draft-ietf-lsr-isis-srv6-extensions-09.txt		draft-ietf-lsr-isis-srv6-extensions-10.txt
	Networking Working Group P. Psenak, Ed.		Networking Working Group P. Psenak, Ed.
	Internet-Draft C. Filsfils		Internet-Draft C. Filsfils
	Intended status: Standards Track Cisco Systems		Intended status: Standards Track Cisco Systems
	Expires: March 12, 2021 A. Bashandy		Expires: March 27, 2021 A. Bashandy
	Individual		Individual
	B. Decraene		B. Decraene
	Orange		Orange
	Z. Hu		Z. Hu
	Huawei Technologies		Huawei Technologies
	September 8, 2020		September 23, 2020
	IS-IS Extension to Support Segment Routing over IPv6 Dataplane		IS-IS Extension to Support Segment Routing over IPv6 Dataplane
	draft-ietf-lsr-isis-srv6-extensions-09.txt		draft-ietf-lsr-isis-srv6-extensions-10.txt
	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 by encoding paths as sequences of topological sub-paths, called		paths by encoding paths as sequences of topological sub-paths, called
	"segments". Segment routing architecture can be implemented over an		"segments". Segment routing architecture can be implemented over an
	MPLS data plane as well as an IPv6 data plane. This draft describes		MPLS data plane as well as an IPv6 data plane. This draft describes
	the IS-IS extensions required to support Segment Routing over an IPv6		the IS-IS extensions required to support Segment Routing over an IPv6
	data plane.		data plane.
	skipping to change at page 1, line 49 ¶		skipping to change at page 1, line 49 ¶
	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 March 12, 2021.		This Internet-Draft will expire on March 27, 2021.
	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 2, line 33 ¶		skipping to change at page 2, line 33 ¶
	2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . . . . 4		2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . . . . 4
	3. Advertising Supported Algorithms . . . . . . . . . . . . . . 4		3. Advertising Supported Algorithms . . . . . . . . . . . . . . 4
	4. Advertising Maximum SRv6 SID Depths . . . . . . . . . . . . . 5		4. Advertising Maximum SRv6 SID Depths . . . . . . . . . . . . . 5
	4.1. Maximum Segments Left MSD Type . . . . . . . . . . . . . 5		4.1. Maximum Segments Left MSD Type . . . . . . . . . . . . . 5
	4.2. Maximum End Pop MSD Type . . . . . . . . . . . . . . . . 5		4.2. Maximum End Pop MSD Type . . . . . . . . . . . . . . . . 5
	4.3. Maximum H.Encaps MSD Type . . . . . . . . . . . . . . . . 5		4.3. Maximum H.Encaps MSD Type . . . . . . . . . . . . . . . . 5
	4.4. Maximum End D MSD Type . . . . . . . . . . . . . . . . . 6		4.4. Maximum End D MSD Type . . . . . . . . . . . . . . . . . 6
	5. SRv6 SIDs and Reachability . . . . . . . . . . . . . . . . . 6		5. SRv6 SIDs and Reachability . . . . . . . . . . . . . . . . . 6
	6. Advertising Anycast Property . . . . . . . . . . . . . . . . 7		6. Advertising Anycast Property . . . . . . . . . . . . . . . . 7
	7. Advertising Locators and End SIDs . . . . . . . . . . . . . . 8		7. Advertising Locators and End SIDs . . . . . . . . . . . . . . 8
	7.1. SRv6 Locator TLV Format . . . . . . . . . . . . . . . . . 9		7.1. SRv6 Locator TLV Format . . . . . . . . . . . . . . . . . 8
	7.2. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . . . 10		7.2. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . . . 10
	8. Advertising SRv6 Adjacency SIDs . . . . . . . . . . . . . . . 12		8. Advertising SRv6 Adjacency SIDs . . . . . . . . . . . . . . . 11
	8.1. SRv6 End.X SID sub-TLV . . . . . . . . . . . . . . . . . 12		8.1. SRv6 End.X SID sub-TLV . . . . . . . . . . . . . . . . . 12
	8.2. SRv6 LAN End.X SID sub-TLV . . . . . . . . . . . . . . . 14		8.2. SRv6 LAN End.X SID sub-TLV . . . . . . . . . . . . . . . 13
	9. SRv6 SID Structure Sub-Sub-TLV . . . . . . . . . . . . . . . 16		9. SRv6 SID Structure Sub-Sub-TLV . . . . . . . . . . . . . . . 15
	10. Advertising Endpoint Behaviors . . . . . . . . . . . . . . . 17		10. Advertising Endpoint Behaviors . . . . . . . . . . . . . . . 16
	11. Implementation Status . . . . . . . . . . . . . . . . . . . . 17		11. Implementation Status . . . . . . . . . . . . . . . . . . . . 17
	11.1. Cisco . . . . . . . . . . . . . . . . . . . . . . . . . 18		11.1. Cisco . . . . . . . . . . . . . . . . . . . . . . . . . 17
	11.2. Huawei . . . . . . . . . . . . . . . . . . . . . . . . . 18		11.2. Huawei . . . . . . . . . . . . . . . . . . . . . . . . . 17
	11.3. Juniper . . . . . . . . . . . . . . . . . . . . . . . . 18		11.3. Juniper . . . . . . . . . . . . . . . . . . . . . . . . 17
	11.4. Arrcus . . . . . . . . . . . . . . . . . . . . . . . . . 18		11.4. Arrcus . . . . . . . . . . . . . . . . . . . . . . . . . 17
	11.5. Interoperability Testing. . . . . . . . . . . . . . . . 19		11.5. Interoperability Testing. . . . . . . . . . . . . . . . 18
	12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19		12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
	12.1. SRv6 Locator TLV . . . . . . . . . . . . . . . . . . . . 19		12.1. SRv6 Locator TLV . . . . . . . . . . . . . . . . . . . . 18
	12.1.1. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . 19		12.1.1. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . 18
	12.1.2. Revised sub-TLV table . . . . . . . . . . . . . . . 19		12.1.2. Revised sub-TLV table . . . . . . . . . . . . . . . 18
	12.2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . 20		12.2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . 19
	12.3. SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs . . . . . 20		12.3. SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs . . . . . 19
	12.4. MSD Types . . . . . . . . . . . . . . . . . . . . . . . 20		12.4. MSD Types . . . . . . . . . . . . . . . . . . . . . . . 20
	12.5. Sub-Sub-TLVs for SID Sub-TLVs . . . . . . . . . . . . . 21		12.5. Sub-Sub-TLVs for SID Sub-TLVs . . . . . . . . . . . . . 20
	12.6. Prefix Attribute Flags Sub-TLV . . . . . . . . . . . . . 21		12.6. Prefix Attribute Flags Sub-TLV . . . . . . . . . . . . . 20
	13. Security Considerations . . . . . . . . . . . . . . . . . . . 21		13. Security Considerations . . . . . . . . . . . . . . . . . . . 21
	14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 21		14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 21
	15. References . . . . . . . . . . . . . . . . . . . . . . . . . 22		15. References . . . . . . . . . . . . . . . . . . . . . . . . . 22
	15.1. Normative References . . . . . . . . . . . . . . . . . . 22		15.1. Normative References . . . . . . . . . . . . . . . . . . 22
	15.2. Informative References . . . . . . . . . . . . . . . . . 24		15.2. Informative References . . . . . . . . . . . . . . . . . 24
	15.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 25		15.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 25
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25
	1. Introduction		1. Introduction
	With Segment Routing (SR) [I-D.ietf-spring-segment-routing], a node		With Segment Routing (SR) [RFC8402], a node steers a packet through
	steers a packet through an ordered list of instructions, called		an ordered list of instructions, called segments.
	segments.
	Segments are identified through Segment Identifiers (SIDs).		Segments are identified through Segment Identifiers (SIDs).
	Segment Routing can be directly instantiated on the IPv6 data plane		Segment Routing can be directly instantiated on the IPv6 data plane
	through the use of the Segment Routing Header defined in		through the use of the Segment Routing Header defined in [RFC8754].
	[I-D.ietf-6man-segment-routing-header]. SRv6 refers to this SR		SRv6 refers to this SR instantiation on the IPv6 dataplane.
	instantiation on the IPv6 dataplane.
	The network programming paradigm		The network programming paradigm
	[I-D.ietf-spring-srv6-network-programming] is central to SRv6. It		[I-D.ietf-spring-srv6-network-programming] is central to SRv6. It
	describes how any behavior can be bound to a SID and how any network		describes how any behavior can be bound to a SID and how any network
	program can be expressed as a combination of SIDs.		program can be expressed as a combination of SIDs.
	This document specifies IS-IS extensions that allow the IS-IS		This document specifies IS-IS extensions that allow the IS-IS
	protocol to encode some of these SIDs and their behaviors.		protocol to encode some of these SIDs and their behaviors.
	Familiarity with the network programming paradigm		Familiarity with the network programming paradigm
	skipping to change at page 4, line 13 ¶		skipping to change at page 4, line 10 ¶
	instantiated at the node.		instantiated at the node.
	The SRv6 End SID sub-TLV, the SRv6 End.X SID sub-TLV, and the SRv6		The SRv6 End SID sub-TLV, the SRv6 End.X SID sub-TLV, and the SRv6
	LAN End.X SID sub-TLV are used to advertise which SIDs are		LAN End.X SID sub-TLV are used to advertise which SIDs are
	instantiated at a node and what Endpoint behavior is bound to each		instantiated at a node and what Endpoint behavior is bound to each
	instantiated SID.		instantiated SID.
	2. SRv6 Capabilities sub-TLV		2. SRv6 Capabilities sub-TLV
	A node indicates that it supports the SR Segment Endpoint Node		A node indicates that it supports the SR Segment Endpoint Node
	functionality as specified in [I-D.ietf-6man-segment-routing-header]		functionality as specified in [RFC8754] by advertising a new SRv6
	by advertising a new SRv6 Capabilities sub-TLV of the router		Capabilities sub-TLV of the router capabilities TLV [RFC7981].
	capabilities TLV [RFC7981].
	The SRv6 Capabilities sub-TLV may contain optional sub-sub-TLVs. No		The SRv6 Capabilities sub-TLV may contain optional sub-sub-TLVs. No
	sub-sub-TLVs are currently defined.		sub-sub-TLVs are currently defined.
	The SRv6 Capabilities sub-TLV has the following format:		The SRv6 Capabilities 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 | Flags |		| Type | Length | Flags |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| optional sub-sub-TLVs...		| optional sub-sub-TLVs...
	Type: Suggested value 25, to be assigned by IANA		Type: 25
	Length: 2 + length of sub-sub-TLVs		Length: 2 + length of sub-sub-TLVs
	Flags: 2 octets The following flags are defined:		Flags: 2 octets The following flags are defined:
	0 1		0 1
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| |O| |		| |O| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	skipping to change at page 5, line 19 ¶		skipping to change at page 5, line 19 ¶
	advertised in a sub-TLV of the Router Capabilities TLV [RFC7981].		advertised in a sub-TLV of the Router Capabilities TLV [RFC7981].
	Link MSDs are advertised in a sub-TLV of TLVs 22, 23, 141, 222, and		Link MSDs are advertised in a sub-TLV of TLVs 22, 23, 141, 222, and
	223.		223.
	This document defines the relevant SRv6 MSDs and requests MSD type		This document defines the relevant SRv6 MSDs and requests MSD type
	assignments in the MSD Types registry created by [RFC8491].		assignments in the MSD Types registry created by [RFC8491].
	4.1. Maximum Segments Left MSD Type		4.1. Maximum Segments Left MSD Type
	The Maximum Segments Left MSD Type specifies the maximum value of the		The Maximum Segments Left MSD Type specifies the maximum value of the
	"SL" field [I-D.ietf-6man-segment-routing-header] in the SRH of a		"SL" field [RFC8754] in the SRH of a received packet before applying
	received packet before applying the Endpoint behavior associated with		the Endpoint behavior associated with a SID.
	a SID.
	SRH Max SL Type: 41 (Suggested value - to be assigned by IANA)		SRH Max SL Type: 41
	If no value is advertised the supported value is assumed to be 0.		If no value is advertised the supported value is assumed to be 0.
	4.2. Maximum End Pop MSD Type		4.2. Maximum End Pop MSD Type
	The Maximum End Pop MSD Type specifies the maximum number of SIDs in		The Maximum End Pop MSD Type specifies the maximum number of SIDs in
	the SRH to which the router can apply "PSP" or USP" behavior, as		the SRH to which the router can apply "PSP" or USP" behavior, as
	defined in [I-D.ietf-spring-srv6-network-programming] flavors.		defined in [I-D.ietf-spring-srv6-network-programming] flavors.
	SRH Max End Pop Type: 42 (Suggested value - to be assigned by IANA)		SRH Max End Pop Type: 42
	If the advertised value is zero or no value is advertised		If the advertised value is zero or no value is advertised
	then it is assumed that the router cannot apply PSP or USP flavors.		then it is assumed that the router cannot apply PSP or USP flavors.
	4.3. Maximum H.Encaps MSD Type		4.3. Maximum H.Encaps MSD Type
	The Maximum H.Encaps MSD Type specifies the maximum number of SIDs		The Maximum H.Encaps MSD Type specifies the maximum number of SIDs
	that can be included as part of the "H.Encaps" behavior as defined in		that can be included as part of the "H.Encaps" behavior as defined in
	[I-D.ietf-spring-srv6-network-programming] .		[I-D.ietf-spring-srv6-network-programming].
	SRH Max H.encaps Type: 44 (Suggested value - to be assigned by IANA)		SRH Max H.encaps Type: 44
	If the advertised value is zero then the router can apply H.Encaps		If the advertised value is zero or no value is advertised
	only by encapsulating the incoming packet in another		then the router can apply H.Encaps only by encapsulating
	IPv6 header without SRH the same way IPinIP encapsulation is		the incoming packet in another IPv6 header without SRH
	performed.		the same way IPinIP encapsulation is performed.
	If the advertised value is non-zero then the router supports both		If the advertised value is non-zero then the router supports both
	IPinIP and SRH encapsulation subject to the SID limitation		IPinIP and SRH encapsulation subject to the SID limitation
	specified by the advertised value.		specified by the advertised value.
	4.4. Maximum End D MSD Type		4.4. Maximum End D MSD Type
	The Maximum End D MSD Type specifies the maximum number of SIDs in an		The Maximum End D MSD Type specifies the maximum number of SIDs in an
	SRH when performing decapsulation associated with "End.Dx" behaviors		SRH when performing decapsulation associated with "End.Dx" behaviors
	(e.g., "End.DX6" and "End.DT6") as defined in		(e.g., "End.DX6" and "End.DT6") as defined in
	[I-D.ietf-spring-srv6-network-programming].		[I-D.ietf-spring-srv6-network-programming].
	SRH Max End D Type: 45 (Suggested value - to be assigned by IANA)		SRH Max End D Type: 45
	If the advertised value is zero or no value is advertised		If the advertised value is zero or no value is advertised
	then it is assumed that the router cannot apply		then it is assumed that the router cannot apply
	"End.DX6" or "End.DT6" behaviors if the outer IPv6 header contains an SRH.		"End.DX6" or "End.DT6" behaviors if the outer IPv6 header
			contains an SRH.
	5. SRv6 SIDs and Reachability		5. SRv6 SIDs and Reachability
	As discussed in [I-D.ietf-spring-srv6-network-programming], an SRv6		As discussed in [I-D.ietf-spring-srv6-network-programming], an SRv6
	Segment Identifier (SID) is 128 bits and consists of Locator,		Segment Identifier (SID) is 128 bits and consists of Locator,
	Function and Argument parts.		Function and Argument parts.
	A node is provisioned with topology/algorithm specific locators for		A node is provisioned with topology/algorithm specific locators for
	each of the topology/algorithm pairs supported by that node. Each		each of the topology/algorithm pairs supported by that node. Each
	locator is a covering prefix for all SIDs provisioned on that node		locator is a covering prefix for all SIDs provisioned on that node
	skipping to change at page 8, line 8 ¶		skipping to change at page 7, line 44 ¶
	6. Advertising Anycast Property		6. Advertising Anycast Property
	Both prefixes and SRv6 Locators may be configured as anycast and as		Both prefixes and SRv6 Locators may be configured as anycast and as
	such the same value can be advertised by multiple routers. It is		such the same value can be advertised by multiple routers. It is
	useful for other routers to know that the advertisement is for an		useful for other routers to know that the advertisement is for an
	anycast identifier.		anycast identifier.
	A new flag in "Bit Values for Prefix Attribute Flags Sub-TLV"		A new flag in "Bit Values for Prefix Attribute Flags Sub-TLV"
	registry [RFC7794] is defined to advertise the anycast property:		registry [RFC7794] is defined to advertise the anycast property:
	Bit #: 4 (Suggested - to be assigned by IANA)		Bit #: 4
	Name: Anycast Flag (A-flag)		Name: Anycast Flag (A-flag)
	When the prefix/SRv6 locator is configured as anycast, the A-flag		When the prefix/SRv6 locator is configured as anycast, the A-flag
	SHOULD be set. Otherwise, this flag MUST be clear.		SHOULD be set. Otherwise, this flag MUST be clear.
	The A-flag MUST be preserved when leaked between levels.		The A-flag MUST be preserved when leaked between levels.
	The A-flag and the N-flag MUST NOT both be set.		The A-flag and the N-flag MUST NOT both be set.
	If both N-flag and A-flag are set in the prefix/SRv6 Locator		If both N-flag and A-flag are set in the prefix/SRv6 Locator
	advertisement, the receiving routers MUST ignore the N-flag.		advertisement, the receiving routers MUST ignore the N-flag.
	The same prefix/SRv6 Locator can be advertised by multiple routers.		The same prefix/SRv6 Locator can be advertised by multiple routers.
	If at least one of them sets the A-Flag in its advertisement, the		If at least one of them sets the A-Flag in its advertisement, the
	prefix/SRv6 Locator SHOULD be considered as anycast.		prefix/SRv6 Locator SHOULD be considered as anycast.
	Locator that is advertised by a single node and without an A-Flag		A prefix/SRv6 Locator that is advertised by a single node and without
	SHOULD be interpreted as a node specific locator.		an A-Flag SHOULD be interpreted as a node specific locator.
	All the nodes advertising the same anycast locator MUST instantiate		All the nodes advertising the same anycast locator MUST instantiate
	the exact same set of SIDs under such anycast locator. Failure to do		the exact same set of SIDs under such anycast locator. Failure to do
	so may result in traffic being black-holed or mis-routed.		so may result in traffic being black-holed or mis-routed.
	The Prefix Attribute Flags Sub-TLV can be carried in the SRv6 Locator		The Prefix Attribute Flags Sub-TLV can be carried in the SRv6 Locator
	TLV as well as the Prefix Reachability TLVs. When a router		TLV as well as the Prefix Reachability TLVs. When a router
	originates both the Prefix Reachability TLV and the SRv6 Locator TLV		originates both the Prefix Reachability TLV and the SRv6 Locator TLV
	for a given prefix, and the router is originating the Prefix		for a given prefix, and the router is originating the Prefix
	Attribute Flags Sub-TLV in one of the TLVs, the router SHOULD		Attribute Flags Sub-TLV in one of the TLVs, the router SHOULD
	skipping to change at page 9, line 15 ¶		skipping to change at page 8, line 47 ¶
	7.1. SRv6 Locator TLV Format		7.1. SRv6 Locator TLV Format
	The SRv6 Locator TLV has the following format:		The SRv6 Locator 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 |R|R|R|R| MTID |		| Type | Length |R|R|R|R| MTID |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Type: 27 (Suggested value to be assigned by IANA)		Type: 27
	Length: variable.		Length: variable.
			R bits: reserved for future use. They SHOULD be
			set to zero on transmission and MUST be ignored on receipt.
	MTID: Multitopology Identifier as defined in [RFC5120].		MTID: Multitopology Identifier as defined in [RFC5120].
	Note that the value 0 is legal.		Note that the value 0 is legal.
	Followed by one or more locator entries of the form:		Followed by one or more locator entries of the form:
	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
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Metric |		| Metric |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	skipping to change at page 11, line 23 ¶		skipping to change at page 10, line 42 ¶
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| SID (cont . . .) |		| SID (cont . . .) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| SID (cont . . .) |		| SID (cont . . .) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| SID (cont . . .) |		| SID (cont . . .) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|Sub-sub-tlv-len| sub-sub-TLVs (variable) . . . |		|Sub-sub-tlv-len| sub-sub-TLVs (variable) . . . |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Type: 5 (Suggested value to be assigned by IANA).		Type: 5.
	Length: variable.		Length: variable.
	Flags: 1 octet. No flags are currently defined.		Flags: 1 octet. No flags are currently defined.
	Endpoint Behavior: 2 octets, as defined in [I-D.ietf-spring-srv6-		Endpoint Behavior: 2 octets, as defined in [I-D.ietf-spring-srv6-
	network-programming]. Legal behavior values for this sub-TLV are		network-programming]. Legal behavior values for this sub-TLV are
	defined in Section 10 of this document.		defined in Section 10 of this document.
	SID: 16 octets. This field encodes the advertised SRv6 SID.		SID: 16 octets. This field encodes the advertised SRv6 SID.
	skipping to change at page 12, line 8 ¶		skipping to change at page 11, line 26 ¶
	Multiple SRv6 End SIDs MAY be associated with the same locator. In		Multiple SRv6 End SIDs MAY be associated with the same locator. In
	cases where the number of SRv6 End SID sub-TLVs exceeds the capacity		cases where the number of SRv6 End SID sub-TLVs exceeds the capacity
	of a single TLV, multiple Locator TLVs for the same locator MAY be		of a single TLV, multiple Locator TLVs for the same locator MAY be
	advertised. For a given MTID/Locator the algorithm MUST be the same		advertised. For a given MTID/Locator the algorithm MUST be the same
	in all TLVs. If this restriction is not met all TLVs for that MTID/		in all TLVs. If this restriction is not met all TLVs for that MTID/
	Locator MUST be ignored.		Locator MUST be ignored.
	8. Advertising SRv6 Adjacency SIDs		8. Advertising SRv6 Adjacency SIDs
	Certain SRv6 Endpoint behaviors		Certain SRv6 Endpoint behaviors
	[I-D.ietf-spring-srv6-network-programming] must be associated with a		[I-D.ietf-spring-srv6-network-programming] are associated with a
	particular neighbor, and in case of multiple links to the same		particular adjacency.
	neighbor, with a particular link in order to be correctly applied.
	This document defines two new sub-TLVs of TLV 22, 23, 222, 223, and		This document defines two new sub-TLVs of TLV 22, 23, 222, 223, and
	141 - namely "SRv6 End.X SID" and "SRv6 LAN End.X SID".		141 - namely "SRv6 End.X SID" and "SRv6 LAN End.X SID".
	IS-IS Neighbor advertisements are topology specific - but not		IS-IS Neighbor advertisements are topology specific - but not
	algorithm specific. End.X SIDs therefore inherit the topology from		algorithm specific. End.X SIDs therefore inherit the topology from
	the associated neighbor advertisement, but the algorithm is specified		the associated neighbor advertisement, but the algorithm is specified
	in the individual SID.		in the individual SID.
	All End.X SIDs MUST be a subnet of a Locator with matching topology		All End.X SIDs MUST be a subnet of a Locator with matching topology
	skipping to change at page 13, line 25 ¶		skipping to change at page 12, line 33 ¶
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| SID (cont . . .) |		| SID (cont . . .) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| SID (cont . . .) |		| SID (cont . . .) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| SID (cont . . .) |		| SID (cont . . .) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|Sub-sub-tlv-len| Sub-sub-TLVs (variable) . . . |		|Sub-sub-tlv-len| Sub-sub-TLVs (variable) . . . |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Type: 43 (Suggested value to be assigned by IANA).		Type: 43
	Length: variable.		Length: variable.
	Flags: 1 octet.		Flags: 1 octet.
	0 1 2 3 4 5 6 7		0 1 2 3 4 5 6 7
	+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+
	|B|S|P|Reserved |		|B|S|P|Reserved |
	+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+
	skipping to change at page 14, line 5 ¶		skipping to change at page 13, line 14 ¶
	S-Flag. Set flag. When set, the S-Flag indicates that the		S-Flag. Set flag. When set, the S-Flag indicates that the
	End.X SID refers to a set of adjacencies (and therefore MAY be		End.X SID refers to a set of adjacencies (and therefore MAY be
	assigned to other adjacencies as well).		assigned to other adjacencies as well).
	P-Flag. Persistent flag. When set, the P-Flag indicates that		P-Flag. Persistent flag. When set, the P-Flag indicates that
	the End.X SID is persistently allocated, i.e., the End.X SID		the End.X SID is persistently allocated, i.e., the End.X SID
	value remains consistent across router restart and/or interface		value remains consistent across router restart and/or interface
	flap.		flap.
	Other bits: MUST be zero when originated and ignored when		Reserved bits: MUST be zero when originated and ignored when
	received.		received.
	Algorithm: 1 octet. Associated algorithm. Algorithm values are		Algorithm: 1 octet. Associated algorithm. Algorithm values are
	defined in the IGP Algorithm Type registry.		defined in the IGP Algorithm Type registry.
	Weight: 1 octet. The value represents the weight of the End.X SID		Weight: 1 octet. The value represents the weight of the End.X SID
	for the purpose of load balancing. The use of the weight is		for the purpose of load balancing. The use of the weight is
	defined in [I-D.ietf-spring-segment-routing].		defined in [RFC8402].
	Endpoint Behavior: 2 octets. As defined in [I-D.ietf-spring-srv6-		Endpoint Behavior: 2 octets. As defined in [I-D.ietf-spring-srv6-
	network-programming] Legal behavior values for this sub-TLV are		network-programming] Legal behavior values for this sub-TLV are
	defined in Section 10.		defined in Section 10.
	SID: 16 octets. This field encodes the advertised SRv6 SID.		SID: 16 octets. This field encodes the advertised SRv6 SID.
	Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub-		Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub-
	TLVs.		TLVs.
	skipping to change at page 15, line 8 ¶		skipping to change at page 14, line 8 ¶
	may exist on a given LAN a large number of SRv6 LAN END.X SID sub-		may exist on a given LAN a large number of SRv6 LAN END.X SID sub-
	TLVs may be associated with the same LAN. Note that multiple TLVs		TLVs may be associated with the same LAN. Note that multiple TLVs
	for the same DIS neighbor may be required in order to advertise all		for the same DIS neighbor may be required in order to advertise all
	of the SRv6 End.X SIDs associated with that neighbor.		of the SRv6 End.X SIDs associated with that neighbor.
	The SRv6 LAN End.X SID sub-TLV has the following format:		The SRv6 LAN End.X SID 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 | System ID (6 octets) |		| Type | Length | |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
	| |		| Neighbor System-ID (ID length octets) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Flags | Algorithm | Weight |		| Flags | Algorithm | Weight |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Endpoint Behavior |		| Endpoint Behavior |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| SID (128 bits) . . . |		| SID (128 bits) . . . |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| SID (cont . . .) |		| SID (cont . . .) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| SID (cont . . .) |		| SID (cont . . .) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| SID (cont . . .) |		| SID (cont . . .) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|Sub-sub-tlv-len| sub-sub-TLVs (variable) . . . |		|Sub-sub-tlv-len| sub-sub-TLVs (variable) . . . |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Type: 44 (Suggested value to be assigned by IANA).		Type: 44
	Length: variable.		Length: variable.
	System-ID: 6 octets of IS-IS System-ID of length "ID Length" as		Neighbor System-ID: IS-IS System-ID of length "ID Length" as
	defined in [ISO10589].		defined in [ISO10589].
	Flags: 1 octet.		Flags: 1 octet.
	0 1 2 3 4 5 6 7		0 1 2 3 4 5 6 7
	+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+
	|B|S|P|Reserved |		|B|S|P|Reserved |
	+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+
	where B,S, and P flags are as described in Section 8.1. Other		where B,S, and P flags are as described in Section 8.1.
	bits: MUST be zero when originated and ignored when received.		Reserved bits MUST be zero when originated and MUST be ignored
			when received.
	Algorithm: 1 octet. Associated algorithm. Algorithm values are		Algorithm: 1 octet. Associated algorithm. Algorithm values are
	defined in the IGP Algorithm Type registry.		defined in the IGP Algorithm Type registry.
	Weight: 1 octet. The value represents the weight of the End.X SID		Weight: 1 octet. The value represents the weight of the End.X SID
	for the purpose of load balancing. The use of the weight is		for the purpose of load balancing. The use of the weight is
	defined in [I-D.ietf-spring-segment-routing].		defined in [RFC8402].
	Endpoint Behavior: 2 octets. As defined in [I-D.ietf-spring-srv6-		Endpoint Behavior: 2 octets. As defined in [I-D.ietf-spring-srv6-
	network-programming] Legal behavior values for this sub-TLV are		network-programming] Legal behavior values for this sub-TLV are
	defined in Section 10.		defined in Section 10.
	SID: 16 octets. This field encodes the advertised SRv6 SID.		SID: 16 octets. This field encodes the advertised SRv6 SID.
	Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub-		Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub-
	TLVs.		TLVs.
	skipping to change at page 17, line 26 ¶		skipping to change at page 16, line 28 ¶
	Endpoint behaviors are defined in		Endpoint behaviors are defined in
	[I-D.ietf-spring-srv6-network-programming]. The codepoints for the		[I-D.ietf-spring-srv6-network-programming]. The codepoints for the
	Endpoint behaviors are defined in the "SRv6 Endpoint Behaviors"		Endpoint behaviors are defined in the "SRv6 Endpoint Behaviors"
	registry defined in [I-D.ietf-spring-srv6-network-programming]. This		registry defined in [I-D.ietf-spring-srv6-network-programming]. This
	section lists the Endpoint behaviors which MAY be advertised by ISIS,		section lists the Endpoint behaviors which MAY be advertised by ISIS,
	together with their codepoints. If this behavior is advertised it		together with their codepoints. If this behavior is advertised it
	MUST only be advertised in the TLV[s] as indicated by "Y" in the		MUST only be advertised in the TLV[s] as indicated by "Y" in the
	table below, and MUST NOT be advertised in the TLV[s] as indicated by		table below, and MUST NOT be advertised in the TLV[s] as indicated by
	"N" in the table below.		"N" in the table below.
	Endpoint |Endpoint | End | End.X | Lan End.X |		Endpoint |Endpoint | End | End.X | Lan End.X |
	Behavior |Behavior Codepoint | SID | SID | SID |		Behavior |Behavior Codepoint| SID | SID | SID |
	-----------------------|--------------------|-------|-------|-----------|		----------------------|------------------|-----|-------|-----------|
	End (PSP, USP, USD) | 1-4, 28-31 | Y | N | N |		End (PSP, USP, USD)| 1-4, 28-31 | Y | N | N |
	-----------------------|--------------------|-------|-------|-----------|		----------------------|------------------|-----|-------|-----------|
	End.X (PSP, USP, USD) | 5-8, 32-35 | N | Y | Y |		End.X (PSP, USP, USD)| 5-8, 32-35 | N | Y | Y |
	-----------------------|--------------------|-------|-------|-----------|		----------------------|------------------|-----|-------|-----------|
	End.T (PSP, USP, USD) | 9-12, 36-39 | Y | N | N |		End.T (PSP, USP, USD)| 9-12, 36-39 | Y | N | N |
	-----------------------|--------------------|-------|-------|-----------|		----------------------|------------------|-----|-------|-----------|
	End.DX6 | 16 | N | Y | Y |		End.DX6 | 16 | N | Y | Y |
	-----------------------|--------------------|-------|-------|-----------|		----------------------|------------------|-----|-------|-----------|
	End.DX4 | 17 | N | Y | Y |		End.DX4 | 17 | N | Y | Y |
	-----------------------|--------------------|-------|-------|-----------|		----------------------|------------------|-----|-------|-----------|
	End.DT6 | 18 | Y | N | N |		End.DT6 | 18 | Y | N | N |
	-----------------------|--------------------|-------|-------|-----------|		----------------------|------------------|-----|-------|-----------|
	End.DT4 | 19 | Y | N | N |		End.DT4 | 19 | Y | N | N |
	-----------------------|--------------------|-------|-------|-----------|		----------------------|------------------|-----|-------|-----------|
	End.DT64 | 20 | Y | N | N |		End.DT64 | 20 | Y | N | N |
	11. Implementation Status		11. Implementation Status
	This section describes the implementation status of the ISIS SRv6		This section describes the implementation status of the ISIS SRv6
	extensions.		extensions.
	11.1. Cisco		11.1. Cisco
	Cisco's ISIS SRv6 implementation supports following functionalities:		Cisco's ISIS SRv6 implementation supports following functionalities:
	skipping to change at page 19, line 12 ¶		skipping to change at page 18, line 17 ¶
	SID Structure Sub-Sub-TLV: Yes		SID Structure Sub-Sub-TLV: Yes
	11.5. Interoperability Testing.		11.5. Interoperability Testing.
	EANTC interoperability testing has been performed in April 2019.		EANTC interoperability testing has been performed in April 2019.
	Results can be found at EANTC site [1].		Results can be found at EANTC site [1].
	12. IANA Considerations		12. IANA Considerations
	This document requests allocation for the following TLVs, sub- TLVs,		This document requests allocation for the following TLVs, sub-TLVs,
	and sub-sub-TLVs as well updating the ISIS TLV registry and defining		and sub-sub-TLVs as well updating the ISIS TLV registry and defining
	a new registry.		a new registry.
	12.1. SRv6 Locator TLV		12.1. SRv6 Locator TLV
	This document adds one new TLV to the IS-IS TLV Codepoints registry.		This document makes the following registrations in the the IS-IS TLV
			Codepoints registry:
	Value: 27 (suggested - to be assigned by IANA)		Type: 27
	Name: SRv6 Locator		Description: SRv6 Locator TLV.
	This TLV shares sub-TLV space with existing "Sub-TLVs for TLVs 135,		Reference: This document (Section 7.1).
	235, 236 and 237 registry". The name of this registry needs to be
	changed to "Sub-TLVs for TLVs 27, 135, 235, 236 and 237 registry".		A Locator TLV shares sub-TLV space with existing "Sub-TLVs for TLVs
			135, 235, 236 and 237 registry". The name of this registry needs to
			be changed to "Sub-TLVs for TLVs 27, 135, 235, 236 and 237 registry".
	12.1.1. SRv6 End SID sub-TLV		12.1.1. SRv6 End SID sub-TLV
	This document adds the following new sub-TLV to the (renamed) "Sub-		This document makes the following registrations in the (renamed)
	TLVs for TLVs 27, 135, 235, 236 and 237 registry".		"Sub-TLVs for TLVs 27, 135, 235, 236 and 237 registry":
	Value: 5 (suggested - to be assigned by IANA)		Type: 5
	Name: SRv6 End SID		Description: SRv6 End SID sub-TLV.
			Reference: This document (Section 7.2).
	12.1.2. Revised sub-TLV table		12.1.2. Revised sub-TLV table
	The revised table of sub-TLVs for the (renamed) "Sub-TLVs for TLVs		The revised table of sub-TLVs for the (renamed) "Sub-TLVs for TLVs
	27, 135, 235, 236 and 237 registry" is shown below:		27, 135, 235, 236 and 237 registry" is shown below:
	Type 27 135 235 236 237		Type 27 135 235 236 237
	1 y y y y y		1 y y y y y
	2 y y y y y		2 y y y y y
	3 n y y y y		3 n y y y y
	4 y y y y y		4 y y y y y
	5 y n n n n		5 y n n n n
	6 n y y y y		6 n y y y y
	11 y y y y y		11 y y y y y
	12 y y y y y		12 y y y y y
	32 n y y y y		32 n y y y y
	12.2. SRv6 Capabilities sub-TLV		12.2. SRv6 Capabilities sub-TLV
	This document adds the definition of a new sub-TLV in the "Sub- TLVs		This document makes the following registrations in the "Sub- TLVs for
	for TLV 242 registry".		TLV 242 registry":
	Type: 25 (Suggested - to be assigned by IANA)		Type: 25
	Description: SRv6 Capabilities		Description: SRv6 Capabilities sub-TLV.
			Reference: This document (Section 2).
	This document requests the creation of a new IANA managed registry		This document requests the creation of a new IANA managed registry
	for sub-sub-TLVs of the SRv6 Capability sub-TLV. The registration		for sub-sub-TLVs of the SRv6 Capability sub-TLV. The registration
	procedure is "Expert Review" as defined in [RFC7370]. Suggested		procedure is "Expert Review" as defined in [RFC7370]. Suggested
	registry name is "sub-sub-TLVs for SRv6 Capability sub-TLV". No sub-		registry name is "sub-sub-TLVs for SRv6 Capability sub-TLV". No sub-
	sub-TLVs are defined by this document except for the reserved value.		sub-TLVs are defined by this document except for the reserved value.
	0: Reserved		0: Reserved
	1-255: Unassigned		1-255: Unassigned
	12.3. SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs		12.3. SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs
	This document adds the definition of two new sub-TLVs in the "sub-		This document makes the following registrations in the "sub- TLVs for
	TLVs for TLV 22, 23, 25, 141, 222 and 223 registry".		TLV 22, 23, 25, 141, 222 and 223 registry":
	Type: 43 (suggested - to be assigned by IANA)		Type: 43
	Description: SRv6 End.X SID		Description: SRv6 End.X SID sub-TLV.
	Type: 44 (suggested - to be assigned by IANA)		Reference: This document (Section 8.1).
	Description: SRv6 LAN End.X SID		Type: 44
			Description: SRv6 LAN End.X SID sub-TLV.
			Reference: This document (Section 8.2).
	Type 22 23 25 141 222 223		Type 22 23 25 141 222 223
	43 y y y y y y		43 y y y y y y
	44 y y y y y y		44 y y y y y y
	12.4. MSD Types		12.4. MSD Types
	This document defines the following new MSD types. These types are		This document makes the following registrations in the IGP MSD Types
	to be defined in the IGP MSD Types registry defined in [RFC8491] .		registry:
	All values are suggested values to be assigned by IANA.
	Type Description		Type Description
	------------------		------------------
	41 SRH Max SL		41 SRH Max SL
	42 SRH Max End Pop		42 SRH Max End Pop
	44 SRH Max H.encaps		44 SRH Max H.encaps
	45 SRH Max End D		45 SRH Max End D
	12.5. Sub-Sub-TLVs for SID Sub-TLVs		12.5. Sub-Sub-TLVs for SID Sub-TLVs
	skipping to change at page 23, line 5 ¶		skipping to change at page 23, line 5 ¶
	Email rhanzl@cisco.com		Email rhanzl@cisco.com
	Ketan Talaulikar		Ketan Talaulikar
	Cisco Systems, Inc.		Cisco Systems, Inc.
	Email: ketant@cisco.com		Email: ketant@cisco.com
	15. References		15. References
	15.1. Normative References		15.1. Normative References
	[I-D.ietf-6man-segment-routing-header]
	Filsfils, C., Dukes, D., Previdi, S., Leddy, J.,
	Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
	(SRH)", draft-ietf-6man-segment-routing-header-26 (work in
	progress), October 2019.
	[I-D.ietf-6man-spring-srv6-oam]		[I-D.ietf-6man-spring-srv6-oam]
	Ali, Z., Filsfils, C., Matsushima, S., Voyer, D., and M.		Ali, Z., Filsfils, C., Matsushima, S., Voyer, D., and M.
	Chen, "Operations, Administration, and Maintenance (OAM)		Chen, "Operations, Administration, and Maintenance (OAM)
	in Segment Routing Networks with IPv6 Data plane (SRv6)",		in Segment Routing Networks with IPv6 Data plane (SRv6)",
	draft-ietf-6man-spring-srv6-oam-07 (work in progress),		draft-ietf-6man-spring-srv6-oam-07 (work in progress),
	July 2020.		July 2020.
	[I-D.ietf-spring-srv6-network-programming]		[I-D.ietf-spring-srv6-network-programming]
	Filsfils, C., Camarillo, P., Leddy, J., Voyer, D.,		Filsfils, C., Camarillo, P., Leddy, J., Voyer, D.,
	Matsushima, S., and Z. Li, "SRv6 Network Programming",		Matsushima, S., and Z. Li, "SRv6 Network Programming",
	draft-ietf-spring-srv6-network-programming-18 (work in		draft-ietf-spring-srv6-network-programming-20 (work in
	progress), August 2020.		progress), September 2020.
	[ISO10589]		[ISO10589]
	Standardization", I. ". O. F., "Intermediate system to		Standardization", I. ". O. F., "Intermediate system to
	Intermediate system intra-domain routeing information		Intermediate system intra-domain routeing information
	exchange protocol for use in conjunction with the protocol		exchange protocol for use in conjunction with the protocol
	for providing the connectionless-mode Network Service (ISO		for providing the connectionless-mode Network Service (ISO
	8473), ISO/IEC 10589:2002, Second Edition.", Nov 2002.		8473), ISO/IEC 10589:2002, Second Edition.", Nov 2002.
	[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,
	skipping to change at page 24, line 39 ¶		skipping to change at page 24, line 30 ¶
	"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>.
	[RFC8667] Previdi, S., Ed., Ginsberg, L., Ed., Filsfils, C.,		[RFC8667] Previdi, S., Ed., Ginsberg, L., Ed., Filsfils, C.,
	Bashandy, A., Gredler, H., and B. Decraene, "IS-IS		Bashandy, A., Gredler, H., and B. Decraene, "IS-IS
	Extensions for Segment Routing", RFC 8667,		Extensions for Segment Routing", RFC 8667,
	DOI 10.17487/RFC8667, December 2019,		DOI 10.17487/RFC8667, December 2019,
	<https://www.rfc-editor.org/info/rfc8667>.		<https://www.rfc-editor.org/info/rfc8667>.
			[RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J.,
			Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
			(SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,
			<https://www.rfc-editor.org/info/rfc8754>.
	15.2. Informative References		15.2. Informative References
	[I-D.ietf-lsr-flex-algo]		[I-D.ietf-lsr-flex-algo]
	Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and		Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and
	A. Gulko, "IGP Flexible Algorithm", draft-ietf-lsr-flex-		A. Gulko, "IGP Flexible Algorithm", draft-ietf-lsr-flex-
	algo-10 (work in progress), August 2020.		algo-11 (work in progress), September 2020.
	[I-D.ietf-spring-segment-routing]
	Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B.,
	Litkowski, S., and R. Shakir, "Segment Routing
	Architecture", draft-ietf-spring-segment-routing-15 (work
	in progress), January 2018.
	[RFC8355] Filsfils, C., Ed., Previdi, S., Ed., Decraene, B., and R.		[RFC8355] Filsfils, C., Ed., Previdi, S., Ed., Decraene, B., and R.
	Shakir, "Resiliency Use Cases in Source Packet Routing in		Shakir, "Resiliency Use Cases in Source Packet Routing in
	Networking (SPRING) Networks", RFC 8355,		Networking (SPRING) Networks", RFC 8355,
	DOI 10.17487/RFC8355, March 2018,		DOI 10.17487/RFC8355, March 2018,
	<https://www.rfc-editor.org/info/rfc8355>.		<https://www.rfc-editor.org/info/rfc8355>.
			[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
			Decraene, B., Litkowski, S., and R. Shakir, "Segment
			Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
			July 2018, <https://www.rfc-editor.org/info/rfc8402>.
	15.3. URIs		15.3. URIs
	[1] http://www.eantc.de/fileadmin/eantc/downloads/events/2017-		[1] http://www.eantc.de/fileadmin/eantc/downloads/events/2017-
	2020/MPLS2019/Segment_Routing_IPv6__SRv6_.pdf		2020/MPLS2019/Segment_Routing_IPv6__SRv6_.pdf
	Authors' Addresses		Authors' Addresses
	Peter Psenak (editor)		Peter Psenak (editor)
	Cisco Systems		Cisco Systems
	Pribinova Street 10		Pribinova Street 10
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	126 lines changed or deleted		133 lines changed or added
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