draft-ietf-lsr-ospf-prefix-originator-04.txt		draft-ietf-lsr-ospf-prefix-originator-05.txt
	LSR Working Group A. Wang		LSR Working Group A. Wang
	Internet-Draft China Telecom		Internet-Draft China Telecom
	Intended status: Standards Track A. Lindem		Intended status: Standards Track A. Lindem
	Expires: March 15, 2020 Cisco Systems		Expires: May 28, 2020 Cisco Systems
	J. Dong		J. Dong
	Huawei Technologies		Huawei Technologies
	P. Psenak		P. Psenak
	K. Talaulikar		K. Talaulikar
	Cisco Systems		Cisco Systems
	September 12, 2019		November 25, 2019
	OSPF Prefix Originator Extension		OSPF Prefix Originator Extension
	draft-ietf-lsr-ospf-prefix-originator-04		draft-ietf-lsr-ospf-prefix-originator-05
	Abstract		Abstract
	This document defines Open Shortest Path First (OSPF) encodings to		This document defines Open Shortest Path First (OSPF) encodings to
	advertise the router-id of the originator of inter-area prefixes for		advertise the router-id of the originator of inter-area prefixes for
	OSPFv2 and OSPFv3 Link-State Advertisements (LSAs). The source		OSPFv2 and OSPFv3 Link-State Advertisements (LSAs). The source
	originator is needed in several multi-area OSPF use cases.		originator is needed in several multi-area OSPF use cases.
	Status of This Memo		Status of This Memo
	skipping to change at page 1, line 39 ¶		skipping to change at page 1, line 39 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at https://datatracker.ietf.org/drafts/current/.		Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on March 15, 2020.		This Internet-Draft will expire on May 28, 2020.
	Copyright Notice		Copyright Notice
	Copyright (c) 2019 IETF Trust and the persons identified as the		Copyright (c) 2019 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 16 ¶		skipping to change at page 2, line 16 ¶
	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 . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Conventions used in this document . . . . . . . . . . . . . . 3		2. Conventions used in this document . . . . . . . . . . . . . . 3
	3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3		3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
	4. Inter-Area Prefix Source Advertisement Use Cases . . . . . . 4		4. Inter-Area Prefix Source Advertisement Use Cases . . . . . . 4
	5. Prefix Source Router-ID sub-TLV . . . . . . . . . . . . . . . 5		5. External Prefix Source Advertisement Use Cases . . . . . . . 5
	6. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 6		6. Prefix Source Router-ID sub-TLV . . . . . . . . . . . . . . . 6
	7. Security Considerations . . . . . . . . . . . . . . . . . . . 6		7. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 7
	8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7		7.1. Inter-Area Prefixes . . . . . . . . . . . . . . . . . . . 7
	9. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 7		7.2. External Prefixes . . . . . . . . . . . . . . . . . . . . 7
	10. References . . . . . . . . . . . . . . . . . . . . . . . . . 7		8. Security Considerations . . . . . . . . . . . . . . . . . . . 7
	10.1. Normative References . . . . . . . . . . . . . . . . . . 7		9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
	10.2. Informative References . . . . . . . . . . . . . . . . . 9		10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 8
	Appendix A. Inter-Area Topology Retrieval Process . . . . . . . 9		11. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
			11.1. Normative References . . . . . . . . . . . . . . . . . . 9
			11.2. Informative References . . . . . . . . . . . . . . . . . 10
			Appendix A. Inter-Area Topology Retrieval Process . . . . . . . 10
	Appendix B. Special Considerations on Inter-Area Topology		Appendix B. Special Considerations on Inter-Area Topology
	Retrieval . . . . . . . . . . . . . . . . . . . . . 10		Retrieval . . . . . . . . . . . . . . . . . . . . . 11
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
	1. Introduction		1. Introduction
	[I-D.ietf-ospf-mpls-elc] defines mechanisms to advertise Entropy		[I-D.ietf-ospf-mpls-elc] defines mechanisms to advertise Entropy
	Readable Label Depth (ERLD) for ingress Label Switching Routers (LSR)		Readable Label Depth (ERLD) for ingress Label Switching Routers (LSR)
	to discover other LSR's capability of performing Entropy Label based		to discover other LSR's capability of performing Entropy Label based
	load-balancing in MPLS networks. The ingress LSR can use this		load-balancing in MPLS networks. The ingress LSR can use this
	information to construct the appropriate label stack for specific		information to construct the appropriate label stack for specific
	traffic requirements, especially in segment routed networks and other		traffic requirements, especially in segment routed networks and other
	deployments requiring stacked LSPs.		deployments requiring stacked LSPs.
	skipping to change at page 3, line 32 ¶		skipping to change at page 3, line 35 ¶
	rebuild the inter-area topology.		rebuild the inter-area topology.
	[RFC7794] introduces the Intermediate System to Intermediate System		[RFC7794] introduces the Intermediate System to Intermediate System
	(IS-IS) "IPv4/IPv6 Source Router IDs" Type-Length-Value (TLV) to		(IS-IS) "IPv4/IPv6 Source Router IDs" Type-Length-Value (TLV) to
	advertise the source of prefixes leaked from a different IS-IS level.		advertise the source of prefixes leaked from a different IS-IS level.
	This TLV can be used in the above scenarios. Such solution can also		This TLV can be used in the above scenarios. Such solution can also
	be applied in networks that run the OSPF protocol, but existing OSPF		be applied in networks that run the OSPF protocol, but existing OSPF
	LSAs TLVs must be extended to include the router originating the		LSAs TLVs must be extended to include the router originating the
	prefix.		prefix.
	This draft provides such solution for the OSPFv2 and OSPFv3		This draft provides such solution for the OSPFv2 [RFC2328] and OSPFv3
	protocols.		[RFC5340] protocols.
	2. Conventions used in this document		2. Conventions used in this document
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and		"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
	"OPTIONAL" in this document are to be interpreted as described in BCP		"OPTIONAL" in this document are to be interpreted as described in BCP
	14 [RFC2119] [RFC8174] when, and only when, they appear in all		14 [RFC2119] [RFC8174] when, and only when, they appear in all
	capitals, as shown here.		capitals, as shown here.
	3. Terminology		3. Terminology
	The following terms are used in this document:		The following terms are used in this document:
	o ABR: Area Border Router		o ABR: Area Border Router
			o ASBR: Autonomous System Border Router
	o ERLD: Entropy Readable Label Depth		o ERLD: Entropy Readable Label Depth
	o EL: Entropy Label		o EL: Entropy Label
	o IS-IS: Intermediate System to Intermediate System		o IS-IS: Intermediate System to Intermediate System
	o LSA: Link-State Advertisement		o LSA: Link-State Advertisement
	o MSD: Maximum SID Depths		o MSD: Maximum SID Depths
	o NLRI: Network Layer Reachability Information		o NLRI: Network Layer Reachability Information
	o OSPF: Open Shortest Path First		o OSPF: Open Shortest Path First
	skipping to change at page 5, line 13 ¶		skipping to change at page 5, line 38 ¶
	another area, it should know the ERLD and MSD values associated with		another area, it should know the ERLD and MSD values associated with
	the node T1, and then construct the right label stack at the ingress		the node T1, and then construct the right label stack at the ingress
	node for traffic destined to prefix Lt1.		node for traffic destined to prefix Lt1.
	In another scenario, If R0 has some method to learn the originator of		In another scenario, If R0 has some method to learn the originator of
	network N1 and reports such information to IP SDN controller, then it		network N1 and reports such information to IP SDN controller, then it
	is possible for the controller to reconstruct the topology in the		is possible for the controller to reconstruct the topology in the
	non-backbone areas. The topology reconstruction process and its		non-backbone areas. The topology reconstruction process and its
	limitations are described in the Appendix A and Appendix B.		limitations are described in the Appendix A and Appendix B.
	From the above scenarios, we can conclude it is useful to define the		5. External Prefix Source Advertisement Use Cases
	OSPF prefix originator sub TLV .
	5. Prefix Source Router-ID sub-TLV		Figure 2 illustrates a topology where OSPF is running in different
			domain that is connected by an Autonomous System Border Router
			(ASBR). A, B, and C are routers in the Domain 1; C, D, and E are
			routers in Domain 2. Router C is the ASBR between the two domains.
			When router E receives an external prefix, it will redistribute it as
			an AS-External LSA within domain 2. When C receives such LSA, the
			originator information for such external prefix will be lost when it
			encodes the prefix information with the current LSA format field. In
			some situations, it will be helpful if C can advertise such
			originator information.
			+-------------------------------------------------------------------+
			| | External Prefix |
			| +---+ +---+ +---+ +---+ +-|-+ |
			| | A +-------+ B +----------| C +---------+ D +---------+ E |------|
			| +---+ +---+ +---+ +---+ +---+ |
			| Domain 1 | Domain 2 |
			+-------------------------------------------------------------------+
			Figure 2: OSPF External Prefix Originator Scenario
			From the above scenarios, we can conclude that it is useful to define
			the OSPF prefix originator sub TLV .
			6. Prefix Source Router-ID sub-TLV
	[RFC7684] and [RFC8362] respectively define TLV-based LSAs for OSPFv2		[RFC7684] and [RFC8362] respectively define TLV-based LSAs for OSPFv2
	and OSPFv3. These documents facilitate addition of new attributes		and OSPFv3. These documents facilitate addition of new attributes
	for prefixes and provide the basis for a sub-TLV to advertise the		for prefixes and provide the basis for a sub-TLV to advertise the
	"Prefix Source Router ID". For OSPFv2, this sub-TLV is a sub-TLV of		"Prefix Source Router ID". For OSPFv2, this sub-TLV is a sub-TLV of
	OSPFv2 Extended Prefix TLV which SHOULD be included in the "OSPFv2		OSPFv2 Extended Prefix TLV which SHOULD be included in the "OSPFv2
	Extended Prefix Opaque LSA" [RFC7684] for inter-area prefixes. For		Extended Prefix Opaque LSA" [RFC7684] for inter-area prefixes. For
	OSPFv3, this sub-TLV is a sub-TLV of "Inter-Area-Prefix TLV", which		OSPFv3, this sub-TLV is a sub-TLV of "Inter-Area-Prefix TLV", which
	SHOULD be included in the "E-Inter-Area-Prefix-LSA" [RFC8362].		SHOULD be included in the "E-Inter-Area-Prefix-LSA" [RFC8362].
	The "Prefix Source Router-ID" sub-TLV has the following format:		The "Prefix Source Router-ID" 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 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Prefix Source Router-ID |		| Prefix Source Router-ID |
	+---------------------------------------------------------------+		+---------------------------------------------------------------+
	Figure 2: Prefix Source Router-ID sub-TLV Format		Figure 3: Prefix Source Router-ID sub-TLV Format
	o Source Router-ID Sub-TLV Type: TBD1 [RFC7684] or TBD2 [RFC8362]		o Source Router-ID Sub-TLV Type: 4 (IANA TEMPORARY allocation)
			[RFC7684] or 27 (IANA TEMPORARY allocation) [RFC8362]
	o Length: 4		o Length: 4
	o Value: Router-ID of OSPFv2/OSPFv3 router that is the source of the		o Value: Router-ID of OSPFv2/OSPFv3 router that is the source of the
	prefix.		prefix.
	This sub-TLV provides the same functionality as the IS-IS "IPv4/IPv6		This sub-TLV provides the same functionality as the IS-IS "IPv4/IPv6
	Source Router" TLV defined in [RFC7794].		Source Router" TLV defined in [RFC7794].
	6. Elements of Procedure		7. Elements of Procedure
			The following sections describe the procedure to include the newly
			defined "Source Router-ID Sub-TLV" in the related LSA for inter-area
			prefixes and external prefixes respectively.
			7.1. Inter-Area Prefixes
	When an ABR, for example R2 in Figure 1, receives a Router-LSA		When an ABR, for example R2 in Figure 1, receives a Router-LSA
	advertisement in area 2, it SHOULD originate the corresponding		advertisement in area 2, it SHOULD originate the corresponding
	"OSPFv2 Extended Prefix Opaque LSA" for OSPFv2 or "E-Inter-Area-		"OSPFv2 Extended Prefix Opaque LSA" for OSPFv2 or "E-Inter-Area-
	Prefix-LSA" for OSPFv3 that includes the Source Router-ID sub-TLV for		Prefix-LSA" for OSPFv3 that includes the Source Router-ID sub-TLV for
	the network prefixes. For example, to identify the source router		the network prefixes. For example, to identify the source router
	prefix Lt1 and other inter-area prefixes in Figure 1.		prefix Lt1 and other inter-area prefixes in Figure 1.
	When a router in another area, e.g., S1, receives such LSA, it then		When a router in another area, e.g., S1, receives such LSA, it then
	can ascertain that prefix Lt1 is associated with node T1 and obtain		can ascertain that prefix Lt1 is associated with node T1 and obtain
	skipping to change at page 6, line 29 ¶		skipping to change at page 7, line 35 ¶
	When a router in another area, e.g., R0, receives such LSA, it learns		When a router in another area, e.g., R0, receives such LSA, it learns
	the Prefix Source Router-id and includes it in the prefix information		the Prefix Source Router-id and includes it in the prefix information
	advertised to an SDN controller as described in		advertised to an SDN controller as described in
	[I-D.ietf-idr-bgp-ls-segment-routing-ext]. The SDN controller can		[I-D.ietf-idr-bgp-ls-segment-routing-ext]. The SDN controller can
	then use such information to build the inter-area topology according		then use such information to build the inter-area topology according
	to the process described in the Appendix A. The topology retrieval		to the process described in the Appendix A. The topology retrieval
	process may not suitable for some environments as stated in		process may not suitable for some environments as stated in
	Appendix B.		Appendix B.
	7. Security Considerations		7.2. External Prefixes
			When an ASBR, for example C in Figure 2, receives an AS-External LSA
			for an external prefix in domain 2, it SHOULD extract the originator
			information from the "Advertising Router" field from the LSA header.
			When the prefix is advertised into domain 1 as an AS-External LSA,
			router C may also advertise the Source Router-ID using a AS-scoped
			OSPFv2 Extended Prefix Opaque LSA or as a Sub-TLV in the OSPFv3 AS-
			External LSA.
			8. Security Considerations
	Since this document extends the "OSPFv2 Extended Prefix LSA" and		Since this document extends the "OSPFv2 Extended Prefix LSA" and
	"OSPFv3 E-Inter-Area-Prefix LSA", the security considerations for		"OSPFv3 E-Inter-Area-Prefix LSA", the security considerations for
	[RFC7684] and [RFC8362] are applicable.		[RFC7684] and [RFC8362] are applicable.
	Modification of the "Prefix Source Sub-TLV" could be used for a		Modification of the "Prefix Source Sub-TLV" could be used for a
	Denial-of-Service attack and could inhibit the use cases described in		Denial-of-Service attack and could inhibit the use cases described in
	Section 4. If the OSPF domain is vulnerable to such attacks, OSPF		Section 4. If the OSPF domain is vulnerable to such attacks, OSPF
	authentication should be used as defined for OSPFv2 in [RFC5709] and		authentication should be used as defined for OSPFv2 in [RFC5709] and
	[RFC7474] and for OSPFv3 in [RFC7166].		[RFC7474] and for OSPFv3 in [RFC7166].
	Additionally, advertisement of the prefix source for inter-area		Additionally, advertisement of the prefix source for inter-area
	prefixes facilitates reconstruction of the OSPF topology for other		prefixes facilitates reconstruction of the OSPF topology for other
	areas. Network operators may consider their topologies to be		areas. Network operators may consider their topologies to be
	sensitive confidential data. For OSPFv3, IPsec can be used to		sensitive confidential data. For OSPFv3, IPsec can be used to
	provide confidentiality [RFC4552]. Since there is no standard		provide confidentiality [RFC4552]. Since there is no standard
	defined for native OSPFv2 IPsec, some form of secure tunnel is		defined for native OSPFv2 IPsec, some form of secure tunnel is
	required to provide confidentiality.		required to provide confidentiality.
	8. IANA Considerations		9. IANA Considerations
	This specification defines the Prefix Source Router-ID sub-TLV as		This specification defines the Prefix Source Router-ID sub-TLV as
	described in Section 5. This value should be added to the both		described in Section 6. This value should be added to the both
	existing "OSPFv2 Extended Prefix TLV Sub-TLVs" and "OSPFv3 Extended-		existing "OSPFv2 Extended Prefix TLV Sub-TLVs" and "OSPFv3 Extended-
	LSA Sub-TLVs" registries.		LSA Sub-TLVs" registries.
	The following sub-TLV is added to the "OSPFv2 Extended Prefix TLV		The following sub-TLV is added to the "OSPFv2 Extended Prefix TLV
	Sub-TLVs" registry. The allocation policy is IETF Review as defined		Sub-TLVs" registry. The allocation policy is IETF Review as defined
	in [RFC7684]		in [RFC7684]
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Code Point | Description | Status |		| Code Point | Description | Status |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| TBD | Prefix Source Sub-TLV | Allocation from IANA |		| 4 | Prefix Source Sub-TLV | Allocation from IANA |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Figure 3: Code Point in "OSPFv2 Extended Prefix TLV Sub-TLVs"		Figure 4: Code Point in "OSPFv2 Extended Prefix TLV Sub-TLVs"
	The following sub-TLV is added to the "OSPFv3 Extended-LSA Sub-TLVs"		The following sub-TLV is added to the "OSPFv3 Extended-LSA Sub-TLVs"
	registry. The allocation policy is IETF Review as defined in		registry. The allocation policy is IETF Review as defined in
	[RFC8362]		[RFC8362]
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Code Point | Description | Status |		| Code Point | Description | Status |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| TBD | Prefix Source Sub-TLV | Allocation from IANA |		| 27 | Prefix Source Sub-TLV | Allocation from IANA |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Figure 4: Code Point in "OSPFv3 Extended-LSA Sub-TLVs"		Figure 5: Code Point in "OSPFv3 Extended-LSA Sub-TLVs"
	9. Acknowledgement		10. Acknowledgement
	Many thanks to Les Ginsberg for his suggestions on this draft. Also		Many thanks to Les Ginsberg for his suggestions on this draft. Also
	thanks to Jeff Tantsura, Rob Shakir, Gunter Van De Velde, Goethals		thanks to Jeff Tantsura, Rob Shakir, Gunter Van De Velde, Goethals
	Dirk, Shaofu Peng, and John E Drake for their valuable comments.		Dirk, Smita Selot, Shaofu Peng, and John E Drake for their valuable
			comments.
	10. References		11. References
	10.1. Normative References		11.1. Normative References
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<https://www.rfc-editor.org/info/rfc2119>.		<https://www.rfc-editor.org/info/rfc2119>.
			[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
			DOI 10.17487/RFC2328, April 1998,
			<https://www.rfc-editor.org/info/rfc2328>.
	[RFC4552] Gupta, M. and N. Melam, "Authentication/Confidentiality		[RFC4552] Gupta, M. and N. Melam, "Authentication/Confidentiality
	for OSPFv3", RFC 4552, DOI 10.17487/RFC4552, June 2006,		for OSPFv3", RFC 4552, DOI 10.17487/RFC4552, June 2006,
	<https://www.rfc-editor.org/info/rfc4552>.		<https://www.rfc-editor.org/info/rfc4552>.
			[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
			for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
			<https://www.rfc-editor.org/info/rfc5340>.
	[RFC5709] Bhatia, M., Manral, V., Fanto, M., White, R., Barnes, M.,		[RFC5709] Bhatia, M., Manral, V., Fanto, M., White, R., Barnes, M.,
	Li, T., and R. Atkinson, "OSPFv2 HMAC-SHA Cryptographic		Li, T., and R. Atkinson, "OSPFv2 HMAC-SHA Cryptographic
	Authentication", RFC 5709, DOI 10.17487/RFC5709, October		Authentication", RFC 5709, DOI 10.17487/RFC5709, October
	2009, <https://www.rfc-editor.org/info/rfc5709>.		2009, <https://www.rfc-editor.org/info/rfc5709>.
	[RFC7166] Bhatia, M., Manral, V., and A. Lindem, "Supporting		[RFC7166] Bhatia, M., Manral, V., and A. Lindem, "Supporting
	Authentication Trailer for OSPFv3", RFC 7166,		Authentication Trailer for OSPFv3", RFC 7166,
	DOI 10.17487/RFC7166, March 2014,		DOI 10.17487/RFC7166, March 2014,
	<https://www.rfc-editor.org/info/rfc7166>.		<https://www.rfc-editor.org/info/rfc7166>.
	skipping to change at page 9, line 5 ¶		skipping to change at page 10, line 24 ¶
	[RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and		[RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and
	F. Baker, "OSPFv3 Link State Advertisement (LSA)		F. Baker, "OSPFv3 Link State Advertisement (LSA)
	Extensibility", RFC 8362, DOI 10.17487/RFC8362, April		Extensibility", RFC 8362, DOI 10.17487/RFC8362, April
	2018, <https://www.rfc-editor.org/info/rfc8362>.		2018, <https://www.rfc-editor.org/info/rfc8362>.
	[RFC8476] Tantsura, J., Chunduri, U., Aldrin, S., and P. Psenak,		[RFC8476] Tantsura, J., Chunduri, U., Aldrin, S., and P. Psenak,
	"Signaling Maximum SID Depth (MSD) Using OSPF", RFC 8476,		"Signaling Maximum SID Depth (MSD) Using OSPF", RFC 8476,
	DOI 10.17487/RFC8476, December 2018,		DOI 10.17487/RFC8476, December 2018,
	<https://www.rfc-editor.org/info/rfc8476>.		<https://www.rfc-editor.org/info/rfc8476>.
	10.2. Informative References		11.2. Informative References
	[I-D.ietf-idr-bgp-ls-segment-routing-ext]		[I-D.ietf-idr-bgp-ls-segment-routing-ext]
	Previdi, S., Talaulikar, K., Filsfils, C., Gredler, H.,		Previdi, S., Talaulikar, K., Filsfils, C., Gredler, H.,
	and M. Chen, "BGP Link-State extensions for Segment		and M. Chen, "BGP Link-State extensions for Segment
	Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-16		Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-16
	(work in progress), June 2019.		(work in progress), June 2019.
	[I-D.ietf-ospf-mpls-elc]		[I-D.ietf-ospf-mpls-elc]
	Xu, X., Kini, S., Psenak, P., Filsfils, C., and S.		Xu, X., Kini, S., Psenak, P., Filsfils, C., Litkowski, S.,
	Litkowski, "Signaling Entropy Label Capability and Entropy		and M. Bocci, "Signaling Entropy Label Capability and
	Readable Label-stack Depth Using OSPF", draft-ietf-ospf-		Entropy Readable Label-stack Depth Using OSPF", draft-
	mpls-elc-09 (work in progress), September 2019.		ietf-ospf-mpls-elc-12 (work in progress), October 2019.
	[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and		[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
	S. Ray, "North-Bound Distribution of Link-State and		S. Ray, "North-Bound Distribution of Link-State and
	Traffic Engineering (TE) Information Using BGP", RFC 7752,		Traffic Engineering (TE) Information Using BGP", RFC 7752,
	DOI 10.17487/RFC7752, March 2016,		DOI 10.17487/RFC7752, March 2016,
	<https://www.rfc-editor.org/info/rfc7752>.		<https://www.rfc-editor.org/info/rfc7752>.
	Appendix A. Inter-Area Topology Retrieval Process		Appendix A. Inter-Area Topology Retrieval Process
	When an IP SDN Controller receives BGP-LS [RFC7752] information, it		When an IP SDN Controller receives BGP-LS [RFC7752] information, it
End of changes. 29 change blocks.
	39 lines changed or deleted		94 lines changed or added
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