< draft-ietf-isis-segment-routing-extensions-14.txt		draft-ietf-isis-segment-routing-extensions-15.txt >
	IS-IS for IP Internets S. Previdi, Ed.		IS-IS for IP Internets S. Previdi, Ed.
	Internet-Draft L. Ginsberg, Ed.		Internet-Draft L. Ginsberg, Ed.
	Intended status: Standards Track C. Filsfils		Intended status: Standards Track C. Filsfils
	Expires: June 18, 2018 A. Bashandy		Expires: June 22, 2018 A. Bashandy
	Cisco Systems, Inc.		Cisco Systems, Inc.
	H. Gredler		H. Gredler
	RtBrick Inc.		RtBrick Inc.
	S. Litkowski		S. Litkowski
	B. Decraene		B. Decraene
	Orange		Orange
	J. Tantsura		J. Tantsura
	Individual		Individual
	December 15, 2017		December 19, 2017
	IS-IS Extensions for Segment Routing		IS-IS Extensions for Segment Routing
	draft-ietf-isis-segment-routing-extensions-14		draft-ietf-isis-segment-routing-extensions-15
	Abstract		Abstract
	Segment Routing (SR) allows for a flexible definition of end-to-end		Segment Routing (SR) allows for a flexible definition of end-to-end
	paths within IGP topologies by encoding paths as sequences of		paths within IGP topologies by encoding paths as sequences of
	topological sub-paths, called "segments". These segments are		topological sub-paths, called "segments". These segments are
	advertised by the link-state routing protocols (IS-IS and OSPF).		advertised by the link-state routing protocols (IS-IS and OSPF).
	This draft describes the necessary IS-IS extensions that need to be		This draft describes the necessary IS-IS extensions that need to be
	introduced for Segment Routing operating on an MPLS data-plane.		introduced for Segment Routing operating on an MPLS data-plane.
	skipping to change at page 2, line 4 ¶		skipping to change at page 2, line 4 ¶
	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 June 18, 2018.		This Internet-Draft will expire on June 22, 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
	(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 12, line 52 ¶		skipping to change at page 12, line 52 ¶
	A label is encoded in 3 octets (in the 20 rightmost bits).		A label is encoded in 3 octets (in the 20 rightmost bits).
	An index is encoded in 4 octets.		An index is encoded in 4 octets.
	2.3. SID/Label Sub-TLV		2.3. SID/Label Sub-TLV
	The SID/Label sub-TLV may be present in the following TLVs/sub-TLVs		The SID/Label sub-TLV may be present in the following TLVs/sub-TLVs
	defined in this document:		defined in this document:
	SR Capability (Section 3.1)		SR-Capabilities Sub-TLV (Section 3.1)
	SRLB (Section 3.3)		SR Local Block Sub-TLV (Section 3.3)
	Binding TLV (Section 2.4)		SID/Label Binding TLV (Section 2.4)
	MT Binding TLV (Section 2.5)		Multi-Topology SID/Label Binding TLV (Section 2.5)
	Note that when used in the SR Capability and SRLB sub-TLVs the code		Note that the code point used in all of the above cases is the SID/
	point used is the same as the sub-TLV code point assigned by IANA in		Label Sub-TLV code point assigned by IANA in the "sub-TLVs for TLV
	the sub-TLVs for TLV 149 and 150 registry.		149 and 150" registry.
	The SID/Label sub-TLV contains a SID or a MPLS Label. The SID/Label		The SID/Label sub-TLV contains a SID or a MPLS Label. The SID/Label
	sub-TLV has the following format:		sub-TLV has the following format:
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Type | Length |		| Type | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| SID/Label (variable) |		| SID/Label (variable) |
	skipping to change at page 17, line 37 ¶		skipping to change at page 17, line 37 ¶
	Only the most significant octets of the Prefix are encoded. (i.e., 1		Only the most significant octets of the Prefix are encoded. (i.e., 1
	octet for prefix length 1 up to 8, 2 octets for prefix length 9 to		octet for prefix length 1 up to 8, 2 octets for prefix length 9 to
	16, 3 octets for prefix length 17 up to 24 and 4 octets for prefix		16, 3 octets for prefix length 17 up to 24 and 4 octets for prefix
	length 25 up to 32, ...., 16 octets for prefix length 113 up to 128).		length 25 up to 32, ...., 16 octets for prefix length 113 up to 128).
	2.4.4. Mapping Server Prefix-SID		2.4.4. Mapping Server Prefix-SID
	The Prefix-SID sub-TLV (suggested value 3) is defined in Section 2.1		The Prefix-SID sub-TLV (suggested value 3) is defined in Section 2.1
	and contains the SID/index/label value associated with the prefix and		and contains the SID/index/label value associated with the prefix and
	range. The Prefix-SID SubTLV MUST be present in the SID/Label		range. The Prefix-SID SubTLV MUST be present in the SID/Label
	Binding TLV.		Binding TLV unless the M-flag is set in the Flags field of the parent
			TLV.
	A node receiving a MS entry for a prefix MUST check the existence of		A node receiving a MS entry for a prefix MUST check the existence of
	such prefix in its link-state database prior to consider and use the		such prefix in its link-state database prior to consider and use the
	associated SID.		associated SID.
	2.4.4.1. Prefix-SID Flags		2.4.4.1. Prefix-SID Flags
	The Prefix-SID flags are defined in Section 2.1. The Mapping Server		The Prefix-SID flags are defined in Section 2.1. The Mapping Server
	MAY advertise a mapping with the N flag set when the prefix being		MAY advertise a mapping with the N flag set when the prefix being
	mapped is known in the link-state topology with a mask length of 32		mapped is known in the link-state topology with a mask length of 32
	skipping to change at page 19, line 45 ¶		skipping to change at page 19, line 45 ¶
	MTID: a 12-bit field containing the non-zero ID of the topology		MTID: a 12-bit field containing the non-zero ID of the topology
	being announced. The TLV MUST be ignored if the ID is zero.		being announced. The TLV MUST be ignored if the ID is zero.
	This is to ensure the consistent view of the standard unicast		This is to ensure the consistent view of the standard unicast
	topology.		topology.
	The other fields and SubTLVs are defined in Section 2.4.		The other fields and SubTLVs are defined in Section 2.4.
	3. Router Capabilities		3. Router Capabilities
			This section defines sub-TLVs which are inserted into the IS-IS
			Router Capability TLV-242 that is defined in [RFC7981].
	3.1. SR-Capabilities Sub-TLV		3.1. SR-Capabilities Sub-TLV
	Segment Routing requires each router to advertise its SR data-plane		Segment Routing requires each router to advertise its SR data-plane
	capability and the range of MPLS label values it uses for Segment		capability and the range of MPLS label values it uses for Segment
	Routing in the case where global SIDs are allocated (i.e., global		Routing in the case where global SIDs are allocated (i.e., global
	indexes). Data-plane capabilities and label ranges are advertised		indexes). Data-plane capabilities and label ranges are advertised
	using the newly defined SR-Capabilities sub-TLV inserted into the IS-		using the newly defined SR-Capabilities sub-TLV.
	IS Router Capability TLV-242 that is defined in [RFC7981].
	The Router Capability TLV specifies flags that control its		The Router Capability TLV specifies flags that control its
	advertisement. The SR Capabilities sub-TLV MUST be propagated		advertisement. The SR Capabilities sub-TLV MUST be propagated
	throughout the level and MUST NOT be advertised across level		throughout the level and MUST NOT be advertised across level
	boundaries. Therefore Router Capability TLV distribution flags are		boundaries. Therefore Router Capability TLV distribution flags are
	set accordingly, i.e., the S flag in the Router Capability TLV		set accordingly, i.e., the S flag in the Router Capability TLV
	([RFC7981]) MUST be unset.		([RFC7981]) MUST be unset.
	The SR Capabilities sub-TLV has following format:		The SR Capabilities sub-TLV has following format:
	skipping to change at page 22, line 51 ¶		skipping to change at page 22, line 51 ¶
	state protocols, algorithm 0 permits any node to overwrite the SPF		state protocols, algorithm 0 permits any node to overwrite the SPF
	path with a different path based on local policy.		path with a different path based on local policy.
	1: Strict Shortest Path First (SPF) algorithm based on link		1: Strict Shortest Path First (SPF) algorithm based on link
	metric. The algorithm is identical to algorithm 0 but algorithm 1		metric. The algorithm is identical to algorithm 0 but algorithm 1
	requires that all nodes along the path will honor the SPF routing		requires that all nodes along the path will honor the SPF routing
	decision. Local policy MUST NOT alter the forwarding decision		decision. Local policy MUST NOT alter the forwarding decision
	computed by algorithm 1 at the node claiming to support algorithm		computed by algorithm 1 at the node claiming to support algorithm
	1.		1.
	The SR-Algorithm sub-TLV is inserted into the IS-IS Router Capability
	TLV-242 that is defined in [RFC7981].
	The Router Capability TLV specifies flags that control its		The Router Capability TLV specifies flags that control its
	advertisement. The SR-Algorithm MUST be propagated throughout the		advertisement. The SR-Algorithm MUST be propagated throughout the
	level and MUST NOT be advertised across level boundaries. Therefore		level and MUST NOT be advertised across level boundaries. Therefore
	Router Capability TLV distribution flags are set accordingly, i.e.,		Router Capability TLV distribution flags are set accordingly, i.e.,
	the S flag MUST be unset.		the S flag MUST be unset.
	The SR-Algorithm sub-TLV is optional, it MAY only appear a single		The SR-Algorithm sub-TLV is optional, it MAY only appear a single
	time inside the Router Capability TLV.		time inside the Router Capability TLV.
	When the originating router does not advertise the SR-Algorithm sub-		When the originating router does not advertise the SR-Algorithm sub-
	skipping to change at page 28, line 6 ¶		skipping to change at page 28, line 6 ¶
	Reference: This document (Section 3.1)		Reference: This document (Section 3.1)
	Type: TBD (suggested value 19)		Type: TBD (suggested value 19)
	Description: Segment Routing Algorithm		Description: Segment Routing Algorithm
	Reference: This document (Section 3.2)		Reference: This document (Section 3.2)
	Type: TBD (suggested value 22)		Type: TBD (suggested value 22)
	Description: Segment Routing Local Base (SRLB)		Description: Segment Routing Local Block (SRLB)
	Reference: This document (Section 3.3)		Reference: This document (Section 3.3)
	Type: TBD (suggested value 24)		Type: TBD (suggested value 24)
	Description: Segment Routing Mapping Server Preference (SRMS		Description: Segment Routing Mapping Server Preference (SRMS
	Preference)		Preference)
	Reference: This document (Section 3.4)		Reference: This document (Section 3.4)
	skipping to change at page 32, line 29 ¶		skipping to change at page 32, line 29 ¶
	[RFC7981] Ginsberg, L., Previdi, S., and M. Chen, "IS-IS Extensions		[RFC7981] Ginsberg, L., Previdi, S., and M. Chen, "IS-IS Extensions
	for Advertising Router Information", RFC 7981,		for Advertising Router Information", RFC 7981,
	DOI 10.17487/RFC7981, October 2016,		DOI 10.17487/RFC7981, October 2016,
	<https://www.rfc-editor.org/info/rfc7981>.		<https://www.rfc-editor.org/info/rfc7981>.
	9.2. Informative References		9.2. Informative References
	[I-D.ietf-spring-resiliency-use-cases]		[I-D.ietf-spring-resiliency-use-cases]
	Filsfils, C., Previdi, S., Decraene, B., and R. Shakir,		Filsfils, C., Previdi, S., Decraene, B., and R. Shakir,
	"Resiliency use cases in SPRING networks", draft-ietf-		"Resiliency use cases in SPRING networks", draft-ietf-
	spring-resiliency-use-cases-11 (work in progress), May		spring-resiliency-use-cases-12 (work in progress),
	2017.		December 2017.
	[I-D.ietf-spring-segment-routing-ldp-interop]		[I-D.ietf-spring-segment-routing-ldp-interop]
	Filsfils, C., Previdi, S., Bashandy, A., Decraene, B., and		Filsfils, C., Previdi, S., Bashandy, A., Decraene, B., and
	S. Litkowski, "Segment Routing interworking with LDP",		S. Litkowski, "Segment Routing interworking with LDP",
	draft-ietf-spring-segment-routing-ldp-interop-09 (work in		draft-ietf-spring-segment-routing-ldp-interop-09 (work in
	progress), September 2017.		progress), September 2017.
	[RFC5311] McPherson, D., Ed., Ginsberg, L., Previdi, S., and M.		[RFC5311] McPherson, D., Ed., Ginsberg, L., Previdi, S., and M.
	Shand, "Simplified Extension of Link State PDU (LSP) Space		Shand, "Simplified Extension of Link State PDU (LSP) Space
	for IS-IS", RFC 5311, DOI 10.17487/RFC5311, February 2009,		for IS-IS", RFC 5311, DOI 10.17487/RFC5311, February 2009,
End of changes. 14 change blocks.
	20 lines changed or deleted		20 lines changed or added
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