . . . . 16
17. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 16 17. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 16
18. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 18. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16
18.1. Normative References . . . . . . . . . . . . . . . . . . . 16 18.1. Normative References . . . . . . . . . . . . . . . . . . . 16
18.2. Informative References . . . . . . . . . . . . . . . . . . 16 18.2. Informative References . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18
Intellectual Property and Copyright Statements . . . . . . . . . . 19 Intellectual Property and Copyright Statements . . . . . . . . . . 20
1. Introduction 1. Introduction
The requirements for inter-area and inter-AS MPLS Traffic Engineering The requirements for inter-area and inter-AS MPLS Traffic Engineering
(TE) have been developed by the Traffic Engineering Working Group (TE (TE) have been developed by the Traffic Engineering Working Group (TE
WG) and have been stated in [RFC4105] and [RFC4216], respectively. WG) and have been stated in [RFC4105] and [RFC4216], respectively.
The framework for inter-domain Multiprotocol Label Switching (MPLS) The framework for inter-domain Multiprotocol Label Switching (MPLS)
Traffic Engineering (TE) has been provided in [RFC4726]. Traffic Engineering (TE) has been provided in [RFC4726].
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Each branch of the VSPT tree (path) may be returned in the form of an Each branch of the VSPT tree (path) may be returned in the form of an
explicit path (in which case all the hops along the path segment are explicit path (in which case all the hops along the path segment are
listed) or a loose path (in which case only the BN is specified) so listed) or a loose path (in which case only the BN is specified) so
as to preserve confidentiality along with the respective cost. In as to preserve confidentiality along with the respective cost. In
the later case, various techniques can be used in order to retrieve the later case, various techniques can be used in order to retrieve
the computed explicit paths on a per domain basis during the the computed explicit paths on a per domain basis during the
signaling process thanks to the use of path keys as described in signaling process thanks to the use of path keys as described in
[I-D.ietf-pce-path-key]. [I-D.ietf-pce-path-key].
A PCE that can compute the requested path for more than one
consecutive domain on the path SHOULD perform this computation for
all such domains before passing the PCRep to the previous PCE in the
sequence.
BRPC guarantees to find the optimal (shortest) constrained inter- BRPC guarantees to find the optimal (shortest) constrained inter-
domain TE LSP according to a set of defined domains to be traversed. domain TE LSP according to a set of defined domains to be traversed.
Note that other variants of the BRPC procedure relying on the same Note that other variants of the BRPC procedure relying on the same
principles are also possible. principles are also possible.
Note also that in case of ECMP paths, more than one path could be Note also that in case of ECMP paths, more than one path could be
returned to the requesting LSR. returned to the requesting LSR.
5. PCEP Protocol Extensions 5. PCEP Protocol Extensions
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Y., Kumaki, K., Vasseur, J., and J. Roux, "Path Y., Kumaki, K., Vasseur, J., and J. Roux, "Path
Computation Element (PCE) Communication Protocol (PCEP)", Computation Element (PCE) Communication Protocol (PCEP)",
draft-ietf-pce-pcep-12 (work in progress), March 2008. draft-ietf-pce-pcep-12 (work in progress), March 2008.
[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.
18.2. Informative References 18.2. Informative References
[I-D.ietf-ccamp-isis-interas-te-extension] [I-D.ietf-ccamp-isis-interas-te-extension]
Chen, M. and R. Zhang, "ISIS Extensions in Support of Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in
Inter-AS Multiprotocol Label Switching (MPLS) and Support of Inter-AS Multiprotocol Label Switching (MPLS)
Generalized MPLS (GMPLS) Traffic Engineering", and Generalized MPLS (GMPLS) Traffic Engineering",
draft-ietf-ccamp-isis-interas-te-extension-00 (work in draft-ietf-ccamp-isis-interas-te-extension-02 (work in
progress), February 2008. progress), April 2008.
[I-D.ietf-ccamp-ospf-interas-te-extension] [I-D.ietf-ccamp-ospf-interas-te-extension]
Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in
Support of Inter-AS Multiprotocol Label Switching (MPLS) Support of Inter-AS Multiprotocol Label Switching (MPLS)
and Generalized MPLS (GMPLS) Traffic Engineering", and Generalized MPLS (GMPLS) Traffic Engineering",
draft-ietf-ccamp-ospf-interas-te-extension-02 (work in draft-ietf-ccamp-ospf-interas-te-extension-05 (work in
progress), November 2007. progress), April 2008.
[I-D.ietf-pce-manageability-requirements] [I-D.ietf-pce-manageability-requirements]
Farrel, A., "Inclusion of Manageability Sections in PCE Farrel, A., "Inclusion of Manageability Sections in PCE
Working Group Drafts", Working Group Drafts",
draft-ietf-pce-manageability-requirements-03 (work in draft-ietf-pce-manageability-requirements-03 (work in
progress), February 2008. progress), February 2008.
[I-D.ietf-pce-monitoring] [I-D.ietf-pce-monitoring]
Vasseur, J., Roux, J., and Y. Ikejiri, "A set of Vasseur, J., Roux, J., and Y. Ikejiri, "A set of
monitoring tools for Path Computation Element based monitoring tools for Path Computation Element based
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