draft-ietf-lsr-isis-srv6-extensions-03.txt		draft-ietf-lsr-isis-srv6-extensions-04.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: April 5, 2020 A. Bashandy		Expires: July 18, 2020 A. Bashandy
	Arrcus		Arrcus
	B. Decraene		B. Decraene
	Orange		Orange
	Z. Hu		Z. Hu
	Huawei Technologies		Huawei Technologies
	October 3, 2019		January 15, 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-03.txt		draft-ietf-lsr-isis-srv6-extensions-04.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 April 5, 2020.		This Internet-Draft will expire on July 18, 2020.
	Copyright Notice		Copyright Notice
	Copyright (c) 2019 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
	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
	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 . . . . . . . . . . . . . 4		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 T.Insert MSD Type . . . . . . . . . . . . . . . . 5		4.3. Maximum H.Encaps MSD Type . . . . . . . . . . . . . . . . 5
	4.4. Maximum T.Encaps MSD Type . . . . . . . . . . . . . . . . 5		4.4. Maximum End D MSD Type . . . . . . . . . . . . . . . . . 6
	4.5. Maximum End D MSD Type . . . . . . . . . . . . . . . . . 6
	5. SRv6 SIDs and Reachability . . . . . . . . . . . . . . . . . 6		5. SRv6 SIDs and Reachability . . . . . . . . . . . . . . . . . 6
	6. Advertising Anycast Property . . . . . . . . . . . . . . . . 8		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 . . . . . . . . . . . . . . . . . 8		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 . . . . . . . . . . . . . . . 12
	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 . . . . . . . . . . . . . . . 14
	9. SRv6 SID Structure Sub-Sub-TLV . . . . . . . . . . . . . . . 15		9. SRv6 SID Structure Sub-Sub-TLV . . . . . . . . . . . . . . . 15
	10. Advertising Endpoint Behaviors . . . . . . . . . . . . . . . 16		10. Advertising Endpoint Behaviors . . . . . . . . . . . . . . . 16
	11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17		11. Implementation Status . . . . . . . . . . . . . . . . . . . . 17
	11.1. SRv6 Locator TLV . . . . . . . . . . . . . . . . . . . . 17		11.1. Cisco . . . . . . . . . . . . . . . . . . . . . . . . . 17
	11.1.1. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . 17		11.2. Huawei . . . . . . . . . . . . . . . . . . . . . . . . . 17
	11.1.2. Revised sub-TLV table . . . . . . . . . . . . . . . 18		11.3. Juniper . . . . . . . . . . . . . . . . . . . . . . . . 18
	11.2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . 18		11.4. Interoperability Testing. . . . . . . . . . . . . . . . 18
	11.3. SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs . . . . . 19		12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
	11.4. MSD Types . . . . . . . . . . . . . . . . . . . . . . . 19		12.1. SRv6 Locator TLV . . . . . . . . . . . . . . . . . . . . 18
	11.5. Sub-Sub-TLVs for SID Sub-TLVs . . . . . . . . . . . . . 19		12.1.1. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . 18
	11.6. Prefix Attribute Flags Sub-TLV . . . . . . . . . . . . . 20		12.1.2. Revised sub-TLV table . . . . . . . . . . . . . . . 19
	12. Security Considerations . . . . . . . . . . . . . . . . . . . 20		12.2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . 19
	13. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 20		12.3. SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs . . . . . 19
	14. References . . . . . . . . . . . . . . . . . . . . . . . . . 21		12.4. MSD Types . . . . . . . . . . . . . . . . . . . . . . . 20
	14.1. Normative References . . . . . . . . . . . . . . . . . . 21		12.5. Sub-Sub-TLVs for SID Sub-TLVs . . . . . . . . . . . . . 20
	14.2. Informative References . . . . . . . . . . . . . . . . . 23		12.6. Prefix Attribute Flags Sub-TLV . . . . . . . . . . . . . 20
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24		13. Security Considerations . . . . . . . . . . . . . . . . . . . 21
			14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 21
			15. References . . . . . . . . . . . . . . . . . . . . . . . . . 22
			15.1. Normative References . . . . . . . . . . . . . . . . . . 22
			15.2. Informative References . . . . . . . . . . . . . . . . . 24
			15.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 25
			Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25
	1. Introduction		1. Introduction
	With Segment Routing (SR) [I-D.ietf-spring-segment-routing], a node		With Segment Routing (SR) [I-D.ietf-spring-segment-routing], a node
	steers a packet through an ordered list of instructions, called		steers a packet through 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
	[I-D.ietf-6man-segment-routing-header]. SRv6 refers to this SR		[I-D.ietf-6man-segment-routing-header]. 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 function 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 SID's.		program can be expressed as a combination of SID's.
	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 functions.		protocol to encode some of these SIDs and their behaviors.
	Familiarity with the network programming paradigm		Familiarity with the network programming paradigm
	[I-D.ietf-spring-srv6-network-programming] is necessary to understand		[I-D.ietf-spring-srv6-network-programming] is necessary to understand
	the extensions specified in this document.		the extensions specified in this document.
	This document defines one new top level IS-IS TLV and several new IS-		This document defines one new top level IS-IS TLV and several new IS-
	IS sub-TLVs.		IS sub-TLVs.
	The SRv6 Capabilities sub-TLV announces the ability to support SRv6.		The SRv6 Capabilities sub-TLV announces the ability to support SRv6.
	Several new sub-TLVs are defined to advertise various SRv6 Maximum		Several new sub-TLVs are defined to advertise various SRv6 Maximum
	SID Depths.		SID Depths.
	The new SRv6 Locator top level TLV announces SRv6 locators - a form		The new SRv6 Locator top level TLV announces SRv6 locators - a form
	of summary address for the set of topology/algorithm specific SIDs		of summary address for the set of topology/algorithm specific SIDs
	associated with a 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 function 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 has support for SRv6 by advertising a new		A node indicates that it has support for SRv6 by advertising a new
	SRv6- capabilities sub-TLV of the router capabilities TLV [RFC7981].		SRv6 Capabilities sub-TLV of the router 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 |
	skipping to change at page 4, line 38 ¶		skipping to change at page 4, line 40 ¶
	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| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	where:		where:
	O-flag: If set, the router supports use of the O-bit		O-flag: If set, the router supports use of the O-bit
	in the Segment Routing Header(SRH) as defined in		in the Segment Routing Header(SRH) as defined in
	[I-D.ali-spring-srv6-oam].		[I-D.ietf-6man-spring-srv6-oam].
	3. Advertising Supported Algorithms		3. Advertising Supported Algorithms
	SRv6 capable router indicates supported algorithm(s) by advertising		SRv6 capable router indicates supported algorithm(s) by advertising
	the SR Algorithm TLV as defined in		the SR Algorithm TLV as defined in [RFC8667].
	[I-D.ietf-isis-segment-routing-extensions].
	4. Advertising Maximum SRv6 SID Depths		4. Advertising Maximum SRv6 SID Depths
	[RFC8491] defines the means to advertise node/link specific values		[RFC8491] defines the means to advertise node/link specific values
	for Maximum SID Depths (MSD) of various types. Node MSDs are		for Maximum SID Depths (MSD) of various types. Node MSDs are
	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 [I-D.ietf-6man-segment-routing-header] in the SRH of a
	skipping to change at page 5, line 15 ¶		skipping to change at page 5, line 20 ¶
	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 [I-D.ietf-6man-segment-routing-header] in the SRH of a
	received packet before applying the Endpoint function associated with		received packet before applying 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 (Suggested value - to be assigned by IANA)
	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 top SRH in an SRH stack to which the router can apply "PSP" or		the top SRH in an SRH stack to which the router can apply "PSP" or
	USP" as defined in [I-D.ietf-spring-srv6-network-programming]		USP" as defined in [I-D.ietf-spring-srv6-network-programming]
	flavors.		flavors.
	SRH Max End Pop Type: 42 (Suggested value - to be assigned by IANA)		SRH Max End Pop Type: 42 (Suggested value - to be assigned by IANA)
	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 T.Insert MSD Type		4.3. Maximum H.Encaps MSD Type
	The Maximum T.Insert MSD Type specifies the maximum number of SIDs
	that can be inserted as part of the "T.insert" behavior as defined in
	[I-D.ietf-spring-srv6-network-programming].
	SRH Max T.insert Type: 43 (Suggested value - to be assigned by IANA)
	If the advertised value is zero or no value is advertised
	then the router is assumed not to support any variation
	of the "T.insert" behavior.
	4.4. Maximum T.Encaps MSD Type
	The Maximum T.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 "T.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 T.encaps Type: 44 (Suggested value - to be assigned by IANA)		SRH Max H.encaps Type: 44 (Suggested value - to be assigned by IANA)
	If the advertised value is zero then the router can apply T.Encaps		If the advertised value is zero then the router can apply H.Encaps
	only by encapsulating the incoming packet in another		only by encapsulating the incoming packet in another
	IPv6 header without SRH the same way IPinIP encapsulation is		IPv6 header without SRH the same way IPinIP encapsulation is
	performed.		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.
	4.5. 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" functions		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 (Suggested value - to be assigned by IANA)
	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" functions if the extension		"End.DX6" or "End.DT6" behaviors if the extension
	header right underneath the outer IPv6 header is an SRH.		header right underneath the outer IPv6 header is 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 represented as		Segment Identifier (SID) is 128 bits and consists of Locator,
			Function and Argument parts.
	LOC:FUNCT
	where LOC (the locator portion) is the L most significant bits and
	FUNCT is the 128-L least significant bits. L is called the locator
	length and is flexible. Each operator is free to use the locator
	length it chooses.
	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
	which have the matching topology/algorithm.		which have the matching topology/algorithm.
	Locators MUST be advertised in the SRv6 Locator TLV (see		Locators MUST be advertised in the SRv6 Locator TLV (see
	Section 6.1). Forwarding entries for the locators advertised in the		Section 6.1). Forwarding entries for the locators advertised in the
	SRv6 Locator TLV MUST be installed in the forwarding plane of		SRv6 Locator TLV MUST be installed in the forwarding plane of
	receiving SRv6 capable routers when the associated topology/algorithm		receiving SRv6 capable routers when the associated topology/algorithm
	is supported by the receiving node.		is supported by the receiving node.
	Locators are routable and MAY also be advertised in Prefix		Locators are routable and MAY also be advertised in Prefix
	Reachability TLVs (236 or 237).		Reachability TLVs (236 or 237).
	Locators associated with Flexible Algorithms SHOULD NOT be advertised		Locators associated with Flexible Algorithms [I-D.ietf-lsr-flex-algo]
	in Prefix Reachability TLVs (236 or 237).		SHOULD NOT be advertised in Prefix Reachability TLVs (236 or 237).
	Locators associated with algorithm 0 (for all supported topologies)		Locators associated with algorithm 0 (for all supported topologies)
	SHOULD be advertised in a Prefix Reachability TLV (236 or 237) so		SHOULD be advertised in a Prefix Reachability TLV (236 or 237) so
	that legacy routers (i.e., routers which do NOT support SRv6) will		that legacy routers (i.e., routers which do NOT support SRv6) will
	install a forwarding entry for algorithm 0 SRv6 traffic.		install a forwarding entry for algorithm 0 SRv6 traffic.
	In cases where a locator advertisement is received in both in a		In cases where a locator advertisement is received in both in a
	Prefix Reachability TLV and an SRv6 Locator TLV, the Prefix		Prefix Reachability TLV and an SRv6 Locator TLV, the Prefix
	Reachability advertisement MUST be preferred when installing entries		Reachability advertisement MUST be preferred when installing entries
	in the forwarding plane. This is to prevent inconsistent forwarding		in the forwarding plane. This is to prevent inconsistent forwarding
	skipping to change at page 10, line 14 ¶		skipping to change at page 10, line 8 ¶
	Locator. The Locator is encoded in the minimal number of		Locator. The Locator is encoded in the minimal number of
	octets for the given number of bits.		octets for the given number of bits.
	Sub-TLV-length: 1 octet. Number of octets used by sub-TLVs		Sub-TLV-length: 1 octet. Number of octets used by sub-TLVs
	Optional sub-TLVs.		Optional sub-TLVs.
	7.2. SRv6 End SID sub-TLV		7.2. SRv6 End SID sub-TLV
	The SRv6 End SID sub-TLV is introduced to advertise SRv6 Segment		The SRv6 End SID sub-TLV is introduced to advertise SRv6 Segment
	Identifiers (SID) with Endpoint functions which do not require a		Identifiers (SID) with Endpoint behaviors which do not require a
	particular neighbor in order to be correctly applied		particular neighbor in order to be correctly applied
	[I-D.ietf-spring-srv6-network-programming]. SRv6 SIDs associated		[I-D.ietf-spring-srv6-network-programming]. SRv6 SIDs associated
	with a neighbor are advertised using the sub-TLVs defined in		with a neighbor are advertised using the sub-TLVs defined in
	Section 6.		Section 6.
	This new sub-TLV is advertised in the SRv6 Locator TLV defined in the		This new sub-TLV is advertised in the SRv6 Locator TLV defined in the
	previous section. SRv6 End SIDs inherit the topology/algorithm from		previous section. SRv6 End SIDs inherit the topology/algorithm from
	the parent locator.		the parent locator.
	The SRv6 End SID sub-TLV has the following format:		The SRv6 End 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 |		| Type | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Flags | SRv6 Endpoint Function |		| Flags | 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: 5 (Suggested value to be assigned by IANA)		Type: 5 (Suggested value to be assigned by IANA)
	Length: variable.		Length: variable.
	Flags: 1 octet. No flags are currently defined.		Flags: 1 octet. No flags are currently defined.
	SRv6 Endpoint Function: 2 octets. As defined in		Endpoint Behavior: 2 octets, as defined in [I-D.ietf-spring-srv6-network-programming].
	[I-D.ietf-spring-srv6-network-programming]		Legal behavior values for this sub-TLV are defined in Section 9 of this document.
	Legal function values for this sub-TLV are defined in Section 9.
	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-TLVs		Sub-sub-TLV-length: 1 octet. Number of octets used by sub-sub-TLVs
	Optional sub-sub-TLVs		Optional sub-sub-TLVs
	The SRv6 End SID MUST be a subnet of the associated Locator. SRv6		The SRv6 End SID MUST be a subnet of the associated Locator. SRv6
	End SIDs which are NOT a subnet of the associated locator MUST be		End SIDs which are NOT a subnet of the associated locator MUST be
	ignored.		ignored.
	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 functions		Certain SRv6 Endpoint behaviors
	[I-D.ietf-spring-srv6-network-programming] must be associated with a		[I-D.ietf-spring-srv6-network-programming] must be associated with a
	particular neighbor, and in case of multiple layer 3 links to the		particular neighbor, and in case of multiple links to the same
	same neighbor, with a particular link in order to be correctly		neighbor, with a particular link in order to be correctly applied.
	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 12, line 40 ¶		skipping to change at page 12, line 39 ¶
	The SRv6 End.X SID sub-TLV has the following format:		The SRv6 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 |		| Type | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Flags | Algorithm | Weight |		| Flags | Algorithm | Weight |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| SRv6 Endpoint Function |		| 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: 43 (Suggested value to be assigned by IANA)
			Type: 43 (Suggested value to be assigned by IANA)
	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 |
	+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+
	where:		where:
	skipping to change at page 13, line 39 ¶		skipping to change at page 13, line 37 ¶
	Other bits: MUST be zero when originated and ignored when		Other bits: MUST be zero when originated and ignored when
	received.		received.
	Algorithm: 1 octet. Associated algorithm. Algorithm values		Algorithm: 1 octet. Associated algorithm. Algorithm values
	are defined in the IGP Algorithm Type registry.		are defined in the IGP Algorithm Type registry.
	Weight: 1 octet. The value represents the weight of the		Weight: 1 octet. The value represents the weight of the
	End.X SID for the purpose of load balancing. The use		End.X SID for the purpose of load balancing. The use
	of the weight is defined in [I-D.ietf-spring-segment-routing].		of the weight is defined in [I-D.ietf-spring-segment-routing].
	SRv6 Endpoint Function: 2 octets. As defined in		Endpoint Behavior: 2 octets. As defined in
	[I-D.ietf-spring-srv6-network-programming]		[I-D.ietf-spring-srv6-network-programming]
	Legal function values for this sub-TLV are defined in Section 9.		Legal behavior values for this sub-TLV are defined in Section 9.
	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
	Note that multiple TLVs for the same neighbor may be required in		Note that multiple TLVs for the same neighbor may be required in
	order to advertise all of the SRv6 End.X SIDs associated with that		order to advertise all of the SRv6 End.X SIDs associated with that
	neighbor.		neighbor.
	skipping to change at page 14, line 28 ¶		skipping to change at page 14, line 28 ¶
	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 | System ID (6 octets) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
	| |		| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Flags | Algorithm | Weight |		| Flags | Algorithm | Weight |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| SRv6 Endpoint Function |		| 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) . . . |
	skipping to change at page 15, line 5 ¶		skipping to change at page 15, line 5 ¶
	System-ID: 6 octets of IS-IS System-ID of length "ID Length" as		System-ID: 6 octets of 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 6.1.		where B,S, and P flags are as described in Section 8.1.
	Other bits: MUST be zero when originated and ignored when		Other bits: MUST be zero when originated and ignored when
	received.		received.
	Algorithm: 1 octet. Associated algorithm. Algorithm values		Algorithm: 1 octet. Associated algorithm. Algorithm values
	are defined in the IGP Algorithm Type registry.		are defined in the IGP Algorithm Type registry.
	Weight: 1 octet. The value represents the weight of the		Weight: 1 octet. The value represents the weight of the
	End.X SID for the purpose of load balancing. The use		End.X SID for the purpose of load balancing. The use
	of the weight is defined in [I-D.ietf-spring-segment-routing].		of the weight is defined in [I-D.ietf-spring-segment-routing].
	SRv6 Endpoint Function: 2 octets. As defined in		Endpoint Behavior: 2 octets. As defined in
	[I-D.ietf-spring-srv6-network-programming]		[I-D.ietf-spring-srv6-network-programming]
	Legal function values for this sub-TLV are defined in Section 9.		Legal behavior values for this sub-TLV are defined in Section 9.
	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.
	9. SRv6 SID Structure Sub-Sub-TLV		9. SRv6 SID Structure Sub-Sub-TLV
	SRv6 SID Structure Sub-Sub-TLV is an optional Sub-Sub-TLV of:		SRv6 SID Structure Sub-Sub-TLV is an optional Sub-Sub-TLV of:
	skipping to change at page 16, line 22 ¶		skipping to change at page 16, line 22 ¶
	Arg. Length: 1 octet. SRv6 SID Arguments length in bits.		Arg. Length: 1 octet. SRv6 SID Arguments length in bits.
	ISIS SRv6 SID Structure Sub-Sub-TLV MUST NOT appear more than once in		ISIS SRv6 SID Structure Sub-Sub-TLV MUST NOT appear more than once in
	its parent sub-TLV. If it appears more than once in its parent TLV,		its parent sub-TLV. If it appears more than once in its parent TLV,
	the parent TLV MUST be ignored by the receiver.		the parent TLV MUST be ignored by the receiver.
	10. Advertising Endpoint Behaviors		10. Advertising Endpoint Behaviors
	Endpoint behaviors are defined in		Endpoint behaviors are defined in
	[I-D.ietf-spring-srv6-network-programming] and		[I-D.ietf-spring-srv6-network-programming] and
	[I-D.ali-spring-srv6-oam]. The numerical identifiers for the		[I-D.ietf-6man-spring-srv6-oam]. The codepoints for the Endpoint
	Endpoint behaviors are defined in the "SRv6 Endpoint Behaviors"		behaviors are defined in the "SRv6 Endpoint Behaviors" registry
	registry defined in [I-D.ietf-spring-srv6-network-programming]. This		defined in [I-D.ietf-spring-srv6-network-programming]. This section
	section lists the Endpoint behaviors and their identifiers, which MAY		lists the Endpoint behaviors and their codepoints, which MAY be
	be advertised by IS-IS and the SID sub-TLVs in which each type MAY		advertised by IS-IS and the SID sub-TLVs in which each type MAY
	appear.		appear.
	Endpoint |Endpoint | End | End.X | Lan End.X |		Endpoint |Endpoint | End | End.X | Lan End.X |
	Behavior |Behavior Identifier | 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 |
	skipping to change at page 17, line 28 ¶		skipping to change at page 17, line 28 ¶
	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 |
	-----------------------|--------------------|-------|-------|-----------|		-----------------------|--------------------|-------|-------|-----------|
	End.OP | 40 | Y | N | N |		End.OP | 40 | Y | N | N |
	-----------------------|--------------------|-------|-------|-----------|		-----------------------|--------------------|-------|-------|-----------|
	End.OTP | 41 | Y | N | N |		End.OTP | 41 | Y | N | N |
	11. IANA Considerations		11. Implementation Status
			This section describes the implementation status of the ISIS SRv6
			extensions.
			11.1. Cisco
			Cisco's ISIS SRv6 implementation supports following functionalities:
			Types of SID supported: End, End.X, LAN End.X, END.OP
			Intra/Inter area/level support: Yes
			Anycast SID support: Yes, including A-flag (Section 6)
			SID Structure Sub-Sub-TLV: Yes
			11.2. Huawei
			Huawei ISIS SRv6 implementation supports following functionalities:
			Types of SID supported: End, End.X
			Intra/Inter area/level support: Yes
			Anycast SID support: Yes, no A-flag support (Section 6)
			SID Structure Sub-Sub-TLV: No
			11.3. Juniper
			Juniper's implementation is in beta stage and supports most of the
			sections of the this draft.
			11.4. Interoperability Testing.
			EANTC interoperability testing has been performed in April 2019.
			Results can be found at EANTC site [1].
			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.
	11.1. SRv6 Locator TLV		12.1. SRv6 Locator TLV
	This document adds one new TLV to the IS-IS TLV Codepoints registry.		This document adds one new TLV to the IS-IS TLV Codepoints registry.
	Value: 27 (suggested - to be assigned by IANA)		Value: 27 (suggested - to be assigned by IANA)
	Name: SRv6 Locator		Name: SRv6 Locator
	This TLV shares sub-TLV space with existing "Sub-TLVs for TLVs 135,		This 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		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".		changed to "Sub-TLVs for TLVs 27, 135, 235, 236 and 237 registry".
	11.1.1. 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 adds the following new sub-TLV to the (renamed) "Sub-
	TLVs for TLVs 27, 135, 235, 236 and 237 registry".		TLVs for TLVs 27, 135, 235, 236 and 237 registry".
	Value: 5 (suggested - to be assigned by IANA)		Value: 5 (suggested - to be assigned by IANA)
	Name: SRv6 End SID		Name: SRv6 End SID
	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 End SID sub-TLV. The registration		for sub-sub-TLVs of the SRv6 End SID 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 End SID sub-TLV". No sub-		registry name is "sub-sub-TLVs for SRv6 End SID 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
	11.1.2. 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 n y y y y		1 n y y y y
	2 n y y y y		2 n 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
	11 y y y y y		11 y y y y y
	12 y y y y y		12 y y y y y
	11.2. 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 adds the definition of a new sub-TLV in the "Sub- TLVs
	for TLV 242 registry".		for TLV 242 registry".
	Type: 25 (Suggested - to be assigned by IANA)		Type: 25 (Suggested - to be assigned by IANA)
	Description: SRv6 Capabilities		Description: SRv6 Capabilities
	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
	11.3. 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 adds the definition of two new sub-TLVs in the "sub-
	TLVs for TLV 22, 23, 25, 141, 222 and 223 registry".		TLVs for TLV 22, 23, 25, 141, 222 and 223 registry".
	Type: 43 (suggested - to be assigned by IANA)		Type: 43 (suggested - to be assigned by IANA)
	Description: SRv6 End.X SID		Description: SRv6 End.X SID
	Type: 44 (suggested - to be assigned by IANA)		Type: 44 (suggested - to be assigned by IANA)
	Description: SRv6 LAN End.X SID		Description: SRv6 LAN End.X SID
	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
	11.4. MSD Types		12.4. MSD Types
	This document defines the following new MSD types. These types are		This document defines the following new MSD types. These types are
	to be defined in the IGP MSD Types registry defined in [RFC8491] .		to be defined in the IGP MSD Types registry defined in [RFC8491] .
	All values are suggested values to be assigned by IANA.		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
	43 SRH Max T.insert		44 SRH Max H.encaps
	44 SRH Max T.encaps
	45 SRH Max End D		45 SRH Max End D
	11.5. Sub-Sub-TLVs for SID Sub-TLVs		12.5. Sub-Sub-TLVs for SID Sub-TLVs
	This document creates the following Sub-Sub-TLV Registry within the		This document creates the following Sub-Sub-TLV Registry within the
	"IS-IS TLV Codepoints" registry:		"IS-IS TLV Codepoints" registry:
	Registry: Sub-Sub-TLVs for SID Sub-TLVs		Registry: Sub-Sub-TLVs for SID Sub-TLVs
	Registration Procedure: Expert review		Registration Procedure: Expert review
	Reference: This document (Section 7.2, Section 8.1, Section 8.2).		Reference: This document (Section 7.2, Section 8.1, Section 8.2).
	This document defines the following Sub-Sub-TLV in the "Sub-Sub-TLVs		This document defines the following Sub-Sub-TLV in the "Sub-Sub-TLVs
	for SID Sub-TLVs" registry:		for SID Sub-TLVs" registry:
	Type: 1		Type: 1
	Description: SRv6 SID Structure Sub-Sub-TLV.		Description: SRv6 SID Structure Sub-Sub-TLV.
	Reference: This document (Section 9).		Reference: This document (Section 9).
	11.6. Prefix Attribute Flags Sub-TLV		12.6. Prefix Attribute Flags Sub-TLV
	This document adds a new bit in the "Bit Values for Prefix Attribute		This document adds a new bit in the "Bit Values for Prefix Attribute
	Flags Sub-TLV" registry:		Flags Sub-TLV" registry:
	Bit #: 4		Bit #: 4
	Description: A bit		Description: A bit
	Reference: This document (Section 6).		Reference: This document (Section 6).
	12. Security Considerations		13. Security Considerations
	Security concerns for IS-IS are addressed in [ISO10589], [RFC5304],		Security concerns for IS-IS are addressed in [ISO10589], [RFC5304],
	and [RFC5310].		and [RFC5310].
	13. Contributors		14. Contributors
	The following people gave a substantial contribution to the content		The following people gave a substantial contribution to the content
	of this document and should be considered as co-authors:		of this document and should be considered as co-authors:
	Stefano Previdi		Stefano Previdi
	Huawei Technologies		Huawei Technologies
	Email: stefano@previdi.net		Email: stefano@previdi.net
	Paul Wells		Paul Wells
	Cisco Systems		Cisco Systems
	skipping to change at page 21, line 44 ¶		skipping to change at page 22, line 44 ¶
	Robert Hanzl		Robert Hanzl
	Cisco Systems		Cisco Systems
	Millenium Plaza Building, V Celnici 10, Prague 1,		Millenium Plaza Building, V Celnici 10, Prague 1,
	Prague, Czech Republic		Prague, Czech Republic
	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
	14. References		15. References
	14.1. Normative References
	[I-D.ali-spring-srv6-oam]		15.1. Normative References
	Ali, Z., Filsfils, C., Kumar, N., Pignataro, C.,
	faiqbal@cisco.com, f., Gandhi, R., Leddy, J., Matsushima,
	S., Raszuk, R., daniel.voyer@bell.ca, d., Dawra, G.,
	Peirens, B., Chen, M., and G. Naik, "Operations,
	Administration, and Maintenance (OAM) in Segment Routing
	Networks with IPv6 Data plane (SRv6)", draft-ali-spring-
	srv6-oam-02 (work in progress), October 2018.
	[I-D.ietf-6man-segment-routing-header]		[I-D.ietf-6man-segment-routing-header]
	Filsfils, C., Dukes, D., Previdi, S., Leddy, J.,		Filsfils, C., Dukes, D., Previdi, S., Leddy, J.,
	Matsushima, S., and d. daniel.voyer@bell.ca, "IPv6 Segment		Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
	Routing Header (SRH)", draft-ietf-6man-segment-routing-		(SRH)", draft-ietf-6man-segment-routing-header-26 (work in
	header-23 (work in progress), September 2019.		progress), October 2019.
	[I-D.ietf-isis-segment-routing-extensions]		[I-D.ietf-6man-spring-srv6-oam]
	Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A.,		Ali, Z., Filsfils, C., Matsushima, S., Voyer, D., and M.
	Gredler, H., and B. Decraene, "IS-IS Extensions for		Chen, "Operations, Administration, and Maintenance (OAM)
	Segment Routing", draft-ietf-isis-segment-routing-		in Segment Routing Networks with IPv6 Data plane (SRv6)",
	extensions-25 (work in progress), May 2019.		draft-ietf-6man-spring-srv6-oam-03 (work in progress),
			December 2019.
	[I-D.ietf-spring-srv6-network-programming]		[I-D.ietf-spring-srv6-network-programming]
	Filsfils, C., Camarillo, P., Leddy, J.,		Filsfils, C., Camarillo, P., Leddy, J., Voyer, D.,
	daniel.voyer@bell.ca, d., Matsushima, S., and Z. Li, "SRv6		Matsushima, S., and Z. Li, "SRv6 Network Programming",
	Network Programming", draft-ietf-spring-srv6-network-		draft-ietf-spring-srv6-network-programming-08 (work in
	programming-03 (work in progress), September 2019.		progress), January 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 23, line 37 ¶		skipping to change at page 24, line 33 ¶
	[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC		[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
	2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,		2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
	May 2017, <https://www.rfc-editor.org/info/rfc8174>.		May 2017, <https://www.rfc-editor.org/info/rfc8174>.
	[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>.
	14.2. Informative References		[RFC8667] Previdi, S., Ed., Ginsberg, L., Ed., Filsfils, C.,
			Bashandy, A., Gredler, H., and B. Decraene, "IS-IS
			Extensions for Segment Routing", RFC 8667,
			DOI 10.17487/RFC8667, December 2019,
			<https://www.rfc-editor.org/info/rfc8667>.
			15.2. Informative References
			[I-D.ietf-lsr-flex-algo]
			Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and
			A. Gulko, "IGP Flexible Algorithm", draft-ietf-lsr-flex-
			algo-05 (work in progress), November 2019.
	[I-D.ietf-spring-segment-routing]		[I-D.ietf-spring-segment-routing]
	Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B.,		Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B.,
	Litkowski, S., and R. Shakir, "Segment Routing		Litkowski, S., and R. Shakir, "Segment Routing
	Architecture", draft-ietf-spring-segment-routing-15 (work		Architecture", draft-ietf-spring-segment-routing-15 (work
	in progress), January 2018.		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>.
			15.3. URIs
			[1] http://www.eantc.de/fileadmin/eantc/downloads/events/2017-
			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
	Bratislava 81109		Bratislava 81109
	Slovakia		Slovakia
	Email: ppsenak@cisco.com		Email: ppsenak@cisco.com
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