draft-ietf-pce-segment-routing-09.txt   draft-ietf-pce-segment-routing-10.txt 
PCE S. Sivabalan PCE S. Sivabalan
Internet-Draft C. Filsfils Internet-Draft C. Filsfils
Intended status: Standards Track Cisco Systems, Inc. Intended status: Standards Track Cisco Systems, Inc.
Expires: October 12, 2017 J. Tantsura Expires: April 13, 2018 J. Tantsura
Individual Individual
W. Henderickx W. Henderickx
Nokia Nokia
J. Hardwick J. Hardwick
Metaswitch Networks Metaswitch Networks
April 10, 2017 October 10, 2017
PCEP Extensions for Segment Routing PCEP Extensions for Segment Routing
draft-ietf-pce-segment-routing-09 draft-ietf-pce-segment-routing-10
Abstract Abstract
Segment Routing (SR) enables any head-end node to select any path Segment Routing (SR) enables any head-end node to select any path
without relying on a hop-by-hop signaling technique (e.g., LDP or without relying on a hop-by-hop signaling technique (e.g., LDP or
RSVP-TE). It depends only on "segments" that are advertised by Link- RSVP-TE). It depends only on "segments" that are advertised by Link-
State Interior Gateway Protocols (IGPs). A Segment Routed Path can State Interior Gateway Protocols (IGPs). A Segment Routed Path can
be derived from a variety of mechanisms, including an IGP Shortest be derived from a variety of mechanisms, including an IGP Shortest
Path Tree (SPT), explicit configuration, or a Path Computation Path Tree (SPT), explicit configuration, or a Path Computation
Element (PCE). This document specifies extensions to the Path Element (PCE). This document specifies extensions to the Path
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document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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
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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
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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 October 12, 2017. This Internet-Draft will expire on April 13, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
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12.1. Normative References . . . . . . . . . . . . . . . . . . 18 12.1. Normative References . . . . . . . . . . . . . . . . . . 18
12.2. Informative References . . . . . . . . . . . . . . . . . 19 12.2. Informative References . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20
1. Introduction 1. Introduction
SR technology leverages the source routing and tunneling paradigms. SR technology leverages the source routing and tunneling paradigms.
A source node can choose a path without relying on hop-by-hop A source node can choose a path without relying on hop-by-hop
signaling protocols such as LDP or RSVP-TE. Each path is specified signaling protocols such as LDP or RSVP-TE. Each path is specified
as a set of "segments" advertised by link-state routing protocols as a set of "segments" advertised by link-state routing protocols
(IS-IS or OSPF). [I-D.filsfils-rtgwg-segment-routing] provides an (IS-IS or OSPF). [I-D.ietf-spring-segment-routing] provides an
introduction to SR architecture. The corresponding IS-IS and OSPF introduction to SR architecture. The corresponding IS-IS and OSPF
extensions are specified in extensions are specified in
[I-D.ietf-isis-segment-routing-extensions] and [I-D.ietf-isis-segment-routing-extensions] and
[I-D.ietf-ospf-segment-routing-extensions], respectively. SR [I-D.ietf-ospf-segment-routing-extensions], respectively. SR
architecture defines a "segment" as a piece of information advertised architecture defines a "segment" as a piece of information advertised
by a link-state routing protocols, e.g. an IGP prefix or an IGP by a link-state routing protocols, e.g. an IGP prefix or an IGP
adjacency. Several types of segments are defined. A Node segment adjacency. Several types of segments are defined. A Node segment
represents an ECMP-aware shortest-path computed by IGP to a specific represents an ECMP-aware shortest-path computed by IGP to a specific
node, and is always global within SR/IGP domain. An Adjacency node, and is always global within SR/IGP domain. An Adjacency
Segment represents unidirectional adjacency. An Adjacency Segment is Segment represents unidirectional adjacency. An Adjacency Segment is
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The number of SIDs that can be imposed on a packet depends on PCC's The number of SIDs that can be imposed on a packet depends on PCC's
data plane's capability. An MSD value MUST be non-zero otherwise the data plane's capability. An MSD value MUST be non-zero otherwise the
receiver of the SR-PCE-CAPABILITY TLV MUST assume that the sender is receiver of the SR-PCE-CAPABILITY TLV MUST assume that the sender is
not capable of imposing a MSD of any depth and hence is not SR-TE not capable of imposing a MSD of any depth and hence is not SR-TE
capable. capable.
Note that the MSD value exchanged via SR-PCE-CAPABILITY TLV indicates Note that the MSD value exchanged via SR-PCE-CAPABILITY TLV indicates
the SID/label imposition limit for the PCC node. However, if a PCE the SID/label imposition limit for the PCC node. However, if a PCE
learns MSD value of a PCC node via different means, e.g routing learns MSD value of a PCC node via different means, e.g routing
protocols, as specified in: [I-D.tantsura-isis-segment-routing-msd]; protocols, as specified in: [I-D.ietf-isis-segment-routing-msd];
[I-D.tantsura-ospf-segment-routing-msd]; [I-D.ietf-ospf-segment-routing-msd];
[I-D.tantsura-idr-bgp-ls-segment-routing-msd], then it ignores the [I-D.tantsura-idr-bgp-ls-segment-routing-msd], then it ignores the
MSD value in the SR-PCE-CAPABILITY TLV. Furthermore, whenever a PCE MSD value in the SR-PCE-CAPABILITY TLV. Furthermore, whenever a PCE
learns MSD for a link via different means, it MUST use that value for learns MSD for a link via different means, it MUST use that value for
that link regardless of the MSD value exchanged via SR-PCE-CAPABILITY that link regardless of the MSD value exchanged via SR-PCE-CAPABILITY
TLV. TLV.
Once an SR-capable PCEP session is established with a non-zero MSD Once an SR-capable PCEP session is established with a non-zero MSD
value, the corresponding PCE MUST NOT send SR-TE paths with number of value, the corresponding PCE MUST NOT send SR-TE paths with number of
SIDs exceeding that MSD value. If a PCC needs to modify the MSD SIDs exceeding that MSD value. If a PCC needs to modify the MSD
value, the PCEP session MUST be closed and re-established with the value, the PCEP session MUST be closed and re-established with the
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PCEP implementation: PCEP implementation:
o Can enable SR PCEP capability either by default or via explicit o Can enable SR PCEP capability either by default or via explicit
configuration. configuration.
o May generate PCEP error due to unsupported number of SR-ERO or SR- o May generate PCEP error due to unsupported number of SR-ERO or SR-
RRO subobjects either by default or via explicit configuration. RRO subobjects either by default or via explicit configuration.
7.2. The PCEP Data Model 7.2. The PCEP Data Model
A PCEP MIB module is defined in [I-D.ietf-pce-pcep-mib] needs be A PCEP MIB module is defined in [RFC7420]needs be extended to cover
extended to cover additional functionality provided by [RFC5440] and additional functionality provided by [RFC5440] and
[I-D.ietf-pce-pce-initiated-lsp]. Such extension will cover the new [I-D.ietf-pce-pce-initiated-lsp]. Such extension will cover the new
functionality specified in this document. functionality specified in this document.
8. Security Considerations 8. Security Considerations
The security considerations described in [RFC5440] and The security considerations described in [RFC5440] and
[I-D.ietf-pce-pce-initiated-lsp] are applicable to this [I-D.ietf-pce-pce-initiated-lsp] are applicable to this
specification. No additional security measure is required. specification. No additional security measure is required.
9. IANA Considerations 9. IANA Considerations
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11. Acknowledgements 11. Acknowledgements
We like to thank Ina Minei, George Swallow, Marek Zavodsky, Dhruv We like to thank Ina Minei, George Swallow, Marek Zavodsky, Dhruv
Dhody, Ing-Wher Chen and Tomas Janciga for the valuable comments. Dhody, Ing-Wher Chen and Tomas Janciga for the valuable comments.
12. References 12. References
12.1. Normative References 12.1. Normative References
[I-D.filsfils-rtgwg-segment-routing]
Filsfils, C., Previdi, S., Bashandy, A., Decraene, B.,
Litkowski, S., Horneffer, M., Milojevic, I., Shakir, R.,
Ytti, S., Henderickx, W., Tantsura, J., and E. Crabbe,
"Segment Routing Architecture", draft-filsfils-rtgwg-
segment-routing-01 (work in progress), October 2013.
[I-D.ietf-isis-segment-routing-extensions] [I-D.ietf-isis-segment-routing-extensions]
Previdi, S., Filsfils, C., Bashandy, A., Gredler, H., Previdi, S., Filsfils, C., Bashandy, A., Gredler, H.,
Litkowski, S., and J. Tantsura, "IS-IS Extensions for Litkowski, S., Decraene, B., and j. jefftant@gmail.com,
Segment Routing", draft-ietf-isis-segment-routing- "IS-IS Extensions for Segment Routing", draft-ietf-isis-
extensions-00 (work in progress), April 2014. segment-routing-extensions-11 (work in progress), March
2017.
[I-D.ietf-isis-segment-routing-msd]
Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg,
"Signaling MSD (Maximum SID Depth) using IS-IS", draft-
ietf-isis-segment-routing-msd-03 (work in progress), March
2017.
[I-D.ietf-ospf-segment-routing-extensions] [I-D.ietf-ospf-segment-routing-extensions]
Psenak, P., Previdi, S., Filsfils, C., Gredler, H., Psenak, P., Previdi, S., Filsfils, C., Gredler, H.,
Shakir, R., Henderickx, W., and J. Tantsura, "OSPF Shakir, R., Henderickx, W., and J. Tantsura, "OSPF
Extensions for Segment Routing", draft-ietf-ospf-segment- Extensions for Segment Routing", draft-ietf-ospf-segment-
routing-extensions-00 (work in progress), June 2014. routing-extensions-12 (work in progress), March 2017.
[I-D.ietf-ospf-segment-routing-msd]
Tantsura, J., Chunduri, U., Aldrin, S., and P. Psenak,
"Signaling MSD (Maximum SID Depth) using OSPF", draft-
ietf-ospf-segment-routing-msd-04 (work in progress), March
2017.
[I-D.ietf-pce-lsp-setup-type] [I-D.ietf-pce-lsp-setup-type]
Sivabalan, S., Medved, J., Minei, I., Crabbe, E., and R. Sivabalan, S., Medved, J., Minei, I., Crabbe, E., Varga,
Varga, "Conveying path setup type in PCEP messages", R., Tantsura, J., and J. Hardwick, "Conveying path setup
draft-ietf-pce-lsp-setup-type-00 (work in progress), type in PCEP messages", draft-ietf-pce-lsp-setup-type-03
October 2014. (work in progress), June 2015.
[I-D.ietf-pce-pce-initiated-lsp] [I-D.ietf-pce-pce-initiated-lsp]
Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "PCEP Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "PCEP
Extensions for PCE-initiated LSP Setup in a Stateful PCE Extensions for PCE-initiated LSP Setup in a Stateful PCE
Model", draft-ietf-pce-pce-initiated-lsp-01 (work in Model", draft-ietf-pce-pce-initiated-lsp-09 (work in
progress), June 2014. progress), March 2017.
[I-D.ietf-pce-pcep-mib]
Koushik, K., Stephan, E., Zhao, Q., King, D., and J.
Hardwick, "PCE communication protocol (PCEP) Management
Information Base", draft-ietf-pce-pcep-mib-04 (work in
progress), February 2013.
[I-D.ietf-pce-stateful-pce] [I-D.ietf-pce-stateful-pce]
Crabbe, E., Medved, J., Minei, I., and R. Varga, "PCEP Crabbe, E., Minei, I., Medved, J., and R. Varga, "PCEP
Extensions for Stateful PCE", draft-ietf-pce-stateful- Extensions for Stateful PCE", draft-ietf-pce-stateful-
pce-05 (work in progress), July 2013. pce-18 (work in progress), December 2016.
[I-D.ietf-spring-segment-routing]
Filsfils, C., Previdi, S., Decraene, B., Litkowski, S.,
and R. Shakir, "Segment Routing Architecture", draft-ietf-
spring-segment-routing-11 (work in progress), February
2017.
[I-D.tantsura-idr-bgp-ls-segment-routing-msd] [I-D.tantsura-idr-bgp-ls-segment-routing-msd]
Tantsura, J., Mirsky, G., Sivabalan, S., and U. Chunduri, Tantsura, J., Chunduri, U., Mirsky, G., and S. Sivabalan,
"Signaling Maximum SID Depth using Border Gateway Protocol "Signaling Maximum SID Depth using Border Gateway Protocol
Link-State", draft-tantsura-idr-bgp-ls-segment-routing- Link-State", draft-tantsura-idr-bgp-ls-segment-routing-
msd-01 (work in progress), July 2016. msd-02 (work in progress), January 2017.
[I-D.tantsura-isis-segment-routing-msd]
Tantsura, J. and U. Chunduri, "Signaling MSD (Maximum SID
Depth) using IS-IS", draft-tantsura-isis-segment-routing-
msd-01 (work in progress), July 2016.
[I-D.tantsura-ospf-segment-routing-msd]
Tantsura, J. and U. Chunduri, "Signaling MSD (Maximum SID
Depth) using OSPF", draft-tantsura-ospf-segment-routing-
msd-01 (work in progress), September 2016.
[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, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[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>. <https://www.rfc-editor.org/info/rfc5440>.
[RFC5462] Andersson, L. and R. Asati, "Multiprotocol Label Switching [RFC5462] Andersson, L. and R. Asati, "Multiprotocol Label Switching
(MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic (MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic
Class" Field", RFC 5462, DOI 10.17487/RFC5462, February Class" Field", RFC 5462, DOI 10.17487/RFC5462, February
2009, <http://www.rfc-editor.org/info/rfc5462>. 2009, <https://www.rfc-editor.org/info/rfc5462>.
[RFC7420] Koushik, A., Stephan, E., Zhao, Q., King, D., and J.
Hardwick, "Path Computation Element Communication Protocol
(PCEP) Management Information Base (MIB) Module",
RFC 7420, DOI 10.17487/RFC7420, December 2014,
<https://www.rfc-editor.org/info/rfc7420>.
12.2. Informative References 12.2. Informative 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>. <https://www.rfc-editor.org/info/rfc3209>.
[RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label [RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Resource ReserVation Protocol- Switching (GMPLS) Signaling Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE) Extensions", RFC 3473, Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
DOI 10.17487/RFC3473, January 2003, DOI 10.17487/RFC3473, January 2003,
<http://www.rfc-editor.org/info/rfc3473>. <https://www.rfc-editor.org/info/rfc3473>.
[RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links [RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links
in Resource ReSerVation Protocol - Traffic Engineering in Resource ReSerVation Protocol - Traffic Engineering
(RSVP-TE)", RFC 3477, DOI 10.17487/RFC3477, January 2003, (RSVP-TE)", RFC 3477, DOI 10.17487/RFC3477, January 2003,
<http://www.rfc-editor.org/info/rfc3477>. <https://www.rfc-editor.org/info/rfc3477>.
[RFC4657] Ash, J., Ed. and J. Le Roux, Ed., "Path Computation [RFC4657] Ash, J., Ed. and J. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol Generic Element (PCE) Communication Protocol Generic
Requirements", RFC 4657, DOI 10.17487/RFC4657, September Requirements", RFC 4657, DOI 10.17487/RFC4657, September
2006, <http://www.rfc-editor.org/info/rfc4657>. 2006, <https://www.rfc-editor.org/info/rfc4657>.
Authors' Addresses Authors' Addresses
Siva Sivabalan Siva Sivabalan
Cisco Systems, Inc. Cisco Systems, Inc.
2000 Innovation Drive 2000 Innovation Drive
Kanata, Ontario K2K 3E8 Kanata, Ontario K2K 3E8
Canada Canada
Email: msiva@cisco.com Email: msiva@cisco.com
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