draft-ietf-lsr-isis-srv6-extensions-04.txt		draft-ietf-lsr-isis-srv6-extensions-05.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: July 18, 2020 A. Bashandy		Expires: August 20, 2020 A. Bashandy
	Arrcus		Individual
	B. Decraene		B. Decraene
	Orange		Orange
	Z. Hu		Z. Hu
	Huawei Technologies		Huawei Technologies
	January 15, 2020		February 17, 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-04.txt		draft-ietf-lsr-isis-srv6-extensions-05.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 July 18, 2020.		This Internet-Draft will expire on August 20, 2020.
	Copyright Notice		Copyright Notice
	Copyright (c) 2020 IETF Trust and the persons identified as the		Copyright (c) 2020 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 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 . . . . . . . . . . . . . . . . . 8		7.1. SRv6 Locator TLV Format . . . . . . . . . . . . . . . . . 9
	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. Implementation Status . . . . . . . . . . . . . . . . . . . . 17		11. Implementation Status . . . . . . . . . . . . . . . . . . . . 17
	11.1. Cisco . . . . . . . . . . . . . . . . . . . . . . . . . 17		11.1. Cisco . . . . . . . . . . . . . . . . . . . . . . . . . 17
	11.2. Huawei . . . . . . . . . . . . . . . . . . . . . . . . . 17		11.2. Huawei . . . . . . . . . . . . . . . . . . . . . . . . . 17
	11.3. Juniper . . . . . . . . . . . . . . . . . . . . . . . . 18		11.3. Juniper . . . . . . . . . . . . . . . . . . . . . . . . 18
	11.4. Interoperability Testing. . . . . . . . . . . . . . . . 18		11.4. Interoperability Testing. . . . . . . . . . . . . . . . 18
	12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18		12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
	12.1. SRv6 Locator TLV . . . . . . . . . . . . . . . . . . . . 18		12.1. SRv6 Locator TLV . . . . . . . . . . . . . . . . . . . . 18
	12.1.1. SRv6 End SID sub-TLV . . . . . . . . . . . . . . . . 18		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 . . . . . . . . . . . . . . . 19		12.2. SRv6 Capabilities sub-TLV . . . . . . . . . . . . . . . 19
	12.3. SRv6 End.X SID and SRv6 LAN End.X SID sub-TLVs . . . . . 19		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 . . . . . . . . . . . . . 20		12.5. Sub-Sub-TLVs for SID Sub-TLVs . . . . . . . . . . . . . 20
	12.6. Prefix Attribute Flags Sub-TLV . . . . . . . . . . . . . 20		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
	skipping to change at page 3, line 29 ¶		skipping to change at page 3, line 29 ¶
	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 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 SID's.		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
	[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.
	skipping to change at page 4, line 9 ¶		skipping to change at page 4, line 9 ¶
	of summary address for the set of topology/algorithm specific SIDs		of summary address for the set of topology/algorithm specific SIDs
	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 has support for SRv6 by advertising a new		A node indicates that it supports the SR Segment Endpoint Node
	SRv6 Capabilities sub-TLV of the router capabilities TLV [RFC7981].		functionality as specified in [I-D.ietf-6man-segment-routing-header]
			by advertising a new 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 5, line 30 ¶		skipping to change at page 5, line 30 ¶
	received packet before applying the Endpoint behavior 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 SRH to which the router can apply "PSP" or USP" behavior, as
	USP" as defined in [I-D.ietf-spring-srv6-network-programming]		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 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
	skipping to change at page 6, line 23 ¶		skipping to change at page 6, line 23 ¶
	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 (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" behaviors if the extension		"End.DX6" or "End.DT6" behaviors if the outer IPv6 header contains 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 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 7, line 5 ¶		skipping to change at page 7, line 5 ¶
	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 [I-D.ietf-lsr-flex-algo]		Locators associated with Flexible Algorithms [I-D.ietf-lsr-flex-algo]
	SHOULD NOT be advertised 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 and 1 (for all supported
	SHOULD be advertised in a Prefix Reachability TLV (236 or 237) so		topologies) SHOULD be advertised in a Prefix Reachability TLV (236 or
	that legacy routers (i.e., routers which do NOT support SRv6) will		237) so that legacy routers (i.e., routers which do NOT support SRv6)
	install a forwarding entry for algorithm 0 SRv6 traffic.		will install a forwarding entry for algorithm 0 and 1 SRv6 traffic.
	In cases where a locator advertisement is received in both in a		In cases where a locator advertisement is received in both a Prefix
	Prefix Reachability TLV and an SRv6 Locator TLV, the Prefix		Reachability TLV and an SRv6 Locator TLV, the Prefix Reachability
	Reachability advertisement MUST be preferred when installing entries		advertisement MUST be preferred when installing entries in the
	in the forwarding plane. This is to prevent inconsistent forwarding		forwarding plane. This is to prevent inconsistent forwarding entries
	entries on SRv6 capable/SRv6 incapable routers.		between SRv6 capable and SRv6 incapable routers.
	SRv6 SIDs are advertised as sub-TLVs in the SRv6 Locator TLV except		SRv6 SIDs are advertised as sub-TLVs in the SRv6 Locator TLV except
	for SRv6 End.X SIDs/LAN End.X SIDs which are associated with a		for SRv6 End.X SIDs/LAN End.X SIDs which are associated with a
	specific Neighbor/Link and are therefore advertised as sub-TLVs in		specific Neighbor/Link and are therefore advertised as sub-TLVs in
	TLVs 22, 23, 222, 223, and 141.		TLVs 22, 23, 222, 223, and 141.
	SRv6 SIDs are not directly routable and MUST NOT be installed in the		SRv6 SIDs are not directly routable and MUST NOT be installed in the
	forwarding plane. Reachability to SRv6 SIDs depends upon the		forwarding plane. Reachability to SRv6 SIDs depends upon the
	existence of a covering locator.		existence of a covering locator.
	Adherence to the rules defined in this section will assure that SRv6		Adherence to the rules defined in this section will assure that SRv6
	SIDs associated with a supported topology/algorithm pair will be		SIDs associated with a supported topology/algorithm pair will be
	forwarded correctly, while SRv6 SIDs associated with an unsupported		forwarded correctly, while SRv6 SIDs associated with an unsupported
	topology/algorithm pair will be dropped. NOTE: The drop behavior		topology/algorithm pair will be dropped. NOTE: The drop behavior
	depends on the absence of a default/summary route covering a given		depends on the absence of a default/summary route covering a given
	locator.		locator.
	In order for forwarding to work correctly, the locator associated		In order for forwarding to work correctly, the locator associated
	with SRv6 SID advertisements MUST be the longest match prefix		with SRv6 SID advertisements MUST be the longest match prefix
	installed in the forwarding plane for those SIDs. There are a number		installed in the forwarding plane for those SIDs. There are a number
	of ways in which this requirement could be compromised		of ways in which this requirement could be compromised. In order to
			ensure correct forwarding, network operators should take steps to
			make sure that this requirement is not compromised.
	o Another locator associated with a different topology/algorithm is		o Another locator associated with a different topology/algorithm is
	the longest match		the longest match
	o A prefix advertisement (i.e., from TLV 236 or 237) is the longest		o A prefix advertisement (i.e., from TLV 236 or 237) is the longest
	match		match
	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
	skipping to change at page 8, line 22 ¶		skipping to change at page 8, line 25 ¶
	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
			SHOULD be interpreted as a node specific locator.
			All the nodes advertising the same anycast locator MUST instantiate
			the exact same set of SIDs under such anycast locator. Failure to do
			so may result in traffic being black-holed or mis-routed.
			The Prefix Attribute Flags Sub-TLV can be carried in the SRv6 Locator
			TLV as well as the Prefix Reachability TLVs. When a router
			originates both the Prefix Reachability TLV and the SRv6 Locator TLV
			for a given prefix, and the router is originating the Prefix
			Attribute Flags Sub-TLV in one of the TLVs, the router SHOULD
			advertise identical versions of the Prefix Attribute Flags Sub-TLV in
			both TLVs.
	7. Advertising Locators and End SIDs		7. Advertising Locators and End SIDs
	The SRv6 Locator TLV is introduced to advertise SRv6 Locators and End		The SRv6 Locator TLV is introduced to advertise SRv6 Locators and End
	SIDs associated with each locator.		SIDs associated with each locator.
	This new TLV shares the sub-TLV space defined for TLVs 135, 235, 236		This new TLV shares the sub-TLV space defined for TLVs 135, 235, 236
	and 237.		and 237.
	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)
			Length: variable.
			MTID: Multitopology Identifier as defined in [RFC5120].
			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 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Flags | Algorithm |		| Flags | Algorithm |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Loc Size | Locator (variable)...		| Loc Size | Locator (variable)...
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Sub-tlv-len | Sub-TLVs (variable) . . . |		| Sub-tlv-len | Sub-TLVs (variable) . . . |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Type: 27 (Suggested value to be assigned by IANA)
	Length: variable.
	MTID: Multitopology Identifier as defined in [RFC5120].
	Note that the value 0 is legal.
	Locator entry:
	Metric: 4 octets. As described in [RFC5305].		Metric: 4 octets. As described in [RFC5305].
	Flags: 1 octet. The following flags are defined		Flags: 1 octet. The following flags are defined
	0		0
	0 1 2 3 4 5 6 7		0 1 2 3 4 5 6 7
	+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+
	|D| Reserved |		|D| Reserved |
	+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+
	skipping to change at page 9, line 37 ¶		skipping to change at page 10, line 11 ¶
	bit MUST be set. Otherwise, this bit MUST be clear. Locators		bit MUST be set. Otherwise, this bit MUST be clear. Locators
	with the D bit set MUST NOT be leaked from level-1 to level-2.		with the D bit set MUST NOT be leaked from level-1 to level-2.
	This is to prevent looping.		This is to prevent looping.
	The remaining bits are reserved for future use. They SHOULD be		The remaining bits are reserved for future use. They SHOULD be
	set to zero on transmission and MUST be ignored on receipt.		set to zero on transmission and MUST be ignored on receipt.
	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.
	Loc-Size: 1 octet. Number of bits in the Locator field.		Loc-Size: 1 octet. Number of bits in the SRv6 Locator field.
	(1 - 128)		(1 - 128)
	Locator: 1-16 octets. This field encodes the advertised SRv6		Locator: 1-16 octets. This field encodes the advertised SRv6
	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. Trailing bits MUST be set
			to zero and ignored when received.
	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 behaviors 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
	skipping to change at page 12, line 24 ¶		skipping to change at page 12, line 24 ¶
	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
	and algorithm which is advertised by the same node in an SRv6 Locator		and algorithm which is advertised by the same node in an SRv6 Locator
	TLV. End.X SIDs which do not meet this requirement MUST be ignored.		TLV. End.X SIDs which do not meet this requirement MUST be ignored.
			All End.X and LAN End.X SIDs MUST be subsumed by the subnet of a
			Locator with the matching algorithm which is advertised by the same
			node in an SRv6 Locator TLV. End.X SIDs which do not meet this
			requirement MUST be ignored. This ensures that the node advertising
			the End.X or LAN End.X SID is also advertising its corresponding
			Locator with the algorithm that will be used for computing paths
			destined to the SID.
	8.1. SRv6 End.X SID sub-TLV		8.1. SRv6 End.X SID sub-TLV
	This sub-TLV is used to advertise an SRv6 SID associated with a point		This sub-TLV is used to advertise an SRv6 SID associated with a point
	to point adjacency. Multiple SRv6 End.X SID sub-TLVs MAY be		to point adjacency. Multiple SRv6 End.X SID sub-TLVs MAY be
	associated with the same adjacency.		associated with the same adjacency.
	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
	skipping to change at page 16, line 15 ¶		skipping to change at page 16, line 28 ¶
	LB Length: 1 octet. SRv6 SID Locator Block length in bits.		LB Length: 1 octet. SRv6 SID Locator Block length in bits.
	LN Length: 1 octet. SRv6 SID Locator Node length in bits.		LN Length: 1 octet. SRv6 SID Locator Node length in bits.
	Fun. Length: 1 octet. SRv6 SID Function length in bits.		Fun. Length: 1 octet. SRv6 SID Function length in bits.
	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 Sub-
	the parent TLV MUST be ignored by the receiver.		TLV, the parent Sub-TLV MUST be ignored by the receiver.
			The sum of all four sizes advertised in ISIS SRv6 SID Structure Sub-
			Sub-TLV must be lower or equal to 128 bits. If the sum of all four
			sizes advertised in the ISIS SRv6 SID Structure Sub-Sub-TLV is larger
			than 128 bits, the parent Sub-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.ietf-6man-spring-srv6-oam]. The codepoints for the Endpoint		[I-D.ietf-6man-spring-srv6-oam]. The codepoints for the Endpoint
	behaviors are defined in the "SRv6 Endpoint Behaviors" registry		behaviors are defined in the "SRv6 Endpoint Behaviors" registry
	defined in [I-D.ietf-spring-srv6-network-programming]. This section		defined in [I-D.ietf-spring-srv6-network-programming]. This section
	lists the Endpoint behaviors and their codepoints, which MAY be		lists the Endpoint behaviors and their codepoints, which MAY 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
	skipping to change at page 18, line 13 ¶		skipping to change at page 18, line 13 ¶
	Types of SID supported: End, End.X		Types of SID supported: End, End.X
	Intra/Inter area/level support: Yes		Intra/Inter area/level support: Yes
	Anycast SID support: Yes, no A-flag support (Section 6)		Anycast SID support: Yes, no A-flag support (Section 6)
	SID Structure Sub-Sub-TLV: No		SID Structure Sub-Sub-TLV: No
	11.3. Juniper		11.3. Juniper
	Juniper's implementation is in beta stage and supports most of the		Juniper's implementation is in beta stage and supports most of the
	sections of the this draft.		sections of this draft.
	11.4. Interoperability Testing.		11.4. 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
	skipping to change at page 18, line 47 ¶		skipping to change at page 18, line 47 ¶
	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 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
	for sub-sub-TLVs of the SRv6 End SID sub-TLV. The registration
	procedure is "Expert Review" as defined in [RFC7370]. Suggested
	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.
	0: Reserved
	1-255: Unassigned
	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 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
	skipping to change at page 23, line 21 ¶		skipping to change at page 23, line 21 ¶
	[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-03 (work in progress),		draft-ietf-6man-spring-srv6-oam-03 (work in progress),
	December 2019.		December 2019.
	[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-08 (work in		draft-ietf-spring-srv6-network-programming-09 (work in
	progress), January 2020.		progress), February 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 25, line 34 ¶		skipping to change at page 25, line 34 ¶
	Email: ppsenak@cisco.com		Email: ppsenak@cisco.com
	Clarence Filsfils		Clarence Filsfils
	Cisco Systems		Cisco Systems
	Brussels		Brussels
	Belgium		Belgium
	Email: cfilsfil@cisco.com		Email: cfilsfil@cisco.com
	Ahmed Bashandy		Ahmed Bashandy
	Arrcus		Individual
	Email: abashandy.ietf@gmail.com		Email: abashandy.ietf@gmail.com
	Bruno Decraene		Bruno Decraene
	Orange		Orange
	Issy-les-Moulineaux		Issy-les-Moulineaux
	France		France
	Email: bruno.decraene@orange.com		Email: bruno.decraene@orange.com
End of changes. 25 change blocks.
	55 lines changed or deleted		74 lines changed or added
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