< 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
	skipping to change at page 1, line 45 ¶		skipping to change at page 1, line 45 ¶
	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
	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 https://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 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.
	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		(https://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
	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
	skipping to change at page 3, line 18 ¶		skipping to change at page 3, line 18 ¶
	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
	skipping to change at page 8, line 10 ¶		skipping to change at page 8, line 10 ¶
	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
	skipping to change at page 15, line 37 ¶		skipping to change at page 15, line 37 ¶
	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
	skipping to change at page 18, line 9 ¶		skipping to change at page 18, line 9 ¶
	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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