< draft-ietf-idr-bgp-ls-segment-routing-msd-13.txt		draft-ietf-idr-bgp-ls-segment-routing-msd-14.txt >
	IDR Working Group J. Tantsura		IDR Working Group J. Tantsura
	Internet-Draft Apstra, Inc.		Internet-Draft Apstra, Inc.
	Intended status: Standards Track U. Chunduri		Intended status: Standards Track U. Chunduri
	Expires: September 4, 2020 Futurewei Technologies		Expires: September 10, 2020 Futurewei Technologies
	K. Talaulikar		K. Talaulikar
	Cisco Systems		Cisco Systems
	G. Mirsky		G. Mirsky
	ZTE Corp.		ZTE Corp.
	N. Triantafillis		N. Triantafillis
	Amazon Web Services		Amazon Web Services
	March 3, 2020		March 9, 2020
	Signaling MSD (Maximum SID Depth) using Border Gateway Protocol - Link		Signaling MSD (Maximum SID Depth) using Border Gateway Protocol - Link
	State		State
	draft-ietf-idr-bgp-ls-segment-routing-msd-13		draft-ietf-idr-bgp-ls-segment-routing-msd-14
	Abstract		Abstract
	This document defines a way for a Border Gateway Protocol - Link		This document defines a way for a Border Gateway Protocol - Link
	State (BGP-LS) speaker to advertise multiple types of supported		State (BGP-LS) speaker to advertise multiple types of supported
	Maximum SID Depths (MSDs) at node and/or link granularity.		Maximum SID Depths (MSDs) at node and/or link granularity.
	Such advertisements allow entities (e.g., centralized controllers) to		Such advertisements allow entities (e.g., centralized controllers) to
	determine whether a particular Segment Identifier (SID) stack can be		determine whether a particular Segment Identifier (SID) stack can be
	supported in a given network.		supported in a given network.
	skipping to change at page 1, line 44 ¶		skipping to change at page 1, line 44 ¶
	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 https://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 September 4, 2020.		This Internet-Draft will expire on September 10, 2020.
	Copyright Notice		Copyright Notice
	Copyright (c) 2020 IETF Trust and the persons identified as the		Copyright (c) 2020 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
	(https://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
	skipping to change at page 3, line 41 ¶		skipping to change at page 3, line 41 ¶
	link on a node		link on a node
	PCC: Path Computation Client		PCC: Path Computation Client
	PCE: Path Computation Element		PCE: Path Computation Element
	PCEP: Path Computation Element Protocol		PCEP: Path Computation Element Protocol
	SID: Segment Identifier as defined in [RFC8402]		SID: Segment Identifier as defined in [RFC8402]
	SR: Segment routing		SR: Segment Routing
	Label Imposition: Imposition is the act of modifying and/or adding		Label Imposition: Imposition is the act of modifying and/or adding
	labels to the outgoing label stack associated with a packet. This		labels to the outgoing label stack associated with a packet. This
	includes:		includes:
	o replacing the label at the top of the label stack with a new		o replacing the label at the top of the label stack with a new
	label.		label.
	o pushing one or more new labels onto the label stack.		o pushing one or more new labels onto the label stack.
	skipping to change at page 7, line 26 ¶		skipping to change at page 7, line 26 ¶
	left to the consumer of the BGP-LS information (e.g. an application		left to the consumer of the BGP-LS information (e.g. an application
	or a controller) and not the BGP protocol.		or a controller) and not the BGP protocol.
	A consumer of the BGP-LS information retrieves this information over		A consumer of the BGP-LS information retrieves this information over
	a BGP-LS session (refer Section 1 and 2 of [RFC7752]).		a BGP-LS session (refer Section 1 and 2 of [RFC7752]).
	This document only introduces new Attribute TLVs and any syntactic		This document only introduces new Attribute TLVs and any syntactic
	error in them would result in the BGP-LS Attribute being discarded		error in them would result in the BGP-LS Attribute being discarded
	[RFC7752]. The MSD information introduced in BGP-LS by this		[RFC7752]. The MSD information introduced in BGP-LS by this
	specification, may be used by BGP-LS consumer applications like a SR		specification, may be used by BGP-LS consumer applications like a SR
	path computation engine (PCE) to learn the SR SID-stack handling		path computation engine (PCE) to learn the SR SID stack handling
	capabilities of the nodes in the topology. This can enable the SR		capabilities of the nodes in the topology. This can enable the SR
	PCE to perform path computations taking into consideration the size		PCE to perform path computations taking into consideration the size
	of SID Stack that the specific headend node may be able to impose.		of SID stack that the specific head-end node may be able to impose.
	Errors in the encoding or decoding of the MSD information may result		Errors in the encoding or decoding of the MSD information may result
	in the unavailability of such information to the SR PCE or incorrect		in the unavailability of such information to the SR PCE or incorrect
	information being made available to it. This may result in the		information being made available to it. This may result in the head-
	headend node not being able to instantiate the desired SR path in its		end node not being able to instantiate the desired SR path in its
	forwarding and provide the SR based optimization functionality. The		forwarding and provide the SR based optimization functionality. The
	handling of such errors by applications like SR PCE may be		handling of such errors by applications like SR PCE may be
	implementation specific and out of scope of this document.		implementation specific and out of scope of this document.
	The extensions specified in this document, do not specify any new		The extensions specified in this document, do not specify any new
	configuration or monitoring aspects in BGP or BGP-LS. The		configuration or monitoring aspects in BGP or BGP-LS. The
	specification of BGP models is an ongoing work based on the		specification of BGP models is an ongoing work based on the
	[I-D.ietf-idr-bgp-model].		[I-D.ietf-idr-bgp-model].
	8. Security Considerations		8. Security Considerations
	skipping to change at page 8, line 30 ¶		skipping to change at page 8, line 30 ¶
	9. Contributors		9. Contributors
	Siva Sivabalan		Siva Sivabalan
	Cisco Systems Inc.		Cisco Systems Inc.
	Canada		Canada
	Email: msiva@cisco.com		Email: msiva@cisco.com
	10. Acknowledgements		10. Acknowledgements
	We like to thank Acee Lindem, Stephane Litkowski and Bruno Decraene		We like to thank Acee Lindem, Stephane Litkowski, Bruno Decraene and
	for their reviews and valuable comments.		Alvaro Retana for their reviews and valuable comments.
	11. References		11. References
	11.1. Normative References		11.1. 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,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<https://www.rfc-editor.org/info/rfc2119>.		<https://www.rfc-editor.org/info/rfc2119>.
	skipping to change at page 9, line 20 ¶		skipping to change at page 9, line 20 ¶
	[RFC8491] Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg,		[RFC8491] Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg,
	"Signaling Maximum SID Depth (MSD) Using IS-IS", RFC 8491,		"Signaling Maximum SID Depth (MSD) Using IS-IS", RFC 8491,
	DOI 10.17487/RFC8491, November 2018,		DOI 10.17487/RFC8491, November 2018,
	<https://www.rfc-editor.org/info/rfc8491>.		<https://www.rfc-editor.org/info/rfc8491>.
	11.2. Informative References		11.2. Informative References
	[I-D.ietf-idr-bgp-model]		[I-D.ietf-idr-bgp-model]
	Jethanandani, M., Patel, K., Hares, S., and J. Haas, "BGP		Jethanandani, M., Patel, K., Hares, S., and J. Haas, "BGP
	YANG Model for Service Provider Networks", draft-ietf-idr-		YANG Model for Service Provider Networks", draft-ietf-idr-
	bgp-model-07 (work in progress), October 2019.		bgp-model-08 (work in progress), February 2020.
	[I-D.ietf-idr-rfc7752bis]		[I-D.ietf-idr-rfc7752bis]
	Talaulikar, K., "Distribution of Link-State and Traffic		Talaulikar, K., "Distribution of Link-State and Traffic
	Engineering Information Using BGP", draft-ietf-idr-		Engineering Information Using BGP", draft-ietf-idr-
	rfc7752bis-02 (work in progress), November 2019.		rfc7752bis-02 (work in progress), November 2019.
	[I-D.ietf-isis-mpls-elc]		[I-D.ietf-isis-mpls-elc]
	Xu, X., Kini, S., Psenak, P., Filsfils, C., Litkowski, S.,		Xu, X., Kini, S., Psenak, P., Filsfils, C., Litkowski, S.,
	and M. Bocci, "Signaling Entropy Label Capability and		and M. Bocci, "Signaling Entropy Label Capability and
	Entropy Readable Label Depth Using IS-IS", draft-ietf-		Entropy Readable Label Depth Using IS-IS", draft-ietf-
	isis-mpls-elc-10 (work in progress), October 2019.		isis-mpls-elc-10 (work in progress), October 2019.
	[I-D.ietf-isis-sr-yang]
	Litkowski, S., Qu, Y., Sarkar, P., Chen, I., and J.
	Tantsura, "YANG Data Model for IS-IS Segment Routing",
	draft-ietf-isis-sr-yang-07 (work in progress), January
	2020.
	[I-D.ietf-ospf-mpls-elc]		[I-D.ietf-ospf-mpls-elc]
	Xu, X., Kini, S., Psenak, P., Filsfils, C., Litkowski, S.,		Xu, X., Kini, S., Psenak, P., Filsfils, C., Litkowski, S.,
	and M. Bocci, "Signaling Entropy Label Capability and		and M. Bocci, "Signaling Entropy Label Capability and
	Entropy Readable Label-stack Depth Using OSPF", draft-		Entropy Readable Label-stack Depth Using OSPF", draft-
	ietf-ospf-mpls-elc-12 (work in progress), October 2019.		ietf-ospf-mpls-elc-12 (work in progress), October 2019.
	[I-D.ietf-ospf-sr-yang]
	Yeung, D., Qu, Y., Zhang, Z., Chen, I., and A. Lindem,
	"YANG Data Model for OSPF SR (Segment Routing) Protocol",
	draft-ietf-ospf-sr-yang-11 (work in progress), February
	2020.
	[I-D.ietf-spring-sr-yang]
	Litkowski, S., Qu, Y., Lindem, A., Sarkar, P., and J.
	Tantsura, "YANG Data Model for Segment Routing", draft-
	ietf-spring-sr-yang-15 (work in progress), January 2020.
	[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol		[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
	Label Switching Architecture", RFC 3031,		Label Switching Architecture", RFC 3031,
	DOI 10.17487/RFC3031, January 2001,		DOI 10.17487/RFC3031, January 2001,
	<https://www.rfc-editor.org/info/rfc3031>.		<https://www.rfc-editor.org/info/rfc3031>.
	[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A		[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
	Border Gateway Protocol 4 (BGP-4)", RFC 4271,		Border Gateway Protocol 4 (BGP-4)", RFC 4271,
	DOI 10.17487/RFC4271, January 2006,		DOI 10.17487/RFC4271, January 2006,
	<https://www.rfc-editor.org/info/rfc4271>.		<https://www.rfc-editor.org/info/rfc4271>.
End of changes. 12 change blocks.
	29 lines changed or deleted		12 lines changed or added
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